Lumbo-pelvic core stability: profiles of female long-distance runners
Running is a sport characterised by a 90% prevalence of predominantly lower-limb overuse injuries. Stress urinary incontinence (SUI) is also prevalent and its hindrance in terms of participation falls within the definition of running injuries. Neuromuscular mechanisms within the proximal kinetic chain have been correlated to these injuries and conditions, however contrasting views exist. Adaptations within the tonic and phasic characteristics of core musculature have been shown to elicit a series of kinetic adaptations within the movement system predisposing injury/recurrence of injury. The aim of this research was to discuss the changes in core muscle characteristics in relation to risk of injury after exposure to a functional activity. Changes were presented by means of profiling. A secondary objective was to identify numerous internal and external risk factors of running-injury. A descriptive, cohort analytical study design was used with a convenience sample of fifteen (15) eligible experienced female long-distance runners registered in Bloemfontein-based accredited running-clubs. The baseline- and post-exercise profiling test battery included electromyography (EMG) of the pelvic floor muscles (PFM) and M. Transversus Abdominus (TrA)(ICC 0.98), pressure biofeedback testing (PBU) (ICC 0.90) and functional endurance testing (ICC 0.97). Any 24+ km functional longrun served as functional task. External, internal and demographic factors were identified using a self-compiled questionnaire. The majority of the TrA EMG, PBU and Dominant-Side lateral muscle group profiles displayed an increase in post-exercise value. The profiles illustrated both failure (decrease in value) and or possible neuromuscular mechanisms (increase in value) attempting to augment stability. These mechanisms are suggestive of a loss of stability on a more central level. The cohort also displayed remarkably low-level integrated stability activity (PBU) both at baseline and post-exercise. There were no statistical significant difference between the baseline and post-exercise profiles for any of the PFM (p=0.7957), TrA (p=0.2769), PBU (p=0.1875), Anterior Muscle Group (p=0.1688), Posterior Muscle Group (p=0.1909), Lateral Dominant Muscle Group (p=0.5897) or Non-Dominant Lateral Muscle Group measurements (p=0.1848). Knee injury was identified as the most prevalent previous running injury (47%). Only 20% of the 67% of participants that included muscle conditioning in training programs included the PFM. Running training errors were the most significant external causative factors present within the cohort together with insufficient periodisation and recovery from longruns. The results of this research support the inclusion of core-stability components in running injury risk management and rehabilitation. The major limitations of this research were the small sample size and absence of a control group. This may be addressed by future research on valid functional core testing. Future research should also establish scientific indicators of fatigue and correlation between corecharacteristics and risk of injury.