Plank Crisscross

Instructions

1. 
   Begin in a full plank position, arms extended with palms on floor, head in line with hips.
2. 
   Draw right knee toward left elbow. Repeat on opposite side, bringing left knee toward right elbow. Repeat, this time bringing right knee toward right elbow, followed by left knee toward left elbow. Repeat sequence from the top for given time.