The effect of a core stability, m. gluteus medius and 
proprioceptive exercise program on dynamic postural 
control in netball players
Marelise Wilson
The effect of a core stability, m. gluteus medius and 
proprioceptive exercise program on dynamic postural control 
in netball players
Researcher: Marelise Wilson
Student number: 1991015783
Study leader: R.Y. Barnes
Submission date: 15 November 2014
A research report submitted in fulfilment of the requirements of the M.Sc. Physiotherapy with 
specialization in Clinical Sports Physiotherapy degree in the Faculty of Health Sciences, at the 
University of the Free State.
2
Declarations
1. I, Marelise Wilson, declare that the master’s research mini-dissertation or publishable, 
interrelated articles that I herewith submit at the University of the Free State, is my independent work 
and that I have not previously submitted it for a qualification at another institution of higher education.
2. I, Marelise Wilson, hereby declare that I am aware that the copyright is vested in the University 
of the Free State.
3. I, Marelise Wilson, hereby declare that all royalties as regards intellectual property that was 
developed during the course of and/or in connection with the study at the University of the Free State, 
will accrue to the University.
4. I, Marelise Wilson hereby declare that I am aware that the research may only be published with 
the dean’s approval.
__________________________
Marelise Wilson
15thday of November 2014
3
Acknowledgements
It would not have been possible to complete this research study without the help and support of kind 
people around me.
This script would not have been possible without the expert advice, encouragement and guidance of my 
research supervisor, Roline Barnes, who has been invaluable on both academic and personal level, for 
which I am extremely grateful.
I would like to acknowledge Dr. J. Raubenheimer for the statistical analysis of the study results.
I would also like to personally thank Burtha de Kock and all the Kovsie netball players who partook in the 
study, for their enthusiasm and commitment towards this study.
A special word of thanks to my sister, Izanne, for the technical assistance required for the completion of 
this study.
Lastly, to my husband, Keith and twin boys, Dylan and Kyle for their unwavering love and support.
4
Abstract
Introduction: Maintaining dynamic postural control is essential for netball players as netball players 
frequently find themselves on one leg having to make an accurate pass. Evaluation of the physical 
profile of elite university netball players found poor balance in these netball players during pre-season.  
No literature could be found regarding studies investigating a programme that utilized the combination 
of core stability, m.gluteus medius (GMed) strengthening and proprioceptive balance exercises on 
dynamic postural control or studies investigating the effect of an exercise programme on dynamic 
postural control in netball players.
Aim: The research study was undertaken to determine if an exercise programme that incorporates core 
stability, m.GMed strengthening and proprioceptive balance exercises would lead to an improvement in 
dynamic postural control in a group of netball players.
Methodology: A cross-over randomised clinical trial was performed. Sixteen female university netball 
players participated in this study. Participants were randomly divided in two groups.  Group A 
participated three times a week for six weeks in the exercise programme while group B was considered 
as the control group after which the roles were reversed.  All participants were assessed at baseline, 
after six weeks and after 12 weeks using the Star Excursion Balance Test (SEBT).  Data were analyzed by 
a biostatistician using student’s and paired t-tests.
Results: Dynamic postural control as measured with the SEBT demonstrated a statistically significant 
improvement (p<0.05) across three reach directions (anterior, medial and posterior) in a group of netball 
players post participation in an exercise programme that incorporated core stability, m.GMed 
strengthening and proprioceptive balance exercises three times a week over a period of six weeks. The 
student’s t-tests on difference in improvement in reach directions between groups were p=0.0027 
(anterior), p=0.0003 (medial) and p=0.0001 (posterior) after group A participated in the exercise 
program.  The student’s t-tests were p=0.0005 (anterior), p=0.0001 (medial) and p<.0001 (posterior) 
after group B participated in the exercise program.
Conclusion: An exercise programme that incorporates core stability, m.GMed and proprioceptive 
balance exercises could be beneficial for improving dynamic postural control in a group of netball 
players.
5
Table of Contents
Declarations......................................................................................................................................................... 3
Acknowledgements............................................................................................................................................. 4
Abstract................................................................................................................................................................ 5
Table of Contents ................................................................................................................................................ 6
List of Figures.....................................................................................................................................................10
List of Tables ......................................................................................................................................................11
List of Graphs.....................................................................................................................................................13
List of Appendices .............................................................................................................................................14
Acronyms ...........................................................................................................................................................15
Glossary..............................................................................................................................................................16
Chapter 1 Introduction ..................................................................................................................................17
Chapter 2 Literature Review..........................................................................................................................20
2.1 Dynamic postural control ........................................................................................................................20
2.2 Influence of exercise programmes on dynamic postural control.........................................................22
2.2.1 Core stability .....................................................................................................................................22
2.2.2 Gluteus Medius muscle strengthening ...........................................................................................23
2.2.3 Proprioceptive balance ....................................................................................................................23
2.2.4 A combination of exercise programmes or comparison of different exercise programmes......24
2.3 Principles of an exercise programme .....................................................................................................26
2.3.1 Principles of a core stability exercise programme .........................................................................26
2.3.2 Principles of a m. GMed exercise programme ...............................................................................28
2.3.3 Principles of a proprioceptive balance programme.......................................................................32
2.4 Netball players..........................................................................................................................................33
2.5 Netball Season..........................................................................................................................................34
6
2.6 Star Excursion Balance Test.....................................................................................................................34
2.7 Execution of the SEBT ..............................................................................................................................35
2.8 Conclusion ................................................................................................................................................36
Chapter 3 Methodology.................................................................................................................................38
3.1 Research aim: ...........................................................................................................................................38
3.2 Objectives .................................................................................................................................................38
3.3 Research design........................................................................................................................................38
3.4 Study participants ....................................................................................................................................39
3.4.1 Inclusion criteria ...............................................................................................................................39
3.4.2 Exclusion criteria...............................................................................................................................39
3.4.3 Fall out criteria..................................................................................................................................39
3.5 Training of data collector and assistant..................................................................................................40
3.6 Pilot study.................................................................................................................................................40
3.7 Recruitment..............................................................................................................................................41
3.8 Randomization .........................................................................................................................................41
3.9 Measurement...........................................................................................................................................42
3.10 Procedures................................................................................................................................................43
3.11 Contamination..........................................................................................................................................52
3.12 Ethical aspects ..........................................................................................................................................52
3.13 Data analysis.............................................................................................................................................53
Chapter 4 Results ...........................................................................................................................................55
4.2 Attendance ...............................................................................................................................................55
4.3 Participants’ supporting leg during SEBT................................................................................................56
4.4 First testing session..................................................................................................................................56
4.5 Improvement from first to second testing session................................................................................59
7
4.6 Improvement from second to third testing session .............................................................................62
4.7 Improvement from first to third testing session...................................................................................65
Chapter 5 Discussion, Conclusion and Recommendations .........................................................................71
5.1 Brief summary ..........................................................................................................................................71
5.2 First testing session..................................................................................................................................72
5.3 Improvement from first to second testing session................................................................................72
5.4 Improvement from second to third testing session ..............................................................................73
5.5 Lateral reach direction.............................................................................................................................74
5.6 Comparison with previous studies on dynamic postural control .........................................................76
5.7 Contribution of different components ...................................................................................................80
5.8 Injury profile of netball players...............................................................................................................81
5.9 Limitations ................................................................................................................................................82
5.10 Conclusion ................................................................................................................................................83
5.11 Clinical recommendations .......................................................................................................................83
References .........................................................................................................................................................85
Appendices.........................................................................................................................................................91
Appendix 1 Permission letters from authorities .........................................................................................91
Appendix 2 Information to participants .....................................................................................................100
Appendix 3 An informed consent letter to get permission from the participant...................................104
Appendix 4 Data sheet ................................................................................................................................112
Appendix 5 Attendance record sheet ........................................................................................................113
Appendix 6 Description of exercise programme........................................................................................114
Appendix 7 Ethics Committee approval letter ..........................................................................................125
Appendix 8 Consent form for the use of photographs.............................................................................128
Summaries .......................................................................................................................................................129
8
A summary of the mini-script.........................................................................................................................129
‘n Opsomming van die mini-verhandeling.....................................................................................................131
9
List of Figures
Figure 1: Synonyms for dynamic postural control ..........................................................................................16
Figure 2: Somatosensory system......................................................................................................................21
Figure 3: Reach direction lines for right and left stance.................................................................................35
10
List of Tables
Table 1: Comparison of exercises for recruitment of GMed using % MVIC..................................................29
Table 2: Timeframe of testing session .............................................................................................................43
Table 3: Short summary of the exercise programme .....................................................................................44
Table 4: Group attendance (n=16)...................................................................................................................56
Table 5: Baseline SEBT anterior measurements between groups (n=16) .....................................................57
Table 6: Baseline SEBT medial measurements between groups (n=16) .......................................................57
Table 7: Baseline SEBT posterior measurements between groups (n=16) ...................................................57
Table 8: Baseline SEBT lateral measurements between groups (n=16)........................................................58
Table 9: SEBT anterior measurements within and between groups comparing the 1st and 2nd testing 
sessions (n=16) ..................................................................................................................................................59
Table 10: SEBT medial measurements within and between groups comparing the 1st and 2nd testing 
sessions (n=16) ..................................................................................................................................................59
Table 11: SEBT posterior measurements within and between groups comparing the 1st and 2nd testing 
sessions (n=16) ..................................................................................................................................................60
Table 12: SEBT lateral measurements within and between groups comparing the 1st and 2nd testing 
sessions (n=16) ..................................................................................................................................................60
Table 13: SEBT anterior measurements within and between groups comparing the2nd and 3rd testing 
sessions (n=16) ..................................................................................................................................................62
Table 14: SEBT medial measurements within and between groups comparing the2nd and 3rd testing 
sessions (n=16) ..................................................................................................................................................62
Table 15: SEBT posterior measurements within and between groups comparing the2nd and 3rd testing 
sessions (n=16) ..................................................................................................................................................63
Table 16: SEBT lateral measurements within and between groups comparing the2nd and 3rd testing 
sessions (n=16) ..................................................................................................................................................63
Table 17: SEBT anterior measurements between groups comparing the 1st and 3rd testing sessions (n=16)
............................................................................................................................................................................65
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Table 18: SEBT medial measurements between groups comparing the 1st and 3rd testing sessions (n=16)
............................................................................................................................................................................65
Table 19: SEBT posterior measurements between groups comparing the 1st and 3rd testing sessions 
(n=16) .................................................................................................................................................................66
Table 20: SEBT lateral measurements between groups comparing the 1st and 3rd testing sessions (n=16)
............................................................................................................................................................................66
Table 21: Summary of t-tests on improvement within and between groups (n=16)...................................69
Table 22: Timeframe of testing sessions .........................................................................................................71
Table 23: Summary of t-tests on improvement within groups of different studies.....................................76
Table 24: Summary of t-tests on improvement between groups of different studies ................................77
12
List of Graphs
Graph 1: Group attendance (n=16)..................................................................................................................55
Graph 2: Participants' supporting leg during SEBT (n=16) .............................................................................56
Graph 3: Average measurements of reach direction during first testing session (n=16) ............................58
Graph 4: Average improvement from first to second testing session (n=16)...............................................61
Graph 5: Average improvement from second to third testing session (n=16) .............................................64
Graph 6: Average improvement from first to third testing session (n=16)..................................................67
Graph 7: Improvement from first to second to third testing session (n=16)................................................70
13
List of Appendices
Appendix 1 Permission letters from authorities .........................................................................................91
Appendix 2 Information to participants .....................................................................................................100
Appendix 3 An informed consent letter to get permission from the participant...................................104
Appendix 4 Data sheet ................................................................................................................................112
Appendix 5 Attendance record sheet ........................................................................................................113
Appendix 6 Description of exercise programme........................................................................................114
Appendix 7 Ethics Committee approval letter ..........................................................................................125
Appendix 8 Consent form for the use of photographs.............................. Error! Bookmark not defined.8
14
Acronyms
CNS: - central nervous system
EMG: - electromyographic activity / electromyography
GMed: - gluteus medius
IFNA: - International Federation of Netball Associations
L: - left
LM: - lumbar multifidus
MVIC: - maximum voluntary contraction
NWB: - non-weight-bearing
Rep: - repetitions
R: - right
Sec: - seconds
SEBT: - Star Excursion Balance Test
TrA: - transversus abdominis
TFL: - tensor fascia lata
UFS: - University of the Free State
WB: - weight-bearing
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Glossary
Dynamic postural control: The ability to perform a functional task with purposeful movements that 
translates the body’s centre of gravity without compromising a stable base of support. The functional 
task might involve jumping or hopping to a new location and immediately attempting to remain as still 
as possible or attempting to create movements such as reaching or throwing without compromising the 
base of support (Winter, Patla and Frank, 1990; Kahle and Gribble, 2009, Gribble, Hertel and Plisky, 
2012).  Dynamic postural control was also termed dynamic postural stability or dynamic balance in 
previous research studies (Madras and Barr, 2003; Kahle and Gribble, 2009). For this study the term 
dynamic postural control will be used as well as the operation definition as described above.
Figure 1: Synonyms for dynamic postural control
Core stability: The capacity to control intervertebral and global trunk movements which contributes to 
the control of distal segmental movements and loading forces via coordinated muscle recruitment
(Smith, Nyland, Caudill, Brosky and Caborn, 2008: 703).
Proprioception: The awareness of body segment positions and orientations (Ashton-Miller, Wojtys, 
Huston and Fry-Welch, 2001: 128). Proprioception involves stimulus detection, processing of the 
stimulus and a reactive output from the neuromuscular system (Clark and Burden, 2005: 182).
16
Chapter 1 Introduction
Maintaining dynamic postural control is essential for netball players as netball players frequently find 
themselves on one leg having to make an accurate pass, while still having to comply with the 
International Federation of Netball Associations (IFNA) footwork rule that once the landing foot is lifted, 
it may not be re-grounded until the ball is released.  Research by Ferreira and Spamer (2010) evaluated 
the physical profile of elite university netball players and found poor balance in these netball players 
during pre-season computerised balance testing.
Numerous research studies (Kahle and Gribble, 2009; Fatma, Kaya, Baltact, Taskin, and Erkmen, 2010;
Hosseinimehr and Norasteh, 2010; Amrinder, Deepender and Singh, 2012; Sandrey and Mitzel, 2013)
have investigated the effect of exercise programmes consisting of core stability, m. gluteus medius 
(GMed) strengthening or proprioceptive balance programmes on dynamic postural control. On the 
other hand researchers (Aggarwal, Zutshi, Munjal, Kumar and Sharma, 2010; Filipa, Byrnes, Paterno, 
Myer and Hewett, 2010; Leavey, Sandrey and Dahmer, 2010) examined exercise programmes consisting 
of a combination of two components or compared the effect of different exercise programmes on 
dynamic postural control.
The reason for the inclusion of core stability in exercise programmes (Kahle and Gribble, 2009; Aggarwal 
et al., 2010; Filipa et al., 2010; Sandrey and Mitzel, 2013) for improving dynamic postural control is that
core muscle recruitment and coordination occur during expected and unexpected perturbations so that 
dynamic balance during the intended movement can be maintained (Smith et al., 2008). M.GMed 
exercises were also included in exercise programmes (Filipa et al., 2010; Leavey et al., 2010) due to the 
possibility that the m.GMed muscle contributes to dynamic postural control by stabilizing the hip to 
prevent the pelvis dropping on the unsupported side and controlling knee valgus (internal rotation and 
adduction of the femur) during single-limb support (Fujisawa, Masuda, Inaoka, Fukuoka, Ishida and 
Minamitanu, 2005; Distefano, Blackburn and Marshall, 2009; French, Dunleavy and Cusack, 2010; Boren,
Conrey, Le Coguic, Paprocki, Voight and Robinson, 2011).
Another component considered by researchers for the improvement of dynamic postural control was
proprioceptive balance exercises (Clark and Burden, 2005; Leavey et al., 2010; Zech, Hübscher, Vogt, 
Banzer, Hänsel and Pfeifer, 2010). Improved proprioception increases the ability of mechanoreceptors 
to detect motion in the foot and make adjustments to restore balance and contributes to dynamic
17
postural control (Clark and Burden, 2005; Leavey et al., 2010). Although all these studies including core 
stability, m. gluteus medius (GMed) strengthening or proprioceptive balance programmes (Kahle and 
Gribble, 2009; Aggarwal et al., 2010, Filipa et al., 2010; Fatma et al., 2010; Amrinder et al., 2012; Sandrey 
and Mitzel, 2013) showed varying levels of benefit on dynamic postural control; Aggarwal et al’s (2010) 
study found greater improvement in the core stability group when compared to the balance training 
group.
Research studies conducted by Filipa et al. (2010) and Leavey et al. (2010) investigated exercise 
programmes consisting of a combination of two of the above mentioned components with interesting 
results. Filipa et al. (2010) determined the effect of a neuromuscular training programme that focused 
on lower extremity strength and core stability in female soccer players. Dynamic postural control was 
improved in the neuromuscular training group while no change was found in the control group.  Leavey 
et al. (2010) compared the effects of a six week balance, m.GMed strengthening, and a combination 
programme consisting of balance and m.GMed strengthening on dynamic postural control in healthy, 
active individuals. The combination programme consisting of two components demonstrated greater
improvement when compared to only one component. It was hypothesised that an exercise programme
consisting of a combination of these factors will lead to a greater improvement in dynamic postural 
control.
No literature could be found regarding studies investigating a programme that utilized the combination 
of core stability, m.GMed strengthening and proprioceptive balance exercises on dynamic postural 
control or studies investigating the effect of an exercise programme on dynamic postural control in 
netball players. As mentioned previously poor balance was found in netball players during pre-season 
(Ferreira and Spamer, 2010). Therefore research on the effect of a core stability, m.GMed strengthening
and proprioceptive balance exercise programme might substantiate evidence that an exercise 
programme could possibly eliminate shortcomings in the physical profile of netball players, with regards 
to dynamic postural control. 
Poor dynamic postural control has been theorized to decrease performance and increase the incidence 
of injury secondary to a lack of control of the centre of mass, especially in female athletes (Filipa et al., 
2010). During an epidemiology study of injuries in elite South African netball players (Langeveld, 
Coetzee and Holtzhausen, 2012), the injury rate was calculated at 500.7 injuries per 1000 playing hours 
and the direct probability that a player could sustain an injury was calculated at 0.15 per player. After 
the study was completed, Langeveld et al. (2012) recommended a structured programme to enhance 
18
core stability, neuromuscular control and proprioception to reduce the amount of lower extremity 
injuries in netball players.  Previously conducted research studies (Emery, Casidy, Klassen, Rosychuk and 
Rowe, 2005; Elphinston and Hardman, 2006; Kibler, Press and Sciascia, 2006; McGuine and Keene, 2006)
also suggested that improvement in core stability, neuromuscular control and proprioceptive exercise 
could limit sport injuries. The results of a research study by Saeterbakken, Roland and Seiler (2011) 
suggested that core stability training can significantly improve maximal throwing velocity in female 
handball players.  Improved maximal throwing velocity could also lead to improved performance on the 
netball court.
Further research is warranted and therefore the aim of the study is to determine whether an exercise 
programme that incorporates core stability, m.GMed and proprioceptive balance exercises could lead to 
an improvement in dynamic postural control in a group of netball players and could contribute to
improved performance and injury prevention.
The design of the research document is as follows:
In chapter two dynamic postural control is discussed, the influence of exercise programmes on dynamic 
postural control including core stability, m.GMed strengthening, proprioceptive balance as well as a 
combination of exercise programmes or the comparison of different exercise programmes.  This 
discussion is followed by a review of the principles of a core stability, m.GMed strengthening and 
proprioceptive balance programme. The rules and requirements of netball as well as the physical profile 
and injury prevalence of netball players in South Africa are also reviewed.  This chapter is concluded with 
a discussion of the reliability and validity as well as the execution of the Star Excursion Balance Test 
(SEBT).
In chapter three the aim of the study, the study design, the study population as well as the recruitment 
and randomization of the participants is discussed in detail.  This discussion is followed by a step by step 
discussion of the measurement and procedures of the study.  In conclusion the ethical aspects of the 
study are addressed.
In chapter four the results are discussed using charts and tables.  The information obtained from the 
statistical analyses was divided into attendance of the participants, the participants’ supporting leg used 
during the SEBT, the measurements during the first testing session as well as the improvement from one 
testing sessions to the next testing session. In chapter five reflective practice is used to link the findings 
of the study with the available literature.  Critical reasoning skills were implemented to discuss the 
findings and to reach a conclusion.
19
Chapter 2 Literature Review
In this chapter dynamic postural control is discussed as introductory.  The influence of exercise 
programmes on dynamic postural control including core stability, m.GMed strengthening, proprioceptive 
balance as well as a combination of exercise programmes or comparison of different exercise 
programmes are discussed in full.  An in-depth review of the principles of core stability, m.GMed 
strengthening and proprioceptive balance programmes are included.  This discussion is followed with a 
review of the rules and requirements of netball as well as the physical profile and injury prevalence of 
netball players in South Africa.  In conclusion the reliability and validity as well as the execution of the 
SEBT are discussed.
2.1 Dynamic postural control
Dynamic postural control requires afferent information from somatosensory, visual and vestibular 
systems regarding the body’s position; processing and integration of this information by the 
central nervous system (CNS); coordination and selection of appropriate responses; and execution 
of these responses by the musculoskeletal system (Nakagawa and Hoffmann, 2004; Bressel, 
Yonker, Kras and Heath, 2007; Fatma et al., 2010). The visual system moves the head in relation to 
surrounding objects and provides information about the environment and the orientation and 
movement of the body (Winter et al., 1990; Hosseinimehr and Norasteh, 2010). Previous studies 
(Krishan and Aruin, 2011; Mohapatra and Aruin, 2013) suggested that adequate visual information 
is necessary for anticipatory activation of muscles prior to the disturbance of balance.  This 
anticipatory activation of muscles increases postural stability and improves movement 
performance.  The vestibular system detects acceleration of the head in relation to the body and 
the environment and allows independent control of head and eye positions (Winter et al.,1990; 
Bernier and Perrin, 1998), whilst the somatosensory system which includes muscle spindles, Golgi 
tendon organs, joint and subcutaneous receptors, relays information regarding the position and 
movement of muscles and joints as well as body movements in space to the CNS (Hosseinimehr 
and Norasteh, 2010; Hutt and Redding, 2014).
20
Figure 2: Somatosensory system
Online: Available from http://frankdag.com/wordpress/wp-content/uploads/2013/12/GTO.jpg
[Accessed 8 June 2014]
Balter, Stokroos, Akkermans and Kingma (2004:75) suggested that improvement in dynamic 
postural control is largely the result of “repetitive training of the motor system that influences 
motor responses and not greater sensitivity of the vestibular system”.  Ashton-Miller et al.
(2001:133) argued that improvement in dynamic postural control is the result of “improved ability 
of the CNS to attend to relevant sensory and proprioceptive cues”. Although disagreement exists 
between Balter et al. (2004) and Ashton-Miller et al. (2001) regarding the influence of sensory and 
motor system training on dynamic postural control; most other authors suggest that both sensory 
and motor system training influence postural control (Bressel et al., 2007; Gribble, Robinson, 
Hertel and Denegar, 2009).
From the above literature it can therefore be hypothesised that both sensory and motor system 
training influences dynamic postural control due to the fact that increased proprioceptive input 
from different sources could improve the ability of the CNS to integrate all the information and 
orchestrate an appropriate motor response. On the other hand, increased neural activation, 
21
coordination, strength and endurance of the motor system could lead to a more effective response 
and improve dynamic postural control.
Various studies investigating the effect of a variety of sensory and motor training exercise 
programmes, including core stability, m. GMed strength and proprioceptive balance, on dynamic 
postural control have been conducted. The findings and conclusions of these studies (Kahle and 
Gribble, 2009; Aggarwal et al., 2010; Fatma et al., 2010; Filipa et al., 2010; Hosseinimehr and 
Norasteh, 2010; Leavey et al., 2010; Amrinder et al., 2012; Sandrey and Mitzel, 2013) are
summarized in paragraph 2.2 below.
2.2 Influence of exercise programmes on dynamic postural control
2.2.1 Core stability
All movements are initiated in the gravitational centre in the lumbo-pelvic region.  The local and 
global core muscles surround the centre of gravity and during activity the centre of gravity
constantly shifts and the core muscles play an important role by maintaining a stable base of 
support.  The core muscles are constantly working to maintain posture, absorb loads, assist in 
changing postures and dynamic movements, and to transfer force between the upper and lower
extremities (Kahle and Gribble, 2009; Aggarwal et al., 2010; Sandrey and Mitzel, 2013). Therefore,
core stability forms an integral part of dynamic postural control.
A hypothesis was tested by Kahle and Gribble (2009) that training of the core muscles would lead 
to improving dynamic postural control in young physically active individuals. In the study dynamic 
postural control was measured using three reach directions of the SEBT.  The core stability group 
demonstrated a significant increase in the three reach directions (Anteromedial direction: p=0.001,
Medial direction: p 0˂.001 and Posteromedial direction: p=0.013) compared to a control group.
The study results indicated that strengthening of the mm. transversus abdominis (TrA), internal 
and external obliques and rectus abdominis were beneficial for improving dynamic balance. 
Sandrey and Mitzel (2013) examined the effect of a six-week core-stability training programme on 
dynamic balance in high school track and field athletes. The athletes performed exercises three 
times a week for 30 minutes.  The programme focused on strengthening abdominal, low-back and 
pelvic muscles while maintaining neuromuscular control.  The athletes were evaluated using the 
SEBT for posteromedial, medial and anteromedial directions and demonstrated significant 
22
improvement in the medial (p=0.002) and anteromedial (p=0.008) reach distances.  The 
researchers concluded that the core-stability training programme resulted in improvements of 
dynamic postural control, but that further investigation is warranted due to the small sample size 
and absence of a control group.
2.2.2 Gluteus Medius muscle strengthening
The m.GMed is the largest hip abductor and it accounts for about 60% of the total abductor cross-
sectional area (Neumann, 2010). The m.GMed is important in controlling the frontal plane motion 
of the pelvic hip complex (Ayotte, Stetts, Keenan and Greenway, 2007; French et al., 2010). During 
single-limb support the m.GMed stabilises the hip to prevent the pelvis dropping on the 
unsupported side and controls internal rotation and adduction of the femur (French et al., 2010; 
Boren et al., 2011, Reiman, Bolgla and Loudon, 2012). Dynamic knee valgus, which results from 
coupled hip internal rotation and adduction, is an example of poor lower extremity control and the 
m.GMed resists hip internal rotation and adduction and contributes to dynamic postural control
(Reiman et al., 2012). It is evident from research that m.GMed strengthening is an important 
aspect that needs to be addressed during the rehabilitation of dynamic postural control (Fujisawa
et al., 2005; Distefano et al., 2009). This finding was emphasized in a study conducted by Leavey et 
al. (2010) when the researchers found that the use of m.GMed exercises improved the dynamic 
postural control in healthy, active individuals. In the study college students were evaluated using 
the SEBT and significant improved distances (p<0.001) was found in all eight reach directions.
2.2.3 Proprioceptive balance
Proprioception is dependent on joint position sense, kinaesthesia, muscle spindles output and the 
strength of surrounding muscles (Madras and Barr, 2003; Kiers, Brumagne, van Dieen, van de 
Wees and Vanhees, 2012).  According to Clark and Burden (2005) disruption of the proprioception 
system affects balance and dynamic postural control negatively due to the lack of joint position 
sense and a delay in protective muscle activity.  Improved proprioception increases the ability of 
mechanoreceptors to detect motion in the foot and make adjustments to restore balance or 
postural control (Clark and Burden, 2005; Leavey et al., 2010).  Other researchers (Amrinder et al., 
2012; Kiers et al., 2012) disagreed and claimed that joint mechanoreceptors are stimulated at end 
range of motion and that improved proprioception and balance are due to joint compression and 
increased muscle spindle sensitivity rather than increased sensitivity of joint mechanoreceptors.  
23
Kiers et al. (2012) further suggested that different strategies are used to maintain balance on 
stable and unstable surfaces.  Proprioceptive signals from muscles surrounding the ankle lead to 
maintaining balance on a stable surface whereas the CNS gives more priority to proprioceptive 
signals from muscles of the hip and lower back and the vestibular system when maintaining 
balance on an unstable surface.  Kiers et al. (2012) postulated the reason for the difference being 
that when standing on a stable surface the proprioceptive information from the muscle spindles of 
the muscles surrounding the ankle and ankle joint correlate with the change in body orientation; 
whereas when standing on foam or a wobble board proprioceptive information from the muscle 
spindles of the muscles surrounding the ankle and ankle joint may or may not correlate with 
changes in body orientation.  This inconsistency of proprioceptive information from the ankle 
causes the CNS to integrate proprioceptive signals from other body regions and the vestibular 
system to maintain balance.
Fatma et al. (2010) examined the effect of an eight week proprioception programme that included 
single-leg balance and wobble board exercises on dynamic postural control in taekwondo athletes
and came to the conclusion that proprioceptive training significantly improved (p<0.05) the
dynamic postural control performance of these athletes as measured with the Biodex postural 
control system. Twenty randomised controlled trials testing healthy and physically active 
participants aged up to 40 years of age were included in a systematic review by Zech et al. (2010).  
The review was performed by two independent reviewers and the results indicated that 
proprioceptive balance training was an effective intervention to improve dynamic balance in both
athletes and non-athletes. Amrinder et al. (2012) also examined the effect of proprioceptive 
exercises on balance and centre of pressure in 80 athletes with self-reported functional ankle 
instability. The exercises included balancing on a wobble board, exercise mats, air squabs and an 
uneven walkway. The study results indicated that after a six week proprioceptive exercise 
programme there was a significant improvement (p<0.05) in the balance of athletes with 
functional ankle instability.
2.2.4 A combination of exercise programmes or comparison of different exercise programmes
Leavey et al. (2010) compared the effects of a six week balance, m.GMed strengthening, and a 
combination programme consisting of balance and m.GMed strengthening on dynamic postural 
control in healthy, active individuals. 
24
Proprioceptive balance exercises included fixed-surface balancing with eyes open and closed, tilt-
board and wobble-board exercises as well as functional hops.  M.GMed exercises consisted of side-
lying hip abduction, walking with a weight in the opposite hand, gorilla walking, single-leg squats 
and lateral step-downs.  The participants performed three sets of ten repetitions increasing to 
three sets of twenty repetitions of side-lying hip abduction.  In the “walking with a weight in the 
opposite hand” exercise the participants walked for three minutes around an 80 meter track, 
carrying a dumbbell in the hand opposite from the dominant leg.  The weight of the dumbbell was 
5% of their body weight progressing to 15% of their body weight.  Three sets of 20 repetitions 
progressing to three sets of 40 repetitions of gorilla walking or lateral walking with Theraband 
wrapped around both legs just above the knees, was performed.  Two sets of five increasing to 
four sets of five squats and lateral step-downs were also completed by the m.GMed strengthening 
group.
Dynamic postural control was measured with the SEBT and the difference between the pre-test 
and post-test reach distances of all three groups were significant at p˂0.001. Although no 
significant differences were found between the groups as far as post-test reach improvement was
concerned, the combination group demonstrated the most improvement.  The results of the study 
indicated that the use of exercises for proprioception, or m.GMed strength, or a combination will 
improve dynamic postural control in healthy, active individuals.
A randomised controlled trial (Aggarwal et al., 2010) compared lumbar core stabilization training 
with balance training in recreationally active individuals. The core stabilization exercise 
programme focused on awareness and activation of mm. TrA and lumbar multifidus (LM) in 
various positions with progression to maintain the contraction of mm. TrA and LM while 
attempting various functional tasks. The balance training protocol included drills targeting the 
ankle muscles progressing to balance activities in more functional positions, consisting of one leg 
standing, one leg standing on a trampoline and doing ball catching activities whilst standing on one 
leg. Both the core stabilization training group and balance training group showed significant 
(p 0˂.05) improvement in dynamic balance compared to the control group. Dynamic postural 
control was measured with the SEBT and the core stabilization and balance training groups showed 
an improvement in the reach distance of seven of the eight directions of the SEBT.  The group 
doing core stability training showed greater improvement in dynamic balance compared to the 
balance training group.
25
The objective of Filipa et al’s (2010) study was to determine if a neuromuscular training 
programme that focused on lower extremity strengthening and core stability, would improve the 
lower extremity dynamic stability measured with the SEBT in female soccer players. Lower 
extremity strength exercises included barbell squats, walking lunges, lateral lunges and lateral 
step-downs. Core stability exercises included lateral crunches, double-crunches, pelvic bridges and 
Swiss ball back hyperextensions. Subjects in the neuromuscular training programme showed 
improved performance of the SEBT composite score on both limbs (p=0.03 for the right limb and 
p=0.04 for the left limb) after eight weeks of training, while no change was observed in the control 
group.
All the above mentioned studies showed improved dynamic postural control after the exercise 
programmes were completed as measured with the SEBT. It was interesting to note that when
two components were combined during an exercise programme, greater improvement was found 
when compared to only one component (Filipa et al., 2010; Leavey et al., 2010). From the above 
literature it can therefore be hypothesised that a programme consisting of a combination of core 
stability, m.GMed strengthening and proprioceptive balance exercises could lead to further 
improvement in dynamic postural control due to the fact that all the sensory and motor systems
are targeted (paragraph 2.1) (Bressel et al., 2007; Gribble et al., 2009).
After an extensive search of the available literature, no studies investigating a programme that 
utilised the combination of core stability, m.GMed strengthening and proprioceptive balance 
exercises on dynamic postural control could be found.
2.3 Principles of an exercise programme
2.3.1 Principles of a core stability exercise programme
Core stability exercises should be included in a rehabilitation programme to improve dynamic 
postural control as core stability forms an integral part of dynamic postural control (paragraph 
2.2.1) (Smith et al., 2008; Sandrey and Mitzel, 2013). A core stability programme begins with 
recognition of the neutral spine position as this is the position of power and balance for optimal 
athletic performance in many sports (Akuthota, Ferreiro, Moore and Fredericson, 2008: 41).
Learning to co-activate the local muscle system (mm.TrA, LM, internal oblique and muscles of the 
pelvic floor) is the next step in a core stability programme as the intrinsic mechanism increases 
trunk stiffness by feed-forward neuromuscular pre-activation in anticipation of a perturbation 
26
(Akuthota et al., 2008; Smith et al., 2008). The TrA contracts 30ms before movement of the 
shoulder and 110ms before movement in the leg in healthy people (Akuthota et al., 2008). Once 
optimal local co-activation has been recruited, the interplay between local and global muscles is 
necessary for functional stability (Hodges and Moseley, 2003). The global muscle system is 
responsible for movement and includes the more superficial muscles e.g.mm. rectus abdominis, 
external oblique, erector spinae and gluteus maximus (Reiman, 2009). Local co-activation should
then be progressed to endurance exercises in supine, crook-lying or quadruped positions e.g. curl-
up, side-bridging and bird dog, while maintaining neutral spine position (Akuthota et al., 2008;
Smith et al., 2008).
Phase two of the core stability programme should progress to higher velocity, more dynamic 
multiplanar endurance, strength, and coordination challenges incorporating upper and lower 
extremity movements e.g. physio ball exercises (Akuthota et al., 2008; Smith et al., 2008). Local
muscles provide intrinsic spinal stability and activating a few local muscles is insufficient to achieve 
stability during high-velocity and high-load perturbations (Smith et al., 2008; Reiman, 2009).
Global muscles provide composite stability, large movements and torque production and are 
essential in providing dynamic stability (Smith et al., 2008; Reiman, 2009).  Isolated exercises do 
not represent the typical pattern and load demands of functional movement and is insufficient in 
providing dynamic stability (Smith et al., 2008; Reiman, 2009).  A comprehensive programme
incorporating all the aspects of dynamic stability is therefore warranted. 
Akuthota et al. (2008), Smith et al. (2008) and Reiman (2009) placed emphasis on functional sport-
specific exercises in phase three of a core stability programme as non-weight bearing exercises 
might not provide a learning component and will not translate to improved athletic performance. 
The failure to train athletes in functional activities is one of the main reasons for poor results 
following exercise programmes (Reiman, 2009).  Physiotherapists use sport-specific exercises 
during the final rehabilitation of patients according to the principles of specificity and learning.  
Specificity relates to the specific adaptation of the muscle to the imposed demands and
rehabilitation needs to mirror the functional activity it aims to improve (Petty, 2004). Balance and 
coordination should be developed while performing a variety of movement patterns in the sagittal, 
frontal and transverse planes of movement (Akuthota et al., 2008), because specific 
neuromuscular activation patterns differ depending on characteristics and spinal loads (Smith et 
al., 2008). An advanced core stabilizing programme should include training of the reflexive control 
27
and postural regulation as the stability of the spine is not only dependent on muscle strength, but 
also sensory input. This sensory input alerts the central nervous system (CNS) regarding 
interaction between the body and the environment (Akuthota et al., 2008). Both sensory and
motor system training is a requirement for dynamic postural control (paragraph 2.1). Research 
performed by Kahle and Gribble (2009) and Aggarwal et al. (2010) indicated that three sessions a 
week for six weeks of a core stability programme was sufficient for improving dynamic postural 
control.
2.3.2 Principles of a m. GMed exercise programme
Due to the importance of m.GMed in dynamic postural control (paragraph 2.2), several research 
studies (Bolgla and Uhl, 2005; Ayotte et al., 2007; Ekstrom, Donatelli and Carp, 2007; Distefano et 
al., 2009; Boren et al., 2011) analysed the electromyographic (EMG) activity of m.GMed during 
exercises used in the rehabilitation of m.GMed. Electromyography can be used to measure and 
compare muscle activity during different exercises (French et al., 2010). Greater EMG amplitude is 
related to an increase of motor units recruited and an increase in m.GMed activity during the 
exercise (Ekstrom et al., 2007; French et al., 2010). Researchers therefore postulate that exercises 
producing higher EMG amplitudes results in greater strengthening of the muscle (Ayotte et al., 
2007). EMG amplitudes can also be used to determine the efficacy of the exercise and to make a 
decision during which stage of rehabilitation the exercises should be implemented (Ayotte et al., 
2007). The exercises analysed and their m.GMed EMG activity expressed as a percentage of 
maximum voluntary contraction (MVIC) is indicated in Table 1 below.
28
Table 1: Comparison of exercises for recruitment of GMed using % MVIC
Exercise Boren, et Distefano, Ayotte, Ekstrom, et Bolgla 
al. 2011 et al. 2009 et al. al. 2007 and Uhl,
2007 2005
Side plank abduction 103%
Side plank to neutral 74%
position
Single limb squat 82% 64%
Single limb mini-squat 36%
Single limb wall squat 52%
Front plank with hip 75%
extension
Side-lying hip abduction 63& 81% 39% 42%
Lateral step-up 60% 38% 43%
Pelvic drop 58% 57%
Single-limb dead lift 56% 58%
Forward step-up 55% 44%
Sideways hop 57% 57%
Clamshell 1 (30… hip flexion) 47% 40%
Clamshell 2 (60… hip flexion) 38%
Clamshell 4 (hip extension) 77%
Quadruped with 42%
contralateral arm and leg lift
Retro step-up 37%
Lunge – neutral trunk 29%
position
Bridging on a stable surface 28%
Unilateral bridge 47%
Prone bridge plank 27%
Sideways lunge 42%
Transverse lunge 48%
29
Ayotte et al. (2007) indicated an expected strength gain when EMG activity is greater than 40% 
MVIC, but argued that exercises with lower EMG activity can be used to facilitate neuromuscular 
activation. A literature review of studies evaluating m.GMed activation during rehabilitation 
exercises (Reiman et al., 2012) divided the exercises into four categories according to levels of 
activation.  The categories include exercises with low-level activation (0-20% MVIC), moderate-
level activation (21-40% MVIC), high-level activation (41-60% MVIC) and very high-level activation 
(higher than 60% MVIC).
None of the studies that met the inclusion criteria as stipulated (Bolgla and Uhl, 2005; Ayotte et al., 
2007; Ekstrom et al., 2007; Distefano et al., 2009) in the literature review (Reiman et al., 2012)
included any exercises in the category of low-level activation. Exercises in the category of 
moderate-level activation (21-40% MVIC) included prone bridge plank, bridging on a stable 
surface, lunge with a neutral trunk position, single limb mini-squat, retro step-up, clamshell two
with 60° hip flexion, sideways lunge and clamshell one with 30° hip flexion. Exercises in the 
category of high-level activation (41-60% MVIC) included lateral step-up, quadruped with 
contralateral arm and leg lift, forward step-up, unilateral bridge, transverse lunge, single limb wall 
squat, side-lying hip abduction, pelvic drop and single limb dead lift.  Exercises in the category of 
very high-level activation (higher than 60% MVIC) included single limb squat and side plank to 
neutral position.
Greater EMG amplitudes of m.GMed were observed during exercises in which the base of support 
was minimal, e.g. side plank abduction, single-limb squat and lateral step-up, in comparison to 
exercises in which the base of support was greater, such as lunges (Boudreau, Dwyer, Mattacola, 
Lattermann, Uhl and McKeon, 2009).  Lesser EMG amplitudes were noted during exercises with a 
larger base of support due to the fact that these exercises involved m.GMed stabilizing in the 
sagittal plane to keep the pelvis level (Reiman et al., 2012).  The greater EMG amplitudes during 
exercises with a minimal base of support were due to the fact that such exercises directly involved 
the primary function of m.GMed as a stabiliser in the frontal plane (Distefano et al., 2009). 
Bolgla and Uhl (2005) further reported that weight-bearing (WB) exercises (pelvic drop, WB hip 
abduction) resulted in greater EMG amplitudes of m.GMed than non-weight-bearing (NWB) 
exercises (NWB standing hip abduction).  The only exception was side-lying hip abduction and 
Distefano et al. (2009: 538) argued that the reason for the higher EMG amplitude in this NWB 
30
exercise was “the large external moment arm created by the mass and the extended position of the 
lower extremity being lifted.”
Greater EMG amplitudes of m.GMed were also noted during exercises which involved a 
combination of hip abduction and lateral rotation e.g. clamshell; exercises controlling multiple 
planes of movement e.g. unilateral bridge; during exercises where the body’s centre of mass is 
displaced away from the base of support e.g. single limb wall squat and single limb dead lift; and 
exercises which involved a combination of eccentric and concentric muscle contraction e.g. pelvic 
drop (Reiman et al., 2012). Lee, Choi, Yoon and Jeong (2013) tested the effects of different hip 
rotations on mm.GMed and tensor fascia lata (TFL) muscle activity during isometric side-lying hip 
abduction. The study concluded that side-lying hip abduction when the hip is in medial rotation 
resulted in greater m.GMed activation and a higher mm.GMed:TFL ratio.  The researchers
hypothesised that during side-lying hip abduction, when the hip is in lateral rotation, the hip is 
pulled into extension which results in placing the m.TFL anterior to the hip joint causing m.TFL 
activity to increase and m.GMed activity to decrease.  The contradiction between Reiman et al.
(2012) and Lee et al. (2013) whether hip lateral or medial rotation are more beneficial for m.GMed
activation in side-lying hip abduction could be explained due to the fact that only one set of 
electrodes over the middle m.GMed were used in Lee et al’s (2013) study.  The m.GMed is divided 
into an anterior, middle and posterior set of fibres and all these fibres contribute to hip abduction 
whilst the anterior fibres also assists with hip medial rotation and the posterior fibres with hip 
extension and lateral rotation (Neumann, 2010; Reiman et al., 2012).
As a result of EMG activity, it is suggested that progression of exercises should be from exercises in 
a single plane to multi-planar exercises; from exercises with a larger base of support to exercises 
with a smaller base of support; and from exercises where the body’s centre of mass fall within the 
base of support to exercises where the body’s centre of mass is displaced away from the base of 
support (Distefano et al., 2009; Reiman et al., 2012).
It is important to consider “functional demands on the muscle in athletes when selecting an 
exercise for muscle training and strengthening” (Boren et al., 2011: 213). “For optimal transfer, 
training has to comprise of similar movement patterns and context to the goal task” (Lederman in 
Aggarwal et al., 2010). Pelvic drop, single-limb squat, single-limb dead lift, and sideways hop are 
functional exercises that demand frontal-plane pelvic stability needed by netball players for pelvic 
stabilization in single limb stance (Distefano et al., 2009; Boren et al., 2011). 
31
M.GMed is a “global stabiliser which generates force to control movement through eccentric 
control” (Petty, 2004:175).  To improve endurance of a muscle, the muscle must be progressively 
overloaded through an increase in duration and frequency (Bruton, 2002). While aiming to 
improve muscle endurance a muscle must contract 30% to 50% of its maximum contraction, for 
20-30 minutes three times a week and 25 to 35 repetitions need to occur at each session (Petty, 
2004). A six week m.GMed programme showed an improvement in dynamic postural control in 
healthy, active individuals (Leavey et al., 2010). The participants performed six exercises three 
times a week.  During the first two weeks three sets of ten repetitions were performed, increasing 
to three sets of 15 repetitions the third and fourth weeks and three sets of 20 repetitions the final 
two weeks. The exercise programme therefore followed the guidelines as discussed above, with 
the exception that slightly more repetitions were performed.  No other study could be found to 
compare the effect that a certain or predetermined amount of repetitions would have on 
improvement of dynamic postural control.
2.3.3 Principles of a proprioceptive balance programme
Proprioceptive balance training is an effective intervention to improve dynamic balance 
(paragraph 2.2.3) (Fatma et al., 2010; Zech et al., 2010; Amrinder et al., 2012) and should be 
incorporated in a dynamic postural control programme.  Proprioceptive training incorporates both 
static and dynamic balance exercises (Leavey et al., 2010).  Static balance exercises aim to maintain 
the centre of pressure of the body within the base of support, while dynamic balance exercises aim 
to move the centre of pressure in a given direction within the limits of stability (Aggarwal et al., 
2010).  Single-leg balance on fixed and unstable surfaces, tilt board, wobble-board and functional 
hop exercises were effectively used in research studies to improve dynamic postural control 
(Paragraph 2.2.3; Paragraph 2.2.4.1) (Rasool and George, 2007).  According to Aggarwal et al. 
(2010) weight bearing exercises are advised in proprioceptive balance training as it stimulates joint 
mechanoreceptors leading to increased proprioceptive input.  Closed eyes training was effective in 
a randomised controlled pilot study conducted by Hutt and Redding (2014) in improving dynamic 
postural ability of dancers.  The results of a systematic review on 20 randomised controlled trials 
(Paragraph 2.2.3) (Zech et al., 2010) showed more pronounced improvement in neuromuscular 
control with a training duration of at least six weeks.  No consensus could be reached in the 
systematic review (Zech et al., 2010) regarding the duration of each session, which lasted between 
five and 90 minutes per day, and the training frequency from two to seven times a week. 
32
2.4 Netball players
Maintaining dynamic postural control is essential in netball players due to the fact that netball 
players accelerate rapidly to break free from an opponent, change direction suddenly in 
combination with leaps to receive a pass, intercept a ball or rebound after attempting a goal 
(McGrath and Ozanne-Smith, 1998).  Netball is an interval type game involving less than fifteen 
seconds work intervals of sprints, jumps and shuffling movements interspersed with rest-relief 
periods of slow jogging, goal shooting and passive defence (Ashfield, 1998).  IFNA footwork rule 
states that a player can receive the ball with both feet grounded or jump to catch the ball and land 
on two feet simultaneously.  The player may then take a step in any direction with one foot and 
pivot on the spot with the other foot.  An alternative is to receive the ball with one foot grounded 
or jump to catch the ball and land on one foot.  The landing foot cannot be moved, other than to 
pivot on the spot, whilst the other foot can be moved in any direction.  Once the landing foot is 
lifted, it may not be re-grounded until the ball is released. It is evident that netball players 
frequently find themselves on one leg whilst still having to make an accurate pass and therefore 
require good balance and dynamic postural control.  Research by Ferreira and Spamer (2010) 
evaluated the physical profile of elite university netball players and a computerised balance test 
was used to evaluate the balance of the netball players pre-season and post-season.  The results of 
the study indicated that netball players demonstrated poor balance during pre-season testing.
Studies conducted in South Africa (Ferreira and Spamer,2010; Langeveld et al., 2012; Pillay and 
Frantz, 2012) which evaluated the injury prevalence of netball players reported the most common 
injured structures were the knee and ankle and the most common mechanism of injury to the 
lower limb was landing.  Ferreira and Spamer (2010) reported an injury prevalence of 39% and 28% 
for the ankle and knee during one season among university netball players.  Their findings are 
similar to the more recent studies conducted by Langeveld et al. (2012) and Pillay and Frantz 
(2012) who determined the epidemiology of injuries among elite South African netball players.  
Langeveld et al. (2012) reported an injury prevalence of 34% and 18% for the ankle and knee 
compared to Pillay and Frantz (2012) who reported an injury prevalence of 37.5% and 28.6% for 
the ankle and knee. According to Pillay and Frantz (2012) research is needed regarding measures 
to prevent lower limb injuries within South African netball players (Pillay and Frantz, 2012); whilst 
Langeveld et al. (2012) recommended an exercise programme consisting of core stability, 
neuromuscular control and proprioception in order to reduce lower limb injuries in netball players.
33
2.5 Netball Season
The duration of the pre-season in netball is from January to May of each calendar year, but this 
could vary depending on institutions and academic terms.
2.6 Star Excursion Balance Test
Dynamic postural control is assessed with the SEBT (Nakagawa and Hoffman, 2004; Gribble et al., 
2009; Kahle and Gribble, 2009; Filipa et al., 2010; Leavey et al., 2010), the Biodex postural control 
system (Filipa et al., 2010) and with a force plate (Puls and Gribble, 2007). The SEBT is a valuable 
test for assessing dynamic balance as it has high inter-rater and intra-rater reliability (Gribble, 
2003; Demura and Yamada, 2010; Gribble, Kelly, Refshauge and Hiller, 2013). A literature and 
systematic review (Gribble et al., 2012) found that the SEBT is a valid and reliable test in predicting 
risk of musculoskeletal injury; to identify dynamic postural control deficits in individuals with lower 
extremity conditions; and has the ability to demonstrate improved performance from 
rehabilitative and preventive exercise programmes in healthy individuals and in those with lower 
extremity conditions.  The SEBT is a simple, low cost alternative to more expensive instruments 
e.g. the Biodex and force plate (Leavey et al., 2010) and the testing is not confined to a laboratory. 
The SEBT is a useful clinical measure as it challenges the athletes’ postural control system as the 
body’s centre of mass is moved in relation to its base of support (Gribble, 2003; Kahle and Gribble, 
02009).  As a netball player’s centre of mass is moved in relation to her base of support, the SEBT 
can therefore be used as a valuable measurement tool in the assessment of dynamic postural 
control in netball players.
Participants’ leg length was measured in previous studies (Kahle and Gribble, 2009; Aggarwal et al., 
2010; Filipa et al., 2010; Leavey et al., 2010; Arminder et al., 2012; Sandrey and Mitzel, 2013) and 
used to normalize reach distance data.  Participants in this study were only compared to 
themselves and not to other participants and therefore leg length were not measured to avoid the 
possibility of unnecessary measurement errors.
34
2.7 Execution of the SEBT
Two marker lines are placed on a hard surface at an angle of 90ᴼ from each other to form four 
direction lines (Figure 2).  A measuring tape is placed on each line to avoid the measuring point to 
differ between participants and to increase measurement accuracy (Demura and Yamada, 2010).  
The reach direction labels changes for right versus left stance or supporting leg (Figure 2) (Gribble, 
2003).
Right leg supporting Left leg supporting
Figure 3: Reach direction lines for right and left stance
The participant maintains a base of support with one leg while reaching in the four directions with 
the opposite leg, without compromising the base of support on the stance leg (Gribble, 2003, 
Demura and Yamada, 2010).  Participants are asked to stand with their supporting leg on the 
centre of the cross.  Participants are then instructed to reach as far as possible along the four 
direction lines without lifting the supporting foot from the floor while holding their hands on their 
hips and facing forwards (Hosseinimehr and Norasteh, 2010).  The beginning reach direction is 
anterior and a clockwise direction is followed for a participant with a left stance leg and a counter-
clockwise direction for a participant with a right stance leg (Hosseinimehr and Norasteh, 2010).  
Participants perform a light touch with their big toe on the line as near as possible to their 
maximum reach, and then return to double-leg stance before attempting movement in the next 
35
direction (Hosseinimehr and Norasteh, 2010).  If the participant cannot touch the line; or if the 
participant’s weight is shifted to the reach leg; or if the support leg is lifted from the centre; or if
the participant loses balance; or cannot return to the beginning position under control, the trial is
then discarded and the participant is instructed to repeat all four reach directions of the trial they 
are currently engaged in (Gribble, 2003, Hosseinimehr and Norasteh, 2010).
Demura and Yamada (2010) also shows that testers can accurately point to and read the distance 
from the scale placed on the lines and this technique makes it possible to measure a large number 
of participants with the same four direction lines.  To avoid a parallax fault, the data collector 
touches with a pencil on the measuring tape and reads the distance reached by the most distal 
part of the participant’s big toe.  The distance is recorded by an assistant on the participant’s data 
sheet (see Appendix 4) and repeated back to the tester to evade measurement errors.
According to Kahle and Gribble (2009) and Demura and Yamada(2010) the same validity will be 
achieved measuring three trials and four directions (anterior, medial, posterior, lateral) as with the 
original test of ten trials and eight directions.  The simple SEBT with three trials and four directions 
is more practical due to a reduction (about 85%) in measurement time and less physical burden on 
the subject (Demura and Yamada, 2010).
2.8 Conclusion
Research was warranted to determine whether an exercise programme that incorporated 
scientifically grounded core stability, m.GMed strengthening and proprioceptive balance exercises 
three times a week over a period of six weeks (see principles of an exercise programme in 
paragraph 2.3.1, 2.3.2 and 2.3.3) could lead to an improvement in dynamic postural control as 
measured with the SEBT in a group of netball players.  Poor core stability and decreased muscular 
synergy of the trunk and hip stabilisers have been theorized to decrease performance and increase 
the incidence of injury secondary to a lack of control of the centre of mass and dynamic posture, 
especially in female athletes (Filipa et al., 2010; Langeveld et al., 2012).  Since poor balance was 
found in netball players pre-season (paragraph 2.4), research on the effect of a core stability, 
m.GMed strengthening and proprioceptive balance exercise programme in netball players could 
therefore substantiate evidence of the effectiveness of such an exercise programme to improve 
dynamic postural control.  An exercise programme could contribute towards the elimination of 
shortcomings in the physical profile of netball players regarding dynamic postural control as well 
as contribute towards increased performance and injury prevention. 
36
In the next chapter the methodology of the study will be described in detail including the pilot 
study, the recruitment of participants, the method of measurement, the exercise programme, 
procedures followed during the study as well as ethical aspects.
37
Chapter 3 Methodology
In chapter three the aim of the study, the study design, the study population as well as the recruitment 
and randomization of the participants are discussed. Included in this chapter is a discussion of the 
training of the data collector and assistant as well as the pilot study.  In conclusion the measurement, 
procedures and ethical aspects of the study are discussed step by step.
3.1 Research aim:
The aim of the study was to determine whether an exercise programme that incorporates core 
stability, m.GMed strengthening and proprioceptive balance exercises three times a week over a 
period of six weeks would lead to a statistically significant improvement (p 0˂.05) in dynamic 
postural control in a group of netball players.
3.2 Objectives
The objectives of the study were:
1) To compile an exercise programme that incorporated scientifically grounded core stability, 
m.GMed strengthening and proprioceptive balance exercises.
2) To assess the dynamic postural of the netball players using the SEBT to determine the efficacy 
of the exercise programme.
3.3 Research design
A cross-over randomised clinical trial was performed.  The participants were randomly divided into 
two groups and for the first six weeks group A participated in the exercise programme while group 
B was considered as the control group after which the roles were reversed. The participants had 
been selected to one of the groups on a random basis to ensure that, on average, the two groups 
are quite similar and that any differences between them are due entirely to chance.  A cross-over 
trial was performed to have a control group, but still allow all the participants to partake in the 
exercise programme.  A control group was needed for the internal validity of the study to allow the 
researcher to draw accurate conclusions about the cause-and-effect within the data (Leedy and 
Ormrod, 2010).
38
3.4 Study participants
The study population was female netball players of the University of the Free State (UFS) selected 
into the top junior netball group consisting of 20 netball players.  The following criteria were used 
to determine the inclusion, elimination and fall-out of eligible netball players.
3.4.1 Inclusion criteria
1) Voluntary agreement to participate.
2) Informed consent.
3.4.2 Exclusion criteria
1) A history of lower extremity injuries in the past six months (any injury preventing the 
participant from partaking in physical activity for longer than two days) (Kahle and Gribble, 2009).
2) Lower extremity surgery in the past year (Leavey et al., 2010).
3) Currently partaking in any balance, core stability or m.GMed exercise programme, not included 
in their standard exercise programme (Leavey et al., 2010).
Inaccurate history recall and information could be given regarding the exclusion criteria (history of 
lower extremity injuries in the past six months or lower extremity surgery in the past year).  
However a research study (Gabbe, Finch, Bennel and Wajswelner, 2003) assessed the accuracy of a 
12 month injury history recall in a population of Australian football players and showed that 100% 
of participants could recall whether or not they were injured in the past year.  Seventy-nine 
percent of participants reliably recalled the body region and number of injuries, but not the 
specific diagnosis (only 61% of participants).  A 12 month sport injury history self-reported 
questionnaire in the study by Gabbe et al. (2003) showed good validity regarding recall for past 
injury status.  An accurate diagnosis was not required in this research study, therefore an injury 
profile questionnaire which was attached to the informed consent form (Appendix 3) was used to 
determine whether a participant had a history of lower extremity injuries in the past six months or 
lower extremity surgery in the past year.  The exclusion criteria were applied once the participants 
completed the injury profile questionnaire.
3.4.3 Fall out criteria
The participants needed to attend at least 14 of the 18 training sessions (approximately 77% 
attendance) and had to return for post testing in order for the data of the participants to be 
39
included in the study results (Leavey et al., 2010).  The participants’ attendances were recorded on 
an attendance record sheet (Appendix 5).
3.5 Training of data collector and assistant
The simple SEBT was selected to measure dynamic postural control (paragraph 2.6).  Two 
individuals, other than the researcher, were required to assist in the research study as a data 
collector and assistant to ensure objectivity and reliability during the data collection.  The data 
collector’s task was to measure the distances reached by the participant during the SEBT test.  The 
assistant’s task was to document the distances reached by participants during the SEBT test on the 
participant’s data sheet (paragraph 2.7).
Two qualified physiotherapists were recruited to be the data collector and assistant.  During a 
special session on the 11th of January 2014, before the pilot study the data collector and assistant 
underwent training by the researcher in order to execute the SEBT accurately.
3.6 Pilot study
Female hostel netball players of the UFS were approached and three netball players were 
recruited to participate in the pilot study.  The data collector and assistant assessed the 
participants in the pilot study by means of the SEBT.  The assessment during the pilot study was 
executed by the data collector and assistant in the exact same manner as the study.  The three 
participants in the pilot study attended three exercise sessions in order to determine the accuracy 
and applicability of the exercise programme.  
During the pilot study it was established that the data collector would be more accurate when 
touching with the edge of a small ruler instead of a pencil on the measuring tape as this made 
reading the distance reached by the most distal part of the participant’s big toe easier.  The 
participants were unsure if they should return to double-leg stance or single-leg stance before 
attempting movement in the next direction and the significance of clear instructions regarding 
return to double-leg stance were realized.
The data collector and assistant used the correct techniques and followed the stipulated 
procedures given by the researcher.  The assistant was able to complete the data form as well as 
repeating the participant’s reach distance back to the data collector with accuracy.  The assistant 
confirmed the ease of use of the data sheet.
40
Although the participants in the pilot study could execute the exercise programme regarding 
difficulty, number and sets of exercises in a session, it was recognized that the co-activation of TrA 
and LM as well as the accuracy of the exercises needed to be checked regularly by the researcher.
The results of the pilot study were excluded from the official study results, due to the fact that the 
pilot study participants participated in only three exercise sessions and not the full six weeks of 
exercise sessions as required in the main study.
3.7 Recruitment
After the top junior netball group of the UFS had been selected, the researcher held an 
information session on the 31st of January 2014 with the group and explained the reason and goal 
of the study, the requirements and commitment from participants as well as the possible benefits 
and risks involved.  Once the information session had been completed, all twenty netball players 
indicated their interest in participating in the research study.  Each participant was given an 
information leaflet as well as a consent form which had an injury profile questionnaire attached 
(Appendix 2 and 3).  The injury profile questionnaire was completed and the consent form signed 
and returned to the researcher before commencement of the exercise programme.
One netball player was excluded due to a grade two hamstring injury during the past six months as
diagnosed by a sport physician and this prevented her from partaking in physical activity for longer 
than two days (refer to paragraph 3.3.2 exclusion criteria).  The netball player was allowed
however to participate in the exercise programme as part of her rehabilitation, but none of her 
data was included in the study results.
3.8 Randomization
Consecutive numbers were given to each of the 20 participants that signed the consent form. 
Numbers were placed in a hat from which the two groups were drawn. The first 10 numbers 
drawn were allocated to group A while the remainder of the numbers was allocated to group B.  
Group A consisted of participants 2, 4, 5, 8, 11, 13, 15, 17 and 19.  Group B consisted of 
participants 1, 3, 6, 7, 9, 10, 12, 14, 16, 18 and 20.  For the first six weeks group A participated in 
the exercise programme while group B was considered as the control group after which the roles 
were reversed. 
41
3.9 Measurement
The simple SEBT with three trials and four directions were used to measure dynamic postural 
control of the participants (paragraph 2.6 and 2.7).  In a previous study (Kahle and Gribble, 2009) 
on dynamic balance in young, healthy adults; the leg the participant would use to stand on while 
kicking a ball was used as the supporting leg during assessment with the SEBT.  In this study, the 
netball players’ landing leg was used as the supporting leg during assessment with the SEBT.
The same trained physiotherapists (data collector and assistant) did all the measuring and 
recording to limit inter-observer variation.  The data collector gave each participant verbal 
instructions as well as a physical demonstration on how to execute the SEBT.  The data collector 
and assistant followed the procedure of the SEBT as stipulated in paragraph 2.7 with the exception 
that the data collector touched with the edge of a small ruler instead of a pencil on the measuring 
tape as this made reading the distance reached by the most distal part of the participant’s big toe 
more accurate (refer to paragraph 3.5 pilot study).
In spite of some effect of practice by repeating trials, participants were allowed two practice trials 
before any data was recorded as Demura and Yamada (2010) showed that measured values 
became almost constant after the second trial.  After the two practice trials participants were 
tested three times in four directions with a minute rest in between the three trials in the testing 
session. 
All the participants were tested during three separate testing sessions.  The first testing session of 
dynamic postural control took place on the 3rd of February 2014 prior to the commencement of 
the exercise programme of group A.  The second testing session took place between the 
completion of group A’s exercise programme and the start of group B’s exercise programme on 
the 18th of March 2014.  The third testing session took place after the completion of group B’s 
exercise programme on the 2nd of June 2014.  The second and third testing sessions were executed 
in the same venue at the UFS sport centre under similar conditions as the first testing session.
To avoid diagnostic suspicion bias the data collector and assistant were blinded during the second
and third testing session after the completion of the exercise programme regarding the 
participants’ reach distance values obtained during the previous testing sessions.  All participants 
from both groups were tested simultaneously, and the data collector and assistant were blinded to 
which group the participants belonged.
42
3.10 Procedures
The participants (first group A and then after the second testing, group B) trained under the 
researcher’s supervision at the UFS sport centre.  Each training session took approximately 60 
minutes, three days a week for a period of six weeks. Group A trained from the 4th of February 
2014 to the 14th of March 2014 and group B from to 14th of April 2014 to the 30th of May 2014.
Due to public and university holidays Group B had a break of one week from the 28th of April to the 
4th of May.
Although the participants did not partake in any other balance, core stability or m.GMed exercise 
programme during this study, the participants were all first year female netball players selected in 
the top junior group and partook in pre-season netball training while participating in the exercise 
programme as well as during the time period of being in the control group.  The pre-season netball 
training consisted of between four and eight hours of training per week.
Participants’ class schedules were taken into consideration and the training sessions did not 
interfere with class commitments.  Observational notes were taken by the researcher at the 
training sessions to enhance the value of the study.  If a participant failed to attend a training 
session, the participant was contacted the same or the following day on her cellular phone and the 
participant was motivated to continue participation.  The failure to attend at least 14 of the 18 
training sessions lead to the exclusion of the participant’s data from the study results (paragraph 
3.3.3).
Table 2: Timeframe of testing session
3 February 2014 4 February - 14 March 18 March 2014 14 April – 30 May 2 June 2014
2014 2014
First testing Group A - exercise Second testing Group A- control Third testing 
session programme + netball session group + netball session
training training
Group B – control Group B - exercise 
group + netball programme + netball 
training training
43
A short summary of the exercise programme followed during the study by participants is
illustrated in Table 3 below.  For a detailed description of the exercises, please refer to Appendix 6.
Table 3: Short summary of the exercise programme
Exercise Dosage in sessions Aim Source
WEEK 1
1.1 Recognition of neutral spine(centre of Core stability Akuthota et al., 
mass) in sitting and standing 2008
1.2 Co-activation of TrA& LM in crook 1: 10X10 sec. hold Core stability Aggarwal et al., 
supine lying position (base position) 2010
2: 12X12 sec. hold
3: 15X15 sec. hold
1.3 Co-activation of TrA& LM in prone 1: 10X10 sec. hold Core stability Aggarwal et al., 
lying position 2: 12X12 sec. hold 2010
3: 15X15 sec. hold
1.4 Co-activation of TrA& LM in 1: 10X10 sec. hold Core stability Aggarwal et al., 
quadruped position (recognition of centre 2: 12X12 sec. hold 2010
of mass)
3: 15X15 sec. hold
44
1.5 Co-activation of TrA& LM while 1: 10X10 sec. hold Core stability, Aggarwal et 
standing on single limb (recognition of 2: 12X12 sec. hold m.GMed & al., 2010
centre of mass) balance
3: 15X15 sec. hold
1.6 Clamshell 1 1: 3 sets X 10 rep. Core stability & Distefano et al., 
m. GMed 2009; Boren et 
2: 3 sets X 12 rep.
al., 2011
3: 3 sets X 15 rep.
1.7 Pelvic drop 1: 3 sets X 10 rep. Core stability, Bolga et al., 2005; 
2: 3 sets X 12 rep. m.GMed & Boren et al., 2011
balance
3: 3 sets X 15 rep.
WEEK 2
2.1 Supine bent knee-raises 1: 3 sets X 10 rep. Core stability Fredericson and 
2: 3 sets X 12 rep. Moore, 2005; 
Aggarwal et al., 
3: 3 sets X 15 rep.
2010
2.2 Quadruped with alternate arm/leg 1: 3 sets X 10 rep. Core stability & Federicson et al., 
raises (Superman exercise) 2: 3 sets X 12 rep. m.GMed 2005;
3: 3 sets X 15 rep. Aggarwal et al., 
2010
45
2.3 Abdominal crunches 1: 3 sets X 10 rep. Core stability Kahle and 
2: 3 sets X 12 rep. Gribble, 2009
3: 3 sets X 15 rep.
2.4 Bridging 1: 3 sets X 10 rep. Core stability & Fredericson et al., 
m.GMed 2005
2: 3 sets X 12 rep.
3: 3 sets X 15 rep.
2.5 Single limb dead lift 1: 3 sets X 10 rep. m.GMed, core Distefano
2: 3 sets X 12 rep. stability & et al., 2009; 
balance Boren et al., 2011
3: 3 sets X 15 rep.
2.6 Co-activation of TrA & LM while 1: 10X10 sec. hold Core stability, Aggarwal et al., 
standing on single limb with eyes closed 2: 12X12 sec. hold m.GMed & 2010 & Leavey et 
balance al., 2010
3: 15X15 sec. hold
WEEK 3
3.1 Seated marching on physio ball 1: 3 sets X 10 rep. Core stability Fredericson
2: 3 sets X 12 rep. et al., 2005
3: 3 sets X 15 rep.
3.2 Abdominal crunches on a physio ball 1: 3 sets X 10 rep. Fredericson
2: 3 sets X 12 rep. et al., 2005; 
Kahle and 
3: 3 sets X 15 rep.
Gribble, 2009
46
3.3 Superman exercise on a physio ball 1: 3 sets X 10 rep. Core stability & Fredericson
2: 3 sets X 12 rep. m.GMed et al., 2005
3: 3 sets X 15 rep.
3.4 Bridging with alternate leg lifts 1: 3 sets X 10 rep. Core stability & Fredericson
m.GMed et al., 2005; 
2: 3 sets X 12 rep.
Kahle and 
3: 3 sets X 15 rep.
Gribble, 2009
3.5 Lateral step up 1: 3 sets X 10 rep. m.GMed, core Ayotte et al., 
stability & balance 2007; 
2: 3 sets X 12 rep.
Ekstrom et 
3: 3 sets X 15 rep.
al., 2007; 
Boren et al., 
2011
3.6 Tilt board exercises: 1: Double leg with   Balance, Core stability Fredericson 
1) Balance in plantarflexion/ eyes open & m.GMed et al., 2005
dorsiflexion 3 sets X 30 sec of 
each of the 3 planes 
of motion. 30 sec 
rest in between
2: Double leg with 
eyes closed
2) Balance in inversion / eversion
3 sets X 30 sec of 
each of the 3 planes 
of motion. 30 sec 
rest in between
3: Single leg with 
eyes open
3) Balance in diagonal
3 sets X 30 sec of 
each of the 3 planes 
of motion. 30 sec 
rest in between
47
WEEK 4
4.1 Trunk rotation with 2kg medicine ball 1: 3 sets X 10 rep. Core stability & Kahle and 
while seated on physio ball m.GMed Gribble, 2009
2: 3 sets X 12 rep.
3: 3 sets X 15 rep.
4.2 Alternate leg bridge with shoulders on 1: 3 sets X 10 rep. Core stability & Fredericson et al., 
physio ball m.GMed 2005; Kahle and 
2: 3 sets X 12 rep.
Gribble, 2009
3: 3 sets X 15 rep.
4.3 Diagonal curls on physio ball 1: 3 sets X 10 rep. Core stability & Aggarwal et 
2: 3 sets X 12 rep. m.GMed al.,2010
3: 3 sets X 15 rep.
4.4 Front plank with alternate hip 1: 3 sets X 10 rep. Core stability & Fredericson et al., 
extension 2: 3 sets X 12 rep. m.GMed 2005; Boren et 
al., 2011
3: 3 sets X 15 rep.
4.5 Wobbleboard - Unilateral balance 1: 3X20 sec. hold, 40 Balance & Core Leavey et al., 
sec rest in between stability 2010
2: 3X25 sec. hold, 35 
sec rest in between
3: 3X30 sec hold, 30 
sec rest in between
48
WEEK 5
5.1 Standing 2kg medicine ball  or pulley 1: 3 sets X 10 rep. Core stability Fredericson et al., 
rotation 2005
2: 3 sets X 12 rep.
3: 3 sets X 15 rep.
5.2 Lower trunk rotation with shins on 1: 3 sets X 10 rep. Core stability & Kahle and 
physio ball 2: 3 sets X 12 rep. m.GMed Gribble, 2009
3: 3 sets X 15 rep.
5.3 Side plank with upper leg hip 1: 3 sets X 10 rep. Core stability & Fredericson et al., 
abduction 2: 3 sets X 12 rep. m.GMed 2005; Ekstrom et 
al., 2007; Boren 
3: 3 sets X 15 rep.
et al., 2011
5.4 Front plank on physio ball 1: 3 sets X 20 sec. Core stability & Fredericson et 
2: 3 sets X 30 sec. m.GMed al.,2005
3: 3 sets X 40 sec.
49
5.5 Functional hop exercises: 1: 1 set X 10 rep. of Balance & Leavey et al.,
1) Unilateral diagonal forward each of the 5 m.GMed 2010
exercises
2: 1 set X 12 rep. of 
each of the 5 
exercises
3: 1 set X 15 rep. of 
2) Unilateral diagonal backward
each of the 5 
exercises
3) Unilateral forward/backward 
same side 45˚
4) Unilateral forward/backward 
opposite side 45˚
5) Unilateral rotation 45˚
50
WEEK 6
6.1 Forward lunge with a 2kg medicine 1: 3 sets X 10 rep. Core stability & Fredericson et al., 
ball or weight with trunk rotation m.GMed 2005
2: 3 sets X 12 rep.
3: 3 sets X 15 rep.
6.2 Upper extremity-trunk supine 1: 3 sets X 10 rep. Core stability & Smith et al., 2008
overhead throw simulation using a physio m.GMed
2: 3 sets X 12 rep. (Consent 
ball and a netball 
3: 3 sets X 15 rep. obtained for use 
of photo –
Appendix 8)
6.3 Upper extremity-trunk seated 1: 3 sets X 10 rep. Core stability & Smith et al., 2008
overhead throw simulation using a physio m.GMed
2: 3 sets X 12 rep. (Consent 
ball and a netball
3: 3 sets X 15 rep. obtained for use
of photo –
Appendix 8)
6.4 Upper extremity-trunk-lower 1: 3 sets X 10 rep. Core stability, Smith et al., 2008
extremity standing passing simulation 2: 3 sets X 12 rep. m.GMed & (Consent 
using a physio ball and a netball (Smith et balance obtained for use 
3: 3 sets X 15 rep.
al., 2008) of photo –
Appendix 8)
51
6.5  Single-limb 90ᴼAirex hop and hold 1: 3 sets X 10 rep. Balance, Core Filipa et al., 2010
2: 3 sets X 12 rep. stability & 08
m.GMed
3: 3 sets X 15 rep. (Consent 
obtained for use 
of photo –
Appendix 8)
Acronyms: rep: - repetitions; sec: - seconds; TrA: - transversus abdominis; LM: - lumbar multifidus; 
GMed: - gluteus medius.
3.11 Contamination
Participants in the control group could have learnt about the exercise programme and adopted it 
for themselves.  The participants taking part in the exercise programme were requested to keep 
the training programme confidential. Both groups were requested not to take part in any other 
exercise programme except pre-season netball training while involved in the study, therefore 
minimizing contamination.
3.12 Ethical aspects
The protocol was submitted to the Ethics committee of the Faculty of Health Sciences, UFS and the 
study was approved on the 29th of November 2013 (Approval number: 189/2013) after informed 
consent was obtained from the Vice-rector: Academics; the Dean of Student Affairs and the 
Assistant-Director of Kovsie Sport (see Appendix 1 and 7 for approval letters).
The researcher held an information session and each participant received an information letter 
informing them regarding the aim of the research study as well as requirements (see Appendix 2 
for information letter). The netball players could have felt obligated to participate in the study as 
they were in the top junior netball group and the perception could have been created that non-
participation might lead to discrimination during the team selection.  Players were specifically 
informed during the information session that non-participation would not have an influence on 
team selection.  
Informed consent was obtained from the participants once they read the information letter in 
their language of choice, Afrikaans or English (see Appendix 3 for consent form).  The consent 
52
letter indicated that, should a player not wish to participate in the study, they were not required to 
complete the injury profile questionnaire. 
Participants were guaranteed that all information collected during the study will be handled 
confidentially. The confidentiality of information was established by giving each participant 
(netball player) a unique, arbitrary code, which was documented on a master list.  Only the 
researcher had access to the master list.  Any written documents were labelled using the unique 
number to keep the nature of the participants’ information strictly confidential (Leedy and 
Ormrod, 2010).  All documents were locked in a secure cabinet, to which only the researcher had 
access and all information on the computer was password protected.
Participants’ class schedules were taken into consideration and the training sessions did not 
interfere with class commitments. Participation in this study was voluntary and if at any time 
during the study the participant wished to withdraw, she was free to do so without any penalty or 
consequence.  Participants received no remuneration for participation in this study and neither 
were there any costs involved by participants.
Although the study had a degree of risk involved due to the possibility that exercises might cause 
injury, the risk was no bigger than participating in a netball practice and great care was taken by 
the researcher to avoid injury.  If the participant was injured as a result of partaking in the 
assessment or exercise programme of the research study, the researcher would have offered the
injured participant physiotherapy treatment free of charge.  No participant was injured as a result 
of partaking in the assessment or exercise programme.
The meticulous way in which the methodology was followed during the conducting of the study 
ensured that statistically significant results were obtained.  In chapter four the results of the study 
will be illustrated with the use of tables and diagrams.
3.13 Data analysis
The Department of Biostatistics, Faculty of Health Science at the UFS performed the statistical 
analysis. The average of the three trials of each of the four reach directions of each participant for 
each of the three testing sessions were calculated to be used in the further analyses.  In addition to 
this, improvement scores for the four average scores (for the four directions) were computed by 
subtracting the score for the first session from the second session, the second session from the 
third session, and the first session from the third session (the latter providing an overall 
53
improvement score). This allowed the improvement for the time frame during which the 
intervention was applied to be assessed directly.  SEBT scores (being continuous) were presented 
as ranges with means and medians. The change in SEBT scores for all participants between each 
successive round of testing were computed by means of (parametric) paired t-tests for the 
intervention/non-intervention groups separately. Differences between the SEBT scores and the 
SEBT improvements for the two groups at each session were computed by means of (parametric) 
student’s t-tests.  A p-value of p <0.05 was interpreted as statistically significant.
54
Chapter 4 Results
In this chapter the information obtained from the statistical analyses was divided into attendance of the 
participants, the participants’ supporting leg used during the SEBT, the measurements during the first 
testing session, the improvement from the first to the second testing session, the improvement from the 
second to the third testing session as well as the improvement from the first to the third testing session.
The results of the study are illustrated with the use of tables and diagrams.
4.2 Attendance
Nineteen participants were recruited for the study, but three participants were excluded due to 
non-compliance. The criteria for compliance were that participants attend at least 14 of the 18 
training sessions (approximately 77% attendance) and had to return for post testing (paragraph 
3.3). Both group A and B consisted of eight participants.
The attendance of Group A and B are illustrated in graph 1.
4
3
2 Group A
1 Group B
0
14 15 16 17
Training sessions attended
Graph 1: Group attendance (n=16)
Group A had an average attendance of 16 training sessions and group B 15. The student’s t-test 
was p=0.2453 which indicated that there was no significant statistical differences between 
attendance of the two groups (Table 4) (Graph 1).
55
Participants
Table 4: Group attendance (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 14 17 15.5000 1.0690
B 8 14 16 14.8750 0.9910
Diff (A-B) 0 1 0.6250 1.0308 14 1.21 0.2453
Pooled
4.3 Participants’ supporting leg during SEBT
During assessment using the SEBT the netball players’ landing leg was used as the supporting leg.  
Ten participants had a right leg starting stance while six participants had a left leg starting stance. 
Left leg
38%
Right leg
62%
Graph 2: Participants' supporting leg during SEBT (n=16)
4.4 First testing session
The difference in the measurements of the four reach direction distances during the first testing 
session of the SEBT between group A and B were computed by means of the student’s t-test. The 
reason for this calculation was to determine the starting point (baseline) between the two groups.
56
Table 5: Baseline SEBT anterior measurements between groups (n=16)
Group N Minimum Maximum Mean Std Dev DF t Pr > |t|
Value
A 8 63.7333 90.3333 77.5417 8.5683
B 8 69.4000 92.2333 76.1125 7.5982
Diff (A-B) -5.6667 -1.9000 1.4292 8.0978 14 0.35 0.7294
Pooled
The average distance measured during the anterior reach direction for group A was 77.5 cm and 
for Group B 76.1 cm with a difference of 1.4 cm between the groups.  The p-value was p=0.7294
(Table 5).
Table 6: Baseline SEBT medial measurements between groups (n=16)
Group N Minimum Maximum Mean Std Dev DF t Pr > |t|
Value
A 8 58.0667 86.9333 77.9500 9.2489
B 8 66.1333 86.6667 80.7042 6.7596
Diff (A-B) -8.0666 0.2666 -2.7542 8.1004 14 -0.68 0.5076
Pooled
The average distance measured during the medial reach direction for group A was 78 cm and for 
Group B 80.7 cm with a difference of 2.8 cm between the groups.  The p-value was p=0.5076
(Table 6).
Table 7: Baseline SEBT posterior measurements between groups (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr >|t|
A 8 56.20 00 88.9000 78.3000 10.5118
B 8 65.7000 93.3333 81.8417 8.8813
Diff (A-B) -9.5000 -4.4333 -3.5417 9.7308 14 -0.73 0.4787
Pooled
57
The average distance measured during the posterior reach direction for group A was 78.3 cm and 
for Group B 81.8 cm with a difference of 3.5 cm between the groups.  The p-value was p=0.4787
(Table 7).
Table 8: Baseline SEBT lateral measurements between groups (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 45.8000 66.7667 56.2250 6.0922
B 8 37.6000 71.7000 58.6833 10.4962
Diff (A-B) -2.4583 8.5815 14 -0.57 0.5758
Pooled
The average distance measured during the lateral reach direction for group A was 56.2 cm and for 
Group B 58.7 cm with a difference of 2.5 cm between the groups.  The p-value was p=0.5758. The 
difference between the anterior, medial, posterior and lateral reach direction distances between 
group A and B during the first testing session were found statistically insignificant (Table 8).
The average measurements of the reach directions of participants during the first testing session 
are illustrated in graph 3.
Graph 3: Average measurements of reach direction during first testing session (n=16)
58
4.5 Improvement from first to second testing session
During the first six weeks group A participated in the exercise programme while group B was
considered as the control group. The improvement in reach distances from the first testing session
to the second testing session within each group was computed by means of the paired t-test.  The 
difference in improvement in reach distances from the first testing session to the second testing 
session between group A and B was computed by means of the student’s t-test. 
Table 9: SEBT anterior measurements within and between groups comparing the 1st and 2nd
testing sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 0.6333 20.0333 12.4125 6.2163 7 5.65 0.0008
B 8 0.1000 8.2000 3.7500 2.6037 7 4.07 0.0047
Diff (A-B) 0.5333 11.8333 8.6625 4.7655 14 3.64 0.0027
Pooled
During the anterior reach direction the average distance of improvement for group A was 12.4 cm 
and for Group B 3.8 cm with a difference of 8.7 cm between the groups.  The paired t-test was 
p=0.0008 for group A and p=0.0047 for group B.  The improvement within both groups was 
statistically significant.  The student’s t-test on difference in improvement between the groups was 
p=0.0027 and therefore also statistically significant (Table 9).
Table 10: SEBT medial measurements within and between groups comparing the 1st and 2nd
testing sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 25.6000 14.6958 6.3924 7 6.5 0.0003
B 8 7.4000 3.0833 2.6971 7 3.23 0.0144
Diff (A-B) 8.0667 18.2 11.6125 4.9060 14 4.73 0.0003
Pooled
59
During the medial reach direction the average distance of improvement for group A was 14.7 cm 
and for Group B 3.1 cm with a difference of 11.6 cm between the groups.  The paired t-test was 
p=0.0003 for group A and p=0.0144 for group B.  The improvement within both groups was
statistically significant.  The student’s t-test on difference in improvement between the groups was 
p=0.0003 and therefore also statistically significant (Table 10).
Table 11: SEBT posterior measurements within and between groups comparing the 1st and 2nd
testing sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 9.6000 37.9667 21.0833 8.9455 7 6.67 0.0003
B 8 -0.8000 7.3000 3.5000 2.7524 7 3.6 0.0088
Diff (A-B) 10.4000 30.6667 17.5833 6.6181 14 5.31 0.0001
Pooled
During the posterior reach direction the average distance of improvement for group A was 21.1 cm 
and for Group B 3.5 cm with a difference of 17.6 cm between the groups.  The paired t-test was 
p=0.0003 for group A and p=0.0088 for group B.  The improvement within both groups was 
statistically significant.  The student’s t-test on difference in improvement between the groups was 
p=0.0001 and therefore also statistically significant (Table 11).
Table 12: SEBT lateral measurements within and between groups comparing the 1st and 2nd
testing sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 4.5667 18.1000 8.8292 4.8827 7 5.11 0.0014
B 8 -4.1333 25.1000 4.1042 9.2256 7 1.26 0.2486
Diff (A-B) 4.7250 3.6904 14 1.28 0.2212
Pooled
60
During the lateral reach direction the average distance of improvement for group A was 8.8 cm 
and for Group B 4.1cm with a difference of 4.7 cm between the groups.  The paired t-test was 
p=0.0014 for group A and p=0.2486 for group B.  The improvement within group A was statistically 
significant, but the improvement within group B was statistically insignificant.  The student’s t-test 
on difference in improvement between the groups was p=0.2212 and was statistically insignificant 
(Table 12).
Although statistically significant improvement was calculated in the average distance in the 
anterior, medial and posterior reach directions within group A and B;  the average distance of 
improvement in the anterior, medial and posterior reach directions of group A from the first 
testing session to the second testing session were found statistically significant when compared to 
group B.  Contrary, although statistically significant improvement was calculated in the average 
distance in the lateral reach distance within group A; the average distance of improvement in the 
lateral reach direction of group A from the first testing session to the second testing session were 
found statistically insignificant when compared to group B.
A summary of the average improvement in reach directions from the first to the second testing 
session is illustrated in graph 4.
25.0
21.1
20.0
14.7
15.0
12.4
Group A
10.0 8.8
Group B
5.0 3.8 3.1 3.5
4.1
0.0
Anterior Medial Posterior Lateral
Reach directions
Graph 4: Average improvement from first to second testing session (n=16)
61
Distance (cm)
4.6 Improvement from second to third testing session
For the following six weeks (week seven to week 12) group B participated in the exercise 
programme while group A was considered as the control group. The improvement in reach 
distances from the second testing session to the third testing session within each group was
computed by means of the paired t-test. The difference in improvement in reach distances from 
the second testing session to the third testing session between group A and B was computed by 
means of the student’s t-test. 
Table 13: SEBT anterior measurements within and between groups comparing the2nd and 3rd
testing sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 -4.000 5.5333 0.2875 2.9003 7 0.28 0.7873
B 8 5.1000 24.0333 10.6792 5.8332 7 5.18 0.0013
Diff (A-B) -9.1000 -18.5000 -10.3917 4.6064 14 -4.51 0.0005
Pooled
During the anterior reach direction the average distance of improvement for group A was 0.3 cm 
and for Group B 10.7 cm with a difference of 10.4 cm between the groups.  The paired t-test was 
p=0.7873 for group A and p=0.0013 for group B.  The improvement within group B was statistically 
significant, but the improvement within group A was statistically insignificant.  The student’s t-test 
on difference in improvement between the groups was p=0.0005 and therefore statistically 
significant (Table 13).
Table 14: SEBT medial measurements within and between groups comparing the2nd and 3rd
testing sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 -1.6667 5.6333 1.1625 2.3938 7 1.37 0.2119
B 8 5.3667 22.9333 13.1750 6.1383 7 6.07 0.0005
Diff (A-B) -12.0125 4.6588 14 -5.16 0.0001
Pooled
62
During the medial reach direction the average distance of improvement for group A was 1.2 cm 
and for Group B 13.2 cm with a difference of 12 cm between the groups.  The paired t-test was 
p=0.2119 for group A and p=0.0005 for group B.  The improvement within group B was statistically 
significant, but the improvement within group A was statistically insignificant.  The student’s t-test 
on difference in improvement between the groups was p=0.0001 and therefore statistically 
significant (Table 14).
Table 15: SEBT posterior measurements within and between groups comparing the2nd and 3rd
testing sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 -3.2000 8.8000 1.2083 4.2725 7 0.80 0.4500
B 8 8.6000 18.0667 13.8667 3.0654 7 12.79 <.0001
Diff (A-B) -11.8000 -9.2667 -12.6583 3.7182 14 -6.81 <.0001
Pooled
During the posterior reach direction the average distance of improvement for group A was 1.2 cm 
and for Group B 13.9 cm with a difference of 12.7 cm between the groups.  The paired t-test was 
p=0.4500 for group A and p<.0001 for group B.  The improvement within group B was statistically 
significant, but the improvement within group A was statistically insignificant.  The student’s t-test 
on difference in improvement between the groups was p<.0001 and therefore statistically 
significant (Table 15).
Table 16: SEBT lateral measurements within and between groups comparing the2nd and 3rd
testing sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 -11.3667 10.4667 -2.1667 6.6967 7 -0.92 0.3906
B 8 -6.8333 30.6667 7.1708 10.8458 7 1.87 0.1037
Diff (A-B) -4.5334 -20.2 -9.3375 9.0132 14 -2.07 0.0572
Pooled
63
During the lateral reach direction group A decreased with an average distance of 2.2 cm while 
Group B improved with an average distance of 7.2 cm with a difference of 9.3 cm between the 
groups.  The paired t-test was p=0.3906 for group A and p=0.1037 for group B.  The improvement 
within both groups was statistically insignificant.  The student’s t-test on difference in 
improvement between the groups was p=0.0572 and therefore statistically insignificant (Table 16).
Statistically significant improvement was calculated in the average distance in the anterior, medial 
and posterior reach directions within group B, but insignificant improvement within group A.  The 
average distance of improvement in the anterior, medial and posterior reach directions of group B 
from the second testing session to the third testing session were found statistically significant 
when compared to group A.  Contrary, statistically insignificant improvement was calculated in the 
average distance in the lateral reach distances within group A and B; and the average distance of 
improvement in the lateral reach direction of group B from the second testing session to the third 
testing session were found statistically insignificant when compared to group A. 
A summary of the average improvement in reach directions from the second to the third testing 
session is illustrated in graph 5.
16.0
13.9
14.0 13.2
12.0 10.7
10.0
8.0 7.2
6.0 Group A
4.0 Group B
2.0 1.2 1.2
0.3
0.0
Anterior Medial Posterior Lateral
-2.0
-2.2
-4.0
Reach directions
Graph 5: Average improvement from second to third testing session (n=16)
64
Distance (cm)
4.7 Improvement from first to third testing session
At the third testing session both group A and B have participated in the exercise programme. The
improvement in reach distances from the first testing session to the third testing session within
each group was computed by means of the paired t-test. The difference in improvement in reach 
distances from the first testing session to the third testing session between group A and B was
computed by means of the student’s t-test. The global improvement of both groups includes the 
improvement or deterioration (lateral reach direction for group A) during the six weeks in which 
the group was the control.
Table 17: SEBT anterior measurements between groups comparing the 1st and 3rd testing 
sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 0.4000 21.3333 12.7000 6.8660 7 5.23 0.0012
B 8 5.2000 26.2333 14.4292 5.9522 7 6.86 0.0002
Diff (A-B) -4.8000 -4.9000 -1.7292 6.4253 14 -0.54 0.5989
Pooled
During the anterior reach direction the average distance of improvement for group A was 12.7 cm 
and for Group B 14.4 cm.  Group B had an average improvement of 1.7 cm more than group A.  
The paired t-test was p=0.0012 for group A and p=0.0002 for group B.  The improvement within 
both groups was statistically significant.  The student’s t-test was p=0.5989 and therefore 
statistically insignificant (Table 17).
Table 18: SEBT medial measurements between groups comparing the 1st and 3rd testing sessions 
(n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 7.3667 28.6667 15.8583 7.6247 7 5.88 0.0006
B 8 4.1667 26.0333 16.2583 7.4453 7 6.18 0.0005
Diff (A-B) 3.2000 2.6337 -0.4000 7.5355 14 -0.11 0.9170
Pooled
65
During the medial reach direction the average distance of improvement for group A was 15.9 cm 
and for Group B 16.3 cm.  Group B had an average improvement of 0.4 cm more than group A.  
The paired t-test was p=0.0006 for group A and p=0.0005 for group B.  The improvement within 
both groups was statistically significant.  The student’s t-test was p=0.9170 and therefore 
statistically insignificant (Table 18).
Table 19: SEBT posterior measurements between groups comparing the 1st and 3rd testing 
sessions (n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 10.1000 40.2667 22.2917 11.4265 7 5.52 0.0009
B 8 12.9667 24.5667 17.3667 4.2522 7 11.55 <.0001
Diff (A-B) -2.8667 15.7000 4.9250 8.6211 14 1.14 0.2724
Pooled
During the posterior reach direction the average distance of improvement for group A was 22.3 cm 
and for Group B 17.4 cm.  Group A had an average improvement of 4.9 cm more than group B.  
The paired t-test was p=0.0009 for group A and p<0.0001 for group B.  The improvement within 
both groups was statistically significant.  The student’s t-test was p=0.2724 and therefore 
statistically insignificant (Table 19).
Table 20: SEBT lateral measurements between groups comparing the 1st and 3rd testing sessions 
(n=16)
Group N Minimum Maximum Mean Std Dev DF t Value Pr > |t|
A 8 -2.3333 17.8000 6.6625 6.3129 7 2.99 0.0204
B 8 3.4000 26.6333 11.2750 7.6590 7 4.16 0.0042
Diff (A-B) -5.7333 -8.8333 -4.6125 7.0183 14 -1.31 0.2098
Pooled
66
During the lateral reach direction the average distance of improvement for group A was 6.7 cm 
and for Group B 11.3 cm.  Group B had an average improvement of 4.6 cm more than group A.  
The paired t-test was p=0.0204 for group A and p=0.0042 for group B.  The improvement within 
both groups was statistically significant.  The student’s t-test was p=0.2098 and therefore 
statistically insignificant (Table 20).
Statistically significant improvement was calculated in the average distance in the anterior, medial, 
posterior and lateral reach directions within both groups.  When comparing the two groups, the 
average distance of improvement in the anterior, medial, posterior and lateral reach directions 
were found statistically insignificant.
A summary of the average improvement in reach directions from the first to the third testing 
session is illustrated in graph 6
25.0
22.3
20.0
17.4
15.9 16.3
15.0 14.4
12.7
11.3
Group A
10.0
Group B
6.7
5.0
0.0
Anterior Medial Posterior Lateral
Reach directions
Graph 6: Average improvement from first to third testing session (n=16)
Interestingly enough, statistically significant improvement was found in three reach directions 
(anterior, medial and posterior) within group B during the period of being considered the control 
group while group A participated in the exercise programme.  This was not the case for group A.  
Although improvement was found in three reach directions (anterior, medial and posterior) within 
group A during the period of being considered the control group, the improvement was 
statistically insignificant.
67
Distance (cm)
Statistically insignificant improvement was found in the lateral reach direction within group A and 
B during the period of being considered the control group as well as within group B after having 
participated in the exercise programme, but statistically significant improvement was found
globally within both groups.
A summary of the t-tests on improvement in all four reach directions within and between groups 
are illustrated in Table 21 below.
68
Table 21: Summary of t-tests on improvement within and between groups (n=16)
Group A Group B Diff (A-B) Pooled 
(paired t-test) (paired t-test) (Student’s t-test)
First to second testing Pr > |t| Pr > |t| Pr > |t|
session
Anterior 0.0008 0.0047 0.0027
Medial 0.0003 0.0144 0.0003
Posterior 0.0003 0.0088 0.0001
Lateral 0.0014 0.2486 0.2212
Second to third Pr > |t| Pr > |t| Pr > |t|
testing session
Anterior 0.7873 0.0013 0.0005
Medial 0.2119 0.0005 0.0001
Posterior 0.4500 <.0001 <.0001
Lateral 0.3906 0.1037 0.0572
First to third testing Pr > |t| Pr > |t| Pr > |t|
session
Anterior 0.0012 0.0002 0.5989
Medial 0.0006 0.0005 0.9170
Posterior 0.0009 <.0001 0.2724
Lateral 0.0204 0.0042 0.2098
69
The average improvement in all four reach directions from the first to the second to the third 
testing session is illustrated in graph 7.
Graph 7: Improvement from first to second to third testing session (n=16)
The data reflects statistically significant improvement (p<0.05) in the average distance in the 
anterior, medial and posterior reach directions within group A and B after having participated in 
the exercise programme. Although improvement was found in the average distance in the 
anterior, medial and posterior reach directions within group A and B during the period of being 
considered the control group, the improvement within group A was statistically insignificant.  
However, the average distance of improvement in the anterior, medial and posterior reach 
directions of both groups after having participated in the exercise programme, were found 
statistically significant (p<0.05) when compared to the group considered as the control group.
A discussion will follow in chapter five using reflective practice to link the findings of the statistical 
analyses with the available literature. Critical reasoning skills were implemented to discuss the 
findings and to reach a conclusion.
70
Chapter 5 Discussion, Conclusion and Recommendations
In this chapter a brief summary of the conducted research is given, followed by a comprehensive 
discussion of the data found. The chapter will be completed with the conclusion reached by the study as 
well as the value of the study.
5.1 Brief summary
A cross-over randomised clinical trial was performed.  The participants were randomly divided into 
two groups and for the first six weeks group A participated in the exercise programme while group 
B was considered as the control group after which the roles were reversed.  Although the 
participants did not partake in any other balance, core stability or m.GMed exercise programme
during this study, the participants were all first year female netball players selected in the top
junior group and partook in pre-season netball training while participating in the exercise 
programme as well as during the time period of being in the control group.  The pre-season netball 
training consisted of between four and eight hours of training per week.
The simple SEBT with three trials and four directions were used to measure dynamic postural 
control of the participants (paragraph 2.6 and 2.7). All the participants were tested during three 
separate testing sessions.  The first testing session took place prior to the commencement of the 
exercise programme of group A.  The second testing session took place between the completion of 
group A’s exercise programme and the start of group B’s exercise programme.  The third testing 
session took place after the completion of group B’s exercise programme (Table 22).
Table 22: Timeframe of testing sessions
3 February 2014 4 February - 14 March 18 March 2014 14 April – 30 May 2 June 2014
2014 2014
First testing Group A - exercise Second testing Group A- control Third testing 
session programme + netball session group + netball session
training training
Group B – control group Group B - exercise 
+ netball training programme + netball 
training
71
5.2 First testing session
The average of the four reach direction distances during the first testing session of the SEBT was 
used to compare the starting point between group A and B.  The difference between the four 
reach direction distances between group A and B during the first testing session were found 
statistically insignificant. Therefore group A and B started at an equal baseline which made 
comparison between the two groups statistically more reliable. All the participants measured the 
least distance in the lateral reach direction.  The same finding was made by Leavey et al. (2010)
and the researcher hypothesised that a shorter reach distance in the lateral direction could imply 
that it is more difficult to perform the lateral direction or that there is a lack of dynamic postural 
control from participants in the lateral direction.
5.3 Improvement from first to second testing session
After the first six weeks during which group A participated in the exercise programme and group B 
was considered as the control group, there was a statistically significant improvement in the 
average distance in the anterior, medial, posterior and lateral reach directions within group A as 
well as in the average distance in the anterior, medial and posterior reach directions within group 
B. However, the average distance of improvement in the anterior, medial and posterior reach 
directions of group A after having participated in the exercise programme were found statistically 
significant when compared to group B.
The seemingly spontaneous improvement in three reach directions within group B whilst being the 
control group could possibly be attributed to participation in usual netball training.  Netball 
training provides a learning component and could be translated to improved balance according to 
the principle of specificity (Petty, 2004).  Specificity relates to the specific adaptation of the muscle 
to the imposed demands and netball training mirrors dynamic balance as measured with the SEBT.
The lack of statistically significant improvement in the lateral reach direction within group B could 
be due to the fact that crossing one’s legs as measured with the lateral reach direction is not 
frequently used in netball training and therefore a learning component was not provided during 
normal netball training.
72
The improvement within group A could partially be contributed to participation in netball training, 
but the student’s t-test measuring the difference in improvement between group A and B 
indicated a strong statistical difference in three reach directions between the two groups.  The 
student’s t-test for the anterior reach direction was p=0.0027, for the medial reach direction 
P=0.0003 and for the posterior reach direction p=0.0001.  This strong statistical difference 
therefore indicated that the exercise programme made a significant contribution to the 
improvement within group A in the anterior, medial and posterior reach direction distances as 
measured with the SEBT.
5.4 Improvement from second to third testing session
After the following six weeks (week seven to week 12) during which group B participated in the 
exercise programme while group A was considered as the control group, there was a statistically 
significant improvement in the average distance in the anterior, medial and posterior reach 
directions within group B, but insignificant improvement within group A.  Statistically insignificant 
improvement was found in the lateral reach distance within group B and deterioration within 
group A.
Although improvement was found in three reach directions (anterior, medial and posterior) 
between week six and twelve within group A whilst considered as the control group, the 
improvement was statistically insignificant despite their netball training.  This lack of statistically 
significant improvement could be due to the principle of diminishing returns (Petty, 2004).  
According to this principle an exercise programme will result in greater improvement in people in 
poor physical condition than in those in a good physical condition.  Group A was already in a good 
physical condition at the second testing session due to the combination of netball training and 
participating in the exercise programme.  The participants were all first year students that for the 
first time participated in pre-season netball training.  Group B was in a weaker physical condition 
at the first testing session at the beginning of the year compared to group A at the second testing 
session.  Therefore less improvement was found within group A compared to group B during the 
period when each group was considered as the control group and when the groups were only 
participating in netball training.
73
After the six weeks during which group B participated in the exercise programme while group A 
was considered as the control group, the average distance of improvement in the anterior, medial 
and posterior reach directions of group B were found statistically significant when compared to 
group A.  The improvement within group B could partly be contributed to participation in netball 
training, but the student’s t-test measuring the difference in improvement between group B and 
group A again indicated a strong statistical difference in three reach directions.  The student’s t-
test for the anterior reach direction was p=0.0005, for the medial reach direction P=0.0001 and for 
the posterior reach direction p<0.0001.  This strong statistical difference indicates that the exercise 
programme also significantly contributed to the improvement within group B in the anterior, 
medial and posterior reach direction distances as measured with the SEBT.
The most improvement was found in the posterior reach direction distances and the least in the 
lateral reach direction distances.  These findings correlate with a previous study (Leavey et al., 
2010) where the same phenomena were noticed during assessment with the SEBT after a balance, 
m.GMed and combination programme.  Aggarwal et al. (2010) postulated that during the posterior 
reach direction, the leg extends backwards with trunk and hip flexion to maintain balance.  Core 
stability is required to stabilise the trunk against gravity.  Improved core stability provides more 
effective control of the spinal segments and co-contraction of the deep stabilizing muscles 
resulting in better lumbo-pelvic control so that the reaching leg can extend further backwards.  
Filipa et al. (2010) suggested that improvements in the SEBT are due to increased hip and knee 
flexion of the stance leg.  From the literature review it can be hypothesised that enhanced core 
stability, m.GMed strength and proprioception would result in better lumbo-pelvic control as well 
as control of the hip and knee, therefore improved posterior reach direction could be due to either 
one of the postulations or a combination of both
5.5 Lateral reach direction
The insignificant improvement in the lateral reach direction within group B and deterioration 
within group A at the third testing session could be attributed to one or more of the following 
reasons.  During the first six weeks of an exercise programme improved performance is due to 
motor learning, increased neural activation to the muscle and improved coordination. According 
to research (Petty, 2004) it is anticipated that at about 10 to 12 weeks of participation in an
exercise programme muscle hypertrophy takes place where the muscle increases in the cross-
sectional area. If taken into consideration that the control group participated in netball training
74
during the first six weeks, both groups were exposed to twelve weeks of training. During 
assessment of the lateral reach direction, the reaching leg has to cross the supporting leg and the 
movement is obstructed by the mm.adductor mass of the supporting leg.  If there was hypertrophy 
of mm.adductor, the movement could be obstructed earlier in range of movement and reduce the
lateral reach direction distance.  The same scenario could have occurred if participants gained 
weight which is a possibility, as they were all first year female students. To determine the 
influence of mm.adductor mass in measuring lateral reach direction distances, a suggestion would 
be to measure the circumference of the widest part of the supporting leg of participants in future 
studies and compare these measurements pre- and post-exercise programme.
Another possible explanation for insignificant improvement in the lateral reach direction could be 
attributed to the following: During the third testing session the data collector noticed that while 
reaching in the lateral direction some of the participants were indecisive as to whether they should
cross the reaching leg anteriorly or posteriorly to the supporting leg.  When the reaching leg 
crosses anteriorly to the supporting leg, the supporting leg’s hip rotates medially in relation to the 
pelvis.  The opposite occurs when the reaching leg crosses posteriorly to the supporting leg.  The
supporting leg’s hip then rotates laterally in relation to the pelvis. Normal range of motion of
lateral rotation of the hip joint is 45… and medial rotation is 35… (Quinn, 2010). When the reaching 
leg crosses posteriorly, there is also less of an obstruction of the m.adductor mass of the 
supporting leg.  The increased lateral rotation range of motion of the hip as well as the lesser
obstruction of the m.adductor mass when a participant’s reaching leg crosses posteriorly to the 
supporting leg, would lead to increased lateral reach direction distances when compared to the 
reaching leg crossing anteriorly to the supporting leg. A measurement error could have occurred 
during assessment of the SEBT lateral reach direction if the participants were not consistent
between the different testing sessions possibly affecting the results of the lateral reach direction in 
this study.  Other studies (Gribble, 2003; Demura and Yamada, 2010; Gribble et al., 2013)
investigating reliability found high inter-rater and intra-rater reliability in the lateral reach 
direction. The literature describing the SEBT test did not indicate whether the reaching leg of 
participants has to cross anteriorly or posteriorly to the supporting leg while reaching in the lateral 
reach direction.  To avoid measurement errors in future studies, a decision should be made 
regarding a standard test before the commencement of the study and communicated accurately
to the participants.
75
5.6 Comparison with previous studies on dynamic postural control
Results of previous studies (Kahle and Gribble, 2009; Aggarwal et al., 2010; Filipa et al., 2010;
Leavey et al, 2010; Sandrey and Mitzel, 2013) evaluating different exercise programmes on
dynamic postural control using the SEBT are summarized in Table 22 and 23 below.
Table 23: Summary of t-tests on improvement within groups of different studies
Group A Group B Sandrey and Leavey et Aggarwal et Aggarwal et Filipa et al., 
Mitzel, 2013 al, 2010 al., 2010 al., 2010 2010
Pr > |t| Pr > |t| Pr > |t| Pr > |t| Pr > |t| Pr > |t| Pr > |t|
Type of CoreS, CoreS, CoreS GMed / CoreS PB CoreS & GMed
exercise GMed & GMed & PB/ GMed 
s PB PB & PB
Ant 0.0008 0.0013 <.001 <.001 0.005 L leg: 0.193
R leg: 0.321
AM 0.008 <.001 0.24
Med 0.0003 0.0005 0.002 <.001 0.001 0.002
PM 0.280 0.004 L leg: 0.028
R leg: 0.226
Post 0.0003 <.0001 <.001 0.032 0.009
PL 0.032 0.017 L leg: 0.040
R leg: 0.008
Lat 0.0014 0.1037 <.001 0.01 0.05
AL 0.005 0.049
Acronyms: CoreS: - core stability GMed: - gluteus medius; PB: - proprioceptive balance; Ant: - anterior;
AM: - anteromedial; Med: - medial; PM: - posteromedial; Post: - posterior; PL: - posterolateral;
Lat: - lateral; AL: - anterolateral; L: - left; R: - right
76
Table 24: Summary of t-tests on improvement between groups of different studies
Group A after having Group B after having Kahle & Gribble, 2009
participated in CoreS, participated in CoreS, CoreS programme vs 
m.GMed and PB exercise m.GMed and PB exercise control group
programme vs Group B programme vs Group A
Diff (A-B) Pr > |t| Pr > |t| Pr > |t|
Anterior 0.0027 0.0005
AM 0.001
Medial 0.0003 0.0001 <0.001
PM 0.013
Posterior 0.0001 <0.0001
Lateral 0.2212 0.0572
Acronyms: CoreS: - core stability GMed: - gluteus medius; PB: - proprioceptive 
balance; Ant: - anterior; AM: - anteromedial; Med: - medial; PM: - posteromedial; 
Post: - posterior; Lat: - lateral
The studies mentioned in Tables 22 and 23 (Kahle and Gribble, 2009; Aggarwal et al., 2010; Filipa 
et al., 2010; Leavey et al, 2010; Sandrey and Mitzel, 2013) have all been performed on young, 
active people.  The participants in the studies were as follow: young, physically active university 
students (Kahle and Gribble, 2009), high school track and field athletes (Sandrey and Mitzel, 2013), 
healthy college students (Leavey et al., 2010), recreationally active university students (Aggarwal 
et al., 2010) and young female soccer players (Filipa et al., 2010).  Although men and women were 
included in most of the studies, Kahle and Gribble (2009) reported no significant influence of 
gender on their results.  Therefore the above-mentioned studies are all well-matched and 
comparable to the present study results.
The present study evaluated the effect of core stability, m.GMed strengthening and proprioceptive 
balance exercises on dynamic postural control.  When comparing this present study’s results to 
studies (Kahle and Gribble, 2009; Aggarwal et al., 2010; Sandrey and Mitzel, 2013) evaluating the 
effect of only core stability training on dynamic postural control, the following was noticed. Only 
77
one reach direction was compatible in all the studies, namely the medial reach direction. In the 
present study, the improvement in the medial reach direction was p=0.0003 within group A and 
p=0.0005 within group B.  In comparison the improvement in the medial reach direction was 
p=0.002 in Sandrey and Mitzel’s (2013) study and p=0.001 in Aggarwal et al.’s (2009) study. The 
student’s t-test on difference in improvement in medial reach direction between the groups in the 
present study was p=0.0003 after group A participated in the exercise programme and p=0.0001 
after group B participated in the exercise programme.  The difference in improvement in the 
medial reach direction between the core stability training group and a control group in Kahle and 
Gribble’s (2009) study was p<.001.
In the present study, the improvement in the anterior reach direction was p=0.0008 within group A 
and p=0.0013 within group B compared to the improvement within the core stability training 
group (Aggarwal et al., 2010) which was p<.001. The improvement in the posterior reach direction 
within group A was p=0.0003 within group A and p<.0001 within group B compared to the 
improvement within the core stability training group (Aggarwal et al., 2010) which was p=0.032.  
The improvement in the lateral reach direction was p=0.0014 within group A and p=0.1037 within 
group B compared to the improvement within the core stability training group (Aggarwal et al., 
2010) which was p=0.05.
Comparison of the improvement in the anterior, medial, posterior and lateral reach directions 
within group A and B of the present study to the core stability training group in other studies
(Aggarwal et al., 2010; Sandrey and Mitzel, 2013), indicated more improvement within group A 
and B of the present study than studies evaluating core stability (Aggarwal et al., 2010; Sandrey 
and Mitzel, 2013). The only exception is the improvement in the lateral reach direction where 
lesser improvement was found within group B when compared to the core stability training group 
of studies conducted by Aggarwal et al. ( 2010); Sandrey and Mitzel (2013) (see Table 22). These 
findings therefore indicate that an exercise programme that incorporates core stability, m.GMed 
strengthening and proprioceptive balance exercises leads to additional improvement in dynamic 
postural control when compared to an exercise programme consisting of only core stability 
training.
Leavey et al. (2010) compared the effects of a balance, m.GMed strengthening, and a combination 
programme consisting of balance and m.GMed strengthening on dynamic postural control.  
Comparison to the present study was difficult due to the fact that Leavey et al.’s study results were 
78
described as improvement of reach distance divided by leg length.  No p values for separate reach 
distances were calculated, but the difference between the pre-test and post-test reach distances 
of all three groups were significant at p 0˂.001.  Although insignificant differences were found 
between the groups as far as post-test reach improvement was concerned, the combination group 
demonstrated the most improvement.
The effect of balance training on dynamic postural control was assessed in a randomised 
controlled trial (Aggarwal et al., 2010). A comparison between improvements within group A and 
B in the present study and within the balance training group within Aggarwal et al.’s (2010) study 
the following was noticed.  The improvement in the anterior reach direction was p=0.0008 within 
group A and p=0.0013 within group B compared to the improvement within the balance training 
group (Aggarwal et al., 2010) which was p=0.005. The improvement in the medial reach direction 
was p=0.0003 within group A and p=0.0005 within group B compared to the improvement within 
the balance training group (Aggarwal et al., 2010) which was p=0.002.  The improvement in the 
posterior reach direction within group A was p=0.0003 within group A and p<.0001 within group B 
compared to the improvement within the balance training group (Aggarwal et al., 2010) which was 
p=0.009.  The improvement in the lateral reach direction was p=0.0014 within group A and 
p=0.1037 within group B compared to the improvement within the balance training group 
(Aggarwal et al., 2010) which was p=0.05. The findings indicated that more improvement was 
found in all four reach directions within group A and B in the present study which incorporated all 
three components of core stability, m.GMed strengthening and proprioceptive balance training in 
comparison to Aggarwal et al.’s (2010) study which incorporated only balance training (see Table 
22).
A combination programme consisting of lower extremity strengthening and core stability was 
implemented by Filipa et al., 2010 to determine the effect on dynamic postural control.  Only three 
reach directions were measured and significant statistical improvement was found within the 
posteromedial reach direction for the left leg and the anteromedial reach direction for both legs.
Improvement in the anterior reach direction was p=0.193 within the group for the left leg and 
p=0.321 for the right leg. In comparison, greater improvement in the anterior reach direction was
found within group A (p=0.0008) and group B (p=0.0013) in the present study (see Table 22).  The 
anteromedial and posteromedial reach directions were not measured in the netball players in the 
79
present study and therefore no comparison could be made in these reach directions between the 
two studies.
The added improvement in the present study could possibly be attributed to more than one 
component.  Components considered by researchers for the improvement of dynamic postural 
control are core stability, m.GMed strength and proprioceptive balance. Previous studies (Kahle 
and Gribble, 2009; Aggarwal et al., 2010; Filipa et al., 2010; Leavey et al, 2010; Sandrey and Mitzel, 
2013) utilized one or two of the components.  The combination of m.Gmed strength and balance
training resulted in greater improvement in dynamic postural control compared to only m.GMed 
strength or balance training (Leavey et al., 2010). The above mentioned findings when comparing
the combination of all three components in an exercise programme as utilized in the present study
to only one or two components in other studies (Kahle and Gribble, 2009; Aggarwal et al., 2010; 
Filipa et al., 2010; Leavey et al, 2010; Sandrey and Mitzel, 2013) also indicated that the 
combination of all three components resulted in additional benefits.
Another contribution to the better improvement in the present study could be the participation in 
the netball training. As mentioned previously, netball training provides a learning component and 
has the benefit of sport-specific exercises that forms an integral part of rehabilitation (Akuthota et 
al., 2008; Smith et al.; 2008 and Reiman, 2009).  Additionally, the participants were all motivated 
to follow the exercise programme as they were all first year students striving to play for the 
university’s first team. Training was done under the researcher’s supervision and the execution of 
the exercises was checked and corrected if deemed necessary.
5.7 Contribution of different components
No conclusion can be made in the present study regarding the contribution of each of the
components of the exercise programme to the improvement of dynamic postural control due to 
the fact that each component was not individually measured. The core stability exercises improve
both the muscle activation patterns as well as strength of the local and global core muscles. The 
anticipatory activation of TrA before perturbation increases the intra-abdominal pressure and 
tenses the thoracolumbar fascia creating a stable base of support for lower extremity movement.  
The internal and external obliques and rectus abdominis contracts in specific patterns depending 
on the lower extremity movement and add to the postural support as well as the transfer of force 
between the upper and lower extremities.  Therefore, core stability could lead to improved 
80
dynamic postural control (Akuthota et al., 2008; Kahle and Gribble, 2009; Aggarwal et al., 2010; 
Sandrey and Mitzel, 2013).
M.GMed. stabilises the hip to prevent the pelvis dropping on the unsupported side.  M.GMed 
strengthening improves lumbo-pelvic and lower extremity control and is important in dynamic 
postural control (French et al., 2010; Boren et al., 2011, Reiman et al., 2012).  Furthermore 
proprioceptive balance training improves the ability of the CNS and the neuromuscular system to 
integrate information from different peripheral receptors and orchestrate an appropriate motor 
response (Fatma et al., 2010; Kiers et al., 2012).
In a randomised controlled trial (Aggarwal et al., 2010) both the core stabilization training group 
and balance training group showed significant (p 0˂.05) improvement in dynamic balance 
compared to the control group. The group doing core stability training showed greater 
improvement in dynamic balance compared to the balance training group. Comparing the effects 
of a balance, m.GMed strengthening, and a combination programme consisting of balance and 
m.GMed strengthening on dynamic postural control (Leavey et al., 2010), the combination group 
demonstrated the most improvement in four of the reach distances, followed by the m.GMed 
strength group for three reach distances and the proprioception group with only one.  No studies 
could be found that compared the influence of core stability versus m.GMed strength on dynamic 
postural control. The researcher recommends that future studies includes measuring instruments 
such as EMG, dynamometer and force plates etc. to measure core stability, m.GMed strength and 
proprioceptive balance as individual components before and after the exercise programme to 
determine the level of improvement and contribution of each component.
5.8 Injury profile of netball players
An interesting observation made was that none of the participants in this study had any lower 
extremity injuries pre-season or during the netball season while playing matches. This observation 
was made as the researcher was still involved with the team, travelled with the team as the team
physiotherapist and therefore was familiar with the injury profile of the netball players. Studies 
conducted in South Africa (Ferreira and Spamer, 2010; Langeveld et al., 2012; Pillay and Frantz, 
2012) which evaluated the injury prevalence of netball players reported the most common injured 
structures were the ankle (34 to 39%) and knee (18 to 28,6%) and the most common mechanism 
of injury to the lower limb was landing (19 to 29%). Dynamic postural control is essential during
81
landing due to the fact that netball players immediately attempt to remain as still as possible or 
attempt to create movements such as reaching or throwing without compromising the base of 
support (Winter, Patla and Frank, 1990; Kahle and Gribble, 2009, Gribble, Hertel and Plisky, 2012), 
as required by the IFNA footwork rule.
Poor core stability and decreased muscular synergy of the trunk and hip stabilisers have been 
theorized to decrease performance and increase the incidence of injury secondary to a lack of 
control of the centre of mass and dynamic posture, especially in female athletes (Filipa et al., 2010; 
Langeveld et al., 2012).  Previously conducted research studies (Emery, Casidy, Klassen, Rosychuk 
and Rowe, 2005; Elphinston and Hardman, 2006; Kibler, Press and Sciascia, 2006; Langeveld et al., 
2012) suggested that improvement in core stability, neuromuscular control and proprioceptive 
exercise could limit sport injuries. A study by McGuine and Keene (2006) indicated that balance 
training reduced the rate of ankle sprains by 38% in high school basketball and soccer players.  The 
findings of McGuine and Keene (2006) were substantiated by Clark and Burden (2005) who also 
found that a four week wobble board programme reduced the risk of recurrent ankle sprains in 
functionally unstable ankles.  Both studies (Clark and Burden, 2005; McGuine and Keene, 2006) 
used only one component, namely balance, and this already reduced the risk of injuries.  
Therefore, although not specifically investigated, participation of the netball players in the exercise 
programme that incorporated core stability, m.GMed strengthening and balance training in the 
present study could have led to injury prevention due to improved dynamic postural control.
5.9 Limitations
There are mixed results in the literature regarding the influence of core stability on performance.  
The results of a research study by Saeterbakken, Roland and Seiler (2011) suggested that core 
stability training can significantly improve maximal throwing velocity in female handball players.
Contradictory, a previous study (Stanton, Reaburn and Humphries, 2004) found that six weeks of 
Swiss ball training had significant effects on core stability, but did not improve running 
performance in young adolescent male athletes.
Yet a third study by Aggarwal et al. (2010) found that although dynamic postural control as 
measured with the SEBT improved after core stability training and balance training, functional 
balance as measured with the multiple single leg hopping stabilization test did not improve.  The 
researchers (Aggarwal et al. 2010) suggested that core stability should be combined with some 
82
other neuromuscular training to investigate the effect on hopping performance. Netball players 
frequently jump horizontally and vertically. As this study combined core stability, m.GMed 
strengthening and proprioceptive balance, it would have been interesting to investigate the 
influence of the exercise programme on the netball players’ explosive power as measured with e.g. 
a standing vertical jump test.
The present study indicated that an exercise programme that incorporates core stability, m.GMed 
strengthening and proprioceptive balance exercises contributed to dynamic postural control in 
netball players, but future research is warranted to investigate if such an exercise programme
would contribute to improved performance and injury prevention in netball players.
5.10 Conclusion
The aim of the study was to determine whether an exercise programme that incorporates core 
stability, m.GMed strengthening and proprioceptive balance exercises three times a week over a 
period of six weeks would lead to a significant improvement (p 0˂.05) in dynamic postural control 
in a group of netball players.  The results of the study indicated that dynamic postural control as 
measured with the SEBT demonstrated a statistically significant improvement (p<0.05) across 
three reach directions (anterior, medial and posterior) in a group of netball players post 
participation in an exercise programme that incorporated core stability, m.GMed strengthening
and proprioceptive balance exercises three times a week over a period of six weeks. This study 
proposes that an exercise programme that incorporates core stability, m.GMed strengthening and 
proprioceptive balance exercises could be beneficial for improving dynamic postural control in a 
group of netball players.
5.11 Clinical recommendations
 Physiotherapists: The results of the study provided substantial evidence for the use of a 
combination of core stability, m.GMed strengthening and proprioceptive balance exercises in 
programmes rehabilitating netball players with poor dynamic postural control. Ankle and knee 
injuries are a risk in netball players as investigated in previous epidemiology studies of injuries in 
elite South African netball players (Ferreira and Spamer, 2010; Langeveld et al., 2012; Pillay and 
Frantz, 2012). Previously conducted research studies (Clark and Burden, 2005; McGuine and 
Keene, 2006) found that a proprioceptive balance programme alone, already reduced the risk of 
83
recurrent ankle sprains.  Even though the present study was conducted on healthy, active netball 
players, physiotherapists can use the results of the present study as motivation in considering 
including all three components (core stability, m.GMed strengthening and proprioceptive balance) 
in exercise programmes following lower extremity injuries in netball players.
 Netball players: Netball players can confidently use the developed exercise programme in the 
present study to eliminate shortcomings in their physical profile, with regards to dynamic postural 
control. 
 Further research: The present study provides a baseline for further research whether an exercise 
programme that incorporated core stability, m.GMed strengthening and proprioceptive balance 
exercises would contribute towards improved performance and injury prevention in netball 
players.  The effectiveness of the exercise programme described in the present study could be 
implemented and investigated in other sporting codes requiring dynamic postural control. A 
systematic review and meta-analysis can be done on the effectiveness of interventions on the 
improvement of the SEBT.
84
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Appendices
Appendix 1 Permission letters from authorities
Letter asking permission from Vice-rector: Academics
Dear Prof Hay
Re: Permission for research study in netball players at the UFS
Study title: The effect of a core stability, m. gluteus medius and proprioceptive exercise 
programme on dynamic postural control in netball players
I am a M.Sc. student in sport physiotherapy at the University of the Free State (UFS).  Part of the 
requirements of my degree is a research study. My field of interest is netball and I would like to 
perform a research study to determine the effect of an exercise programme on dynamic postural 
control in netball players. 
Dynamic postural control is the ability to perform a functional task with purposeful movements 
that translates the body’s centre of gravity without compromising a stable base of support 
(Winter, Patla and Frank, 1990; Kahle and Gribble, 2009). Research by Ferreira and Spamer (2010) 
measured poor dynamic postural control or balance in elite university netball players during pre-
season testing.  No literature could be found regarding studies investigating a programme that 
utilised the combination of core stability, m.GMed strengthening and proprioceptive balance 
exercises on dynamic postural control or studies investigating an exercise programme on dynamic 
postural control in netball players.  My aim is to investigate the effectiveness of such a programme
on dynamic postural control in netball players.
This research study is a baseline study and an exercise programme compiled from scientific 
literature will be followed. It will incorporate m.GMed (hip) strength, core stability and 
proprioceptive balance exercises. Participation in this study will take approximately 60 minutes 
three days a week for a period of six weeks. A Star Excursion Balance Test will be executed the 
week before, the week after the exercise programme as well as six weeks before the 
commencement or alternatively after the completion of the exercise programme to evaluate the 
dynamic postural control of the participants.
91
My hypothesis is that a core stability, m.GMed and proprioceptive balance exercise programme
might lead to an improvement in dynamic postural control. It might benefit the players’ balance
abilities if the exercise programme leads to an improved outcome.  More potential benefits are 
improvement in their m.GMed (hip) strength and core stability. Improved dynamic postural 
control might also lead to improve performance and help prevent injuries in the netball players.  
The exercise programme will be made available to the UFS netball academy and the participants 
after the completion of the study.  Participants will be female netball players selected into the top 
junior netball group of the UFS.
Participation in this study is voluntary and if at any time during the study the netball player wishes 
to withdraw, she will be free to do so without any consequence.  The netball player will only be 
included if she reports no history of lower extremity injuries in the past 6 months (any injury 
requiring not taking part in physical activity for longer than two days) or lower extremity surgery in 
the past year.
The training programme will take place during February to May 2014.  They will train under the 
researchers’ supervision at the university’s sport centre.  The participants’ class schedule will be 
taken into consideration and the training sessions will not interfere with class commitments.
Although this study has a degree of risk due to the possibility that any exercise may cause injury, 
the risk is no bigger than participating in a netball practice and great care will be taken to avoid 
injury.  If the participant is injured as a result of partaking in the assessment or exercise 
programme of the research study, the researcher will offer the injured participant physiotherapy 
treatment free of charge.
The information of the participants and the results of their individual tests will be strictly 
confidential. Each participant (netball player) will receive a unique, arbitrary code and any written 
documents will be labelled with that number to keep the nature and quality of the participants’ 
information strictly confidential.  Each participant will have access to their own test results.  The 
group result of the study will be communicated to the UFS netball academy after the completion 
of the study and may be published in an accredited journal and presented at a meeting or a 
congress. 
This letter is to ask permission to recruit netball players from the UFS to participate in my study.
92
The protocol for this study will be submitted to the Ethics committee of the University of Free 
State’s Faculty of Health Science for approval.  The protocol of the research is available from the 
secretariat of the Ethics committee of the University of Free State’s Faculty of Health Science on 
request.
For any questions regarding the study, you can contact me at 0835576381 or e-mail me at 
marelisew@telkomsa.net or contact my study leader, Roline Barnes at 0827401069 or contact the 
secretariat of the Ethics committee of the University of Free State’s Faculty of Health Science at 
051-4052812.
If permission is granted for recruitment of netball players from the UFS, please sign the attached 
slip. 
Yours faithfully
Marelise Wilson
(Researcher)(Physiotherapist)
Signature_____________________________ Date_____________________________
------------------------------------------------------------------------------------------------------------------------------
-
To: Marelise Wilson
I, _____________________, Vice-rector: Academics at the UFS have read the information 
document and understand the nature of the study as well as the benefits and risks involved.  I give 
my permission for the recruitment of netball players from the UFS to participate in the research 
study. The research study is to evaluate the effect of an exercise programme on the dynamic 
postural control in netball players.  I wish to be kept informed of any changes to the research study 
as well as the results of the study.
Name: ______________________________________
Signature: ____________________________________
Date: ________________
93
Letter asking permission from Student dean
Dear Mr Buys 
Re: Permission for research study in netball players at the UFS
Study title: The effect of a core stability, m. gluteus medius and proprioceptive exercise 
programme on dynamic postural control in netball players
I am a M.Sc. student in sport physiotherapy at the University of the Free State (UFS).  Part of the 
requirements of my degree is a research study. My field of interest is netball and I would like to 
perform a research study to determine the effect of an exercise programme on dynamic postural 
control in netball players. 
Dynamic postural control is the ability to perform a functional task with purposeful movements 
that translates the body’s centre of gravity without compromising a stable base of support 
(Winter, Patla and Frank, 1990; Kahle and Gribble, 2009). Research by Ferreira and Spamer (2010) 
measured poor dynamic postural control or balance in elite university netball players during pre-
season testing.  No literature could be found regarding studies investigating a programme that 
utilised the combination of core stability, m.GMed strengthening and proprioceptive balance 
exercises on dynamic postural control or studies investigating an exercise programme on dynamic 
postural control in netball players.  My aim is to investigate the effectiveness of such a programme
on dynamic postural control in netball players.
This research study is a baseline study and an exercise programme compiled from scientific 
literature will be followed. It will incorporate m.GMed (hip) strength, core stability and 
proprioceptive balance exercises. Participation in this study will take approximately 60 minutes 
three days a week for a period of six weeks.  A Star Excursion Balance Test will be executed the 
week before, the week after the exercise programme as well as six weeks before the 
commencement or alternatively after the completion of the exercise programme to evaluate the 
dynamic postural control of the participants.
My hypothesis is that a core stability, m.GMed and proprioceptive balance exercise programme
might lead to an improvement in dynamic postural control. It might benefit the players’ balance
abilities if the exercise programme leads to an improved outcome.  More potential benefits are 
improvement in their m.GMed (hip) strength and core stability. Improved dynamic postural 
control might also lead to improve performance and help prevent injuries in the netball players.  
94
The exercise programme will be made available to the UFS netball academy and the participants 
after the completion of the study.  Participants will be female netball players selected into the top 
junior netball group of the UFS.
Participation in this study is voluntary and if at any time during the study the netball player wishes 
to withdraw, she will be free to do so without any consequence.  The netball player will only be 
included if she reports no history of lower extremity injuries in the past 6 months (any injury 
requiring not taking part in physical activity for longer than two days) or lower extremity surgery in 
the past year.
The training programme will take place during February to May 2014. They will train under the 
researchers’ supervision at the university’s sport centre.  The participants’ class schedule will be 
taken into consideration and the training sessions will not interfere with class commitments.
Although this study has a degree of risk due to the possibility that any exercise may cause injury, 
the risk is no bigger than participating in a netball practice and great care will be taken to avoid 
injury.  If the participant is injured as a result of partaking in the assessment or exercise 
programme of the research study, the researcher will offer the injured participant physiotherapy 
treatment free of charge.
The information of the participants and the results of their individual tests will be strictly 
confidential. Each participant (netball player) will receive a unique, arbitrary code and any written 
documents will be labelled with that number to keep the nature and quality of the participants’ 
information strictly confidential.  Each participant will have access to their own test results.  The 
group result of the study will be communicated to the UFS netball academy after the completion 
of the study and may be published in an accredited journal and presented at a meeting or a 
congress. 
This letter is to ask permission to recruit netball players from the UFS to participate in my study.
The protocol for this study will be submitted to the Ethics committee of the University of Free 
State’s Faculty of Health Science for approval.  The protocol of the research is available from the 
secretariat of the Ethics committee of the University of Free State’s Faculty of Health Science on 
request.
For any questions regarding the study, you can contact me at 0835576381 or e-mail me at 
marelisew@telkomsa.net or contact my study leader, Roline Barnes at 0827401069 or contact the 
95
secretariat of the Ethics committee of the University of Free State’s Faculty of Health Science at 
051-4052812.
If permission is granted for recruitment of netball players from the UFS, please sign the attached 
slip. 
Yours faithfully
Marelise Wilson
(Researcher)(Physiotherapist)
Signature_____________________________ Date_____________________________
----------------------------------------------------------------------------------------------------------------------
To: Marelise Wilson
I, _____________________, student dean at the UFS have read the information document and 
understand the nature of the study as well as the benefits and risks involved.  I give my permission 
for the recruitment of netball players from the UFS to participate in the research study. The 
research study is to evaluate the effect of an exercise programme on the dynamic postural control 
in netball players.  I wish to be kept informed of any changes to the research study as well as the 
results of the study.
Name: ______________________________________
Signature: ____________________________________
Date: ________________
96
Letter asking permission from Assistant Director of Kovsie Sport
Dear Mrs de Kock
Re: Permission for research study in netball players at the UFS
Study title: The effect of a core stability, m. gluteus medius and proprioceptive exercise 
programme on dynamic postural control in netball players
I am a M.Sc. student in sport physiotherapy at the University of the Free State (UFS).  Part of the 
requirements of my degree is a research study. My field of interest is netball and I would like to 
perform a research study to determine the effect of an exercise programme on dynamic postural 
control in netball players. 
Dynamic postural control is the ability to perform a functional task with purposeful movements 
that translates the body’s centre of gravity without compromising a stable base of support 
(Winter, Patla and Frank, 1990; Kahle and Gribble, 2009). Research by Ferreira and Spamer (2010) 
measured poor dynamic postural control or balance in elite university netball players during pre-
season testing.  No literature could be found regarding studies investigating a programme that 
utilised the combination of core stability, m.GMed strengthening and proprioceptive balance 
exercises on dynamic postural control or studies investigating an exercise programme on dynamic 
postural control in netball players.  My aim is to investigate the effectiveness of such a programme
on dynamic postural control in netball players.
This research study is a baseline study and an exercise programme compiled from scientific 
literature will be followed. It will incorporate m.GMed (hip) strength, core stability and 
proprioceptive balance exercises. Participation in this study will take approximately 60 minutes 
three days a week for a period of six weeks. A Star Excursion Balance Test will be executed the 
week before, the week after the exercise programme as well as six weeks before the 
commencement or alternatively after the completion of the exercise programme to evaluate the 
dynamic postural control of the participants.
My hypothesis is that a core stability, m.GMed and proprioceptive balance exercise programme
might lead to an improvement in dynamic postural control. It might benefit the players’ balance 
abilities if the exercise programme leads to an improved outcome.  More potential benefits are 
improvement in their m.GMed (hip) strength and core stability.  Improved dynamic postural 
control might also lead to improve performance and help prevent injuries in the netball players.  
97
The exercise programme will be made available to the UFS netball academy and the participants 
after the completion of the study.  Participants will be female netball players selected into the top 
junior netball group of the UFS.
Participation in this study is voluntary and if at any time during the study the netball player wishes 
to withdraw, she will be free to do so without any consequence.  The netball player will only be 
included if she reports no history of lower extremity injuries in the past 6 months (any injury 
requiring not taking part in physical activity for longer than two days) or lower extremity surgery in 
the past year.
The training programme will take place during February to May 2014. They will train under the 
researchers’ supervision at the university’s sport centre.  The participants’ class schedule will be 
taken into consideration and the training sessions will not interfere with class commitments.
Although this study has a degree of risk due to the possibility that any exercise may cause injury, 
the risk is no bigger than participating in a netball practice and great care will be taken to avoid 
injury.  If the participant is injured as a result of partaking in the assessment or exercise 
programme of the research study, the researcher will offer the injured participant physiotherapy 
treatment free of charge.
The information of the participants and the results of their individual tests will be strictly 
confidential. Each participant (netball player) will receive a unique, arbitrary code and any written 
documents will be labelled with that number to keep the nature and quality of the participants’ 
information strictly confidential.  Each participant will have access to their own test results.  The 
group result of the study will be communicated to the UFS netball academy after the completion 
of the study and may be published in an accredited journal and presented at a meeting or a 
congress. 
This letter is to ask permission to recruit netball players from the UFS to participate in my study.
The protocol for this study will be submitted to the Ethics committee of the University of Free 
State’s Faculty of Health Science for approval. The protocol of the research is available from the 
secretariat of the Ethics committee of the University of Free State’s Faculty of Health Science on 
request.
For any questions regarding the study, you can contact me at 0835576381 or e-mail me at 
marelisew@telkomsa.net or contact my study leader, Roline Barnes at 0827401069 or contact the 
98
secretariat of the Ethics committee of the University of Free State’s Faculty of Health Science at 
051-4052812.
If permission is granted for recruitment of netball players from the UFS, please sign the attached 
slip. 
Yours faithfully
Marelise Wilson
(Researcher)(Physiotherapist)
Signature_____________________________ Date_____________________________
------------------------------------------------------------------------------------------------------------------------------
-
To: Marelise Wilson
I, _____________________, assistant director Kovsie sport at the UFS have read the information 
document and understand the nature of the study as well as the benefits and risks involved.  I give 
my permission for the recruitment of netball players from the UFS to participate in the research 
study. The research study is to evaluate the effect of an exercise programme on the dynamic 
postural control in netball players.  I wish to be kept informed of any changes to the research study 
as well as the results of the study.
Name: ______________________________________
Signature: ____________________________________
Date: ________________
99
Appendix 2 Information to participants
Dear netball player
Information on the study regarding the effect of an exerciseprogramme on dynamic postural 
control in netball players.
You have indicated after the information session to be interested to participate in a study 
investigating the effect of an exercise programme on dynamic postural control in netball players. I 
am a M.Sc. student in sport physiotherapy at the University of the Free State (UFS).  Part of the 
requirement of my degree is a research study. I am interested in determining if certain exercises 
will improve movement balance in netball players. Dynamic postural control is balance while 
moving and an important skill in netball players. It is indicated that the results of this study would
be useful in improving exercise programmes for netball players.
The study involves an exercise programme of hip (m.gluteus medius) strength, core stability and 
balance exercises. Participation in this study will take approximately 60 minutes three days a week 
for a period of six weeks. A Star Excursion Balance Test will be executed the week before, the 
week after the exercise programme as well as six weeks before the commencement or 
alternatively after the completion of the exercise programme to evaluate your dynamic postural 
control. Your class schedule will be taken into consideration and the training sessions will not 
interfere with class commitments.
Potential benefits are improvement in your strength, core stability, proprioception and balance. 
My hypothesis is that the training programme would also lead to an improvement in your dynamic 
postural control. Improved dynamic postural control would also lead to improve performance and 
help to prevent injuries.
To participate you need to be selected in the top junior netball group and over the age of 18 years.
To participate in this study, you need to be injury free before the commencement of the study and 
have no history of lower extremity injuries in the past 6 months (any injury requiring not taking 
part in physical activity for longer than two days), or had lower extremity surgery in the past year. 
You should also not be currently partaking in a balance, core stability or m. gluteus medius 
exercise programme that is not included in your standard netball exercise programme.
The training programme will take place during February to May 2014. You will train under the 
researcher’s supervision at the university’s sport centre.
100
Although this study has a degree of risk due to the possibility that any exercise may cause injury, 
the risk is no bigger than participating in a netball practice and great care will be taken to avoid 
injury. If you are injured as a result of partaking in the assessment or exercise programme of the 
research study, the researcher will offer you physiotherapy treatment free of charge. Discomfort
and muscle soreness experienced after a training session is quite normal and should disappear 
after a day or two.
Your participation in this study is voluntary; you are under no obligation to participate. If at any 
time during the study you wish to withdraw, you are free to do so without any penalty or 
consequence. You will receive no remuneration for participation in this study; neither will there 
be any costs involved.
Your information and the results of your tests will be strictly confidential. You will receive a 
unique, arbitrary code and any written documents will be labelled with that code to keep the 
nature and quality of your information strictly confidential. If requested, you will have access to 
your own test results. Only group results will be reported. The group results of the study will be 
communicated to the UFS netball academy after the completion of the study and may be 
published in an accredited journal and presented at a meeting or a congress.
Permission has being asked from the Vice-rector, the Student Dean and the Assistant-Director of 
Kovsie Sport (Burta de Kock) and the study will be submitted to the Ethics committee of the 
University of Free State’s Faculty of Health Science for approval.
If you have any questions prior to your participation in the study, please do not hesitate to contact 
the researcher, Marelise Wilson, at 0835576381. 
Yours faithfully
Marelise Wilson
101
Inligting aan deelnemers
Geagte netbalspeler
Inligting in verband met ‘n studie oor die effek van ‘n oefeningprogramme op dinamiese posturele
beheer van netbalspelers.
Na die inligtingsessie het u aangedui dat u belangstel om deel te neem in ‘n studie wat die effek 
van ‘n oefeningprogramme op die dinamiese posturele beheer van netbalspelers ondersoek. Ek is 
‘n M.Sc. student in sport fisioterapie aan die Universiteit van die Vrystaat (UVS).  ‘n 
Navorsingstudie is `n vereiste om my graad te behaal. Ek stel daarin belang om vas te stel of 
sekere oefeninge dinamiese posturele beheer of bewegingsbalans van netbalspelers sal verbeter.
Dit is aangedui dat die resultate van so ‘n studie sal help om oefeningprogrammeme vir 
netbalspelers te verbeter.
Die studie behels ‘n oefeningprogramme bestaande uit heup- (gluteus medius spier), 
kernstabiliteit- en balansoefeninge. Deelname aan hierdie studies sal plus-minus 60 minute, drie 
dae ‘n week vir ‘n periode van ses weke van u tyd in beslag neem. ‘n “Star Excursion” balans toets 
sal die week voor die aanvang van die oefeningsprogramme, die week na die oefeningsprogramme
en weer ses weke daarna of alternatiewelik ses weke voor die aanvangs van die 
oefeningsprogramme op u uitgevoer word. U klas skedule sal in ag geneem word en die oefentye 
sal nie inmeng met u klas verpligtinge nie.
Potensiёle voordele is die verbetering van u spiersterkte, kernstabiliteit, propriosepsie en balans. 
My hipotese is dat die oefeningprogramme sal lei tot ‘n verbetering van u posturele dinamiese 
beheer. Verbeterde posturele dinamiese beheer mag ook moontlik daartoe lei dat u beter 
presteer en help om beserings te voorkom.
Om deel te neem aan die studie, moet u gekies wees om deel te wees van die top junior 
netbalgroep en moet u ook ouer as 18 jaar wees. U moet beseringsvry voor die aanvang van die 
studie wees, geen geskiedenis hŠ van enige onderste ledemaat beserings in die laaste ses maande 
nie (enige beserings wat u meer as 2 dae weerhou het van enige fisiese aktiwiteit) en geen 
onderste ledemaat chirurgie in die laaste jaar ondergaan het nie. U mag ook nie huidiglik
deelneemaan enige ander balans-, kernstabiliteit- of heup (gluteus medius) oefeningprogramme
behalwe u standaard netbal oefenprogramme nie.
102
Die oefenprogramme sal gedurende Februarie tot Mei 2014 plaasvind. U sal onder die navorser se
toesig by die universiteit se sport sentrum oefen.
Alhoewel die studie ‘n mate van risiko inhou as gevolg van die moontlikheid dat enige oefening ‘n 
besering kan veroorsaak, is die risiko nie groter as wat u aan ‘n netbaloefening deelneem nie en 
sorg sal aan die dag gelŠ word om beserings te voorkom.  As u beseer word as gevolg van u 
deelname aan die evaluering of oefenprogramme van die navorsingstudie, sal die navorser gratis 
fisioterapie behandeling aan u verskaf. Ongemak en spierpyn wat u na ‘n oefensessie kan 
ondervind is normaal en behoort na ‘n dag of twee te verdwyn.
U deelname aan hierdie studie is vrywillig; u is onder geen verpligting om deel te neem nie. U kan 
ter enige tyd gedurende die studie onttrek, sonder enige straf ofnagevolge. U sal geen vergoeding 
vir u deelname aan die studie ontvang nie, maar daar sal ook geen koste daaraan verbonde wees 
nie.
U inligting en die resultate van die studie sal streng vertroulik hanteer word. U sal ‘n unieke,
arbitrŠre kode ontvang en slegs die kode sal op alle geskrewe dokumente gebruik word om die 
aard en stand van jou inligting streng vertroulik te hou. Op versoek, sal u toegang tot u eie 
toetsresultate verkry. Daar sal slegs oor groepresultate verslag gedoen word. Die groepresultate 
sal nadie voltooiing van die studie aan die netbalakademie van die UVS beskikbaar gestel word en 
mag in `n geakkrediteerde joernaal gepubliseer word en op ‘n vergadering of kongres voorgedra
word.
Toestemming is van die Vise-rektor, die Studente Dekaan en van die Assistant-direkteur van Kovsie 
Sport (Burta de Kock) verkry en die studies sal aan die Etiek komitee van die Fakulteit 
Gesondheidswetenskappe van die UVS vir goedkeuring voorgelŠ word.
As u enige vrae het oor u deelname aan die studie, kontak gerus die navorser, Marelise Wilson, by 
0835576381.
Die uwe
----------------------------------------
Marelise Wilson
103
Appendix 3 An informed consent letter to get permission from the participant
Dear participant
Study title: The effect of a core stability, m. gluteus medius and proprioceptive exercise 
programme on dynamic postural control in netball players
Researcher: Marelise Wilson
You have being asked to participate in a research study investigating the effect of an exercise
programme on dynamic postural control in netball players. I am interested in determining if 
certain exercises will improve movement balance in netball players. 
The study and its procedures have been approved by the Ethics committee of the University of 
Free State’s Faculty of Health Science, the student Dean and the Director of Kovsie Sport of the 
University of the Free State. The study involves an exercise programme of hip (m.gluteus medius) 
strength, core stability and balance exercises. Participation in this study will take approximately 60 
minutes three days a week for the six weeks. The training programme will take place during 
February to May 2014 under the supervision of the researcher at the university’s sport centre.
Potential advantages might include improved strength, core stability, proprioception and balance.
My hypothesis is that the training programme might also lead to an improvement in your dynamic 
postural control. Improved dynamic postural control might also lead to improve performance and 
help to prevent injuries.
Although this study has a degree of risk due to the possibility that any exercise may cause injury, 
the risk is no bigger than participating in a netball practice and great care will be taken to avoid 
injury. If you are injured as a result of partaking in the assessment or exercise programme of the 
research study, the researcher will offer you physiotherapy treatment free of charge. Discomfort 
and muscle soreness experienced after a training session is quite normal and should disappear 
after a day or two.
Your participation in this study is voluntary; you are under no obligation to participate. If at any 
time during this study you wish to withdraw, you are free to do so without any penalty or 
consequence. You will receive no remuneration for participation in this study; neither will there 
be any costs involved.
104
If you have any questions prior or during your participation in the study, please do not hesitate to 
contact the researcher, Marelise Wilson at 0835576381 or the study leader, Roline Barnes at 
0827401069. You may also contact the secretariat of the Ethics committee of the University of 
Free State’s Faculty of Health Science at 051-4052812 if any questions arises as to your rights as a 
participant in the research.
The study data will be coded so that they will not be linked to your name. Your identity will not be 
revealed while the study is being conducted or when the study is reported or published. Only 
group results will be reported. All your study data will be stored in a secure place and not shared 
with any other person without your permission.
The group results of the study may be published in an accredited journal and presented at a 
meeting or congress. The training programme will be available to the UFS netball academy and 
participants after the completion of the study.
If you wish to participate in the study, please complete the injury profile questionnaire and sign 
this information sheet as well as the consent form. You will receive a signed copy of the 
information sheet as well as the informed consent form.
If you do not wish to participate in the study, you are not required to complete the injury profile 
questionnaire or to sign the consent form.
______________________ ___________________
Signature of participant Date
105
Informed consent:
I have read this consent form and understand the nature of this study as well as the possible 
benefits and risks involved. I understand that by agreeing to participate in this study I have not 
waived any legal or human right and that I may contact the researcher (Marelise Wilson, 
0835576381) at any time. I understand what my involvement in the study means and I voluntarily
agree to participate in this study. I understand that I may refuse to participate or I may withdraw 
from the study at any time without penalty or consequence. I declare that information I have 
given is correct at this time.
Name of Participant: ___________________________________
__________________ __________________
Participant’s signature Date
Cell nr: _____________
I have explained this study verbally to the above subject and have sought her understanding.
__________________ __________________
Researcher’s signature Date
106
Study title: The effect of a core stability, m. gluteus medius and proprioceptive exercise 
programme on dynamic postural control in netball players
Researcher: Marelise Wilson
Name of participant:__________________________________
Injury profile questionnaire:
Have you had any lower extremity injuries in the past six months that may have prevented you 
from participating in any physical activity for longer than two days? Yes_____ No_____
Have you had any lower extremity surgery in the past year? Yes_____ No______
Are you currently partaking in any balance, core stability or gluteus medius muscle exercise 
programme? 
Yes_____ No_____
_________________________          _____________________
Participant’s signature Date
107
‘n Ingeligte toestemmingsbrief om toestemming van deelnemer te verkry
Geagte deelnemer
Studie titel: Die effek van ‘n kernstabiliteit, m.gluteus medius en propriosepsie oefenprogramme
op dinamiese posturele beheer van netbalspelers
Navorser: Marelise Wilson
U is genader om deel te neem aan ‘n studie wat die effek van ‘n oefenprogramme op dinamiese 
posturele beheer van netbalspelers ondersoek. nteresseerd om te bepaal of sekere 
oefeninge die bewegingsbalans van netbalspelers gaan verbeter.
Die studie en die prosedures is deur die Etiek komitee van die Fakulteit Gesondheidswetenskappe 
van die Universiteit van die Vrystaat (UVS), die Studente Dekaan en die Direkteur van Kovsie sport 
goedgekeur. Die studie behels ‘n oefenprogramme bestaande uit heup (gluteus medius), 
kernstabiliteit en balansoefeninge. Deelname aan hierdie studie sal plus-minus 60 minute, drie 
dae ‘n week vir ‘n periode van ses weke van u tyd in beslag neem. Die oefenprogramme sal 
gedurende Februarie tot Mei 2014 plaasvind. U sal onder die navorser se toesig by die universiteit 
se sport sentrum oefen. Potensiёle voordele is die verbetering van u spiersterkte, kernstabiliteit, 
propriosepsie en balans. My hipotese is dat die oefeningprogramme mag lei tot ‘n verbetering van 
u posturele dinamiese beheer. Verbeterde posturele dinamiese beheer mag ook daartoe lei dat u 
beter presteer en help om beserings te voorkom.
Alhoewel die studie ‘n mate van risiko inhou as gevolg van die moontlikheid dat enige oefening ‘n 
besering kan veroorsaak, is die risiko nie groter as wat u aan ‘n netbaloefening deelneem nie en 
sorg sal aan die dag gelŠ word om beserings te voorkom.  As u beseer word as gevolg van u 
deelname aan die evaluering of oefenprogramme van die navorsingstudie, sal die navorser gratis 
fisioterapie behandeling aan u verskaf. Ongemak en spierpyn wat u kan ondervind na ‘n 
oefensessie is normaal en behoort na ‘n dag of twee te verdwyn.
U deelname aan hierdie studie is vrywillig; u is onder geen verpligting om deel te neem nie. U kan 
ter enige tyd gedurende die studie onttrek, sonder enige straf of nagevolge. U sal geen vergoeding 
vir u deelname aan die studie ontvang nie, maar daar sal ook geen koste daaraan verbonde wees 
nie.
As u enige vrae het voor of tydens u deelname aan die studie, kontak gerus die navorser, Marelise 
Wilson by 0835576381 of die studieleier, Roline Barnes by 0827401069. U mag ook die 
108
sekretariaat van die Etiek komitee van die Fakulteit Gesondheidswetenskappe van die UVS by 051-
4052812 kontak as daar enige vrae ontstaan oor u regte as ‘n deelnemer aan hierdie studie.  
Die studie data sal gekodeer word sodat daar nie ‘n verbinding met u naam is nie. U identiteit sal 
nie tydens die studie bekend gemaak word nie en ook nie as daar oor die studie verslag gelewer 
word of as die studie gepubliseer word nie. Al u studie data sal in ‘n veilige plek bewaar word en 
sal nie aan enige iemand bekend gemaak word sonder u toestemming nie.
Die groepresultate van die studie mag in ‘n geakkrediteerde joernaal gepubliseer word en op ‘n 
vergadering of kongres voorgedra word. Die oefenprogramme sal na die voltooiing van die studie 
aan die netbalakademie van die UVS en die deelnemers beskikbaar gestel word.
As u aan die studie wil deelneem, voltooi asseblief die aangehegte beseringsprofiel vraelys en 
teken die inligtingstuk sowel as die ingeligte toestemmingsbrief. U sal ‘n ondertekende afskrif van 
die inligtingstuk sowel as die ingeligte toestemmingsbrief ontvang.
As u nie aan die studie wil deelneem nie, hoef u nie die beseringsprofiel te voltooi of die ingeligte 
toestemmingsbrief te onderteken nie.
____________________________ _____________________
Handtekening van deelnemer Datum
109
Ingeligte toestemming
Ek het die ingeligte toestemmingsvorm deurgelees en verstaan die aard van die studie sowel as die 
moontlike voordele en risiko`s verbonde van deelname aan die studie. Ek verstaan dat deur in te 
stem om deel te neem aan hierdie studie het ek nie afstand gedoen van enige wetlike of 
menseregte nie. Ek kan die navorser (Marelise Wilson, 0835576381) enige tyd kontak. Ek verstaan 
wat my betrokkenheid by die studie beteken en ek stem vrywilliglik in om deel te neem aan die 
studie. Ek verstaan dat ek mag weier om deel te neem of kan onttrek aan die studie sonder enige 
straf of nagevolge. Ek verklaar die inligting wat ek verskaf het, as huidiglik korrek. 
Naam van deelnemer: _______________________________________
________________________________                    _______________
Handtekening van deelnemer                                                              Datum
Selfoonnr:______________________
Ek het die studie verbaal aan die deelnemer verduidelik en seker gemaak dat sy verstaan.
_______________________________                _______________
Handtekening van navorser                                                                  Datum 
110
Studie titel: Die effek van ‘n kernstabiliteit, m.gluteus medius en propriosepsie oefenprogramme
op dinamiese posturele beheer van netbalspelers
Navorser: Marelise Wilson
Naam van deelnemer:____________________________
Beseringsprofiel vraelys
Het u enige onderste ledemaat beserings in die laaste ses maande gehad wat u langer as twee dae 
verhoed het om aan fisiese aktiwiteite deel te neem? Ja____ Nee_____
Het u enige onderste ledemaat chirurgie gehad in die laaste jaar? Ja____ Nee____
Neem u huidiglik deel aan enige balans, kernstabiliteit of gluteus medius oefenprogramme? 
Ja_____ Nee_____
_______________________ ____________
Handtekening van deelnemer Datum
111
Appendix 4 Data sheet
For Office 
Use
Participant 
no 1-2
Date 3-8
Testing 
session 1 9
2
3
Stance Right 10
Left
Trial 1 Anterior . 11-15
Medial . 16-20
Posterior . 21-25
Lateral . 26-30
Trial 2 Anterior . 31-35
Medial . 36-40
Posterior . 41-45
Lateral . 46-50
Trial 3 Anterior . 51-55
Medial . 56-60
Posterior . 61-65
Lateral . 66-70
112
Appendix 5 Attendance record sheet
For Office use
Participant no 1-2
Week 1 Present Absent
Session 1 3
Session 2 4
Session 3 5
Week 2
Session 1 6
Session 2 7
Session 3 8
Week 3
Session 1 9
Session 2 10
Session 3 11
Week 4
Session 1 12
Session 2 13
Session 3 14
Week  5
Session 1 15
Session 2 16
Session 3 17
Week 6
Session 1 18
Session 2 19
Session 3 20
113
Appendix 6 Description of exercise programme
Exercise Description
Week 1
1.1 Recognition of neutral spine (centre of mass) Recognition of the midrange between lumbar flexion 
in sitting and standing (Akuthota et al., 2008 ) (posterior pelvic tilt) and extension (anterior pelvic tilt) in 
sitting and standing.
1.2 Co-activation of TrA& LM in crook supine lying The participant voluntary activates TrA by pulling the 
position (base position) (Aggarwal et al., 2010) umbilicus inwards towards the spine, and the LM by causing 
the muscles on either side of the lumbar spine to swell, 
while in crook supine lying position.  A pressure biofeedback 
unit (PBU) is used to ensure recruitment of TrA and LM. 
Compensatory movements such as pelvic tilting and rectus 
abdominis and gluteal contraction are discouraged.
1.3 Co-activation of TrA& LM in prone lying The participant voluntary activates TrA by pulling the 
position (Aggarwal et al., 2010) umbilicus inwards towards the spine, and the LM by causing 
the muscles on either side of the lumbar spine to swell, 
while in prone lying position.  A pressure biofeedback unit 
(PBU) is used to ensure recruitment of TrA and LM. 
Compensatory movements such as pelvic tilting and rectus 
abdominis and gluteal contraction are discouraged 
1.4 Co-activation of TrA& LM in quadruped The participant voluntary activates TrA by pulling the 
position (recognition of centre of mass) (Aggarwal umbilicus inwards towards the spine, and the LM by causing 
et al., 2010) the muscles on either side of the lumbar spine to swell, 
while in quadruped position.  Compensatory movements 
such as pelvic tilting and rectus abdominis and gluteal 
contraction are discouraged.
114
1.5 Co-activation of TrA& LM while standing on The participant voluntary activates TrA by pulling the 
single limb (recognition of centre of mass) umbilicus inwards towards the spine, and the LM by causing 
(Aggarwal et al., 2010) the muscles on either side of the lumbar spine to swell, 
while standing on a single limb with eyes closed.  
Compensatory movements such as pelvic tilting are 
discouraged.
1.6 Clamshell 1 (Distefano et al., 2009; Boren et The participant is in R side-lying on the floor; with the knees 
al., 2011) flexed 90° and hips flexed 45°. The participant activates TrA 
and LM and maintains the lumbar spine in a neutral 
position.  The participant abducts and externally rotates the 
L knee off the bottom knee while keeping the heels 
together and the anterior superior iliac spines facing 
forward, and then return to the starting position. After 
completing a set in R side-lying, the exercise is repeated in L 
side-lying.
1.7 Pelvic drop (Bolga et al., 2005; Boren et al., The participant stands with the R leg on the edge of a 5cm 
2011) step.  The participant activates TrA and LM and maintains 
the lumbar spine in a neutral position while lowering the 
heel of the L leg to touch the ground without weight 
bearing.  The participant returns foot to the height of the 
box. After completing a set with the R leg, the exercise is 
repeated with the L leg on the edge of the step.
Week 2
2.1 Supine bent knee-raises (Fredericson et al., The participant is in hook-lying position with knees bent and 
2005; Aggarwal et al., 2010) feet flat on the floor. The participant activates TrA and LM 
and maintains the lumbar spine in a neutral position while 
she slowly raises one foot 15 to 30 cm off the ground with 
alternate legs.  Compensatory movements such as rocking 
the pelvis, abdominal protrusion and an inability to maintain 
a neutral lumbar spine are discouraged.
115
2.2 Quadruped with alternate arm/leg raises The participant is in the quadruped position and activates 
(Superman exercise) (Fredericson et al., 2005; TrA and LM and maintains the lumbar spine in a neutral 
Aggarwal et al., 2010) position.  The participant raises the R arm and the L leg into 
a line with the trunk while preventing any rocking of the 
pelvis or spine (excessive transverse or coronal plane 
motion).  A wooden dowel is placed along the spine to add 
tactile feedback and help the participant to maintain 
alignment. The leg is only raise to the height at which the 
participant can control excessive motion of the pelvis.  The 
exercise is repeated by raising the L arm and R leg.
2.3 Abdominal crunches (Kahle and Gribble, 2009) The participant is in hook-lying position with both hands 
behind the neck, knees bent and feet flat on the floor.  The 
participant activates TrA and LM and tucks her chin in a little 
as if holding a tennis ball between chin and chest. The 
participant curls up, only until the shoulder blades are off 
the ground.  The participant holds the position for five 
seconds and lowers the head and shoulders returning to the 
starting position.
2.4 Bridging (Fredericson et al., 2005) The participant is in hook-lying position with her arms 
resting at her side. The participant activates TrA and LM 
and squeezes the gluteal muscles before initiating 
movement.  The participant lifts the pelvis and hips off the 
ground by keeping the feet on the floor while maintaining 
neutral lumbar spine alignment. The hips should be aligned 
with the knees and shoulders in a straight line and there 
should be no rotation of the pelvis.  The participant holds 
the position for ten seconds and lowers the body back onto 
the ground.
2.5 Single limb dead lift (Distefano et al., 2009; The participant balances on the R leg, with the knee and hip 
Boren et al., 2011) flexed approximately 30° and their hands on their hips. 
Participant activates TrA and LM, slowly flexes at the hip, 
and touches their L middle finger to the floor beside their R 
foot. Participant returns to the starting position. After 
completing a set on the R leg, the exercise is repeated on 
the L leg. Participants are instructed to maintain neutral 
alignment, and to keep their knees over their toes.
116
2.6 Co-activation of TrA& LM while standing on The participant activates TrA by pulling the umbilicus 
single limb with eyes closed (Aggarwal et al., 2010;  inwards towards the spine, and the LM by causing the 
Leavey et al., 2010) muscles on either side of the lumbar spine to swell, while 
standing on single limb with eyes closed.  Compensatory 
movements such as pelvic tilting are discouraged.
Week 3
3.1 Seated marching on physio ball (Fredericson et The participant sits upright on a physio ball, with the lumbar 
al., 2005) spine in neutral position.  The participant’s feet are placed 
hip-width apart.  While activating TrA and LM, she lifts one 
leg and foot slightly off the ground while maintaining 
lumbo-pelvic stability.  
3.2 Abdominal crunches on a physio ball The participant positions herself on the physio ball so that 
(Fredericson et al., 2005; Kahle and Gribble, 2009) her spine contours the ball and is well supported.  The 
position should allow the head to almost touch the ball 
when it drops into full extension and the buttocks should 
remain on the ball. The participant activates TrA and LM 
and tucks her chin in a little as if holding a tennis ball 
between chin and chest. The participant curls up, until the 
shoulder blades are off the physio ball.  The participant 
holds the position for five seconds and returns to the 
starting position.
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3.3 Superman exercise on a physio ball The participant is in the quadruped position with a physio 
(Fredericson et al., 2005) ball underneath the trunk.  The participant activates TrA 
and LM and maintains the lumbar spine in a neutral 
position.  The participant raises the R arm and the L leg into 
a line with the trunk while preventing any rocking of the 
pelvis or spine (excessive transverse or coronal plane 
motion).  A wooden dowel is placed along the spine to add 
tactile feedback and help the participant to maintain 
alignment.  The leg is only raise to the height at which the 
participant can control excessive motion of the pelvis.  The 
exercise is repeated by raising the L arm and R leg.
3.4 Bridging with alternate leg lifts (Fredericson et The participant is in hook-lying position with her arms 
al., 2005; Kahle and Gribble, 2009) resting at her side.  The participant activates TrA and LM 
and squeezes the gluteal muscles before initiating 
movement.  The participant lifts the pelvis and hips off the 
ground by keeping the feet on the floor while maintaining 
neutral lumbar spine alignment.  The hips should be aligned 
with the knees and shoulders in a straight line and there 
should be no rotation of the pelvis.  In the lifted-bridge 
position, while maintain neutral lumbar spine alignment, 
the participant lifts one foot off the ground. The participant 
holds the position for five seconds and first lowers the foot 
and then lowers the body back to the ground.  The exercise 
is repeated with the alternate leg.
3.5 Lateral step up (Ayotte et al., 2007; Ekstrom et Participant stands on the edge of a 15cm step on the R leg 
al., 2007; Boren et al., 2011) and activates TrA and LM and maintains the lumbar spine in 
a neutral position. The participant squats slowly to lower 
the heel of the L leg toward the floor and then returns to 
the start position. After a set, the exercise is repeated with 
the participant standing on the edge on the L leg.
118
3.6 Tilt board exercises: (Fredericson et al., 2005) The participant stands on a tilt board, activates TrA and LM 
1) Balance in plantarflexion/ dorsiflexion and maintains static stability.  The participant keeps lumbo-
pelvic alignment and balance while controlling aberrant 
motion. The participant’s feet are placed in various planes 
of motion on the tilt board.  These planes include 
plantarflexion/dorsiflexion, inversion/eversion and diagonal.  
Progression is made from double leg stance with eyes open 
to double leg stance with eyes closed to single leg stance 
2) Balance in inversion / eversion with eyes open.
3) Balance in diagonal
Week 4
4.1 Trunk rotation with 2kg medicine ball while The participant sits upright on a physio ball, with the lumbar 
seated on physio ball (Kahle and Gribble, 2009) spine in neutral position.  The participant’s feet are placed 
hip-width apart.  A 2kg medicine ball is held in front of the 
chest with the arms extended.  While activating TrA and LM, 
she rotates to one side while maintaining lumbo-pelvic 
alignment and stability.  The trunk rotation is repeated to 
the other side.
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4.2 Alternate leg bridge with shoulders on physio The participant sits on the physio ball and walks forward 
ball (Fredericson et al., 2005; Kahle and Gribble, with her feet on the ground, leaning back until her head, 
2009) neck and shoulder blades are supported on the ball.  Knees 
are bent 90° with the feet flat on the ground.  The 
participant contracts TrA and LM and raises one foot off the 
ground while maintaining lumbar alignment and avoiding 
pelvic rotation.  The participant holds the position for five 
seconds and lowers the foot to the ground.  The exercise is 
repeated with the alternate leg.  
4.3 Diagonal curls on physio ball (Aggarwal et al., The participant position herself on the physio ball so that 
2010) her spine contours the ball and is well supported.  The 
position should allow the head to almost touch the ball 
when it drops into full extension and the buttocks should be 
on the ball. The participant activates TrA and LM and tucks 
her chin in a little as if holding a tennis ball between chin 
and chest. The participant curls up, bringing her shoulder 
across toward the opposite knee while keeping both elbows 
wide and chest open.  The participant holds the position for 
five seconds and returns to the starting position. The 
exercise is repeated to the alternate side.
4.4 Front plank with alternate hip extension The participant supports herself with her forearms, elbows 
(Fredericson et al., 2005; Boren et al., 2011) bent 90°, and the toes resting on the ground.  The spine, 
hips, and knees are in neutral alignment.  The participant 
activates TrA and LM, recruits the gluteal muscles and keeps 
the head level with the ground. The participant lifts the R 
leg off the ground, flexes the knee of the R leg, and extends 
the hip past neutral hip alignment by bringing the heel 
toward the ceiling and then returns to parallel.  Neutral 
lumbar alignment should be maintained and increased 
lumbar lordosis avoided.  After completing a set with the R 
leg, the exercise is repeated with the L leg.
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4.5 Wobbleboard - Unilateral balance(Leavey et The participant stands on wobble board, activates TrA and 
al., 2010) LM and maintains static stability.  The participant keeps 
lumbo-pelvic alignment and balance while controlling 
aberrant motion.  
Week 5
5.1 Standing 2kg medicine ball  or pulley rotation The participant stands with her feet shoulder-width apart 
(Fredericson et al., 2005) and knees slightly bent.  The participant activates TrA and 
LM and maintains neutral spinal alignment throughout the 
movement.  The participant holds a straight-arm position 
(elbows extended) and grasps the pulley handle or medicine 
ball with both hands.  The athlete rotates the trunk by 
activating the abdominal obliques and spinal rotators while 
maintaining a stable pelvis.  The exercise is repeated to the 
alternate side.
5.2 Lower trunk rotation with shins on physio ball The participant begins the exercise by placing her shins on 
(Kahle and Gribble, 2009) the physio ball and her hands directly below her shoulders.  
The participant activates TrA and LM and maintains neutral 
lumbar spine throughout the movement.  The athlete 
rotates the trunk by activating the abdominal obliques and 
spinal rotators while allowing the physio ball to roll.  The 
participant returns to the starting position and the exercise 
is repeated to the alternate side.
5.3 Side plank with upper leg hip abduction The participant lies on her R side with the R arm extended in 
(Fredericson et al., 2005; Ekstrom et al., 2007; a straight line up from the shoulder, with the forearm 
Boren et al., 2011) resting on the mat. Participant activates TrA and LM and is 
instructed to keep shoulders, hips, knees and ankles in line 
bilaterally throughout the movement.  The participant then
raises the hips from the ground to achieve neutral 
alignment of trunk, hips, and knees (side plank position). 
While balancing on elbow and foot, the participant abducts 
the L leg. Participant maintains plank position throughout all 
repetitions.  The exercise is repeated on the alternate side.
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5.4 Front plank on physio ball  (Fredericson et al., The participant kneels behind the physio ball, with both 
2005) forearms on the ball.  Keeping TrA and LM activated and the 
lumbar spine in a neutral position, the participant rolls the 
physio ball away from her body until there is a straight line 
from the shoulders to hips.  While maintaining neutral 
alignment, the participant holds the position for 20 seconds, 
working up to 40 seconds.  If the participant is able to 
maintain neutral alignment throughout a set of repetitions, 
the body is gradually straightened until up to the toes.
5.5 Functional hop exercises: (Leavey et al., 2010) 1) Participant stands on her R leg and hops forward in 
1) Unilateral diagonal forward a zig-zag pattern.  The exercise is repeated on the L 
leg. 
2) Participant stands on her R leg and hops backward 
in a zig-zag pattern.  The exercise is repeated on 
the L leg.
2) Unilateral diagonal backward 3) Participant stands on her R leg and hops forward 
and backward to her R in a zig-zag pattern.  The 
exercise is repeated on the L leg.
4) Participant stands on her R leg and hops forward 
and backward to her L in a zig-zag pattern.  The
3) Unilateral forward/backward same side exercise is repeated on the L leg.
45˚
5) Participant stands on her R leg , hop and rotates 
alternately 45… to her L and R.
4) Unilateral forward/backward opposite 
side 45˚
5) Unilateral rotation 45˚
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WEEK 6
6.1 Forward lunge with a 2kg medicine ball or The participant stands upright, holding a 2kg medicine ball, 
weight with trunk rotation (Fredericson et al., with arms outstretched, perpendicular to the body.  The 
2005) participant steps forward with the medicine ball in front of 
the chest with the arms extended.  The participant lunges 
and after the lunge is completed, the participant rotates the 
trunk by bringing the ball across the body toward the same 
side as the front leg and then returns the ball to the midline 
as the next step is made.  The knee joint of the front limb 
should not come pass the vertical angle relative to the ankle 
joint and the second toe should be aligned perpendicular 
with the patella.
6.2 Upper extremity-trunk supine overhead throw The participant positions herself on the physio ball that her 
simulation using a physio ball and a netball (Smith spine contours the ball and is well supported.  The 
et al., 2008) participant activates TrA and LM and tucks her chin in a little 
(Consent obtained for use of photo – Appendix 8) as if holding a tennis ball between chin and chest.  The 
participant curls up and simulates an overhead throw.
6.3 Upper extremity-trunk seated overhead throw The participant sits upright on a physio ball, with the lumbar 
simulation using a physio ball and a netball (Smith spine in neutral position.  The participant’s L foot is on the 
et al., 2008) floor while the R foot is placed on the L knee with the R shin 
(Consent obtained for use of photo – Appendix 8) parallel to the floor.  The participant activates TrA and LM 
and while maintaining lumbo-pelvic stability simulates a
netball throw.
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6.4 Upper extremity-trunk-lower extremity The participant stands on her L leg with het R foot on a 
standing passing simulation using a physio ball and small physio ball.  The participant activates TrA and LM and 
a netball (Smith et al., 2008) while maintaining lumbo-pelvic stability and balance 
(Consent obtained for use of photo – Appendix 8) simulates a netball throw.
6.5 Single-limb 90ᴼAirex hop and hold (Filipa et al., The participant stands with her R leg on an Airex mat.  The
2010) participant activates TrA and LM and while maintaining 
(Consent obtained for use of photo – Appendix 8) lumbo-pelvic stability, the participant hops on one leg and 
keeps balance for five seconds prior to the next attempt.
Acronyms: R: - right; L: - left; TrA: - transversus abdominis; LM: - lumbar multifidus; GMed: - gluteus 
medius.
124
Appendix 7 Ethics Committee approval letter
125
126
127
Appendix 8 Consent form for the use of photographs
128
Summaries
A summary of the mini-script
Dynamic postural control is the ability to perform a functional task with purposeful movements that 
translates the body’s centre of gravity without compromising a stable base of support.  The functional 
task might involve jumping or hopping to a new location and immediately attempting to remain as still 
as possible or attempting to create movements such as reaching or throwing without compromising the 
base of support (Winter, Patla and Frank, 1990; Kahle and Gribble, 2009, Gribble, Hertel and Plisky, 
2012).
Maintaining dynamic postural control is essential for netball players as netball players frequently find 
themselves on one leg having to make an accurate pass.  Research by Ferreira and Spamer (2010) 
evaluated the physical profile of elite university netball players and found poor balance in these netball 
players during pre-season.
No literature could be found regarding studies investigating a programme that utilized the combination 
of core stability, m.gluteus medius (GMed) strengthening and proprioceptive balance exercises on 
dynamic postural control or studies investigating the effect of an exercise programme on dynamic 
postural control in netball players.  The research study was undertaken to determine if an exercise 
programme that incorporates core stability, m.GMed strengthening and proprioceptive balance 
exercises would lead to a significant improvement (p 0˂.05) in dynamic postural control in a group of 
netball players.
A cross-over randomised clinical trial was performed.  Sixteen female university netball players selected 
in the top junior group participated in this study.  Participants were randomly divided in two groups. 
Group A participated three times a week for six weeks in the exercise programme while group B was 
considered as the control group after which the roles were reversed.
The simple Star Excursion Balance Test (SEBT) with three trials and four directions were used to measure 
dynamic postural control of the participants.  All participants were assessed at baseline, after six weeks 
and after 12 weeks. Participants from both groups were tested simultaneously, and the data collector 
and assistant were blinded to which group the participants belonged. Data were analyzed by a 
biostatistician using student’s and paired t-tests.
129
Dynamic postural control as measured with the SEBT demonstrated a statistically significant 
improvement (p<0.05) across three reach directions (anterior, medial and posterior) in a group of netball 
players post participation in an exercise programme that incorporated core stability, m.GMed 
strengthening and proprioceptive balance exercises.  The study proposes that an exercise programme
that incorporates core stability, m.GMed and proprioceptive balance exercises could be beneficial for 
improving dynamic postural control in a group of netball players.
The results of the study provided substantial evidence for the use of a combination of core stability, 
m.GMed strengthening and proprioceptive balance exercises in programmes rehabilitating netball 
players with poor dynamic postural control. The present study also provides a baseline for further 
research whether an exercise programme that incorporated core stability, m.GMed strengthening and
proprioceptive balance exercises would contribute towards improved performance and injury 
prevention in netball players. The effectiveness of the exercise programme described in the present 
study could be implemented and investigated in other sporting codes requiring dynamic postural 
control. Netball players can also confidently use the developed exercise programme in the present 
study to eliminate shortcomings in their physical profile, with regards to dynamic postural control.
Key terms: dynamic postural control; dynamic balance, dynamic postural stability; core stability; gluteus 
medius strengthening; proprioception; Star Excursion Balance Test; netball players; transversus 
abdominis; neuromuscular control; centre of mass
130
‘n Opsomming van die mini-verhandeling
Dinamiese posturele beheer is die vermo‹ om ‘n funksionele aktiwiteit met doelgerigte bewegings uit te 
voer wat die liggaam se swaartepunt verplaas, sonder om ‘n stabiele ondersteuningsbasis prys te gee.  
Die funksionele aktiwiteit mag spring na ‘n ander area insluit terwyl daar onmiddellik daarna gepoog 
word om so stil te staan of om ‘n beweging soos uitreik of gooi uit te voer sonder om die stabiele basis 
prys te gee (Winter, Patla and Frank, 1990; Kahle and Gribble, 2009, Gribble, Hertel and Plisky, 2012).
Die handhawing van dinamiese posturele beheer is essensieel vir netbalspelers aangesien netbalspelers 
hulself dikwels op een been bevind terwyl hulle nog steeds akkuraat moet gooi.  Navorsing deur Ferreira 
and Spamer (2010) het die fisiese profiel van elite universiteitsvlak netbalspelers pre-seisoen ge‹valueer 
en hulle bevinding was dat netbalspelers swak balans gehad het.
Geen literatuur kon gevind word rakende navorsingstudies wat die invloed van ‘n kombinasie 
oefenprogramme bestaande uit kernstabiliteit, m. gluteus medius (GMed) versterking en 
proprioseptiewe balansoefeninge insluit, op dinamiese posturele beheer ondersoek nie of enige studie 
wat die effek van ‘n oefenproram op dinamiese posturele beheer in netbalspelers ondersoek nie.  Die
navorsingstudie is onderneem om te bepaal of ‘n oefenprogramme wat kernstabiliteit, m.GMed 
versterking en proprioseptiewe balansoefeninge insluit sal lei tot ‘n beduidende verbetering (p 0˂.05) in 
die dinamiese posturele beheer van ‘n groep netbalspelers.
‘n Gerandomiseerde gekruisde kliniese proef is uitgevoer.  Sestien vroulike universiteits netbalspelers 
wat verkies is as die top junior groep, het aan die studie deelgeneem.  Deelnemers is ewekansig verdeel 
in twee groepe.  Groep A het drie maal ‘n week vir ses weke aan die oefenprogramme deelgeneem 
terwyl groep B as die kontrole groep beskou is, daarna is die rolle omgekeer.
Die eenvoudige “Star Excursion Balance Test” (SEBT) met drie proefslae en vier rigtings is gebruik om die 
dinamiese posturele beheer van die deelnemers te bepaal.  Al die deelnemers is evalueer voor die 
aanvang van die oefenprogramme, na ses weke en na 12 weke.  Beide groepe se deelnemers is 
gelyktydig evalueer en die dataversamelaar sowel as die assistant was blind ten opsigte van die groep 
waaraan die deelnemer behoort het. Data is deur ‘n biostatistikus analiseer met studente en gepaarde 
t-toetse.
Dinamiese posturele beheer soos bepaal met die SEBT het ‘n beduidende verbetering (p 0˂.05) getoon in 
drie rigtings (anterior, mediaal and posterior) in ‘n groep netbalspelers na deelname in ‘n 
oefenprogramme wat kernstabiliteit, m.GMed versterking en proprioseptiewe balansoefeninge ingesluit
131
het.  Die huidige studie stel voor dat ‘n oefenprogramme wat kernstabiliteit, m.GMed versterking en 
proprioseptiewe balansoefeninge insluit, voordelig kan wees vir die verbetering van dinamiese posturele 
beheer van ‘n groep netbalspelers.
Die resultate van die studie verskaf beduidende bewyse vir die gebruik van ‘n kombinasie van
kernstabiliteit, m.GMed versterking en proprioseptiewe balansoefeninge in rehabilitasie programmeme 
van netbalspelers met swak posturele beheer. Die huidige studie verskaf ook ‘n grondslag vir verdere 
navorsingstudies om te bepaal of ‘n oefenprogramme wat kernstabiliteit, m.GMed versterking en 
proprioseptiewe balansoefeninge insluit tot verbeterde spel en voorkoming van beserings in 
netbalspelers kan lei.  Die effektiwiteit van die oefenprogramme wat in die huidige studie ontwikkel is, 
kan ook geimplementeer en ondersoek word in ander sportsoorte wat dinamiese posturele beheer 
benodig.  Netbalspelers kan die ontwikkelde oefenprogramme van die huidige studie met vertroue 
gebruik om tekortkominge in hulle fisiese profiel rakende dinamiese posturele beheer uit te skakel.
Sleutelterme: dinamiese posturele beheer; dinamiese balans; dinamiese posturele stabiliteit; 
kernstabiliteit; gluteus medius versterking; propriosepsie; Star Excursion Balance Test; netbalspelers; 
transversus abdominis; neuromuskulêre beheer; swaartepunt.
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