In this article we will analyze the main mechanisms of muscle hypertrophy.

There are 3 mechanisms responsible for growth and therefore muscular hypertrophy:

Muscle tension
Metabolic stress
Muscle damage

Muscle tension

Muscle tension is the most important of the 3 mechanisms for muscle growth. When we perform a contraction against a load (or resistance), we produce a muscle tension. In order for the tension to be able to create a stimulus for muscle growth, it is necessary that there is a minimum degree of intensity from the produced muscular tension.

Generally the minimum intensity is about 60% of your 1RM, even if, from recent studies, it has been seen that sets with an intensity equal to 30-40% of your 1RM are still able to stimulate muscle growth, provided that these sets are taken to exhaustion. The higher the training load, the greater the muscle tension developed by the muscle.

To ensure a good development of muscle tension at each workout, it will be necessary to progressively increase the load to prevent the body from adapting to the current weight.

Metabolic stress

This mechanism of muscle growth is given by the accumulation of waste metabolites inside the muscle. When we bring a set to exhaustion or near exhaustion, we feel the muscle burning; this burning is due to the accumulation of waste metabolites.

Metabolic stress can also be obtained through the BFR technique – Blood Flow Restriction. This training technique allows to obtain an accumulation of metabolites using very low loads, about 30% of 1RM, and to stimulate muscle growth.

Muscle damage

This is the most discussed muscle growth mechanism of all 3. Muscular damage occurs when the training sets are so heavy that they damage the internal structure of the muscle. The days following a high level of muscle damage training, you will feel the so-called DOMS – delayed onset muscle soreness,  the typical pain you can feel the next day when you change training or you start training again after being stopped for a long time.

Recent studies have shown that muscle damage is not necessary to produce a stimulus capable of leading to muscle hypertrophy. In addition, excessive muscle damage could compromise recovery, requiring more time to bring the muscle back to an optimal state, and therefore requiring a lower training frequency resulting in less muscle growth over the long term.