Weighted Sit-Up

Lie on your back, knees bent, feet flat and anchored. Hold your weight at your chest rather than behind your head, where it pulls on your neck instead of your core. Curl your torso up leading with your chest, not by yanking your chin forward. Come all the way up to sitting, then lower back down under control instead of dropping. Keep the weight close to your body throughout the movement rather than letting it drift forward, which turns the exercise into more of a balancing act than a core one.