Ab Facts

A good write up on the "why" situps are not an effective ab enhancement choice from Women's Health.

"You have five lumbar vertebrae, and each one gives you about seven to nine degrees of motion, for a total of 45 degrees," says Mary Kirkland.  That means to truly work your core, you need to stay between zero degrees (like a plank) and 45 degrees (like a crunch).  "From 45 degrees to a full situp, you're engaging your hip flexors, which attach directly to your lumbar spine.  Too many reps will not only make your hip muscles sore, but your lower back will start to hurt too."