Stand with your feet shoulder-width apart, fists up in a loose guard. Jump straight up and, at the top of the hop, turn your knees out and snap your heels together - click - then let your feet separate again to land shoulder-width apart, knees bending to take the impact. Straight up, click, land soft, and go again: the height of the jump buys you the time to make the click.

Works: calves, quads, glutes, hip adductors

Breathing: Exhale on the jump, inhale on the landing - one breath cycle per hop.

Common Mistakes: Jumping too low and rushing a half-click, landing with the feet still together instead of back at shoulder width, and landing stiff-legged on flat feet.

Make Easier: Skip the click and just hop with the knees turning out, or build your bounce with Hops on the Spot and Half Jacks first.

Make Harder: Jump higher and chain the reps without pause between landings, or move on to Jump Squats or Jump Knee-Tucks.