The Fitness Fixer
The Fitness Fixer

Hamstring to Quadriceps Ratios Not the Answer in Knee Injury

A common myth is that injury comes from "muscle imbalance" in the thigh from too much strength in the quadriceps muscles over the hamstring muscles.

Early studies showed poor ratios of quad to hamstring strength. It was concluded that because of this, when the athlete would kick, for example, the overly strong quadriceps would overstraighten the knee, and the overpowered hamstring behind the thigh would not be able to stop the powerful straightening. The knee would overstraighten and hyperextend the joint, injuring it.

Athletes were put on hamstring strengthening training. Then they went back to kicking with the same bad habit of overstraightening as before.

The problem was simply that they athlete would hyperextend the knee. They were allowing it through bad training habits, not being made to do it by a strong quadriceps. Your muscles do not make you move. You learn though training and practice how to move in healthy ways.

What to do?
When you kick, don't fling your leg out and hyperextend (overstraighten) the knee. Control the end point position.
When you land from jumps or descending stairs, don't step down on a locked, straight knee. Control the end point position.

Muscle use is not automatic from muscle strength:


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About the Author


Dr. Bookspan is an award-winning scientist whose goal is to make exercise easier and healthier.