It seems that you are faced with a dilemma: 1) wanting to address factual information, and data-driven practices, in a thoughtful, objective manner, vs 2) not looking bad in your new club environment. I mention the latter only because you have made reference to it in two separate posts:
EireDiver606:
Should I tell him he’s wrong, which will make me look bad seen as I’m new and it will make me look like a know it all.
. . . if I show him the results, I will look like a know it all and won’t make any new friends in the club. Basically because I have so little experience level and their instructors told them about deep stops, they probably won’t believe me
One additional approach might be to ask the instructor in question to share with you some of the background data that contributed to the practice of making deep stops - tell him you are very interested in learning more about deep stops., and would like to read the studies to better understand the specifics of the practice. Don't show him a new paper, don't confront him, simply ask about the history of the research, indicating that you would like to learn from his experience.
If he responds by saying, 'There's lots of data, hard to point to any one paper.', or 'No need to read about them, everyone who knows anything knows that deep stops work.', then you have a clue that he is probably talking about something he was told, but about which he actually knows very little. Nonetheless, the less threatening approach is to ask rather than tell.
In the context of deep stops as one example of evolving understanding (i.e., someting appropriate for discussion in the context of this thread, about 'keeping up'), Simon makes a good point:
Dr Simon Mitchell:
Sea_ledford has touched on the elephant in the room in relation to the deep stops argument: that is, there was never any evidence in support of them.
Sometimes practices emerge because a bit of anecdotal evidence is taken up, and mathematical models, and possibly theoretical constructs, are then used to 'prove' the validity of the premise suggested by the anecdotal data. I suspect this to be the case with deep stops, but I also think the principle is far broader. The irony is that mathematical models can never 'prove' anything.
But, it is also true that there is danger at times in challenging deeply held beliefs.
Better to begin by asking in many cases, than asserting, if the goal is to engage in dialog without alienating those holding the beliefs. But, don't be afraid to ask.