Technique
Bracing, belts and the Valsalva manoeuvre
Trunk stiffness is what lets you transmit force from the ground to the bar. Most people brace by sucking in, which does close to the opposite of what is needed.
Topic
bracing
Every Entire Strength article tagged bracing — 2 pieces across 1 section.
Technique
The overhead press: the lift most people set up wrong
Pressing overhead is the most honest test of upper body strength and the one most compromised by a poor starting position and a trunk that does not hold.