MUSCLES ENGAGED Shoulders The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well. Equipment Used Wooden Dowel A wooden dowel is a solid cylindrical rod made of wood and is used for a variety of mobility drills. Exercise Instructions Step 1 Hold the wooden dowel at your waist and spread your grip out nice and wide. Step 2 Keeping your arms straight, lift the wooden dowel up and shrug it over your head. Step 3 Rotate the wooden dowel behind you until your touch your butt in the back and then pull it back up and over.