Hypertrophy is defined as an increase in muscle size, which can be achieved through exercise. Two main factors contribute to this physiological phenomenon, such as sarcoplasmic hypertrophy (i.e., increased muscle glycogen storage) and myofibrillar hypertrophy (i.e., increased size and number of myofibrils). In this sense, resistance training is considered the gold standard for increasing muscle mass, which is based on three key variables :
- mechanical stress
- metabolic stress
- muscle damage
Traditionally, hypertrophy-focused strength training is characterized by moderate loading, high total volume loading, and short rest periods, although the effects of resistance programs vary depending on the manipulation of their variables. Given that promising effects related to increasing muscle size on both performance and health have been previously reported, it seems justified to search for the most effective methods to generate hypertrophy.
Due to the strong positive relationship observed between the muscle’s ability to generate force and its cross-sectional area (CSA), hypertrophy is one of the main goals pursued by both professional and recreational athletes. Thus, several research studies have analyzed the effects of resistance training on hypertrophy and subsequent strength levels. However, it is important to highlight that most team sports require a high level of strength, but also that athletes must apply it in the minimum amount of time.
In this regard, increasing muscle mass includes a positive influence on the rate of development of strength and power , which improves sports actions such as sprinting, jumping and the ability to change direction. . Furthermore, muscle mass is a key factor in sports disciplines where the quality and quantity of muscle development is judged, such as bodybuilding. Therefore, promoting hypertrophy could be a relevant strategy to improve sports performance.
From the point of view of human health , muscle mass plays an important role in various actions of daily life such as locomotion, so low levels of muscle mass can lead to an increased risk of several diseases.
In this sense, resistance training and its associated hypertrophy adaptations have been shown to have health benefits, such as reducing body fat, increasing metabolic rate, reducing blood pressure and cardiovascular demands of the body. exercise, improvement of blood lipid profile, glucose tolerance and insulin sensitivity, a reduction in the risk of type II diabetes, improvement of mobility and functional capacity, increase in strength, muscle mass and bone, and increase in factors related to quality of life.
Specifically, Balachandran et al. (2014) applied a hypertrophy -oriented resistance program (3 sets of 10-12 repetitions using 70% of their one-repetition maximum and 1-2 min of recovery) with sarcopenic obese adults for 15 weeks, obtaining improvements in capacity. functional and power, as well as a reduction in fat mass.
On the other hand, they observed significant improvements in glycemic control, insulin sensitivity and triglycerides after the application of a hypertrophy training program (2-3 sets of 8-10 repetitions using 60-80% of the maximum of a repetition and 1-2 min recovery) in adults with type 2 Diabetes mellitus.
A comprehensive and controlled increase in muscle mass seems advisable for anyone, regardless of age or level of physical fitness.
Conclusions
Based on the available meta-analyses, it has been observed that the volume, frequency, intensity, type of contraction, duration of repetitions and the application of blood flow restriction condition hypertrophy adaptations in healthy subjects, being the Volume is the only resistance training variable for which a dose-response relationship with hypertrophy adaptations has been observed.
On the contrary, other variables such as the order of the exercises, the time of day and the type of periodization do not seem to directly influence the magnitude of muscle mass gains. These findings provide valuable information for the design and configuration of the resistance training program with the aim of optimizing muscle hypertrophy.
Practical applications From the existing literature, some recommendations should be considered when prescribing resistance training programs focused on muscle mass gain: a ) Volume : Research has reported a graded dose-response relationship between weekly resistance training volume and muscle growth. Therefore, it would be advisable to prescribe 2-3 sets per exercise, covering at least 10 weekly sets for each muscle group, while a higher weekly volume does not seem to offer additional hypertrophy benefits. b) Frequency : although the modification of this variable does not directly influence hypertrophy gains, a significant effect was observed in favor of higher frequencies when volume was not equalized, so training frequency can be used as a tool to modify the total weekly training volume. c) Intensity : the choice of light or heavy loads can be made depending on the characteristics of the subject, although always reaching or close to failure . It is appropriate to prescribe variations in the magnitude of the load (<60% 1RM and >60% 1RM), however, greater load seems to offer greater adaptations. d) Type of contraction : it seems appropriate to combine concentric and eccentric contractions to optimize the hypertrophy response, however, it seems that eccentric contractions may offer some additional advantages compared to concentric ones. e) Duration of repetitions : a wide range of duration of repetitions seems appropriate to stimulate hypertrophic adaptations such as 0.5-8 s, however, a longer duration (very slow movement speed) is counterproductive , so it should be Avoid extending the duration of repetitions beyond 10 s. f) Order of exercises : to modulate this variable, personal preferences or specific objectives must be addressed, such as deliberate overload of a specific muscle group. Currently, we do not have enough evidence to establish adequate guidelines and therefore more research seems necessary. g) Time of day : for the modulation of this variable, personal preferences must be taken into account since no evidence has been found in favor of a specific time of day (morning hours vs. afternoon hours) in hypertrophy adaptations . h) Periodization : individual preferences must be considered when choosing the periodization model to use, but always respecting the training volume and progressive overload. i) Blood flow restriction : It seems appropriate to use this technique in very experienced subjects or in those who cannot use heavy loads (i.e. injured athletes). |
