The process through which our muscles grow is known as muscle hypertrophy. This muscle hypertrophy is nothing more than a thickening of the muscle fibers that make up each muscle or, more technically speaking, an increase in their cross-section.
It is difficult to establish a general rate at which our muscles can grow since it is very difficult to take valid reference values for people of different gender, ethnicity or age, not to mention the genetic background of each person and the adaptation that this will make to training.
Be that as it may, in this article we explain precisely how the process of muscle hypertrophy takes place and what approximate rate of growth we can expect.
How does muscle hypertrophy work?
When we say hypertrophy we mean growth or increase in size of something, in this case muscle. Technically it implies an increase in the diameter of the muscle fibers.
If we delve a little deeper we can talk about two types of hypertrophy that, although we can describe them separately, go hand in hand. On the one hand, we have sarcoplasmic hypertrophy, which is nothing more than an increase in the elements that do not contract in the muscle, and on the other hand, sarcomeric hypertrophy, which involves the elements that do contract. A development of sarcoplasmic hypertrophy causes improvements at the metabolic and energetic level, that is, the metabolic efficiency of the muscle cell is increased.
As for how hypertrophy begins to occur, we must know the meaning of three concepts and mechanisms that are closely related: mechanical tension, metabolic stress and muscle damage.
- Mechanical stress is nothing more than tension that our muscle fibers endure when they contract to produce force against resistance.
- Metabolic stress usually occurs in parallel with mechanical stress, especially as we perform sets and fatigue builds up in our muscles. It has a metabolic origin and not as physical as mechanical stress since It is the result of the accumulation of metabolites produced by energy metabolism from anaerobic glycolysis.
- Muscle damage, on the other hand, is the end result we can expect from training. It is nothing other than the damage at the structural level that muscle tissue can suffer during strength training. This damage, to be repaired, attracts different cells of the immune system that can activate signals that start the hypertrophy process at the cellular level.
All these processes explain muscle hypertrophy and occur to a greater or lesser extent in parallel. In short, they coexist.
When does hypertrophy take place and at what rate?
Regarding when, it is usually said that hypertrophy begins to occur after the first 6 or 8 weeks of starting strength training. If you are a beginner, what takes place in the first 6 or 8 weeks are neurological adaptations, that is, our nervous system automates movements and develops better inter- and intramuscular coordination.
It is considered that from this period we are able to start training with the real intensity that our current neuromuscular system can withstand, so it is from this moment that we can aspire to receive the appropriate training stimulus so that our muscles grow.
Regarding the rate of growth we can only speak of generalities.
In this sense, Lyle McDonald, disseminator, researcher and specialist in body recomposition, established some approximations years ago regarding this topic:
- First year: 10 to 12 kilos of lean muscle mass. Approximately 1 kilo per month.
- Second year: 4.5 to 5.5 kilos of lean muscle mass. About half a kilo a month.
- Third year: 2 to 3 kilos of lean mass. Approximately 250 grams per month.
- Fourth year: approximately one and a half kilos throughout the year.
Let us take these figures with caution as they are general and they assume that all the factors that influence muscle growth are applied perfectly.
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