Primary Muscle Group: Shoulders
Muscle Groups Worked in This Exercise: Trapezius, Deltoideus (anterior and middle)
Preparation: Sit on the ball, keeping your back straight, your abs tight and secure an exercise band under your right foot. Raise and extend your left foot. Grasp the band in both hands and fully extend your arms by your hips. Palms should be facing the ball.
Breathing: Exhale when raising arms, inhale when lowering to start.
Execution: Raise your arms out to the sides, palms facing down, until they are at shoulder level. Inhale and lower them back to start. Switch to raising and extending your left foot and continue until you've finished all reps on each side.
Comments: Raising the opposite leg and foot will force you to engage your abs and back to keep you balanced.