How to do it: Face down with your torso on the Swiss ball, your hands and feet on the ground. Raise your right arm and left leg until they’re parallel to the ground, keeping your core tight. Hold for a count, then return to the starting position. Then raise your left arm and right leg.
Reps: 12 to 15
What it works: Core, neck, biceps, triceps, shoulders, back, hamstrings, glutes, inner and outer thighs