Jumpstart Your Muscles
While the cardio benefits of performing jumping jacks are readily observed through changes in pulse and respiration, muscular benefits are not so obvious. They are felt, however, in the glutes, calves, abs and deltoids. The size of your muscles is not likely to increase from jumping jacks, but there will be a detectable increase in muscle strength, said certified exercise trainer Katie Brown, in an online article for Real Beauty. She cites jumping jacks as one of the top notch, high intensity exercises for building muscle endurance.