Sit on the edge of the chair with your back straight. Pull your belly button in to engage your ab muscles and protect your back muscles. With your knee bent, lift one leg up slightly and hold for a few seconds. Straighten your leg out as far as you can without dropping it down to the floor. Bring your leg back into a bent position but don’t lower your foot back to the ground. Repeat extensions to a straightened leg 20 times. Then lower your leg down and put your foot on the floor. Repeat with the other side. This exercise is great for strengthening your leg muscles!