Can you "break" physical growth for a non-YA player?

[SpHSpH]

There has been a lot of discussion here and elsewhere about "over-training" a player in a way that prevents his physical stats (speed / balance / agility) from growing. You end up with highly technical and skillful ... but slow / weak / wimpy players.

Does this apply to only the YA players? Or to "regular" players as well? What about the regens (sort of a mix between a "new" and "established" player)?

Example ... can I train the hell out of Jonjo Shelvey without worrying about negative consequences to his physical growth?

I am just beginning my career modes ... I do not have any youth prospects yet ... I want to use my available training sessions for the "real" players already on my roster ... are there any negative consequences that I should be aware of?

Thanks!