Our work with elite athletes serves as the proving grounds for our methods. Most people don’t play professional sports. But if our methods help athletes at the highest levels, they can work for anyone.
What do you mean by “squatting with my arch in my foot because I have flat feet”?
If you are changing your foot position you can be using parts of your foot you have not actively used before when squatting. This can change position of things upstream since you are changing something at the base/foundation.
Is there knee pain with any other movements/positions?
Have you watched the episodes linked in your prior post?