Loose kneecaps can result from multiple dislocations of the kneecap from contact sports, genetic predisposition or chronic injury to the knee because of body mechanics. Although loosened ligaments cannot be tightened using exercises, your muscles and the tendons that attach them to your bones can be strengthened to counteract the causes of your loosened kneecap.
If you dislocate your knee multiple times, the ligaments that hold your kneecap in place will be stretched beyond their normal range with every dislocation. This means that at the cellular level, the collagenous fibers that comprise your ligament will be stretched out. Unfortunately, unlike muscle fibers, which can retract to their original length, ligament fibers tend to stay elongated once they are stretched. People with genetically loose ligaments are especially at risk of dislocating body parts, including their kneecaps. The best method of counteracting loose ligaments is to strengthen their surrounding muscles.
Strengthening your Quadriceps Femoris Muscle
Your quads, which consist of four separate muscles, attach at or near your kneecaps by way of tendons. Your rectus femoris is the middle muscle on your thigh, with the vastus medialis on the inside and vastus lateralis on the outside of your thigh. The seated leg extension on a Nautilus or other universal machine with legs parallel to each other will strengthen this group of muscles. Sitting on the machine, extend your legs out and stop just short of a full leg extension. The slower you extend and retract your legs, the more fibers you will engage, and the more effective the exercise.
Strengthening your Sartorius Muscle
Your sartorius muscle starts near the front of your hip bone, also called the iliac spine, and crosses your leg to insert just below your kneecap on the inside of your lower leg. Lying flat on your side with your legs bent to about 45 degrees, slowly bring your knees toward the ceiling and back down to meet your other leg. This exercise will strengthen the sartorius and prevent movement of your kneecap toward the inside of your thighs.
Strengthening your Tensor Faciae Latae and Hamstrings
Even though your hamstrings are on the back of your leg, they can still play a role in stabilizing your knee and by extension, your kneecap. You can strengthen these muscles by doing shallow squats, which require no more than 40 degrees of bending, going up and down stairs, and hamstring curls on Nautilus and universal machines at your gym. Your tensor faciae latae is mostly a tendon on the outside of your leg that inserts near your kneecap, with its muscle high up at your hip level. This tendon can be particularly stiff in men. Standing or lying lateral leg raises will strengthen this muscle and help prevent movement of your kneecap to the outside of your leg.