Train red fibers in Body Building

The red fibers naturally constitute ALL the muscles of the body BUT in EXTREMELY VARIABLE percentages between them. They are predominant in the muscles responsible for gentle and repeated (long-lasting) efforts, also known as tonic-postural muscles.

The red ones are not the preferred fibers in Body Building training but their more or less marked presence significantly affects the training technique to be used.

Briefly: shortening of the fibers

The movement occurs thanks to the nerve stimulus of the neurons on muscles; the latter can be defined tissues organized and responsible for contraction (shortening of the fibers) "enclosed" in a membrane of connective tissue (epimysium). Internally, they are organized in several parallel bundles covered by the perimysium (other membrane) and inside they contain the muscle fiber cells, also called myocells. These fibers are POLYNUCLEATE, a characteristic that suggests the fusion of several units in a single cytoplasm; the unit of contraction of the fibrocellule is the sarcomere, which shortening determines the muscle contraction.

The definitive functional units are made up of two proteins, actin and myosin; to make the contraction happen, they slipping one on the other (thanks to the breakdown of adenosine-tri-phosphate) transforming the molecular energy into energy of movement.

Different types of muscle fibers

Muscle fibers are of three types:

Lens, oxidative and red colored / type I (plus oxidative enzymes, mitochondria, myoglobin and capillaries)
Intermediate, oxidative - glycolytic and white / type IIA (adapt to both energy metabolisms)
Fast, glycolytic and white in color / type IIB (plus glycolytic enzymes, glycogen, phosphocreatine and creatine kinase)

The white fibers (especially the IIB) are responsible for short and intense efforts; together with the motor neuron that innervates them, they determine the performance of voltage And speed of contraction which (translated in athletic terms) is equivalent to strength and speed. These glycolytic fibers are the most useful in the development of mass in Body Building, as they have high reserves of glycogen and creatine-phosphate (CP) in the cytoplasm (greater overall cell volume) which by increasing favor muscle hypertrophy.
NB. In the "hypertrophy (predominant element for the increase of muscle mass in the Natural Body Building) there is another very important factor: the stimulation and specialization of the satellite cells. In reality they are real stem cells, that is small units which, in the absence of external stimuli such as training or intense muscle damage, remain in a vegetative state; on the other hand, if the conditions required it, the satellite cells could evolve into specialized (muscle) units, repairing the lesion or increasing the overall volume of the fibrocells. This is a mechanism that I believe is closer to hypertrophy than to hyperplasia because satellites are cells already present inside the tissue; however, it is common to read about other authors who consider the mechanism a real increase in the number of muscle fibers, hence hyperplasia.
The nature of the muscle fibers (or rather, of the motor units) is influenced by several factors:

Type of muscle (each muscle has a composition of fibers - white and red - different from the others)
Portion of the muscle considered (many muscles, such as the quadriceps and the pectoral, have bundles characterized by a different qualitative prevalence of motor units)
Genetics and individual predisposition (chromosomal heritage and aptitude towards short-intense or prolonged-mild muscular efforts)
Training technique (prevalence of aerobic or anaerobic efforts).

Red fibers in the muscles

The red fibers are concentrated mostly in the muscles and bundles responsible for:

Posture maintenance (internal lodges; spine supporters)
Pulmonary ventilation (internal and external intercostals, scalene, pectoralis minor, diaphragm etc.)
Walking (iliac psoas, vastus lateral quadriceps femoris, soleus, etc.)
Frequently repeated movements of the upper limbs (deltoid, brachial biceps, high pectoral pectoral bundles, etc.).

As can be seen, at times it is possible to identify entire muscle bundles or precise areas of muscles that have motor units (therefore muscle fibers) different from the neighboring ones (this is the case of the pectoralis major); this "variety" is determined above all by the predisposition to a movement and / or by the habit of carrying it out frequently without reaching high intensity of effort. Wanting to give a trivial example, in human evolution, probably the deltoid and the high pectoral bundles have developed with many red fibers to facilitate the "harvesting" of fruit from the trees; similarly, the vastus medialis of the quadriceps (thigh muscle) it has good amounts of white fibers to improve the power of the shots in hunting and / or fleeing.

Red fibers and Body Building

The goal of Body Building is the development of a muscular and proportionate body. To do this it is necessary to train the muscles by aiming mainly at hypertrophy (increase in muscle mass) and cutting (definition of muscle mass).

To train hypertrophy it is necessary to impose a training stimulus on the muscle that determines:

Tensioning of the tissue through SPECIFIC strength exercises
The depletion of creatine phosphate (CP) and glycogen stores

In addition, it is also advisable:

Leave the right recovery to promote supercompensation to the training stimulus (tissue repair and replenishment of reserves)
Eating properly
Get the right sleep and promote hormonal cycles.

In light of the above, a question arises spontaneously: Do muscles with different fibers all train the same way? The answer is no.
Regardless of the technique used, it would be advisable to stimulate the red fibers in a different way from the white ones. In Body Building it is customary to use tables with exercises that are repeated from 3 to 12 times (repetitions) for a variable number of series (from 3 upwards). In order to correctly stimulate a bundle with a prevalence of red fibers it is NOT advisable to use the same repetitions and the same recoveries useful for the development of white fibers! In simple terms: To increase athletic performance and obtain a more "decisive" metabolic response of the red fibers, it is advisable to maintain:

A higher number of repetitions
Lower execution speed
Get more content.

Setting on the development of PURE STRENGTH (for example 3-5 repetitions and recoveries up to 3 ") SINGLE-JOINT exercises such as the" CURL with BALANCE "(which isolate the muscles with a high content of red fibers) DOES NOT confer the same benefits as the same execution performed with more repetitions and shorter recoveries. This difference in the efficacy of the stimulus is determined by the energy metabolism of the red fibers; they are innervated by "slow" motor neurons (which do not allow a rapid contraction speed) and have an energy metabolism that does not allow the production of HIGH quantities of energy and lactic acid in a short time (NB. peaks of lactic acid = stimulation of the hormone anabolic somatotropic GH).
Post-exercise aches are mainly linked to strong tears in the fiber, which will repair itself in a very long time and therefore difficult to contextualize in any training table for hypertrophy. If, on the other hand, we increase the repetitions in order to allow the right production of acid lactic without "massacring" the district (perhaps also reducing the recoveries) we could obtain more satisfactory results; eg: 4 series of 12-10-10-8 or 12-10-8-8 with recoveries from 90 "" to 120 " "In this way, the recovery times will be comparable to those of the other muscle groups and the training schedule will be easier to organize.
In conclusion, in order to draw up an effective training table for Body Building it is first of all necessary to take into account both the subjectivity and the histological variability of the various muscle groups and bundles; the difference between the various motor units requires an extra precaution on the design of the table which, SE provides for the isolation of muscles with a prevalence of red fibers, You must NOT do this with exercises that are too focused on contractile strength.

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