The big white fiber (fast twitch) muscles respond to heavy weight training. This is why strength coaches and powerlifters swear by heavy training. The thing is, if you don't have an abundance of those muscle types, the heavy weight won;t do anything. This is when most strength coaches will dismiss you.
I, on the other hand, work with people who don;t have that advantage. I work with the ones who the so-called experts dismiss. If you have mostly slow twitch type II muscles you need to get them as big and shapely as possible. A classic example is Frank Zane. Not a big, bulky guy. he's a type II guy. Same with Serge Nubret. If they trained like powerfilters they'd just be skinny guys with injuries. Instead, they're gods. because they knew how to train for their bodytype.
For more info:
http://www.elitefitness.com/reports/truth/