The full range of motion necessary to work the entire abdominal muscle group. Crunch exercises and most equipment fall short of the Ab Assist Mat! - A variety of exercises that isolate upper and/or lower abs, as well as the obliques and lower back muscles. - A safe, comfortable design contoured to your lower back to provide support and to help prevent injury. - One size fits all! There is no need to worry about height and weight differences between users. - No more balancing! Unlike fitness balls, the Ab Assist Mat won't roll or wobble on you, so you can focus on your workout - A compact, portable design that requires no set-up or tear-down. Take it with you anywhere!