It’s a common misconception that stretching before/after/during a workout will help relieve the soreness we feel from a challenging workout. While it’s very rare that I’ll tell a client not to stretch, I make sure they understand it’s not going to help soreness disappear.
Stretching before a workout or athletic event also doesn’t appear to prevent injury, although I wouldn’t say that it’s been shown to promote injury either.
This doesn’t mean I’m telling anyone to stop stretching. We sit too much and move too little, so a little stretching couldn’t do us any harm, provided it’s done correctly. When studying the effects of stretching on range of motion, Decoster et al. found that 30 seconds is the magic number. One set of 30 seconds or smaller sets that add up to equal 30 seconds had the same effect on range of motion. Anything over 30 seconds showed no greater result. Hang out in a stretch longer if you want, just don’t expect to become rubberman by stretching for hours at a time.
Andersen JC. Stretching before and after exercise: effect on muscle soreness and injury risk. Journal of Athletic Training. 2005;40(3):218–220.
Decoster LC, Cleland J, Altieri C, Russell P. The effects of hamstring stretching on range of motion: a systematic literature review. J Orthop Sports Phys Ther. 2005;35(6):377-387.