Could some injuries also be part of just how a gymnast is put together? By that I mean are their hips straight, do they have hyper flexibility, do they land straight due to balanced knee alignment? I am a runner and you will see the top runners are all extremely efficient and are very smooth when they run. Top runners usually have naturally perfect form in that they do not pronate when they land with their foot in or out, their hips are level, etc. My legs are not aligned properly (when I was a kid I wore braces to straighten them) and I land on the outside of my foot. This action puts a lot of strain on my knees and I used to get extreme tendonitis when I ran indoor track. I got injured a lot high school and college. I think they have a lot more PT remedies now than they had when I started. I also got into track very quickly and did not have a proper base before I started doing higher mileage and faster workouts. It doesn't mean if you don't have a runner body or gymnast body you can't do the sport or be exceptionally good at it, it just means you have to be a lot more careful on how you train, how much you train, and perhaps have a very strong conditioning/PT program that helps improve your weaknesses. Most club teams do not have access to this type of expertise. I know this might seem harsh in the sense of who gets to be the best and hard work may not always get you to where you want, but unfortunately sports is pretty brutal when it comes to selecting who gets to be the best.