Place both hands on the stair and get into pushup position with wrists directly below your shoulders, feet hip-width apart. Engage your legs and core as you bend your elbows and lower your chest toward the step.
Keeping your body as still as possible, explosively push up so that your hands lift off the step, not compromising body position. Allow hands to return to the stair and lower back down into a pushup position. Repeat movement at a quick pace. Do 10 reps.