Last week, we interviewed Stuart McGill, a professor of spine biomechanics at the University of Waterloo, in a piece about the dangers of sit-ups and crunches.

McGill, author of Ultimate Back Fitness and Performance (Stuart McGill, 2004) was kind enough send us a video demonstrating a better way to work your abs—including a modified move, called the "McGill crunch" by school children all over Canada. Take a look and adjust your workouts accordingly. For more information, visit McGill's site, backfitpro.com