Stretching
When to stretch
Before running? 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.
After running? 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.
When, then? 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.
How runners should stretch. Only a relaxed muscle can be extended safely and comfortably.
Start with a gentle massage. By gently kneading the calf, hamstring, butt and lower back, you increase blood flow and loosen up the muscles. For about five minutes, use your 10 magic fingers to work out any knots, but don't apply any deep penetrating pressure.
Gradually and slowly move into the stretch. Back off from any tension and hold that relaxed extension for at least 10 20 seconds. If you feel the slightest pressure or pain, or if the muscle starts shaking, you've gone too far. Ease back until you are relaxed again.
Finish the stretch by slowly easing out of it.
The Principles of Stretching
Be regular. Benefits come through steady, regular sessions of gentle muscle extension. Just as tightness builds up through years of standing, walking and running so will it subside only gradually through months of gentle extension.
Don't bounce. Decades ago, runners did bouncing stretches. It was thought that a jolt to the muscle gave it the extension it needed. More recent research has shown, however, that bouncing shortens and tightens muscles. It engages the stretch reflex, the body's automatic defense device against injury, which causes the muscle to tighten rather than extend.
Don't compete. Don't try to stretch as far as someone else. Everyone is different in terms of flexibility. And don't try to equal your best stretch of yesterday. Some days you'll be relatively limber; others fairly tight. Just relax and move into the comfortable position that feels good that day.
from Galloway's Book On Running