Fadi
...
This is a common comment which I think is misleading.
Most of the gymnasts we see with well built bodies are world class competitiors.
Most regular gymnasts are quite thin and lightweight as far as I've seen.
So if you look at natural elite strength trainers or bodybuilders, they would likely be equally or better built with less time training.
As Rob has pointed out, these gymnasts do not use weights to build muscles but rely on lifting their own body weights. Now a bodybuilder can learn a lot from that. That is, if a bodybuilder adds an element of progressive overload whilst moving his body through space, he will gain a tremendous amount of muscles and strength.
The only reason the novice gymnast is not big (yet) is because he has not logged up the hours his world class counterpart has. It's all about frequency/volume here.
Fadi.