This is a more advanced exercise, so you shouldn't attempt it until you've already mastered the Single Leg Balance. The purpose is to increase strength and proprioception (balance) in your lower extremities.

Increase strength and balance in your lower extremities. This will assist with increasing joint stability in the knee joint.

Ball such as a basketball, softball, or tennisball

Start by lifting your uninjured leg into the air and balancing on your injured leg with your knee slightly bent.

Toss the ball back and forth with a partner or bounce it against a wall to yourself, all while maintaining your balance.

Do not continue this exercise if there is pain, swelling or a significant increase in skin temperature (skin becomes hot/warm to the touch). Keep in mind that each person is different and you must modify your activity according to the feedback your body provides. If you feel your muscles getting fatigued (a good thing) and you begin losing control (leg begins twitching) stop and return to the exercise at another time.