Lay sideways on a flat bench. Rest your armpit on the top of the bench and hug around the bench to secure your upper body. Bend your bottom leg, and straighten the top (you may have to use your feet/legs to keep yourself secure on the bench).
Reach your working arm down in front of your collar bone, then retract your shoulder blade and lift your arm up until the dumbbell is stacked above your shoulder joint. Slowly lower back down, bringing the arm in front of the collar bone again. Repeat. Keep your shoulders and hips stacked throughout the movement and arm relatively straight.
Common mistakes:
- reaching the arm too far back
- reaching the arm too far down (towards hips instead of in front of collar bone)
- bending the elbows
- not moving through the shoulder blade
