Get into a pushup position with your arms straight, hands on an exercise bench, chair, or on the floor. This is the starting position.
Lift your right foot, raising that knee as close to your chest as you can. Straighten that leg to touch your right foot to the ground and immediately raise your left foot, knee to chest, and return to the starting position. It’s like running uphill.
Go as fast as possible without sacrificing form. Do this for 30 seconds.