injury pool -- how will Anna exit her powerlifting arc?

How will Anna exit this arc and how long will it take? We know she'll get bored and wander away from this as soon as she realizes it takes actual work and consistent effort, but let's pretend in this world, Anna sticks with something. And she can't just admit that she got bored and lazy, she'll have to either claim an injury OR a new passion to replace powerlifting.

What's y'all's predictions? What's going to go out first? Her knees? Ankles? Lower back (that's GOT to be a time bomb, can you imagine her lower spine?). If she stays with it long enough to get injured, I have to go with knee, I've known WAY too many people with fucked up knees who DON'T stand and walk with their legs at a horrifying angle, Anna is racing the clock on that.

How long will this last? I bet she loses interest in 3 weeks, but keeps at it for 1-2 months "to show the hayders". Then she'll fake an injury.