Your abs are always working. Whether you’re throwing a ball or moving furniture, they’re on the move, but they’re almost never working alone. Your abdominal muscles are either contracting to keep your core stable while your legs work, flexing to move your torso up and down or side to side, or all of the above. As a result, it’s best to stay away from a steady diet of conventional crunches, so your abs can instead work the way they were designed to: in concert with the larger muscles that surround them. The following core routine accomplishes all of that and more.
Hanging Knee Lift/Pike/Split
Hang from a pull-up bar with your upper body and legs parallel to the floor. Contract your abs to lift your knees. When your thighs are parallel to the floor, straighten your legs, spread them as far as possible, then lower them to the start position.