Thats interesting Trevor.
Im surprised that fella you mentioned has not got some joint or cartilage problems from doing 1000 squats a day! Maybe he is an anomaly.
Different movements will affect joints in different ways.
A squatting movement would definately affect the flexation of the hip joint and the knees while putting load strain on the ankles.
But getting back to the movements in wfp there is definately a tendency to use arm movement which I think is natural.
But repeated motion does impact the elbow joint, wrist and to some extent the shoulders.
I would of thought the method shown in the video with Ionics would be quite safe to use on the hips because no flexation of the joint is taking place, you are just shifting weight from one leg to the other.