First, I would do some research on her - you have her name, so look up on the internet some info about her. If she has a website, it shuld say if she does training, competition prep, nutrition consultations.
Next time you see her, wait until she is taking a water break / rest and .....
You: "I know you are training, so I don't want to take up your time, but I wanted to tell you I saw you on the cover of XYZ, you looked fantastic."
Her: "Thank you"
You: "My name is Dxxxx. I find you very inspiring, as my future goals are to compete in figure (right?) this year. Do you do any training or consultations?" (you might already know this answer, but doesn't hurt to ask)
Her: "Yes I do"
You: "Would you mind if I called / emailed you to try to set something up?"
Her: "sure, here is my number / email" (hopefully at this point, you can say, oh, I saw your website, I can contact you through that)
You "Thank you, I'll let you get back to training"