From "The Thinker" On EliteFTS.
The reason lies in the function of the type I, IIA, and IIB fibers.
It is for these reasons why there are many effective methods used by bodybuilders as well as powerlifters; however, not so many used by weightlifters, throwers, sprinters, etcetera and perhaps this is most significantly a result of the importance of genetics.
The fastest and most explosive athletes are largely genetically predisposed to excel in such disciplines due to their inherited larger percentage of white fiber, favorable anthropometry, tendon lengths, and so on and the room to advance these capacities is very small to non-existent;
While the goal of becoming only maximally strong or muscle bound is only marginally dependent upon genetic material and nearly anyone, regardless of inherited gifts, can become very muscle bound and strong in the limit sense via proper training and nutrition.
It is for this reason why you will witness a plethora of bodybuilders and powerlifters speak of how they were skinny and/or weak early in life and through years of training and nutrition they reached very high status.
You will not, however, witness elite caliber sprinters, for example, speak of how slow or nonexplosive they were early in life because, for all intents and purposes, you either have it or you don't.
The more dependent the sport result is upon the anaerobic alactic function of the white fiber- the more the athlete's success depends upon inherited genetic material.