A muscle under needless tention is sending constant stress messages to the brain.By stretching legs and lower back,you can increase knee-joint mobility.Lie on your back with your arms at your sides. Raise your upper body off the floor as you roll your head forward,chin toward chest,until you feel the base of your shoulder blades touching the floor.At the same time,pull your right knee into your chest.Place your left hand on your right knee and your right hand on the outside of your right leg midway between your calf and ankle.Extend your left leg at a 45-degree angle with the floor.
I copy this in ebs english book for korean S.A.T