Before you start this move, visualize a large square on the floor where you're standing in the bottom right corner, feet hip-distance apart.
Keeping weight in the heels, bend the knees, and squat down. Take a huge jump forward to the top right corner of that imaginary square, landing quietly back into a squat.
Keep going around the square, jumping to the left, jumping back behind you, and jumping to the right. Now you're back where you started.
Perform as many jumps as you can for 40 seconds.
Take a (well-deserved) 20-second rest and repeat once more, reversing your jumps around the square in the opposite direction.