I was wondering how strength and muscle gain are accomplished at the cellular level. For some reason, knowing this kind of stuff helps me combine other topics so that I can get a better understanding of whatever it's related to.
I can't remember the technical terms, but essentially the separate cellular strands that make up each muscle fiber divide and create more strands per fiber. Also, by recognizing how to properly control the nerves leading to your muscles you can more efficiently use the muscles that are there. One of the reasons it's difficult for someone who's inactive to get back into shape is because they've lost that "muscle memory" which results from having those familiar synaptic pathways to the muscles they're using.