Always check with your doctor before beginning an exercise program. These exercises are designed to help, not hurt. If you experience pain at any time during the exercise, stop. Pain is your body’s way of telling you that something is wrong.
BONUS TIP: If you have increased soreness after doing these exercises, it may help to ice your knee or knees for 10 - 20 minutes. Place a bag of ice (or frozen vegetables) over the joint, with a towel between to protect the skin. Elevate your leg on a chair if ice alone is inadequate.