HOW: Start by laying flat on your back. Perform the exercise by flattening your low back into the ground, then fluttering your legs up and down, back and forth about a foot off the ground.
FEEL: You should feel your abs, legs, and core working with this exercise.
COMPENSATION: Do not let your low back excessively arch. Try to keep your low back pushed into the ground. Do not let your knees bend, keep your quads squeezed to keep your knees straight.
