Do This, Not That!

Have you seen those, “Eat this, not that!” articles as it relates to nutrition, weight loss tips, and health news?

Let’s apply that principle to exercises.

How many physical therapists, personal trainers, or coaches have had their athletes do the Superman exercise? How many of us do this exercise ourselves?

The “Superman” exercise is one that I remember doing well before I started PT school in 2008. I still see it done at the gym on a frequent basis. I remember being told it is a great way to exercise the muscles that support the spine, so I understand why many people still do the exercise. At the time, I didn’t think about what biomechanically is going on with the exercise and whether it was safe to do.

The Superman exercise is when you lie on your stomach and lifts both arms and legs up to train the spinal extensors, gluteal muscles, and secondary muscles as wellsuperman-core-exercise. According to Stuart McGill, who is an expert on low back disorders, the Superman exercise creates nearly 6000 N of compression to a hyperextended spine, transfers the load to your facets, and crushes the interspinous ligaments (You can see all his work in his book: Low Back Disorders: Prevention and Rehabilitation). Simply put, it’s really bad for your back when done repeatedly. For perspective, the National Institute for Occupational Safety and Health (NIOSH) did research and testing regarding the maximum disc compression levels that your back can safely tolerate. They found that level to be 3425 N, or about 770 pounds of force.

If we do some simple conversions knowing that 1 newton = 0.22 pounds, than we see that the Superman exercise at 6000 Newtons is equal to 1349 pounds of force to the lumbar spine. That exercise exceeds the safety guidelines by nearly 600 pounds of force!

So what to do? A core exercise that I think is challenging, but also more safe is the forearm plank.

ab-plank-2x3

Although I haven’t seen research on the levels of compression during a plank, Dr. McGill has found that the side plank creates a force of about 581 pounds to the lumbar spine, and being in a push-up position leads to 413 pounds of force. The more traditional plank is listed under one of his advancements of the side plank exercise, so I am inclined to believe it is still well below the 770 pounds of force noted by the NIOSH to correlate with risk of back injury.

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