Donkey Kick

Start on your hands and knees, hands under your shoulders, knees under your hips. Your back stays neutral — not arched or rounded — and your core braced throughout. Drive one knee up and behind you, leading with your heel as if kicking a door. The power comes from your glute, not from momentum or swinging. Pause and squeeze hard at the top, then control the return to the starting position. Your head stays neutral and still. Switch legs and repeat. The glute does the work; your lower back is just along for the ride.