Drivers Of The Squat

The Squat: What's going on? How do we drive up all that weight?

(Below the surface, yes, there's much more happening: knee flexion; downward forces; proper alignments; etc, etc., etc. Heck, what are the traps doing besides being a shelf for the bar? These are all nuances that will be discussed later, but for this picture's purpose, we're illustrating the engines that drive the machine.)