Cheating is a term used in bodybuilding to describe the involvement of additional muscle groups in what would normally be considered an isolation exercise. Cheating during bicep curls allows you to use a heavier-than-normal load, hit deeper muscle fibers, and build mass and power in your biceps. To perform cheat curls with a barbell, keep your elbows tight to your body but use some momentum, and the power of your core, to swing the weight up to your shoulders. Do not let your shoulders pass the line of your hips at the top of the movement to protect your lower back.