There are two approaches to building muscle. One method is based on increasing the sarcoplasmic fluid in the muscle cells and is called sarcoplasmic hypertrophy. The other method is based on increasing the bundles of actomyosin filiments with a muscle cell and is called myofibrillar hypertrophy.
Simplistically, sarcoplasmic hypertrophy is the domain of bodybuilders, where the goal of their training style is to increase the overall size of the muscle. Everything within the bodybuilders training, recovery and nutrition are brought to bear to bring this about: training cycles and routines, food types and timing, supplementation, active and passive rest, et cetera.
Myofibrillar hypertrophy is more the domain of weight lifters like Olympic lifters and sport-based athletes that compete in weight classes. Their goals are more defined by their respective sports. An Olympic lifter generally cares more about lifting progressively heavier weights in the platform lifts – the snatch and the clean & jerk then about the size or shape of his muscles. That would be considered (if at all) as a secondary or tertiary consideration.
The sports-based athlete that lifts for strength and performance gains as well as injury prevention but has to be aware of weight classes will usually also take the path of myofibrillar hypertrophy over sacroplasmic to keep his weight down, as sarcoplasmic hypertrophy (eventually) adds weight to an athlete as the muscles expand to contain the extra fluid building within the muscle cells. These athletes get stronger as their muscles get denser rather then bigger.
Deciding on a path to building muscle is predicated on the goals of the athlete. For example, do you want bigger muscles to show off at the beach or denser muscles to maximize your performance within a sport defined by a weigh class – like boxing or wrestling?
Only you can decide.