The rope crunch is one of the most common ab exercises-and the one most often performed incorrectly. Many people pull the weight by bending at the waist, which works the hip flexor. The correct technique locks the hips and crunches the sternum toward the pubic bone, engaging the rectus abdominis-the muscle that creates the six-pack.
The rectus abdominis is a single, flat muscle running from the sternum to the pubic bone. Tendinous inscriptions create the six-pack blocks, but they cannot be isolated separately. There is no "upper" or "lower" ab-only one continuous muscle.
To perform the rope crunch correctly: kneel at a high cable station with a rope attachment, place hands behind your head, arch your back, and lock your hips. Pull the weight down by rolling your spine into a hunched contraction, as if touching your elbows to your knees. Use enough weight for at least 20 reps, pushing through the intense burn to reach failure. This deliberate pain is key to building a shredded six-pack.