What's the biggest difference between how Nolan Ryan and Mark Prior moved?

Nolan Ryan vs. Mark Prior

The phrase that keeps popping into my head is this.

Aive.

Nolan Ryan's spine is alive while Mark Prior's is dead.

Nolan Ryan's spine bends and twists as he throws with his entire body and, in particular, his Core.

In contrast, Mark Prior's spine is rigidly upright, forcing him to generate power with his arm rather than his Core.