As for that hands-clasped MM pose, I have a theory.
Maybe, like a great many musclemen, Yates had an irrational hang-up about his right arm being far better than his left. Before the tear, I mean. After that, the hang-up was a whole lot less irrational.
The clasped overhand left hand appears to make the biceps take up more space, reducing the risk of an asymmetrical pose.
The kind of thing no-one else will really give a shit for, but to the guy posing it's a psychological necessity.
TNBT