Most runners think they should stretch just before running. You see them everywhere, legs on benches, leaning against buildings-getting ready to run. I don’t recommend this. Just before running, the muscles are tight and may pull or strain easily. You are particularly at risk early in the morning when you’re cold and blood flow is minimal. Pushing a cold muscle, tendon or joint often leads to injury.
Stretching right after running is also a risky proposition. The muscles don’t simply stop all activity when you stop running. They are still “revved up” and ready to respond for about 30 minutes; stretching may cause them to spasm. When they are working hard like this, a stretch often activates the stretch reflex – leaving you tighter than before.
The best time to stretch is after the body is warmed up, relaxed, and when the blood is moving. Since many runners do stretch incorrectly, it’s best to wait and stretch after warming up. Don’t stretch to warm the muscles up; it won’t work. Stretch in the evening, for example, or throughout the day as you have time. Many of my friends use stretching as a nice way to prepare for sleep.