Swiss Ball Sit Up: How to Get Stronger Abs and a Weaker Back

Many of us suffer from Googleitis – a painful, inflammatory condition of the mind created by a need to find answers on our own.

I made that up but I think it’s true.

For example, if you search for “Core Exercises” in Google or Bing or Yahoo, you’ll get upwards of 125,000,000 things to look through and then you have to figure out if what the site presents is something you can do or should do.

One of the more popular drills that shows up on fitness or “work-out” sites for “core exercises” is the Swiss Ball Sit-Up (or a small variation of it as the Swiss Ball Crunch).

It’s touted as a great way to “strengthen your core muscles, including your abdominal muscles, back muscles, and the muscles around the pelvis” (Mayo Clinic) and a sit-up on the swiss ball is supposedly better because “the shape of the ball creates an unstable environment on which to do core training and strength training programs that strengthen the stabilizer muscles of the body.” (

So, let’s deconstruct it.

A plain, old-school sit-up is a very difficult exercise to do properly – on the floor or anywhere else.

Here’s why.

To do the sit-up correctly, you must curl the trunk up while maintaing a solid, neutral position of the lower back and without using the hip flexors to pull your spine up (since the hip flexors connect from the lumbar spine to the pelvis and upper thigh). To do this, you have to anchor the pelvis while simultaneously using the same muscles to help the trunk curl. Most people don’t have that kind of strength and control so instead, they use the hip flexor to sit up, pulling on the lumbar spine, legs come off the floor, creating a shearing (or slipping) force between the lumbar vertebrae. And there isn’t any joint in the body that likes or wants shear force.

Here’s an example. Watch for the slight upward movement of the legs (this happens at the end of the first sit-up). This motion of the legs indicates that she used her hip flexors instead of her abdominal muscles to perform the curl and that the drill is actually too hard (and one other thing to note is how much extra curve she has in her upper back at the end of the sit-up).

Arguments Against the Swiss Ball Sit-Up

Range of motion. Now that you’ve seen a standard sit-up, imagine what happens when you try this on an unstable base like a swiss ball. The argument for the ball is that it increases the range of motion that the trunk works through and therefore increases the muscle work. Well, your spine isn’t designed to be put through large excursions of motion as, for example, the knee. The spine is best suited for small movements to help position your extremities. Training it through this large of a motion is both unnecessary and risky.

Spinal Pressures. The compression forces of the sit-up exceed safe limits and go even higher with the swiss ball. A sit-up generates approximately 3500 Newtons of pressure or roughly 786 pounds of force. According to Dr. Stuart McGill and The National Institute for Occupational Safety and Health (NIOSH), pressures above 3300 Newtons correlates highly with more lower back injury and pain. A sit up on the swiss ball nearly doubles the spinal pressure of a traditional curl up.*

Time. I don’t know about you but I have a limited amount of time to spend on training and exercise. Isolating types of exercise – as in the swiss ball sit-up – just lengthen my routine. I want a routine that’s focused, with exercises that are spine-friendly, and get a lot done in a short amount of time.

Safer and More Effective Options Than the Swiss Ball Sit Up

Plank. Almost any version of the plank – forearm, tall, side – is a good choice for challenging multiple muscle groups (trunk, buttocks/hips, shoulders, abdominals) and have been shown to be spine friendly with lower spinal forces.

Back Slider X. This one requires you to use a lot of muscle and coordinate the motion. The motion of the arms will automatically cause a contraction in the core muscles.

Standing Plank Burner. This is an original drill I created for a client who could not do a plank because her right great toe didn’t like the position it was in. It’s much more difficult than it looks and is a great way to work your core muscles in an upright position.


Bottom line, you have a lot of other, better choices than a Swiss Ball Sit-Up to challenge the core muscles while sparing your spine. Yes, the Swiss Ball Sit-Up might strengthen your abdominal muscles but the price may be weak back that sets you more than a week back.

For an organized and detailed approach to core strengthening, get my book, “Build a Rock Solid Core“.

*McGill, S. M. (2004). Spinal Pressures in the Curl Up. Ultimate Back Fitness and Performance. Waterloo, Ontario, Wabuno: 235.

Jimtigerpt says

If you have not tried the standing plank burner, you are in for a real surprise. Try this one and make sure you keep your back straight and do NOT lean forward.

    DD Kelsey says

    Right….looks easy enough, huh? A nice variation is an “X” move – one arm over head, the other about 45 degrees abducted down by the side. Then, next rep, switch. You can swap this out as the degree of difficulty is about the same and it has roughly the effect but recruits muscle differently. Try it and let me know what you think.

      Jimtigerpt says

      Nice variation. Is different. A nice drill to alternate positions during the session.

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