Shoulder scaption

Hello everyone. I am new to this forum. Been reading for a bit, and it seems like a great place to learn. I have a quick question… Can anyone please explain the ‘Scaption’ exercise from Don Alessi’s Booming Biceps pt. 2 a little bit better? The picture shows the trainee with his arms above his head, I’m just not sure how that goes along with Don A’s description. Thanks guys!

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Many physical therapists recommend taking this exercise overhead to completely involve the supraspinatus (one of the four muscles of the rotator cuff). Basically, start the shoulder abduction with your thumbs down and slowly rotate them forward (as if pointing in front of you). The thumbs should be facing forward at about 90 degrees of abduction and facing up at all points beyond that (they’ll be facing each other when overhead). It’s imperative that you have the thumbs up for the latter portion of the movement in order to involve the supraspinatus more than the medial delt.