HOW: Start in the tall plank push up position. Engage your core and squeeze your glutes as you go down, slide one arm up and out as far as you can in a diagonal direction. Keep most of your weight on the other arm doing the push up.Alternate sliding each arm out.
FEEL: You should feel your chest working. You should also feel a stretch in your chest and shoulder as that arm goes out.
COMPENSATION: Keep your back flat and your knees straight. Don’t lean to the one side as your arm moves out, stay balanced with most of your weight on that stationary arm.