Judo is about using your opponents energy and momentum against them. In ground work the same applies, Judo does promote standing upright and this can cause problems. Max did dedicate his competition and training to judo from 6 to 16 and did not cross train. The stress of competition did prepare him for the High School stage but you must travel great distances (outside the country) to accomplish that type of advantage.
I hopes this helps....
-g
