[barsonme]

Or she loves running and competing so much that she's willing to let herself go through that?

On HN there are workaholics, people who sit too long programming, people who smoke or drink in excess, etc.

I hit my head a fair amount of times wrestling in junior high and high school, but turned out fine. (I think.)

If she loves running on her own accord, let her. If she runs like that because her parents want to live vicariously through her, then it's absurd and wrong.