This is a rotator cuff strengthening exercise.
Grap one 2.5 lb plate in each hand, set lower back like you were doing a dead lift, and bend forward to about 45-degrees. Hang arms and hands at your side, twist your palms out so your thumps are pointing out. Now raise your arms up, keeping your elbows locked. Raise your arms up slightly to the front, not right up the sides, making a "Y".
Drop them down again, twist your palms in so your thumbs are pointing to your thighs. Lift your elbows to your ears, chicken-wing style. At the top, rotate at the shoulder, pulling our palms up as far as possible, making a "T".