From the NY Times phys Ed blog:
Now, two new studies are giving us additional reasons not to stretch.
One, a study being published this month in The Journal of Strength and Conditioning Research, concluded that if you stretch before you lift weights, you may find yourself feeling weaker and wobblier than you expect during your workout. Those findings join those of another new study from Croatia, a bogglingly comprehensive re-analysis of data from earlier experiments that was published in The Scandinavian Journal of Medicine and Science in Sports. Together, the studies augment a growing scientific consensus that pre-exercise stretching is generally unnecessary and likely counterproductive.
Many issues related to exercise and stretching have remained unresolved. In particular, it is unclear to what extent, precisely, subsequent workouts are changed when you stretch beforehand, as well as whether all types of physical activity are similarly affected.
This was about stretching before a workout. I read the article wondering what they thought about stretching after, but they didn’t mention it. They do say that this is just about ‘static stretching’ and not about warming up with jogging or other exercises that mimic the motions that you’ll be doing in the workout itself.
A better choice, he continued, is to warm-up dynamically, by moving the muscles that will be called upon in your workout. Jumping jacks and toy-soldier-like high leg kicks, for instance, prepare muscles for additional exercise better than stretching. As an unscientific side benefit, they can also be fun.