Thanks to periods of hard work followed by short rests, high-intensity interval training helps you burn calories faster than you would doing steady-state cardio. Bonus for anyone short on time: That means your workouts can last just a few minutes. Case in point: This HIIT boxing workout from Justin Blackwell, master coach and boxing director for BoxUnion, a boxing studio in Los Angeles, takes just 20 minutes. "My motto: 'Pace yourself, but push yourself,'" Blackwell says. |