A big mistake that a lot of people make when pressing overhead is trying to keep the torso as vertical as possible in an effort to maintain "strictness" in their presses.

This Myth was recently perpetuated by FitnessFAQs, who is a highly regarded Calisthenics athlete.

He made a reel a few months ago asserting the superiority of Z presses over standing overhead presses due to the fact that Z presses prevent excessive torso layback due to stability concerns. But this notion is fundamentally flawed.

The natural layback that takes place during a standing overhead press is actually a REQUIREMENT for proper overhead pressing technique. As seen in the clip below, with no layback at all the bar is forced to drift forward of the center of mass (the hips) in order to clear the chin as you initiate the press overhead.

The number one rule in barbell training is to keep the bar as close to the center of mass (again, hips) as possible at all times given the constraints of the exercise you are performing.

The bar should NEVER drift forward.

It should either move straight up and down in a perfectly vertical line, or it should even arc BACK towards you. But it should never move away from you.

With no layback at all there is no choice but to utilize an inefficient, forward drifting bar path on your press. This mechanical inefficiency is highly suboptimal and will hinder your gains in the long run. Point blank.

Further, incorporating a slight layback into your also helps to get more muscle involved in the exercise by allowing the upper chest to engage. More muscle being used on an exercise such as this is generally a good thing, not a bad one. Excessive emphasis on isolation (especially during compound exercises) is a silly notion for natural lifters.

Unless your back and abs are made of glass, a little bit of layback is natural and normal and should not present any issues, especially when proper training parameters are adhered to.