Crunches lack accountability. Form may be top-notch for the first few reps, but it often falters as you go. Plus, it’s the same move, over and over. (Yawn.) This helps explain why building a strong core can be difficult. The reverse banded crunch is different. Adding resistance forces you to work for every rep, and changing up the movement pattern emphasizes different muscles. Pain-Free HIIT Circuits That Burn Fat, Build Muscle, and Save Your Joints “In traditional crunches, the top of the abdominals leads, so the most tension is created there,” says Brandon Mentore, a Philadelphia-based strength and conditioning coach. “The reverse crunch approaches the muscles from the other direction, so tension is greatest at the bottom.” To set up, attach a light resistance band to a rig or pole at shin height. Sit on the floor facing the attachment point, knees bent, the free end of the band across thighs. Scooch back until the band is taut, then lie back and grasp a heavy kettlebell behi