Effect of static and dynamic stretching on hamstring flexibility in the warm-up

Abstract

Introduction: This study compared the acute effects of static and dynamic stretching in the warm-up, on hamstring flexibility using a reliable set-up for measurement.Methodology: Static and dynamic flexibility was measured using five modifications of the Straight Leg Raise test to measure hip flexion range of motion (deg). In the first part of the study (n = 33) hamstring flexibility was measured using a Static-passive, Static-active, Dynamic-supine and Dynamic-standing tests. The results of this study were used to calculate reliability statistics and to compare the various static and dynamic flexibility tests. This was followed by an intervention study (n = 12) where participants were randomly assigned to three intervention treatments of 225 s on separate days: No stretching (Treatment 1), static stretching (Treatment 2) and dynamic stretching (Treatment 3) in a cross-over study design. Results/conclusion: There was a significant difference between Static-passive and the Dynamic-supine hamstring flexibility tests (p .05). When dynamic stretches were included in the warm-up instead of static stretches, it was expected that there would be changes, at least, in dynamic flexibility of the hamstrings. The analysis shows that there were statistically significant differences in both static (t (11) = 2.62, p < .05) and dynamic (t (11) = 5.69, p < .05). These findings were confirmed by non-parametric tests.Static stretching only influenced static flexibility (Wilcoxon, Z =-2.67, p < .05) of the hamstrings, while dynamic stretching produced changes in both static (Wilcoxon, Z =-2.39, p < .05) and dynamic flexibility (Wilcoxon, Z =-2.98, p < .05). The results have implications for the specificity of stretching in sport.