I have proof.
I have been doing my Wii fit exercises. See?
(Photos courtesy of Darren’s iPhone)
Indeed, when I started with my physio E, I couldn’t get my left knee forward level with my big toe.
Try it. Stand in front of a wall with your big toe touching it and see if you can bring your knee forward to touch the wall too.
My knee started 13.5cm short of the wall. Today it was 5.5cm short.
And because I was pretty inflexible anyway, that’s almost half way. My right knee can only get 3.5cm in front of my big toe.