Raising the Red Flag on Leg Extensions
Doug Jackson has always valued a variety of opinions when it comes to the best ways to condition the body. In the following article, his friend and colleague Jonathan Ross, 2006 American Council on Exercise Personal Trainer of the Year, challenges the perceived value of leg extensions. The debate continues…
I’m Raising the Red Flag
I’m normally a believer in the phrase “never say never” as there are always exceptions to most rules. In this case, I have an exception to that rule.
One piece of equipment I’d never purchase for a gym, and an exercise I’d never have a client perform: leg extensions.
Experts that recommend it should know better. Tiger Woods did it for years…then tore an ACL while playing golf!?
This all-too-common exercise needs to disappear. Here’s why.
The seated leg extension machine moves and loads the knee joint in a way unlike anything we do in real life and is completely at odds with the biomechanics of the knee. The excessive torque placed on the knee – and the shearing forces that result – are a sure-fire method of slowly grinding your knees to an injury. In this exercise, the thigh is held fixed by the seat, and resistance is place on the shin just above the foot. From here you extend the knee using the quadriceps muscles. High school physics taught us that every action has an equal and opposite reaction. Thus, when we push our foot hard against the resistance, the top of the shin wants to move down (imagine the opposite ends of a see-saw). But because the seat holds the thigh in place we get an unnatural strain on the knee joint as the lower thigh cannot move along with the upper shin.
In life, we may kick a soccer ball or extend our legs to walk or run. In every real-life example the upper and lower leg move together. As a result, the muscles do the work, and the joints stabilized and allow the muscle actions to move the bone. And all is well in our bodies. Experts who should know better are not immune to recommending this exercise. In a recent fitness column in the Washington Post, a reader asked a question about leg extensions. This person had a knee surgery in 1999, and has been performing leg extensions and leg curls until someone told him they weren’t a good idea. They asked if this is true. The reply quoted Nicholas DiNubile, Philadelphia-based orthopedic surgeon. He stated, “They are the cornerstone for building strong legs.” No. No. No. They might be the cornerstone of a strong surgical practice, but not for strong legs. The author of the column went on to tout the benefits of leg extensions since Tiger Woods does them.
By the way, the article was written on May 13, 2008 – a few weeks before we find out that Tiger won the U.S. Open while playing with a torn ACL. Golf leading to a torn ACL? Almost unheard of.
Could it be that an ACL weakened by years of leg extensions failed under the rotational forces in a golf swing? No one can say for sure as it is almost impossible to link cause and effect. But it sure does raise an eyebrow… I suffered a torn ACL (partially torn playing soccer, then fully torn playing volleyball a few years later) in the early 1990′s and had it surgically repaired.
Beyond the first few months of physical therapy after surgery, I have never done leg extensions. That’s 15 years with no leg extensions and my knees feel stronger now than they ever have.
I’ve never had a client do them and everyone from athletes to knee replacement clients have gotten stronger lower bodies as a result. Further, I’ve removed leg extensions from the programs of many people with non-descript knee pain and the pain often disappears – even while they perform squats, lunges, and other leg exercises. The only time this exercise makes any sense is in the very early days of rehab following surgery when the resistance is very low (and as a result so is the torque) and the goal is very basic muscular activation and strengthening of the quad.Trainers, equipment manufacturers, and everyone else out there: Have the courage and smarts to turn away from this pointless, potentially destructive piece of equipment. We could use the space in the gym for something far more useful!
Visit Jonathan’s website at http://www.aionfitness.com/
