Yoga. What did we forgot?

I am practicing yoga for almost 9 years. And today I can't imagine my life without it. Yoga entered into my life very deep, and start to change it. As a sportsmen in the last there are some injuries in body, that start to worry me, in the knee in the back. Doctor said you need to these, these and these and of course a very long list of medicaments ) if we give our life to the hands of medicine we will just to take medication ) I am sure it is not wright way!
I found that for my knees "downward dog "asana are very helpful and of course others asanas where you work with the legs to release your knees.
"Downward dog" also perfect for the back. If your have injured your back it perfect to pull it. May be only in the light interpretation of "downward dog"
I have always problems with coughing - for me "ustrasana" asana very helpfull !