Sit-ups. The Blog Post.
The first step to answering that is to get the facts right about what we do do. The simple truth is that we do occasionally do sit-ups. We teach a perfect sit-up. We occasionally have people who are comfortable with sit-ups do them. We encourage people who have to pass PT tests to do them. We encourage people who will be competing CrossFit to do them every now and then.
The second step to answering this question is that we don’t do sit-ups because we don’t think they’re anywhere near as functional for making you better at everything ELSE in life and CrossFit as doing other things that emphasize stabilizing the midline. Essentially, research and our own experience tells us that doing a lot of other things can make you better at sit-ups but that getting better at sit-ups doesn’t make you better at these other things.
The third step in explaining why we don’t sit-ups is that for most athletes they aren’t worth the risk. You can read more about the risk here (scroll to the bottom of the article or search “sit-up”). Cressey says, “The psoas major has attachments on the T12 and each of the lumbar vertebrae. When activated [as in a sit-up!], it imposes significant compression (~3,300 N, 730 lbs.) on the spine. Coincidentally, McGill (2004) reported that 3,300 N is also the action limit for low back compression in workers as set forth by the National Institute of Occupational Safety and Health (NIOSH, or the Canadian equivalent of OSHA). In other words, each sit-up you perform exceeds the level of loading that is associated with an increased risk of on-the-job injuries!”
If what you want is rock solid core strength and/or visible abs (let’s all be honest here…) the way to get it is something closer to eating right, and coming to gymnastics – than doing a million gajillion (real number) sit-ups a day.