He has a hinged device up the back of his left leg and op to his butt that attaches to a platform under the rug. The hinges lock so that they only bend so far. Thus, he “sits down” on the arm after it won’t hinge any further. 

 Actually in one shot you can see the brace through his jeans. The shoe also appears fused to the rug. 

 Steel rod hidden in his pants 

 Flexible Metal structures on the back of the body 

 Rod on his pants.  Notice he doesn’t walk off. 

 Magic duh 

 Thanks for noting. 🫂 

 Yea. The whole shoe is integral with the hinged leg brace and the mat. Like a boot and ski. Watch the mat edge lift up when he leans backward.  

 Shoe glued to the mat 🤔 

 Cantilever under the matt, strapped to his calf.  The one part you can see the matt lift ever so slightly when he leans back.