Not only is this workout great for toning butt and thighs, it's also great for building endurance and burning fat. High intensity interval training (HIIT) is also the only kind of cardio training that can actually build muscle, as well. In addition to all of these perks, the exercises in this app also help build coordination, balance, and control over your own body.

When done right, HIIT is your saving cardio grace. A good HIIT workout can deliver a lot of what you want from traditional cardio — burning fat, elevating your heart rate, pushing you to sweat, and improving lung capacity. All this in a fraction of the time, making it especially useful for those of us who can't spend all day in the gym and want to workout at home. To get all these benefits, though, HIIT has to be utilized correctly, and your intensity has to be high.