When you say knock-kneed through training do you mean all the time or one squats and things like that? Also, are your knees just turning inward with the weight or are they touching or almost touching? The latter would tend toward a potentially serious knee problem rather than a muscle problem.
If it is your knees turing inward during squats then it's definitely fixable. Check your stance and make sure you're using the best one for you. I don't know how much this will effect the problem but the stance that allows you to go deepest is the best if you're doing full squats. Keep your toes turned slightly outwards and concentrate on keeping your knees aligned with your toes.
Now I've head all sorts of biomechanical explanations as to why people's knees turn inward. Dr. Squat said it was simply weak quads in general. Some say imbalances between the abducters. Some say imbalances between quads and hams.....all with their different recommedations. It seems to me however if ANYTHING is weak whatever is stronger is going to take over and if this leads to your knees turing inward there is one simple solution.
Try lighter weight. If at a heavier weight your knees cave inward but at a lighter weight you can keep them aligned that sort of tells you what you "kneed" to do
. A common recommendation is to tie an elastic band around the knees during the squat so that you have to actively push your knees out against it. That doesn't sound like a bad idea, either.
I've had this problem at times although maybe not as severe as you and just dropping the weight down and building back up while actively concentrating on keeping my knees out solved the problem. I'm sure there are other things you can do that is just my 2 cents.