A great exercise that combines single-leg balance and stability with upper body strengthening.
To perform this exercise, stand on the middle of the Bosu Ball with your knee and toe pointing forwards. Hold dumbbells with arms at sides. Maintaining balance on the ball, slowly curl the dumbbells upwards by bending at the elbows. Position the dumbbells for a shoulder press by facing the palms outwards and fists towards the ceiling. Slowly press one arm upwards by straightening the elbow and bringing the dumbbell up and inwards towards the mid-line of the body. Keep balanced and slowly lower the arm back down, then repeat with the other arm.
Perform 2 sets of 5-10 repetitions with each arm. Do the first set on the right leg, and the 2nd set on the left leg.