http://AskTheTrainer.com/best-lower-ab-workout.html Personal Trainer Michael Behnken, MS, NASM-CPT-PES, CSCS Big 40s Credit goes to Oregon State Strength and Conditioning Make sure to keep core drawn in. Hands under butt = easier. Hands behind head = much harder. Your Lower back should be flat on the ground for the duration of the motion. Keep the core drawn in tight! San Francisco Personal Training http://fitSF.com