Range is kind of a niche book I'm not sure it represents the consensus yet.
You can find Nino Schurter’s gym workouts on YouTube (elite mountain biker). Same for some top race car drivers.
This to me is the real problem with over specialization. You have less than gifted parents living out their athletic dreams through their kids but if the parent wasn't that good at the sport there will be correlation with the kid not being that good.
Kids shouldn't specialize in sports too young because there is such a great chance they are not in the right sport at 11.
But to play HS sports for example at most schools, either will do the job. And for most people playing the sport they love in high school will be worth it. Even among pro players, their HS experience is often their best experience.
Everything you might be doing in the gym is in support of the task you're trying to accomplish, not the other way around, so I really doubt that the gym is 'the bare minimum' for most athletes.
AAU basketball literally has leader boards ranking the top 6th and 7th graders in the country. And goes all the way down to 3rd grade.
I did not say anything about juniors being prohibited from competing, healthy competition has immense benefits early on.
Key word being playing. It helped me learn teamwork and good sportsmanship, which is supposed to be the point.
When my son was playing youth sports, many of his peers started doing speed/coordination training with a coach in 6th/7th grade. This was usually 1-2x/week and applicable to most sports. Focus was more on first-step speed, running form, and full body movements (jumps, "suicide" sprints/shuttle runs, etc). I thought it was pretty crazy at the time, still do, but at least it was generic.
These days, neighbors have kids in with pitching coaches at age 8, playing travel league baseball 3+ nights/week, plus 2-3 games/weekend. 9 months of the year. That is REALLY crazy to me. How about some swim team, or soccer, or anything else?
Back when I was in high school (mid-90s), the best athletes were all multi-sport athletes. Football/basketball/track-field was a common combo. No idea if that's true today, but I suspect there's a lot more single-sport athletes at the prep level, which is kinda sad.
Today, I wish I'd done a lot more math and statistics before focusing on exclusively physics, even if it'd cost me another 1-3 semesters.
I was spending way too much time trying to re-invent the wheel (statistics) in the experimental part, and particle physics really assumed quite a bit more math than what was listed as prerequisites, simply because the university didn't want to delay progression. (To compensate, the bar at the exam was set pretty low.)