Start in a deep crouch with your hands planted on the floor in front of you, weight leaning into them. Hop both feet off the floor and click your heels together in the air behind you, then land softly back in the crouch and go again. Your arms and shoulders carry you for that airborne moment while your legs do the clicking - it's half animal movement, half playground trick, and it gets your heart rate up faster than it has any right to.

Works: shoulders, quads, calves, abs and obliques

Breathing: Exhale as you hop and click, inhale as you land back in the crouch.

Common Mistakes: Landing hard with straight legs instead of softening back into the crouch, barely leaving the floor so the heels never meet, and letting the hands drift too close to the feet to lean into properly.

Make Easier: Skip the click and just hop both feet a small height off the floor, building up the airtime first.

Make Harder: Hop higher and aim for a crisp, unhurried click, or string reps together continuously without pausing in the crouch.