Fitness guru Brett Hoebel (a.k.a. "El Capitan") has worked as a trainer on NBC's Biggest Loser, as a health expert for the Food Network and now has a series of comprehensive workouts called the 20 Minute Body. The workouts look a lot like weight-free interval training to us – which is a good thing. Here, Brett recommends doing four sets of five moves, with 30 seconds of activity followed by 30 seconds of rest for each move. Shoot for 10 to 12 reps with each set, and feel the burn.