Stretching techniques on hamstring flexibility in female adolescents

This study compared the effi cacy of 4 different hamstring-stretching techniques. Flexibility can be achieved by a vari ety of stretching techniques, yet little research has been performed on the most effective method. The four most bas ic stretches includes: Static stretching where the limb is held stationary at and endpoint for a certain time period; Dynamic stretching, an active stretch where the limb is slowly moved from the neutral position to the endpoint; PNF hold-relax- and PNF contract-relax stretching which is also referred to as active stretches because of the concentric and isometric contractions throughout the stretch (Prentice, 201 0: 11 I). This study's aim was to determine which type of stretching technique is most effective in improving hamstring length. One hundred female subjects between the ages of 13 and 17 years were enrolled in the study. The 90°/90° hamstring length measure was used for a ll measurements to measure knee extension angle. All I 00 subjects were included in a randomized controlled trial of 5 different groups comparing different hamstring-stretching techniques. Outcome measure (hamstring length) was recorded on a ll subjects initiall y, at 3 weeks and at 6 weeks. After 3 weeks of stretching, there was a statistically s ignificant improvement in hamstring length (p<0.000 I) us ing all stretches when compared to the control group. From weeks 3 through 6, hamstring length for all groups again showed stati stically significant improvement when compared to the control group. No s ignificant difference was found comparing the intervention groups after 3 weeks or after 6 weeks of stretching. After both 3 weeks and 6 weeks of stretching the straight-leg-raise (static stretching) group had the greatest improvement in hamstring length, a lthough the di ffe rence was not statisti cally significant.