Where is this fact reported? I found this Pubmed paper that doesn't mention it- and you would think in a survey paper they would lead with stuff like that.
"two studies on isolated hypertrophic fibers of body builders, have shown that in well trained professional body builders increase in size and in force are dissociated"
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7582410/
I just read it so many times I took it as fact, but here's the first goofle result:
"Muscle volume (MV) and anatomical cross-sectional area (CSA) are measurements of muscle size [often measured by magnetic resonance imaging (MRI)] that presents a strong relationship (r > 0.73) with muscle strength (Bamman et al., 2000, Ogasawara et al., 2011, Ogasawara et al., 2013b, Trezise et al., 2016)."
But there's also data that says, I think, the increased size changes the angle of force generation negatively or something like that lol, so it's probably more nuanced.
But generally, in each individual lifter, strength and their muscle size is correlated. Many deny this and say their were stronger than now when they are bigger but I don't buy it at all, they just changed their exercise execution style. When a bb is at say their 8-12 rep peak strength they are most likely their biggest too. Of course you can't compare two dofferent lifters and sat look, that smaller guy is stronger, when there are a multitude of factors affecting
demonstratable strenght, like tendon lenght/placement, aanatomical differences like limb length (could affect bench strength for example), neural efficiency, technique differences and on and on. At least measure a lifter to himself, is he stronger when bigger muscularly? Yes he usually is, unless he changes his technique. I might increase my deadlift max by going sumo or whatever and say, look, my dead max is bigger now yet I'm smaller, but check your lower back strength, it's probably weaker, you just changed your technique. This is how older powerlifters can keep eeking our bigger numbers, just keep refining technique.
And like falco said, there's weight classes for a reason.