Place a BOSU on the floor, flat side down. Come into plank position with both hands on top of the BOSU.
Step the left hand onto the floor and lower into a push-up. As you straighten your arms, bring your left hand back onto the BOSU.
Repeat on the other side, placing the right hand onto the floor as you lower into a push-up; return the right hand onto the BOSU while straightening your arms. This counts as one rep.