This challenging move requires a lot of core work to build balance and strength at the same time.
How to do it: Stand on your right leg with knee slightly bent and left foot lifted off the ground, holding dumbbells (heavy enough to fatigue your shoulders with 10 repetitions). Brace your abs in tight as you bend your right arm and bring the dumbbell to the outside of right shoulder, palm facing forward. Keeping body steady, extend right arm overhead. Bend your elbow and lower the weight to your shoulder. That's one rep. Repeat 10 times total then switch sides and repeat. Do up to 3 sets of 10 repetitions on both sides.