well this link says it all
http://www.everyjoe.com/2009/11/29/entertainment/hawthorne-trick-bobbies-prosthetic-leg/
"Check out the following video to learn all about the filming magic involved in such segments, complete with commentary from Mathews herself. It’s very fascinating how realistic the show makes the artificial limb seem, especially after you realize just how fake the effect is. Cool, no?"
http://www.everyjoe.com/2009/11/29/entertainment/hawthorne-trick-bobbies-prosthetic-leg/
"Check out the following video to learn all about the filming magic involved in such segments, complete with commentary from Mathews herself. It’s very fascinating how realistic the show makes the artificial limb seem, especially after you realize just how fake the effect is. Cool, no?"