Start on all fours with a flat back

Place one of your hands behind your head with your elbow pointed out to the side, keeping your opposite hand on the ground and your arm straight

With the hand that's behind your head, bring your elbow down to the wrist of the hand that is currently on the ground, rotating through the spine

Then, rotate the opposite way until your elbow is pointed straight up into the sky

Be sure to press firmly into the ground with the hand that is currently down

Complete this movement for the allotted reps, then switch sides