I have a real problem with this post.
You are asking, "is the fact that I'm attracted to athletic girls a problem if I'm not that athletic myself"
A legit question, which has been answered. You may be able to find a balance between interests, and you get a little more active, and she sits down for a minute or two...whatever.
BUT
I don't think that was your question.
Your question was, "You are asking, "is the fact that I'm attracted to athletic girls a problem if I'm not that athletic myself...because I want to stare at her ass in yoga pants, and I'm attracted to athletic girls with my penis, not really my mind"
Ammmirite?
And that's going to be a problem, because your penis isn't going to want to get a little more active(outside the bedroom), it just wants to treat your new athletic girlfriend like free arousal at home.
If you were so attracted to the gym rat mentality...you would BE a gym rat and HAVE the mentality.
That's why I know you just like the ass
So let's at least start asking honest questions.
"Hey guys...is there a way my less than athletic self can have sex with a piece of hot yoga ass, as that is what makes my Mr. Winky bounce?"
And the answer is yes! But only if she is into your personality because someone that is into gyming that hard isn't going to want to hang out with a sofa magnet that isn't otherwise.