The Patellofemoral Joint and Athletes

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leg extensions

Working out your leg muscles is a major part of any exercise regimen. The quadriceps muscle is one of the biggest muscles in the body and composes the anterior portion of your thigh. Lower extremity excercises will help you burn calories and will strengthen your overall routine.

One of the most common exercises performed to try to strengthen the quadriceps muscle is a weighted leg extension. This is usually performed on a seated machine where the foot is free and extension of the knee is resisted by weights. This is an example of an open chain exercise, where the terminal part of the extremity is free in space and not grounded.

This type of exercise puts a tremendous amount of load onto your patellofemoral joint, aka the kneecap. This is an exercise that is uncommonly recommended in rehabilitation after surgery and should be reconsidered if it is part of your routine.


By subjecting your patellofemoral joint to these excessive loads, you are subjecting your cartilage in that joint to excessive wear. This may eventually lead to early arthritis and pain. Patellofemoral arthritis is a common form of arthritis seen in our middle-aged population.

People can be in their late 30’s and early 40’s and began to develop anterior knee pain with stairs, sitting, running. It is a painful and debilitating disease process. Performing exercises that may hasten this process or perhaps cause problems in a young active person are therefore unwarranted.

So what can you do to build your quadriceps and prevent excessive loading of your patellofemoral joint? Closed chain exercises are the best method. These exercises work out your quad muscle with the foot on the ground or on a platform. The difference here is that the ground stabilizes the lower extremity. This allows the quadriceps to fire in coordination with the hamstrings on the back of your leg in order to lessen the forces seen by the patellofemoral joint.


Lunges, squats, and leg presses are examples of closed chain exercises that can not only help build muscles mass for your lower extremities, but also engage your core muscles as well. I prefer squats and lunges of any variety because a leg press machine can cause excessive strain on your spine. This is food for thought for any exercise and fitness enthusiast, myself included.

Given that most people will begin working out in their 20’s through 50’s and hopefully their 60’s, it is imperative that we take care of our joints while we strengthen our bodies. You want to be able to stay fit throughout your life. Sustaining an injury or developing arthritis can seriously hinder your ability to sustain a healthy active lifestyle.

This post is just a piece of information to help you choose appropriate exercises to help strengthen your body while at the same time attempting to avoid musculoskeletal problems in the future.

Daniel Acevedo
Daniel C. Acevedo, M.D. is an orthopedic surgeon who has a special interest in weight training and injury prevention. He is the author of a number of book chapters, scientific studies, as well as surgical training videos for the orthopedic surgery community. He hopes to bridge the gap between exercise and orthopedic medicine. His perspective can help avid CrossFitters avoid injury and make them aware of potential problems that can develop with poor technique or form. Daniel holds an M.D. from the UC Irvine, completed his residency in Orthopedic Surgery at the University of Southern California, and is currently finishing his fellowship in advanced Shoulder and Elbow Surgery at the renowned Rothman Institute in Philadelphia, PA.
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  • Thomas White

    Good read…and totally agree!

  • Jonathan Shum

    Squat for health! Nice read…

  • Dave Webber

    quality read

  • Gpaw

    There are some problems here. I’m 60-years old. Have been lifting since I was 18. Squats are undoubtedly great, and the main course for the leg routine. However, leg extensions are an excellent isolation device to build the quads. Keep the weights moderate and you will see some quick gains in strength and size.