This is going to become a semantics battle, and I'd rather it didn't, so briefly...
This quote:
Myofibrillar hypertrophy, on the other hand, is an enlargement of the muscle fiber as it gains more myofibrils, which contract and generate tension in the muscle. With this type of hypertrophy, the area density of myofibrils increases and there is a significantly greater ability to exert muscular strength (2).
made by:
Siff, Mel C. and Yuri V. Verkhoshansky. Supertraining. Colorado: Denver, 1999.
Is the only quote made by an authro who I will grant any respect to. The other authros cited (Poliquin and Tsatsouline) have been proven wrong time and again in numerous publications, forums and mailing lists by the late Drs. Siff and Verkoshansky. And to revisit the statement they made on Myofibrillar Hypertrophy, what they said was, simply, that myofibrillar hypertrophy is an enlargement of the muscle fiber. They did NOT continue to say that it was best achieved with any type of rep range or rest period. They DID, however, go on in the text of Supertraining (Supertraining being by Siff but noting works of Verkoshansky and others) to explain techniques, within the realm of physiology and kinesiology, to attain strength gains and hypertrophy gains. None of which made specific mention of which was better for myofibrillar or sarcoplasmic hypertrophy. Why?
Because there is no evidence, through science, that proves one can be attained via specific methods while other methods will produce the alternate effect. Dr. Siff and Charles Poliquin debated this a LOT. In the end, it always ended with Siff providing proven scientifically backed evidence, and Poliquin losing his temper and resorting to name-calling. Many of these such conversations can be found on the Supertraining mailing list.
I have been accused on this forum of being biased towards Dr. Siff and close-minded towards Charles Poliquin. If I am biased, it is because everything that is, is because of science or can be proven by science. Everything from how air makes us live to why the Earth rotates around the Sun. Dr. Siff always backed his claims with science, whereas many (and most) others always back their claims with pseudo-science or the excuse "well, I've seen it happen." And as I've argued on this forum many times, as well, what you see and what is actually happening do not have to be the same thing. Appearances can be deceiving, science cannot.
I would invite you to venture to
www.elitefts.com and buy the latest edition of Supertraining. Not because I am trying to say "you're wrong, I'm right" but because it will give you a very solid, science backed view into the world of sports training. (Sports encompassing weightlifting, etc.)