Experts at the Rehabilitation Institute of Chicago found that the stretches are the most effective for lengthening the muscles in the backs of your thighs while maximizing muscle and knee flexibility, both of which help diminish or prevent pain. Choose your favorite, and do 3 sets at least 3 times a weekafter working out.
Passive stretch (top left) Lie on your back in a doorway with your left heel against the wall. Bend your hip to a 90-degree angle with your leg as close to straight as possible; your right leg should be on the floor, through the doorway. Move closer to the wall as your hamstring begins to stretch out. Hold for 30 seconds, then switch legs and repeat to complete 1 set.
Assisted stretch (top right) Begin in the Passive Stretch starting position, and place a strap, towel, or belt over the ball of your raised foot. Gently pull down on the strap and back toward your head until you feel a good stretch, then slowly point your toes upward. Continue for 30 seconds, then switch legs and repeat to complete 1 set.