Static stretching worsens endurance exercise performance

You may already know that static stretching impairs high force and velocity athletic performance, but a study published recently in the Journal of Strength and Conditioning Research provides evidence that static stretching worsens muscle endurance performance too.

"Stretching before anaerobic events has resulted in declines in performance; however, the immediate effects of stretching on endurance performance have not been investigated. This study investigated the effects of static stretching on energy cost and endurance performance in trained male runners."

The authors examined trained male distance runners oxygen utilization, calorie expenditure and performance in distance running with and without stretching beforehand. The data were unambiguous:

"Performance was significantly greater in the nonstretching vs. the stretching condition, with significantly greater energy expenditure during the stretching compared with the nonstretching condition. Our findings suggest that stretching before an endurance event may lower endurance performance and increase the energy cost of running."

How might this occur? Static stretching seems to decrease mechanical efficiency of the muscle system by causing the muscle tissue to work harder to produce the same amount of force. The authors further elaborated on their findings:

"In summary, this study provides 2 key findings concerning endurance performance after a bout of static stretching. First, it extends the detrimental effects of stretching from activities requiring high force and velocity components to the domain of muscle endurance performance. Second, this research suggests that static stretching increases the energy cost of running at moderate-intensity exercise. Therefore, in events such as long-distance running, where success is related to producing work with minimal energy cost, it may be unfavorable for coaches to have athletes warm up in a manner that has them perform long, static stretches immediately before a middle- or long-distance running event."