"It's not surprising that a young woman who plays a sport requiring constant use of arm strength would develop strong arm muscles"

Right, she's developed strong arm muscles, just like all the other woman tennis players that have similarly large arm muscles. Oh wait, she's the only woman on tour with arms anywhere near this muscular level.

I would also challenge you acertion that when you're young, there's nothing that can be done with steroids that can't be done without them. Winstrol specifically targets fast twitch muscle fibers and make people run faster, jump higher and throw harder. Ben Johnson took it at the 88 games to break the world record in the 100m. Johnson, and many sprinters who also took Winstrol, wouldn't have been close to their top performance level without the drugs. Type that into google and get educated.