Here’s is the truth: crunches aren't always the best way to tone your abs. In fact experts say the calorie burn from crunches is negligible because crunches target the abdominal muscles – not abdominal fat. This means doing a whole bunch of crunches can help you build muscle but won’t burn belly fat. Moreover you may have to do several reps (30 40 and more) to reach the challenging point to give your abs a serious workout. By that time you’ve already wasted a whole lot of time. With high volumes of repetitive spinal flexion you’re also putting yourself at