15 Minute Whole Body Workouts

It may sound counterintuitive, but slowing down your workout can help speed up your results.

Here's why: Your muscles have three basic contractions-concentric (they shorten), isometric (they stay the same length), and eccentric (they lengthen). "When you focus on - and slow down - the eccentric phase, your muscles are under tension longer, so your body uses more energy to build and repair them," says David Jack, director of Actv8 Phoenix in Acton, Massachusetts, who created this workout. It may not get your heart racing like a spin class does, but it shares the same metabolism-revving perks: Research shows that eccentric-focused training can increase your post-workout calorie burn by up to 7 per cent for as long as 72 hours. (Try this Calorie-Blasting Spinning Workout - we've even paired it with fast-paced tunes to keep you going.)

The initial time through, do the first and third moves slowly (taking five seconds to lower), and the second and fourth moves at a normal speed; the second time, reverse the pattern (doing the first and third moves at a normal pace). Keep alternating for seven minutes, resting as needed between the moves. Reverse the order (start with the dip), and complete another seven-minute round using the same pattern.

Learn how to transform your body forever with the NEW Spartacus Workout!