If you are actually asking, I can go into it in more detail.
Briefly, the lats are predominantly fast twitch muscle fibers that respond best to maximal motor unit recruitment under heavy loads and at high velocity.
You want to accelerate through the contraction phase of a movement as fast as possible which triggers excellent recruitment of fast twitch fibers and resulting adaptation response. Any pull ups or pull downs should be executed as such.
Other things that will significantly improve your pull ups are things like deadlifts/RDLs. These large compound movements have huge lat recruitment and develop a lot of strength. Seriously undervalued.
Happy to talk more about it
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3736486/
