Yeah man, I know that AJ said that, but later on he recommended a slower positive contraction. But I suppose the point is that if on takes 6 seconds or so to complete the positive contraction them momentum is eliminated. And this topic is basically how to make the muscles more dense and granite-like, and not bloated and bloofy

Anyways I like AJ's idea about power production. So I guess part of the question is, which is better for density? A slow and controlled positive contraction or a heavy-ass weight? Remember, if one does a slow and controlled positive contraction then the training load will become much lighter.