Instructions
Holding a water bottle in each hand, stand straight, with your feet shoulder width apart.
Raise the water bottles to head height by rotating your arms forward and up.
Your triceps should be parallel to the floor and your elbows bent at 90 degrees. This is the start position.
Keeping your back straight and using only your arms, extend through your shoulders and elbows to drive the water bottles straight up, exhaling as you do so.
As your arms reach the fully extended position, bring them in towards each other until the water bottles touch lightly together.
Hold for a count of one, while squeezing your shoulder muscles.
In a controlled movement, return to the starting position, inhaling as you do so.
Repeat.