An increase in muscle fibers is called?

Hypertrophy

Hypertrophy is the increase in the size of muscle cells, which leads to an increase in the overall size of the muscle. This is in contrast to hyperplasia, which is the increase in the number of muscle cells.

Hypertrophy is caused by a number of factors, including:

* Increased workload: When a muscle is subjected to increased workload, it will adapt by increasing the size of its muscle cells. This is why people who lift weights or do other forms of resistance exercise often see an increase in muscle mass.

* Increased protein intake: Protein is essential for muscle growth and repair. When you consume more protein than your body needs, it will use the excess protein to build new muscle tissue.

* Increased growth hormone: Growth hormone is a hormone that is produced by the pituitary gland. It is essential for growth and development, including the growth of muscle tissue.

* Increased testosterone: Testosterone is a hormone that is produced by the testes in males and the ovaries in females. It is responsible for a number of male characteristics, including increased muscle mass.

Hypertrophy can be a goal for people who want to improve their appearance, strength, and performance. However, it is important to remember that hypertrophy takes time and effort. There is no quick fix to getting big muscles.