I don't think, in this case, that taking away track is a good idea.
difficult child 1 was brilliant. But his executive functioning hoovered. He was a butt in school a lot of times. Very few incentives/punishments worked with him (the one exception being his horse and we used it for years). But when he got to be 14-15-16...sports was all he had. And he hung right there in the crowd of kids that were drinkers and dopers - they were always right there on the outside of his circle of friends. If I took away sports at any point, they'd have gladly taken him in. For that reason, I never withdrew sports as a punishment for him.
Part of that was an age thing, but nothing is black and white, and if she only has one thing that gives her something to be proud of, to take it away because she struggles elsewhere, in my humble opinion, is just not a good idea.