About the Cable Crunch
The kneeling cable crunch is a tremendous, weighted abdominal exercise designed to help you make blocks out of your six-pack. Even though we can’t completely isolate any portion of the abdominals, whenever you bring your torso forward toward the legs, the upper abs (six-pack) are highly engaged. When you add weight from a cable, that constant tension provides serious stimulus to create deep cuts and a great midsection.
Spot the Error
Choosing a weighted ab movement allows you to train in a lower rep range, but unlike many ab exercises that are tough to get wrong, this one is often tough to get right.
Often you’ll see guys grab the rope and kneel down while settling back on their haunches, almost sitting on their ankles. By doing that, you allow your bodyweight to help bring the weight down, a practice which reduces the tension on the upper abs and drastically shortens the range of motion. The first photo is correct.
Adjust yourself under the rope so that your knees are far enough away from the weight stack to give you plenty of room to maneuver. You might even try spreading your knees slightly to create a good, solid foundation. At the start of the exercise keep your back flat and maintain a big chest, even though you’re facing down. Then take your torso down to the floor while crunching your abs. The only movement should be a bending over at the waist. Don’t sit back, allowing the degree of bend in your knees to change, but think about taking your elbows directly to your knees. That image will help you maintain tension exactly where it should be.
Shoot for high reps before adding weights and doing low-rep sets. Allow yourself to get a feel for the movement. Make sure your hands (with the ends of the rope) remain fixed at either your ears, shoulders or upper chest. They must maintain the same relative position next to your head throughout. Try to move as one unit attached to the rope and avoid letting your arms extend, as that will remove the tension from your midsection.