From Dr. Van Thiel
Lie flat on a mat, your stomach muscles tight, and the right knee bent with your foot on the floor. With the left leg straight on the floor, slowly lift and lower your leg without bending the knee. Repeat this 3x on one side and then switch legs.
With the support of a table or chair if needed, slowly lift your leg of focus forward with your knee straight and return back to the ground. Repeat 10x. If you want more of a challenge, add increasing weight to the ankle over time as you gain strength.
Standing straight, lift your left foot behind you, maintaining a flat, neutral position until it reaches 90°. Bend your right knee slightly for support. Lower your foot to the floor. You may use a chair or other object to help you stabilize. Complete 2-3x per leg and repeat as needed.