thanx razor, how i understood it - depending on your genetics you can get bigger by increae in size of type 2 fibers or it will possibly increase the # of type 2 fibers. either way it seemed to reach relativelay the same amount of Crooss Sectional Area. Eecentric excersice hits the type 1 fibers & concentric hits type 2. For growth make sure to do conc & eccen & for sports where you dont want growth do conc moves or moves with very limited eccen action.