The Rope Crunches exercise is an often forgotten exercise in the gym. This is one of the bodybuilder's favourite exercises for getting the abs into great condition. Keeping a fair distance away from the machine, keep tension on the abdominal wall at all times. Maintain a flat back & always pull in the navel towards the spine whenever crunching your bas to activate the core; the transverse abdominus & the lower abs. Ensure that your movement is controlled on the way up. Don'ts - Avoid arching the lower back too much by having too much range of motion. Being too close to the machine will cause too much range of motion. Ensure the range of motion is short to maintain tension on the abs at all times. Nick Jones - World Bodybuilding Champion & Zoran Lekic - Bodybuilder.