This exercise works both the posterior deltoid (that's the back of your shoulder) and your triceps (the back of your arm).
- Bend your elbows back, keeping your upper arm even with your back, and bring weights to your upper waist. Bend your knees to come into a half squat. Then bend forward creasing at your hips so your spine is almost parallel to the floor.
- Keeping your abs engaged, simultaneously extend your left arm straight out in front of you and the right arm straight behind you. Rotate both wrists so your front palm is down and your back palm is up.
- Bend elbows bringing weights back to your waist, and repeat on the other side punching forward with your right arm. This completes one rep.
- Do two to three sets of 12 reps.