How to do: Iron Crosses (stretch)

Step-by-step instructions

1. 1Lie face down on the floor, with your arms extended out to your side, palms pressed to the floor. This will be your starting position.
2. 2To begin, flex one knee and bring that leg across the back of your body, attempting to touch it to the ground near the opposite hand.
3. 3Promptly return the leg to the starting postion, and quickly repeat with the other leg. Continue alternating for 10-20 repetitions.

Photos & base instructions from the open-source Free Exercise DB (public domain).