Come into an all fours position with your hands under your shoulders and your knees under your hips. Brace your core and maintain a flat back as you lift your knees a few inches off the floor and move both feet back a few inches. This is your start position. Move your right hand forward as you simultaneously move your left leg forwards, repeat the same pattern on the other side, all the while keeping your core braced. Continue this pattern for the required amount of time.