The HealthBeat Ab Crunch and Leg Lift The core is defined as any muscle from the shoulder to the hips. To use the Ab Crunch we are going to lay flat on the bench and have either the feet interlocked into the loop or on top. Beginner users may want to have their feet inside of the loop But then more advanced users can begin putting their feet outside of the loop and on top. We’re going to lift our body up to a 45 degree angle and then lower back down. And since we are using body weight it’s important to remember more repetitions will increase the difficulty of this exercise. To do the leg lift the user is going to grasp the bar in his hands and then begin by lifting his legs to a 45 degree angle and then lowering his legs back down. This is going to engage the lower part of the abdomen. And then again do as many repetitions as you can and because we’re using body weight more repetitions will make this more difficult.