Well, I'll be the 'wet blanket' today. Having been on bikes since 1949 or so and, having broken left wrist, left ankle (twice) right ankle, collar bone and three ribs---the only sure cure is to stop racing dirt bikes. I still ride my old 1948 Norton on the street and I still race vintage cars but, no dirt bikes for me anymore. Another point, IMO, stay away from the 3 and 4 wheel dirt things. When you get off of one of those it tends to follow you!!!
At least it seems that the more experienced you become the less you 'get off' but, the more it hurts when you do!
Rod