Does the evidence support the claims?
Is there really a mountain, metric ton, or butt load of evidence that the levator scapulae is the prime mover of a shrug, followed by the middle delts, and that upper traps are better trained with rows?
In addition to the Castelein 2015 paper, I gathered about 80 papers that I thought might have some relevance. After reading them, about 30 had some relevance, but only 9 were contextually relevant enough in my opinion. 4 of them I had to purchase the full text. You know I’m something of a scientist myself, but zero studies directly looked at the questions in the context of resistance training for hypertrophy.
Let’s start with the Castelein et al 2015 results that were posted in the video making the claims.