High intensity interval training (HIIT) boosts your metabolism and burns more calories then traditional treadmill workouts. Plus, the constant intervals make the workout more fun. Fight the boredom of traditional treadmill workouts with this high intensity interval trainer specifically designed for use with the treadmill. Choose one of 24 workouts! Automatically keep track of which workouts youve done, but feel free to do each workout as many times as you like.