The man who wants to kill crunches - Macleans.caAfter three decades of figuring how out the spine works, Stuart McGill has come to loathe sit-ups. It doesn’t matter whether they are the full sit-ups beloved by military trainers or the crunch versions so ubiquitous in gyms. “What happens when you perform a sit-up?” he asks. “The spine is flexed into the position at which it damages sooner.” The professor of spine biomechanics at the University o
