The effect of 4 different durations of static hamstring stretching on passive knee-extension range of motion

Design: Pretest-posttest. Objective: To determine the effect of 4 durations of static hamstring stretching on knee-extension passive range of motion (KE-PROM). Context: Effects of longer (90 and 120 seconds) static hamstring stretching on PROM have not been established relative to moretypically recommended 30- or 60-second durations. Subjects: 35 healthy college-age subjects with > 20 degrees loss of KE-PROM. Outcome Measure: KE-PROM. Intervention: 5-week program of single daily stretch for 30, 60, 90, or 120 seconds. Results: Static stretching was effective in increasing KE-PROM regardless of stretch duration (P < .0001). A significant improvement was identified in mean PROM for each stretching group, but no difference existed among the 4 stretch-duration groups. The control group's mean PROM decreased (mean = -3.2 degrees, SD = 1.9), whereas each stretching group increased PROM (means 1.9 degrees to 3.6 degrees). Conclusions: Five weeks of daily static hamstring stretching for 30, 60, 90, or 120 seconds increase KE-PROM. Similar benefits were achieved regardless of stretch duration, suggesting that clinicians need not perform static hamstring stretches of more than 30 seconds.