I'm starting to look like the girl in the second pic due to athletics - and I'm excited for that ha ha
One of the best athletes on my team is built just like her, but a little stronger. She has great tone in her body, abs, muscle definition (not too manly though -) but she is one of the sexiest girls at our school lol The football players constantly make comments about her (positive flirty ones,) and her boyfriend is so hot lol
So I think tone and being fit is good - a lot of guys dig a girl with a strong look - but just not overly strong like the girl in the first picture.
You want to preserve a decent amount of femininity.
The first link was a bit too muscular, the second link looked fine. It's definitely not unattractive, and is somewhat attractive, it's just that you'd probably be more fit and in better shape than a lot of guys and they'd find that a bit daunting. So in my opinion, it's attractive, just don't get too muscular haha.