Walk, Jog, Sprint! is an easy to follow app that will walk you through what it takes to get into HIIT shape.
What is HIIT? High Intensity Interval Training or HIIT is a training technique in which you give all-out, one hundred percent effort through quick, intense bursts of exercise, followed by short, sometimes active, recovery periods. This type of training gets and keeps your heart rate up and burns more fat in less time.