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. Glutes Gluteal Muscles (Glutes) are one of the strongest muscles in the body and are the connecting point between your legs and back muscles. Glutes are used in a variety of actions from moving the leg to extending and rotating the hip, as well as extending and rotating the trunk of the body. Exercise Instructions Step 1 Start with your feet slightly wider than shoulder width. Hold the kettlebell in one hand. Step 2 Swing the bell between your legs. Keep your back flat, shoulders set and the bell above your knees. Step 3 Drive through your heels, fully extend your hips and press the kettlebell up towards the ceiling.