I have no “proof” to back this up, but here is my personal experience.
When I was sixteen, I broke my left leg in four places: the tibia was cracked horizontally, as well as vertically. The fibula was broken into three separate pieces, meaning that the muscles and tendons were the only things providing support.
I was in the hospital for a week before the swelling subsided sufficiently to put on a plaster cast ( the prevailing treatment at the time) which went all the way to the hip.
The pain would cause me to black out.
This cast, and an additional one, lasted three months.
During this time of course I was on crutches.
The following three months I was lucky enough to have casts that were only to just below the knee, allowing me to bend my leg but I still needed crutches.
When the final cast came off, my left leg was considerably shrivelled, having lost all muscle mass.
The next step was to learn how to walk again, and again the pain was out of this world.
My doctor told me that the leg was now shorter than the other one and that I would probably need the assistance of a cane for the rest of my life.
As someone who had once run an 11 second 100 metres, this didn’t sit well, so I began my own torturous physical therapy.
I cycled as much as I could, tried ice skating.
My limp was pronounced.
One day, some people in my faith circle wondered if I would consider faith healing, and I agreed.
My feeling was that my leg actually grew, and I could stand straight. Pain vanished.
Neuroscience and psychology could probably explain this differently, but I’ll hold on to my own belief.