Fitness: Little bending required

Jill Barker, Special to The Gazette 


MONTREAL - Sit-ups, once the darling of the fitness community, have fallen out of favour in the past few years. Leading the charge is Stuart McGill, a professor of spine mechanics at the University of Waterloo, who Maclean’s magazine referred to as “the man who wants to kill crunches.”

McGill’s beef with sit-ups, crunches and any other similar exercise is that bending forward is tough on the spine. And since everyday life demands a number of forward bends, like putting on shoes and emptying the dishwasher, why increase the strain on the back by adding sit-ups to the mix?

In place of crunches, McGill suggests performing exercises that work the core muscles without a forward bend. He claims exercises like the plank, the bird dog and “stir the pot” are better choices.

Not everyone agrees with McGill. Strength and conditioning specialists Bret Contreras and Brad Schoenfeld question McGill’s argument that curl-ups have a negative impact on spine health. In an article published in the August 2011 edition of the Strength and Conditioning Journal, Contreras and Schoenfeld contend that experiments like those done by McGill and other researchers don’t replicate the real-life application of the exercise.

“The studies in question attempted to mimic loading patterns of occupational workers by subjecting spinal segments to thousands of continuous bending cycles, which is far beyond what is normally performed in the course of a dynamic exercise program,” said Contreras and Schoenfeld.

They go on to explain that the average ab routine consists of two to three sets of a limited number of crunches punctuated by a rest between sets. This is nowhere near the procedure used in the cited studies measuring the consequences of repeated abdominal curls, which mechanically simulated 4,000, 6,000, 10,000 and 86,400 forward bending cycles using pig spines.

“Thus, total bending cycles per session ultimately amount to a fraction of those used in the cited research protocols, and these cycles are performed intermittently rather than continuously,’ said Contreras and Schoenfeld.


So if the wear and tear of years of forward bends isn’t the culprit behind disc injury, what is? Contreras and Schoenfeld point to studies suggesting that heredity factors such as the size and shape of the spinal structures plays a far more significant role in the degeneration of discs over time than do crunches.


In response, McGill isn’t ready to back down. He suggests that the argument about whether to crunch or not can get complicated and it’s not as easy as labelling an exercise good or bad. The real question is whether the exercise is right for you, based on your personal goals and history of back health.

He also says that he does plenty of experiments with humans and through his clinical practice has experience dealing with athletes, the sedentary and everyone else in between, so his conclusions are not just based on experiments with porcine spines.

And he still advocates against crunches. “Most back pain in young people 20 to 50 years of age is due to excessive forward flexion,” said McGill.


Well, you need to weigh the risks vs. benefits before deciding to add crunches your workout. If you have back pain or a job or activity that demands lots of forward bending like a hockey player or a construction worker, then you should avoid crunches and do a challenging exercise like stir the pot which, according to McGill, does a better job of challenging the core without the stress of a crunch.


One thing McGill, Contreras and Schoenfeld all agree on is that hundreds of crunches a day have few benefits and lots of risk. So get used to the plank, stir the pot and the bird dog – they’re your new best friends.


