I hate to bump this thread, but since it re-emerges so often, here is a link to video of a very large and strong but comparatively untrained man going against black belts and pretty much dominating them on strength alone - not entirely because apparently he has some skill and knowledge, but his strength and size completely overwhelm the other guys.

YouTube

Granted, the big guy is Shaquille O'Neal, but the point stands: strength and size is important in contact/strength sports.