Correct if I am wrong but I thought Brian posted a video of tumble and the issues associated with being underplane. I thought he did, in that video, go over things like beta and gamma.
You may be selling Kevin a bit short. Just because he doesn't publish studies in peer-reviewed golf journals does not mean he is unfamiliar with golf science. While I don't teach golf for a living, I can't imagine Kevin breaking out a computer with swing models and associated equations of motion to fully describe why his drills work. Kevin is burdened with absorbing relevant information (scientific or not) and somehow using it to his student's benefit. For the most part he's likely interacting with golfers who can't break 100 or 90 (perhaps he has better students, but that's not important for the moment). Thus, his information must be of practical value and, with any luck, it gets the job done.
Would you have made this same comment 50 years ago, before the advent of high speed video and an understanding of impact physics? Would you have written off drills given to you by Jacobs or Penick just because they don't have an alphabet soup by their last names?
In short, Kevin and Brian are doing the best they can. I am actually thankful they represent what some might call the "transition" of the latest scientific findings to the practical world. One might say that Brian et al are the golf engineers...they take the careful and important work of Nesbit, Zick, etc and find creative and practical uses.
Erik
Easy... Newtonian Physics covers "what to do"... and Human Perception and Motor Control covers "how to learn what to do".
I know something about both.
Doing some stupid "drill" and declaring it "works" is unscientific and unbelievable ... without explaining WHY it works.