I was sweating watching that. Very cool.

There must be a formula for this, that calculates downward pressure (weight I guess) depending on rate of rotation, mass, length of lever and circumference of the spinning object?

See: http://demoweb.physics.ucla.edu/node/29

It looked really elegant. Makes me wish I could bench-press with a weight like this.

Part 2/ explanation

It's to do with angular momentum. The explanation begins with rotational mechanics and ends a few months later so i'll leave you to it from there

hyperphysics is a fantastic resource for any level of physics.

There's also the fact his arm, wrist, and hand are rotating in a natural way instead of dead lifting without rotation. Grab a 40lb hand dumbbell and lift it straight up and then lift it up allowing your arm to rotate it however it feels.

You note when he dead lifts, he goes from palm-towards himself to palm-away, but with it spinning he rotates from palm towards to palm towards, but facing up during the main lift past his shoulders, rotating to palm away at the top.

The speeding up of precession just accelerates the rise initially not during.