The physical transformation is a long and hard process, in the sense that this progress is not always constant. Instead of progressing in a linear way, muscles grow periodically, in splashes. Unfortunately, these bursts are usually interspersed with long brakes in growing. You often hear about guys who can not gain muscle mass, despite of all their efforts. In fact, these guys are in a phase of a slow muscle growth.
The Body Transformation Blueprint by Sean Nalewanyj