If there is something wrong with her background or personality, gradually alienate yourself and exercise with her, but don't be too cold on the surface. You can also find another exercise partner, so that when she sees you practicing with others, she can understand that you don't want to exercise with her.

But if this is just your own guess, I suggest you don't shut people out hastily. After all, let's exercise together, and don't always set up a heart wall because of your own problems.