HOW: Begin on your hands and knees. Place a slider under one foot. In this position, you will balance on the opposite arm and leg. The wider you are the easier to balance, the more narrow the more challenging this will be. Bring the arm up as high as you can towards the ceiling while you slide the opposite leg back with your toes pushing into the slider. Slowly, return to the starting position and repeat on the other side.
FEEL: With the leg kicking out you will feel the muscles on the back of the hip working, with the arm that is punching out you will feel the muscles on top of the shoulder and back of the shoulder blade working.
COMPENSATION: Avoid rotating the trunk, arching the back as you raise your leg, or shrugging the shoulder as you raise the arm.