How to do it: Lie on the ground with your arms out to your sides, the backs of your hands touching the ground. With the Swiss ball between your legs, raise your legs up so they’re at a 90-degree angle to your torso. Drop your legs to your left side, making sure your shoulder blades remain on the ground. Stop the ball 2 to 5 inches above the ground, hold for one count, then bring legs back to vertical. Repeat to the right side. If your shoulder blades are coming off of the ground, reduce your range of motion.
Reps: 6 on each side
What it works: Back, shoulders, core, inner thighs