Welcome to the site! This page is all about sarcoplasmic hypertrophy, how it works, and why bodybuilders aim for it. I’ll be breaking down the difficult parts into easy-to-digest chunks.
Muscle fibers have a sarcoplasm, which is unique in that it contains a large amount of glycogen. Sarcoplasmic hypertrophy is all about maximising the amount of glycogen in the muscles, which in turn is the most effective way of increasing muscle size.
Bodybuilders are all about sarcoplasmic hypertrophy, and will train in such a way that the body is forced to increase the glycogen storage in the muscles.
Therefore, they will lift weights for higher reps, using above and beyond the amount of glycogen stored in the muscles, so the muscles respond by increase their glycogen stores in case of future stress on the muscle.
This is also why it’s imperative to take in a large amount of carbohydrates that the body can use as glycogen stores in the muscles.