Effects of acute static stretching on exercise efficiency during high-intensity cycling exercise.

Abstract

Static stretching has been shown to reduce exercise efficiency and performance of aerobic exercises as well as decreasing the ability to generate maximum muscle force in momentary movements such as jumping. As a mechanism for the reduced efficiency, the possibility that changes in muscle fiber recruitment occur to compensate for the decrease in maximum voluntary contraction (MVC) has been suggested. We examined whether the stretching-induced decrease in exercise efficiency is accompanied by a decrease in MVC and changes in electromyographic (EMG) activities of exercising muscles. Eight healthy subjects performed 6 min of cycling exercise at 70% of maximal oxygen uptake in the conditions with and without pre-exercise static stretching (stretching condition [SC] and control condition [CC]). MVC was measured before stretching maneuvers (or the resting period in CC) and after the end of exercise. In the 6-min exercise test, respiratory parameters and EMG activities of knee extensors were measured. Oxygen uptake at 3 min and 6 min during the cycling exercise were higher in the SC than in the CC (P<0.05). There was no difference in MVC at the end of 6 min exercise between the two conditions. Similarly, there were no differences in EMG activities during the 6-min exercise between the two conditions. The results suggest that pre-exercise static stretching reduces exercise efficiency independent of its negative effect on MVC exertional capacity.