The knee is the largest joint in the body. Since we use our knees extensively every day to walk, climb, or jump, they easily experience wear and tear. Exercises to strengthen the knee do not affect the knee joint directly. Rather, they strengthen the muscles surrounding it. When you have strong muscles in the legs, your knees will be better supported. This, in turn, prevents future knee pain and injuries.   If you strengthen your quadriceps and hamstring muscles, you can reduce pain. This makes it easier to stay mobile. Physical therapy is the best option for most. A physical therapist can create a personalized strengthening regimen. This will target weak muscles that cause your specific type of pain.