The Slalom

Works: Abs, glutes, quads, calves,hip flexors, agility

Stand on the right side of an 8- to 10-inch-tall box.With your legs and feet glued together and your upperbody as quiet as possible, jump on top, then to the leftside, back to the top and back to the start again. “Keep your arms from flailing around as you jump over the box—it will help your balance, says Keller. Repeat three sets of 30 seconds of continuous jumping, moving up to one-minute intervals after two weeks.