1. For part one of this exercise—the snow angel—you will start by lying on your back. Engaging your core, lift your feet a few inches off the ground and raise your arms from your sides to over your head, as if you were making a snow angel.
2. Then, keeping your feet together and toes pointed, raise both legs up, keeping them completely straight, while raising your upper body off the ground. Touch your hands to your toes. That's one rep.