If you stopped doing crunches years ago thinking planks are the way to go, you may want to reconsider your routine. A new study by the American Council on Exercise (ACE) says the old-school exercise may be the best approach after all.
ACE commissioned researchers at the University of Wisconsin, La Crosse, to evaluate and compare the effectiveness of popular abdominal strengthening equipment such as the Ab Roller, Ab Lounge, and Circle Pro; exercises including yoga boat pose, bicycle crunch, and stability ball crunch; and the traditional crunch.
Using electrodes placed on the subjects’ various abdominal muscles, the scientists measured the subjects’ maximum voluntary contraction as they did each exercise and used piece of equipment.
The result: Traditional crunches showed the greatest muscle activation overall. This is not to say, however, that it’s the best abdominal exercise, says Cedric X. Bryant, Ph.D., chief science officer with the American Council on Exercise. “Although the curl or crunch movement allows you to maximize that contraction of flexing the trunk, there isn’t a single exercise that can address all the musculature of the abdominal region.”
Bryant notes that the study did not measure deeper muscles such as the transverse abdominis, a muscle key to core function and stability and daily functioning. “Our study shows that if you’re just concerned about the contraction of a given exercise in respect to the rectus abdominis—which are responsible for the six-pack effect—crunches are as effective or more effective than all the different devices out there,” he says.
In addition, using abdominal equipment such as those evaluated in the study in general immediately makes it easy to cheat and use momentum. “There’s no way not to cheat with those,” says Gino Caccavale, a New York City personal trainer and creator of the Rezist workout DVDs. “Whenever you’re holding on or hanging on to something, you use other muscles outside of the ones you’re targeting.”
So skip the machines and mix up your abdominal exercises, including core moves (planks, side planks) along with crunches. Training your midsection in a variety of planes of motion—including twisting as well as forward crunching—three times a week ensures a well-rounded abdominal- and core-strengthening program.