Interval training is all about maximum exertion for maximum results. The workouts don't take long, but they aren't for the faint of heart. If you've been thinking about mixing some interval training into your fitness regimen, our partners at Greatist have shared three interval workout routines separated by time and skill. To learn more, check out this interval training guide and scan the poster below.
Want to take your workout onto the street? Check out this video on interval training for city dwellers.