High Intensity Interval Training sessions are shorter but very intense workouts with 20-60 second work periods and shorter rest periods. You should aim to leave nothing behind during these workouts – give it 100% of your effort during each interval. Options for doing these include free workout videos on the Roller Derby Athletics blog; tabata-style workouts; or run/bike/swim intervals. Aim for a 3:1 or 4:1 ratio of work to rest. Push to 5:1 for a super challenge!