[m_gloeckl]

Being a fairly competitive runner in my spare time (38:40 10k, 1:26 half marathon), I'd like to weigh in:

There are two different kinds of flexibility involved in running or exercise in general. 1) Static flexibility: Responsible for your ability to bend over and reach down to your toes. 2) Dynamic flexibility: Remember those drills where you try to kick your heel as high as possible? From standing, bringing up your heel as far as possible is difficult, but even while you're jogging slowly, it's much easier.

While it is important to maintain a good balance between static and dynamic flexibility, the latter is more important during exercise. Consider doing a dynamic warmup before your exercise [1], rather than doing static stretches. The reasoning behind this is that static stretching reduces the tension within your muscle fibers and leads to decreased strength and stability during exercise. After exercise, thorough static stretching is fine. While the effect on lessening muscle soreness is somewhat doubted, stretching muscle fibers after exercise prevents your muscle fibers from shortening and aids in restoring flexibility and tension for your next exercising session.

TL;DR: Rule of the thumb: Pre exercise -> dynamic warm-up; post exercise -> static stretching

[1] http://www.youtube.com/watch?v=djDqDDQl-Y4

[fuzionmonkey]

I thought this was well understood for a while now.

Has anyone advocated static stretching prior to exercise or sports in recent times? I'm in college now, but ever since I can remember, dynamic warmups were done, and static stretching was only post-exercise.