Three cheers for the good old-fashioned crunch. In a recent study, researchers placed electrodes on participants’ abs to measure muscle activation while they did standard crunches, bicycle crunches, planks, curl-ups and used a bunch of fancy ab equipment. Lo and behold, nothing was as effective at strengthening the abdominals than our good friend the crunch. While it might not be the best move for everyone, nothing’s got it beat for sheer effectiveness, no purchase required.
MORE: How to Do Crunches the Right Way