For people with sensitive knees, exercises such as squats and lunges can be painful. But those exercises are great for tightening the muscles in the buttocks and the backs of your thighs. Here's an alternative you can try that will target the thighs without putting a lot of pressure on your knees.
1 Stand on your left leg, resting your left hand on something sturdy -- a chair, fence or bar. Place your right hand on your hip. Place the instep of your right foot against the heel of your left foot. Your right shoulder, hip, thigh and foot should rotate slightly outward.