system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What specifically about puberty negatively impacts female gymnasts to the point that retirement occurs around age 20?

I've been thinking about this and am even starting to get skeptical of whether this is true or not. So I guess my question is divided into two parts: Is the retirement of female gymnasts after puberty for social or for established physical reasons? For instance, are elite female gymnasts forced to retire after their teens due to some wierd aesthetic reasons or is it due to some established medical reason such as: after __ post-pubescent age, the body becomes less compatible with gymnastics training demands? Post some real scientific studies if you can.
gpt
It is a few factors but the biggest two are strength to weight ratio and the change in size of the person. 

When you train things like balance, one of the biggest components of gymnastics, you are training neuromuscular connections. When you grow, those change, performance dips. With girls their highest strength to weight + height ratio happens just before puberty, during puberty they have a lot of hip growth for instance, this will add weight but also change how they can balance. That change needs to be relearned. 

All sports see this dip. Runners get slower at the start of puberty then get faster again, swimmers have a dip in performance...   Pretty much any sport has this dip, gymnasts just experience it to a greater extent. The small stature of gymnasts also is good to maintain, easier to rotate a shorter person.