Acute Effects of Dynamic Stretching on Peak and End-Range Functional Hamstring/Quadriceps Strength Ratios


TURKIYE KLINIKLERI TIP BILIMLERI DERGISI, vol.30, no.1, pp.164-173, 2010 (SCI-Expanded) identifier identifier


Objective: Although recent studies have shown that dynamic stretching may improve individual muscle strength performance, its effects on the functional hamstring/quadriceps (H/Q) strength ratio and thus on injury risk characteristics has not been investigated in depth. The aim of this study was to assess the effects of dynamic stretching on functional H/Q strength ratios for iso-kinetic knee extension and flexion at peak and end range moments in elite women athletes. Material and Methods: A total of twelve healthy elite competitive female athletes (mean age 20 +/- 2 years, mean height 166 6 cm, mean weight 58 +/- 7 kg) volunteered to participate in the study. All subjects completed a non-stretching (control) or a dynamic stretching intervention protocol in a randomized fashion on separate days. The quadriceps and hamstring muscles were stretched during these protocols. Before (pre) and after (post) the intervention, the functional H/Q strength ratio was calculated at 60 degrees.s-1 and 180 degrees.s-1 angular velocities. Results: The strength ratio for knee extension displayed a significant increase and for knee flexion a significant decrease following dynamic stretching during the entire and end range of motion at both angular velocities (p<0.05). Conclusion: The effects of dynamic stretching on functional H/Q strength ratios suggest that the functional H/Q ratio do change positively following a dynamic stretching routine.