You use your medial deltoids with arm movements that go out to the side. This side lateral raise exercise isolates and strengthens these muscles. You can use hand weights (if you have them at the office) or bottles of water.
Step 1: Stand with your feet shoulder-width apart and your hands by your sides.
Step 2: Keep your elbows slightly bent and raise your arms out to your sides and up to shoulder level.
Step 3: Pause for a second with your arms parallel to the floor, then slowly return to the starting position.
Step 4: Keep the focus on your deltoids. Don't swing the weights up using your torso; move only your shoulder joints.
Step 4: Do as many repetitions as you'd like.
If you don't have weights or bottles of water available, you can lift your arms out to your sides and pulse your arms twenty to thirty times. Lower your arms and repeat as many times as you'd like.