Stupid Exercise of the Week: The Leg Press

So I know that in writing this, I'm going to get some flack from people who love to use the Leg Press Machine. I can already hear the complaints of people who think squatting is "dangerous," or the local gym-rat who thinks that it's making his legs "all swole." Sadly this exercise is one that you'll almost never see me using with my clients. Why? Well for one, with people sitting at a chair all day, or rounding over their upper backs (causing excess lumbar lordosis in order to compensate) people have allot of lumbar spine issues. So lets look at a picture of the leg press and see if we can't use some basic reasoning, before going into specifics, about why this exercise is terrible.

Now if you're looking at the picture above and saying, "no big deal" lets rotate this picture and see what a real-world equivalent would look like.

And don't think for a second that the horizontal leg press machine is any different.  Ask yourself this question: Does the above picture portray a healthy way for any human to bear large amounts of weight? Even with a reduced range of motion which many experts recommend to prevent excess rounding of the back, this woman is still loading weight onto a portion of her spine not meant to bear weight. With a few rare exceptions, there is no way you should be loading a rounded spine! To quote one of the great exercise physiologists living today, Dr. Michael Yessis:

The leg press is used to target the quadriceps, hamstrings and gluteus maximus. The potential danger in this exercise is seen when you, in an attempt to get a greater range of motion, bring the knees in close to the chest on the lowering phase. This, in turn, rounds the lumbar spine and because of the heavy weights typically used, (in comparison to the squat), the pressure acting on the spinal discs increases greatly. The high compression forces can cause disc rupture or other low back injury. The problem is compounded greatly the more the spine in the lumbar area flexes, i.e., the closer the knees come to the chest. In this knee-to-chest position the compression forces act on only a very small portion of the discs instead of the entire disc as when the spine is kept neutral.

Now Dr. Yessis and many others go on to explain that you can reduce this problem by limiting your ROM (range of motion), but to what benefit? You could do a normal squat, or if for some reason you're unable, a hack squat machine or smith machine squat (not that the Smith Machine is great for your knees). At least with those two alternatives, you can hold proper back position and posture (assuming you've been properly instructed). Sure you might get away with using a limited ROM leg press, but at it's best it does nothing to help your back, and at it's worst it can cause serious lower back injury. Quote Source: dryessis.com Photo: wikipedia