Which of these two training theories guarantees maximum muscle development?
The choice of the ideal load to guarantee maximum muscle development has always been the subject of numerous debates. Some say that it is better to exhaust the muscles with a high number of repetitions and those who claim it is better to concentrate the stimuli in a few high intensity series. The truth, as the most diplomatic of mediators would say, is always in the middle.
Beyond the various opinions on the subject, it is common opinion to remain between 6 and 12 repetitions per series. This is because numerous studies have shown that:
the ideal stimulus for hypertrophy (muscular development) is given by the lifting of medium-high loads (70-80% of the ceiling) for a medium-low number of repetitions (6-12).
To say that the truth lies in the middle, as we have previously stated, does not mean to maintain that the ideal number of repetitions is given by the average of the two numbers (6 + 12) / 2 = 9 even if this figure represents in itself a good point from which leave.
Anyone who has experienced the extraordinary experience of weight training knows that the difference between performing 6 or 12 repetitions is very significant.
In reality the weight used to perform 12 repetitions is light only at the beginning and becomes gradually heavier as you get closer to the last repetition. The first principle is revealed, as obvious as it is important:
if you use a high or low number of repetitions the load used must always be sufficient to guarantee adaptations
or expressed in other terms:
whether heavy loads or light loads are used, the number of repetitions must always be sufficient to ensure adaptations
The adaptations that allow hypertrophy can be summarized in the following points:
increased intracellular concentration of ATP, CP and glycogen
increased protein synthesis to repair damaged protein structures resulting in increased size of myofibrils
strengthening and thickening of connective tissue
increase in the size and number of capillaries and mitochondria
It is interesting to note that each of these factors is stimulated by different training techniques. For example, using modest loads with a high number of repetitions will affect the capilarization and the increase in the number and size of mitochondria. On the contrary, with heavy loads close to the ceiling, the number and size of myofibrils and the intracellular concentration of phosphocreatine are increased. Here is revealed the second principle, a little less obvious than the first but equally important:
hypertrophy is guaranteed by the sum of numerous adaptations that respond to different stimuli
However, it is necessary to specify that each of these adaptations contributes with different importance to the achievement of the hypertrophic result. The main cause of hypertrophy is the increase in the number and size of myofibrils, followed by mitochondrial, capillary and sarcoplasmic increase.
The techniques to stimulate the different muscular components are numerous and must be appropriately varied in the different training periods. Some will work better for some subjects and others for others but should never be excluded a priori.
Those who respond better to training with heavy loads, like myself, will always have to bear in mind that once certain load limits are exceeded (not so easy to reach) the risk of accidents increases considerably. This is what happens to many professional bodybuilders who prefer to focus on less wearing techniques to prevent injuries, which are quite common at certain levels. Tendons and joints, objectively, need longer times to recover and adapt to external stimuli. Finally, even in these cases the correct technique of performing the exercises should never be forgotten.
The last aspect that we are going to study is the difference in the composition of muscle fibers between the different areas of the body.
There are basically three types of fibers: slow contraction speed (fibers I or red), intermediate (fibers II a) and fast (white fibers II bo).
Among these, we have seen that the best results in terms of hypertrophy are given by the stimulation of white fibers.
According to the principle of recruitment of muscle fibers, the smaller fibers, with slow contraction, are the first to be activated while the larger ones, with fast contraction, are activated only for greater intensities. A high weight (such that it cannot be lifted more than 3-5 times) involves the activation of more muscle fibers than a lighter weight (which can be lifted for 12 or more repetitions). This allows for potentially greater development. And here we come to the third and final principle:
Lightweights only stimulate slow-twitch fibers and may be insufficient to act on fast-contracting ones, limiting muscle development.
The last note is in favor of those muscles composed mainly of red fibers, such as abdominals and calves. If a muscle group consists largely of slow-twitch muscle fibers to respect its physiological function, it must be trained with a high number of repetitions (15-30 per series) and with light weights.
To conclude, although it is very important to reasonably alternate the different training techniques, the optimal muscular development cannot do without a good base of strength obtained thanks to the lifting of heavy loads for a reduced number of repetitions. This aspect, often forgotten, allows to exhaust every single muscle fiber, guaranteeing a potentially greater development.
