Knee Pain
     

What did he say?

Some of the terms used might not be familiar to you. I'll explain them to you.
You can pause the movie at any point and then start again.

Here's the big idea: The foot is flat - The knee rotates in, pain and damage occures. Put an arch under the foot, the knee points forwards and everything stays healthy
     
What?   Explanation in English
     

Patella = Knee cap
Femur
Tibia

  
Lateral   On the Outside
Medial   On the Inside
     
Subtalar Joint  
   
     
Transverse
Sagital