This exercise is the Classic Pilates exercise which is intended to strengthen the opposing fascial connections on the back of the body.
To do this exercise you will need a mat. Start by lying on your belly with your legs long beneath you and your arms reaching long above your head. Inhale as you allow your upper spine, arms, and legs up into the air. Using a continuous breath and being sure that your abdomen is hollow allow your left leg and right arm to lift two inches higher. Then switch to your right leg and left arm. Continue alternating the arms and legs while maintaining a stable and long spine. When you are ready- allow your body to melt to the ground.
Things to think about
Be sure that your shoulder blades are sliding down your back as you do this exercise.
Imagine that the left pinky finger is connected to the right pinky toe and vice versa. This will allow you to find the fascial connections across your back that aid in spinal rotation and rotational sports.