Final answer:
Hypertrophy refers to the increase in muscle fiber size that occurs over weeks or months of consistent resistance training. While the increase in muscle size is due to more sarcomeres and myofibrils, the exact timeframe for hypertrophy varies individually.
Step-by-step explanation:
The time it takes to achieve hypertrophy, which is the increase in the size of muscle fibers, varies based on several factors such as the intensity of the workout, the frequency of workouts, and the individual's body type and genetics. Hypertrophy occurs when there is an increase in the number of sarcomeres and myofibrils within a skeletal muscle, but not an increase in the number of muscle fibers themselves. Resistance exercise builds muscle by causing small micro-tears in muscle fibers that then repair and adapt to withstand greater stress, leading to an increase in muscle size. This process is typically complemented by increased development of connective tissue and stronger tendons, which support the muscles during their increasingly powerful contractions.
Performance-enhancing substances can affect muscle by accelerating muscle growth and recovery, but they can also have significant side effects and are often banned in competitive sports. It is important to note that muscle hypertrophy generally takes place over weeks or months of consistent resistance training. As the science of individual responses to exercise is complex, specifying the exact number of weeks for hypertrophy to occur cannot be generalized and will differ from person to person.