Many sportspeople do sit-ups as part of a raft of exercises which aim to improve their core stability,but research from Thomas Nesser from Indiana State University suggests that improving your corestability doesn't necessarily result in better athletic performance.
Whether or not they provide you with precisely the physique or fitness you desire, could sit-ups bring unintended consequences such as back pain?Stuart McGill, professor of spine biomechanics at the University of Waterloo in Canada has been studying sit-ups for years and is convinced that the traditional crunch does indeed cause usharm.
He conducted dozens of studies in his spine biomechanics lab using the cadavers of pigs,repeatedly flexing their spines in a similar way as a person might when doing a sit-up, but formany, many hours at a time. When he examined the discs in the spine afterwards, he foundthat they had been squeezed to the point where they bulged. If the same thing happened in ahuman this would press on the nerves, causing back pain, and possibly even a herniated disc.
Pigs were chosen for this experiment because their spines are more similar to human spines than those of many other animals, but of course critics of these studies point out, that there are still many differences between people and pigs. Also these studies involved thousands of continuous cycles of bending. Even when training hard, people take breaks between sets of crunches.
Perhaps these results tell us what might happen at the extremes in the unlikely event that you were to do sit-ups for hour upon hour, but in real life it's clearly not the case that most people damage their discs most of the time when doing sets of 15 sit-ups. However, injuries can happen. Research published in 2005 on soldiers stationed at the US military's Fort Bragg attributed 56% of all the injuries sustained during the two-yearly Army Physical Fitness Test,to sit-ups.
Some people seem to be more prone to back problems caused by sit-ups than others. We might be fine doing 30 sit-ups a day for decades, but we might not and it's hard to know which group we fall into. It could come down to our genes. According to one paper, it's not wear-and-tear that causes most of the difficulties, but genetic factors, which account for three-quarters of the differences between the people who do get back problems and those who don't.
So sit-ups might lead to back pain, but only in some people. It's a good excuse not to do them.But if you want to crunch those abs, is there a way of limiting the risk? Professor Stuart McGill recommends sliding your hands under your lower back to stop it flattening against the floor.This minimises the stress on your back.