Key Point from the Article: The sit-up and crunch violate all of these principles. The exercise asks you to pick up something heavy, but because you’re lying o

Key Point from the Article: The sit-up and crunch violate all of these principles. The exercise asks you to pick up something heavy, but because you’re lying on the ground and the heavy thing is your upper body, there’s no way for you to brace your core and shift the effort to the big, high-capacity muscles of your legs. The best way to train your "Core" (both front and back) is to do some Yoga Asanas and Bandhas.