It has been proposed that pre-exercise static stretching may reduce muscle force and power. Recent systematic and meta-analytical reviews have proposed a threshold regarding the effect of short (<45 s) and moderate (>=60 s) stretching durations on subsequent performance in a multi-joint task (e.g. jump performance), although its effect on power output remains less clear. Furthermore, no single experimental study has explicitly compared the effect of short (e.g. 30-s) and moderate (60-s) durations of continuous static stretching on multi-joint performance. Therefore, the aim of the present study was determine the effect of acute short- and moderate-duration continuous stretching interventions on vertical jump performance and power output. Sixteen physically active men (21.0+/-1.9 y; 1.7+/-0.1 m; 78.4+/-12.1 kg) volunteered for the study. After familiarization, subjects attended the laboratory for three testing sessions. In the non-stretching (NS) condition, subjects performed a countermovement jump (CMJ) test without a preceding stretching bout. In the other two conditions, subjects performed 30-s (30SS; 4 min) or 60-s (60SS; 8 min) static stretching bouts in calf muscles, hamstrings, gluteus maximus and quadriceps, respectively, followed by the CMJ test. Results were compared by repeated measures ANOVA. In comparison to NS, 60SS resulted in a lower CMJ height (-3.4%, p<=0.05) and average (-2.7%, p<=0.05) and peak power output (-2.0%, p<=0.05), but no difference was observed between 30SS and the other conditions (p>0.05). These data suggest a dose-dependent effect of stretching on muscular performance, which is in accordance with previous studies. The present results suggest a threshold of continuous static stretching in which muscular power output in a multi-joint task may be impaired immediately following moderate-duration (60-s; 8min) static stretching, while short-duration (30-s; 4 min) stretching has a negligible influence.
Copyright (C) 2014 by the National Strength & Conditioning Association.