Effect of stretching techniques on hamstring flexibility in female adolescents

Abstract

Flexibility can be achieved by a variety of stretching techniques and the benefits of stretching are known. However, controversy remains about the best type of stretching for achieving a particular goal or outcome. The four most basic stretches are static stretching, dynamic stretching, PNF hold-relax and PNF contract-relax stretching. This study‘s aim was to determine which type of stretching technique is most effective in improving hamstring flexibility. One hundred female participants between the ages 13 and 17 years participated in the study. The 90º/90º hamstring length measure was used for all measurements of knee extension angle. All 100 participants were included in a randomised controlled trial of five different groups comparing different hamstring stretching techniques. Outcome measure (hamstring length) was recorded on all participants initially, at three weeks and at six weeks. After three weeks of stretching, there was a statistically significant improvement in hamstring length (p < 0.01) for all types of stretching when compared to the control group. From weeks three through six, hamstring length for all techniques again showed statistically significant improvement when compared to the control group. No significant difference (p > 0.05) was found between the intervention groups after three weeks and six weeks of stretching. After three weeks as well as after six weeks of stretching the straight-leg-raise (static stretching) group had the greatest improvement in hamstring length, although the difference was not statistically significant.

Keywords: Stretching techniques, hamstring flexibility, female adolescents.