This is annoying. I have minor knee pain in both my knees. the pain is located on the inside portion of my thighs. I dont know anything about physiology but I think (based off of this picture) the thing that is bothering me is the Medial Collateral Ligament. I rarely get knee pain when I squat, but I very easily and frequently get it whenever I do any kind of single leg training. Also, I just started doing German Volume Training (or the 10-set method).
I have never trained like this in my life and for the first time in a very long time I had knee pain in the aforementioned location. Affirming my suggestion that the pain is from flat feet, performing farmers walks after the squat is what really hurt them. The pain isnt bad, just annoying at this point, but bad knees run in the family (my father is getting a knee replacement in 2 months and he is in his mid 60’s)
So, am I right about the culprit being flat feet? What kind of work could I do to help correct the problem?