Interesting. When I look at her footwear, it is not consistent with moving big poundage.
In my younger years I did squat workouts going to 315 for 15 reps. Once I got much over 225 (I weighed 165 - about the same as the subject above) pedestrian athletic shoes just got crushed.
I'd think that her footwear would be more robust for such poundage.
An athlete at her level can have custom everything.
It would be interesting to get a look at those shoes.
They might have footbeds that fit her boots in them.