How to do it:
1. Start in a plank position, core engaged, shoulder directly over the wrists, weight in the toes.
2. Drive right foot toward the chest, keep the foot in flexion, until knee reaches chest level. Return foot to starting plank position.
3. Switch legs, continue on other side. Movement should begin to feel like a run, done in a plank position. Continue for 1 minute, rest for 1 minute. Repeat for 3 sets.