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Want a Healthier Knee? Just Squat

The dynamic squat exercise is used widely among sports and fitness enthusiasts. It is also used in various forms by therapists in rehabilitation programs. The author reviewed current research to detail how the squat affects the knee. He looked at the forces that doing a squat puts on various parts of the knee, the muscle activity during a squat, and the squat's effects on knee stability.

This study supports the use of the squat exercise in patients who are undergoing rehabilitation. Squats can be used to treat patients with an injured anterior cruciate ligament (ACL) in the knee. The hamstring muscles on the back of the thigh protect the ACL by keeping the lower leg bone from sliding forward during the squat. And tilting the body forward appears to put even less strain on the ACL.

Patients who've injured the knee's posterior cruciate ligament (PCL), however, should only squat part way down--to about 60 degrees. Going past this point causes the lower leg bone to be pulled backward, which puts a heavy strain on the PCL. The squat can be used to help people with kneecap problems, but the deeper a person squats, the greater the force against the back of the kneecap, where it meets the femur bone of the thigh.

People with healthy knees can benefit by squatting down until the knees bend 90 degrees. This is known as a parallel squat because the knees bend until the thigh is parallel with the ground. This exercise technique stabilizes the knee and ankle by strengthening the hip, thigh, and calf muscles.

Power lifters and Olympic weightlifters sometimes do deep squats where their knees bend more than 90 degrees. The forces on the knee go up dramatically during a deep squat, placing the ligaments and cartilage of the knee at risk of injury. Most athletes should avoid the dangers of the deep squat and perform the parallel squat instead. So for a healthier knee, go ahead and squat.

References: Rafael F. Escamilla. Knee Biomechanics of the Dynamic Squat Exercise. In Medicine & Science in Sports & Exercise. January 2001. Vol. 33. No. 1. Pp. 127-141.

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