This exercise is great for your abdominal area, and especially for your lower abdominal muscles.
Lie on your back with shoulders lift about 5 inches off the floor. Place your arms by your sides with your palms facing down. Lift your heels approximately 6 inches off the floor.
Your upper body stays throughout the entire exercise in the same position as described in the starting position, while you make small and rapid up and down motion with your legs – this is called