What happens in your body when you go to the gym? How do you build muscle?
In this post, we talk about muscle hypertrophy; the science behind building muscle!
Muscle Hypertrophy is known as an increase in muscle mass through addition of sarcomeres in parallel or increase on their size.
Muscle hypertrophy is the term used to describe the increase in muscle mass. Through this process, your muscle cells add altogether, forming a bigger cluster of fibers.
What Causes Muscle Hypertrophy?
Muscle hypertrophy cannot be explained by a single cause; it is a multifactorial phenomenon.
Are many the mechanisms by which muscle hypertrophy can be caused:
- Satellite cells
- Myogenic pathways
- Cell swelling
Satellite cells are the precursors of muscle cells. With no function assigned, they wonder around your muscle, until they are transformed into a muscle cell to form the muscle tissue (source)
This cells are one of the main causes of muscle hypertrophy. First, satellite cells proliferate and evolve. The, they are differentiated into mature muscle cells, and fused to existing muscle.
This is the process by which satellite cells can contribute to muscle hypertrophy.
Metabolic pathways such as mTOR are responsible of upregulating muscle hypertrophy (source). Several other primary anabolic signaling pathways influence muscle hypertrophy, such as mitogen-activated protein kinase (MAPK), and calcium-(Ca2+) dependent pathways.
Hormones and cytokines are largely contributors to muscle hypertrophy. Testosterone, IGF-1, and GH are the strongest anabolic hormones in your organism.
The hormonal regulation of muscle hypertrophy is complex, with many hormones and cytokines believed to contribute to the response (study)
This molecules not only upregulate muscle hypertrophy, but can also influence fat loss.
Hypoxia is the lack of oxygen in your muscles. It contributes to muscle hypertrophy by enlarging the effect of metabolic stress, one of the main mechanisms of muscle hypertrophy.
Hypoxia contributes to increases in muscle hypertrophy, with effects seen even in the absence of exercise (study)
Mechanical tension is the force created when a muscle contracts isotonically against a load. It is produced both by the force and stretch of the muscle.
When the force is generated on the muscle, it causes mechano-chemically transduced molecular and cellular responses in myofibers and satellite cells. This will ultimately lead in muscle hypertrophy
Although mechanical tension alone can produce muscle hypertrophy, it needs of the other two mechanisms to produce the needed effect to build muscle efficiently.
The factors affecting mechanical tension are the time under tension, heavy loads, the force-velocity relationship, and progressive overload.
Metabolic stress, together with mechanical tension, are the two main mechanisms of muscle hypertrophy.
It refers to the accumulation of metabolites in the muscle cell after intense exercise. Lactate, among other waste products, start accumulating and causing different metabolic effects.
Muscle damage is believed to be a consequence of mechanical tension and metabolic stress (study).
Resistance training causes tearing of the membranes in your muscles and stretches molecular channel. The response to muscle damage increases satellite cells proliferation and differentiation into mature muscle cells.
Muscle hypertrophy is the increase of muscle mass by the addition of sarcomeres in parallel. Satellite cells, hormones, protein balance, cell swelling, hypoxia, and myogenic pathways regulate this process.
The main mechanisms by which muscle hypertrophy is achieved are mechanical tension, metabolic stress, and muscle damage.