I looked into this thread after reading brutus's log. Here is something I touched on there lightly:
Myofibrillar hypertrophy refers to an actual increase in size of the muscle fibers and sarcoplasmic hypertrophy to an increase in the volume of the fluid, non-contractile components of the muscle (glycogen, water, minerals, etc.).
I used to train in the 10 to 12 rep range with a lot of supersets, drop sets, and giant sets, and I always hated the inflation-deflation cycle. I would train my chest on Monday and look good for a few days but then wonder where it went come Saturday.
Furthermore, focusing on sarcoplasmic growth fails to build any real strength, so you stay weak, even if you have some size. Focusing on myofibrillar growth, on the other hand, can greatly increase your strength. Now, don’t think that sarcoplasmic growth is worthless. It has a place in an advanced weightlifter’s routine, but it should not be the focus.
Granted, while on cycle you can basically get away with anything and add some strength. But seeing how steroids enhance the results you induce from training, I think progressive Overload should be at least used for 50% of your training on compound lifts. If you want to hit higher rep ranges in the end to get more nutrients, glucose, etc. In the muscle to enhance recovery... cool.
There are two ways for your muscles to produce force:
1. Recruit more muscle fibers
2. Fire muscle fibers more forcefully
The first is exactly what it sounds like: there are so many individual fibers in a muscle, and the more that are recruited to contract, the more force can be produced. The second refers to how quickly the body can send electrical signals to the muscle fibers, and the better it can do this, the more forcefully the muscle fibers can contract. An increase in strength is simply an increase in the number of muscle fibers available for recruitment (bigger muscles), an increase in the existing fibers’ ability to fire, or both.
This, by the way, is why people can get stronger without getting bigger: neuromuscular adaptations in existing muscle fibers can improve their ability to contract without the addition of new fibers. We see this in Olympic lifters, for example.
The bottom line is if strength stalls for extended periods, so does progressive overload and thus myofibrillar hypertrophy , and that’s the end of any real progress in terms of muscle size. This is why all good natural bodybuilding programs have as a primary goal to increase strength and primarily use heavy weightlifting (80% to 95% of 1RM) to accomplish this.