Working out is never fun so you need to get the most out of your workout when you can do it. Sprint-8 is a form of High Intensity Interval Training (HIIT) that allows maximum calorie burn in the shortest timeframe. Usually, this particular workout is done on a treadmill or stationary bicycle. This app lets you do the Sprint-8 workout and not have to have any extra equipment. It tells you when to sprint and then when to rest. Sprint-8 does this on a 30 second sprint/90 second rest cycle.