Some videos posted , very interesting , show 2 quite famous actress : Brooke Shields (Blue Laguna) and Linda Blair (The exorcist), walking on broken glasses.
Without hurt.

I am sure that this actress aren't barefooters,and from the video , is clear that they
do not have tough calllused soles !

So , mi question is : or the glasses are fakes , are not real pieces of broken glasses,or , in some way , is possible to walk over them even with "normal" tender
soles.
In this last case the glass walking is not a "real" test for tough soles !

Some one can explain me more ?

I try to give some type of answer from what girls have told me and some science. Some of it is even weight distrubution and using straight up and down steps. Take a sharp knife and just push the blade against skin, nothing happens. If you slide it you get cut. It takes very tough callous's to slide or twist in broken glass without getting cut. (Like Jenna or Oksana can do in the extreme series) Or like Olga Gavva does in her clips.
It think Blair was the most squeemish, Brooke did get a little cut on the side of her foot, but did good. But you left out the best one, Loni Anderson. I think she did it the best, She did it twice and strolled on the glass like it was nothing. Forget the sharp glass, just the irregular surface would slow anybody down. It didn't her and you could actually hear the glass crunch as she walked on it. But Loni, if you ever followed her career, is a barefooter. Award shows and such she is photgraphed barefoot alot of all the time.
Hope this helped.