We often assume that muscle mass gain (hypertrophy) and strength are two distinct muscle qualities. One relies on an increase in muscle fibers size, while the other relies on the capacity to lift a heavy weight for a small number of repetitions. Adaptations provoked by training will occur on the physiological and muscular planes for hypertrophy, and on the nervous system for maximal strength. However, there exists an important complementarity to take into consideration when we desire to maximize training results for either of these qualities.

In fact, it is false to divide strength from hypertrophy since those muscular qualities rely on one another. Hypertrophy relies on many parameters which have been addressed during a precedent blog [1]. Among the details that we must focus on, intensity (load) is as important a variable for strength. Heavy loads allow a greater muscle fibers recruitment. Thus, if more fibers are stimulated, a greater number of them will potentially increase in volume. From this notion, maximal strength can then come into play. An efficient nervous system will allow the utilization of higher intensities, which will result in greater recruitment of muscle fibers. In addition, the simple fact of regularly training a movement facilitates the activation of the muscles involved in its realization. This is why individuals starting out in training often see their strength increase rapidly. Their nervous system adapts and activates involved muscle fibers more easily.

Muscle is made up of two types of contractile fibers, myosin and actin. Their bond allows muscle contraction and therefore, movement. The muscle fiber size increase that comes with hypertophy training increases the number of myofibrils (actin and myosin) at the same time. Knowing this, you will agree that more muscle mass will increase the potential for strength production, simply because there will be more possible associations between myofibrils. By coupling the increase in the number of possible bridges with an effective interaction between the nervous and muscular system, a greater production of force will be observed.

The optimal number of repetitions or intensity in a mass gain context seems to be between 8 and 12 repetitions maximum, while the maximal strength would be more developed in series with 6 repetitions maximum and less. However, it should not be thought that gains in strength or hypertrophy are impossible in the presence of gains for the other. They follow each other along the continuum of muscular qualities and their complementarity allows for a mutual transfer.

The combination of these becomes interesting when maximizing results (bulk or strength). So, alternating these muscle qualities within our training planning can be beneficial. However, it is important to follow a suitable training progression in order to prepare our body for higher intensities. A health professional like a kinesiologist can help you tailor your training to make it safer and more specific to your goals.

[1] http://squatsetfraises.com/sur-quoi-porter-notre-attention-lorsquon-sentraine-pour-prendre-de-la-masse-musculaire/