Were most of these gymnasts full-time gymnasts? Meaning they trained 3-4 hours a day in the offseason if they didn’t compete in another sport. The athletes who were gymnasts who I worked with no longer did gymnastics as a sport anymore only for fun.
I find the kids who play on the playground and/or gymnastics/tumbling from ages 3-10 do better in sport on average than their peers. It just may be a matter of physical activity levels, creativity in movement patterns, all-around abilities, and the ability to take risks with their bodies that makes them better than there peers over the long run.
Most of the females began tumbling/cheerleading early, at least those that I can remember. The boys began in grade 7, what we called Junior High. Most competed/trained year round. The father of one of my good friends was the coach, and I remember them practicing in the summer for several hours a day. Most stayed with it through high school. I don’t think any of them went on to compete in college, even those who had won state championships. This was late 70’s, and I don’t remember what scholarship opportunities existed for gymnasts back then.
In reference to height, most were average. One girl who won the all around and other titles for two or three years running, was about 5’9″ or 5’10”. Of course the floor routines were not nearly as powerful and intense as they are now. I don’t remember any of the guys being over about 5’9″.
An isolated pocket of observation. As possibly a related observation about sports training crossing over to other sports, I had the unfortunate experience of watching our local varsity soccer team (I’m talking present day, my kid’s high school) play basketball at a post season party after they lost out in regional play last year. I have never witnessed anything more horrific and spastic in my life…if I had a camera I would be a youtube legend.