Raise or lower the box height to increase or decrease the difficulty, respectively.
Kick both feet up onto a box or bench. Place your hands on the floor, shoulder width apart, and create a strong plank position (A). Bend your elbows to slowly lower your nose to the ground, pause here (B), keep your upper arms from flaring out as you push back up explosively. Raise or lower the box height to increase or decrease the difficulty, respectively.