There are numerous studies published on the effects of stretching on exercise performance. If you haven’t had time to read and cross-reference them all, you may be interested in a review of the research, published in the September/October issue of Clinical Journal of Sport Medicine (2004; 14 , 267–73).
According to this analysis, stretching immediately before exercise may actually impede rather than improve sport performance. Ian Shrier, MD, PhD, of SMBD–Jewish General Hospital in Montreal, examined 23 studies. He found that acute stretching reduced performance on various tests, including muscle force, torque and jumping height.
Shrier also identified nine studies of regular stretching programs. Of these, seven found better performance with regular stretching. Areas of improvement included muscle force production and contraction velocity, suggesting that the benefits resulted from muscle strengthening.
The review proposes that stretching improves performance in athletic tests, but only if the stretching is done regularly. In contrast, acute stretching doesn’t seem to improve sport performance; in fact, it may even reduce it. In a press release, Shrier recommended that people stretch either after exercise or “at a time not related to exercise.”