The Undisputed Best Ab Moves, According to Pilates Instructors

Scissor kicks are "a classic example of how Pilates stretches and strengthens simultaneously," says Jennifer Herrera, a Pilates Method-certified teacher who's certified in mat and reformer Pilates. In this Pilates ab exercise, you build core strength by keeping your upper body lifted, Herrera says. "The lower abdominals work as the legs move, and the movement stretches the hamstrings and lower back."

1. Lie on your back with both legs in the air.
2. Lift your head and shoulders off the ground. Hold your right ankle as you lower your left leg toward the floor, hovering a few inches off the ground.
3. Keep your abs pulled to your spine, and switch legs. That's one rep.