Crunches are one of the most universal exercises when it comes to training your core, but they actually aren't that effective. Stuart McGill, PhD, world renowned professor of biomechanics, found that crunches can put up to 340 kilograms of compressive force on the spine when bent in flexion. If you currently have back pain, this is an exercise to avoid at all costs. Instead of doing crunches, try any of these 37 crunch-free exercises to strengthen your core.
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