Assume the starting position: first lie on your back. Place your hands, palms down, under your buttocks. Keeping your legs extended, knees locked, and feet together, lift your heels 6 inches off the ground.

Exercise: Keeping your chin to your chest, knees locked, and toes pointed forward, alternate kicking your heels between about 1-6 inches off the gound. Each time a heel comes down, that is one count. Flutter kicks are normally done as a four-count exercise: 1, 2, 3, 1; 1, 2, 3, 2; 1, 2, 3, 3; 1, 2, 3, 4.

Chin-to-chest, toes pointed, and hands lifting your buttocks off the ground all help to maximize the exercise safely.