Most people think of jumping jacks as a cardio move—and they are, in line with other plyometric exercises like high knees, butt kicks, quick feet, or ladder drills.
But they also help strengthen your lower body muscles. Your shoulders are just resisting gravity so they aren’t doing too much work, but your outer glutes muscle—the gluteus medius—is working to drive the hips apart, while your adductor muscles bring your legs back together.
