1.Thus, swelling seems to be the culprit, but the story doesn't end there. The permanent effect--the reason we seem to have been able to hold part of our gains (one-quarter-to a half an inch) for several months at the time of this writing--is from our continued training. Since returning to our normal training programs, we've maintained the size, meaning we've maintained the overall volume of the tissue simply because we began another breakdown process before the muscle fibers completely returned to normal. In the long run, this may pose a problem, as effects of the swelling-repairing process can overcome your gains if you don't strike the proper balance of training and recuperation. That's a matter of ongoing scientific discovery.
2. Other scientific studies regarding this kind of workout simply don't exist. In the scientific community, the only people crazy enough to try this were in the lab with me that day. Yet some explanations could theoretically be responsible for the gains.
Let's first look at mechanisms for muscle hypertrophy. We know that muscle size increases by increasing the thickness of the myofilaments, or protein strands, within the contractile portion of the muscle. We also know that the number of myofibrils, the contractile structure made up of myofilaments, increase with training. Some research has shown that it may also be possible for muscle fibers themselves to split, known as hyperplasia, after which the new fibers increase in size, although this hasn't been well documented in human beings. Lastly, the entire cellular structure--all the proteins, cell walls and other material that supports and anchors the contractile machine itself--increases in overall size and thickness via training.
The last one is less likely but viable, the first is more interesting. Even to keep a 1/4 inch from one workout for a trained bb'r is pretty amazing. Of course routine would be needed to maintain arm size and overall size..it goes for strength too lol. If you stop working out you would lose that muscle mass. Pretty simple concept.
It seems like an interesting experiment to do as well. I know bodybuilders of old did something similar with squats. There is more at play then water retention or a massive blood pump.