…is the most you can lift.
I have seen many sources discuss this concept of a "true" one rep maximum. Saying something like, "A novice is not capable of performing a true maximum."
It is difficult to be sure what people mean by such vague concepts but it seems as if they are separating the factors of strength in the belief that if one is 'underdeveloped' then a display of ability is not 'real'.
Strength is EVERY factor coming together at ANY phase of development.
The belief is that since a beginner is neurally immature they are not lifting to their true ability..or something like that.
Your ability is your ability. Period. Your ability the next time you lift is your ability that time. Displays of strength at any one time are always a result of your preparedness at that time. The idea that a beginner is not capable of doing a 'true' bench press maximum is such a vague and loosely defined concept it is useless.
This type of thinking also gives rise to all sorts of imaginary goings on about "rep maximums". Sure a beginner or lower intermediate can use a chart to estimate maximal ability somewhat accurately but your max is what you lift! Not what you imagine you can lift.
If one has never trained the first gains in strength will be neural in nature. But other factors such as stability, and motor learning will continue to play a big role.
Reasonably, a true novice has NO REASON to be performing a maximal lift and there are many risks associated with it. Novices do not need to do this and they shouldn't. But it has nothing to do with "trueness", whatever that is. What you lift is what you can lift. It's darn simple.
If a novice swimmer gets into the pool and manages half a lap then he can swim half a lap. We don't say…hmmm…I wonder how far he is truly capable of swimming….
He just showed us. Sounds ridiculous, right? Yet this type of thinking is common in the strength training world.
So, you do not need to wait for the purple unicorn to come to your bedside and whisper your 'true' rep maximum to you. You will never be sure of it on any given occasion since so many factors intertwine at any one time to produce it, many of which cannot be controlled or predicted.