I have a few comments on this as well and questions of my own to add. Just the other night, I was asking Sensei Riggs about this very thing. He told me "westerners" have more knee troubles than Japanese or asians due to customs. In the west, we sit in chairs all day and rarely use our knees to squat or kneel down onto the floor, sit on the floor, etc. Whereas in Japan, sitting seiza is very common even outside martial arts, or just sitting on the floor. They use their legs/knees more than we do.
Strenghthening the legs with particular focus on the inside of the thigh SHOULD help the knees. In addition to the exercises, I try to sit seiza as much as possible, but I have tremndous pain myself. I take "Glucosomine" tablets daily and this helps, but you have to take it daily or don't even bother trying. Glucosemine takes 4 days before you start feeling its affects, but if you stop you go back to 'normal'.
Now then, MY questions would be: Does anyone have any variation of exercises that help with the knees? Does yoga help? or ... well, I'm open to just about any ideas. I have inherited my mother's arthritic knees and compounded this problem with flat feet. Anything I can do to relieve my situation is welcomed.
(*Yes, Sensei. I'm going to get arch supports... just as soon as I can afford them.