To strengthen a specific portion of the medial thigh muscle which has particular influence in knee stability.
Be seated in a chair with buttocks against the back of the chair, spine upright and shoulders relaxed. Feet should be comfortably apart and contacting the floor. Straighten the knee of the affected side so that it is roughly horizontal.
Bend the knee of the suspended leg to about 15° and then rotate the whole leg outwards. In this position slowly raise the whole leg higher, hold for 10-15 seconds, relax and repeat. Placing a small ankle weightincreases the effectiveness of the exercise.
If this exercise is too strenuous or painful, the same muscle can be worked in a different position. Lie on your back on a flat surface with legs straight. Place a rolled bath towel or pillow beneath the knee of the affected leg causing it to bend just slightly. In this position, attempt to push the knee downward into the towel or pillow by squeezing your thigh muscles. Hold the squeeze for 5 seconds then relax.
Tip: rotating the leg being worked on outwards will help recruit more fibres of the vastus medialis muscle.