Below are some of the most important stretches runners should do after each session. A document containing these stretches can be downloaded here.
It is generally recognised that static stretches like those portrayed on this page should not be performed prior to a run when the muscles are still cold. Instead a warm up is preferred before running, with static stretches done afterwards. Stretches should be held for at least 10 seconds, but can be held longer to increase their effect.
Warm ups should start off gently, build in intensity and usually involve movements that will be used in the exercise to follow. They should last about 5 to 10 minutes.