Specifically, jumping jacks fire up your quads and glutes, as well as your core, with proper engagement. Your shoulders will also get some movement in, as will your hip flexors, and this cardio move is sure to get your heart rate up. The bottom line is if you want to get your body moving and muscles working, jumping jacks are the perfect exercise to do so. And since they’re simple to modify (and do pretty much anywhere), they’re a great option for nearly everyone, any time.