THE ROLE OF STRENGTH MOVEMENT DURATION IN OPTIMIZING MUSCLE HYPERTROPHY

ABSTRACT

Muscle hypertrophy is a physiological process primarily stimulated in response to strength exercises. Optimal training parameters, including set duration, number of repetitions, and intensity, are critically important for maximizing hypertrophic stimulation. This review article integrates the latest scientific studies and demonstrates that the optimal duration of strength movements is 30-60 seconds, providing a balance between mechanical tension and metabolic stress. Additionally, the hormonal response, which plays a significant role in the muscle growth process, is discussed. Finally, practical recommendations based on scientific evidence are presented. The results obtained can be applied by both professional athletes and fitness enthusiasts to achieve maximal muscle hypertrophy.

АННОТАЦИЯ

Гипертрофия мышц, это физиологический процесс, стимулируемый в основном силовыми упражнениями. Оптимальные параметры тренировки, включая продолжительность подхода, количество повторений и интенсивность, имеют решающее значение для максимальной стимуляции гипертрофии. В этой обзорной статье объединены последние научные исследования и показано, что оптимальная продолжительность силовых движений составляет 30-60 секунд, обеспечивая баланс между механическим напряжением и метаболическим стрессом. Кроме того, обсуждается гормональный ответ, который играет значительную роль в процессе роста мышц. Наконец, представлены практические рекомендации, основанные на научных данных. Полученные результаты могут быть применены как профессиональными спортсменами, так и любителями фитнеса для достижения максимальной гипертрофии мышц.

Keywords: hypertrophy, strength movement duration, metabolic stress, mechanical tension.

Ключевые слова: гипертрофия, продолжительность силового движения, метаболический стресс, механическое напряжение.

Research Purpose

The aim of this study is to determine the optimal training parameters that contribute to achieving maximal muscle hypertrophy. The analysis focuses on mechanical tension, metabolic stress, and hormonal changes, based on which the optimal duration of strength movements will be identified to ensure maximal hypertrophic effects.

Research Methodology

This study is a review research based on the analysis of authoritative scientific literature. Information was collected from leading international scientific databases, including PubMed, Google* Scholar, and ScienceDirect.

During the selection process, only peer-reviewed articles were considered that investigated the mechanisms of muscle hypertrophy, the influence of workout movement duration, and hormonal responses.

The studies included were specifically focused on the following topics:

- Muscle hypertrophy and the effects of workout duration;

- The impact of mechanical tension, metabolic stress, and hormonal response on hypertrophy.

The collected materials were assessed, compared with each other, and structurally analyzed to identify the workout regime parameters that optimally stimulate muscle hypertrophy.

Introduction

Ensuring muscle mass growth is one of the main objectives of modern fitness and a fundamental component of body shape correction. Despite numerous studies in this field, the question of which training parameters are optimal for maximizing muscle hypertrophy remains relevant. In particular, determining the optimal duration of strength movements, which directly affects the intensity of mechanical tension, metabolic stress, and hormonal response, is of special interest among scientists and practicing specialists. Recent research indicates that the duration of strength movements can significantly influence the effectiveness of training; however, there are still certain inconsistencies in recommendations. Some studies favor shorter, more intensive sets that produce maximal mechanical tension, while other authors emphasize the importance of longer sets to increase metabolic stress.

Literature Review

According to existing scientific literature, mechanical tension is one of the main triggers of muscle hypertrophy. It arises during the performance of strength exercises and leads to microtraumas in muscle fibers. In response, the body initiates a cascade of physiological reactions, including the activation of mechanoreceptors, intracellular signaling pathways, and protein synthesis, ultimately promoting muscle mass growth. For example, Schoenfeld [27, 28, 29] asserts that mechanical tension is the primary stimulus for muscle growth. His studies show that a load exceeding a certain threshold causes microtraumas in muscle fibers and activates intracellular signaling mechanisms that contribute to muscle growth. Goldspink [13] examined the molecular mechanisms of muscle adaptation and demonstrated that mechanical tension induces the release of growth factors, including IGF-1 (insulin-like growth factor 1), which plays an important role in hypertrophy. Lim et al. [20] note that prolonged mechanical tension activates anabolic processes, particularly the mTOR (mechanistic Target of Rapamycin) signaling pathway, which regulates the rate of protein synthesis in muscles. Damas et al. [9] studied the impact of mechanical tension on the activation of satellite cells, which participate in the repair and growth of muscle fibers, confirming their critical role in muscle hypertrophy. Wernbom et al. [34], in one of the largest meta-analyses, concluded that the intensity of mechanical tension should reach certain levels (approximately 65–85% of the maximum) to initiate the hypertrophy process. Ogasawara et al. [24, 25] demonstrated that even when using submaximal loads, significant adaptive changes in muscles can be achieved if mechanical tension remains high. Dankel [10, 11] confirms that increasing workout volume, combined with high mechanical tension, leads to significant muscle mass growth. Campos et al. [6] found that the greatest muscle mass gains occur with a moderate number of repetitions (6–12) and a corresponding load that ensures sufficient mechanical tension. Morton et al. [23] demonstrated that mechanical tension is necessary not only for hypertrophy but also for maintaining the results achieved, even when workout volume decreases.

Based on the available scientific data, it can be concluded that mechanical tension is one of the key determinants of muscle hypertrophy. Its effects on muscle fibers are expressed through microtraumas that activate intracellular signaling mechanisms, the release of growth factors (e.g., IGF-1), and protein synthesis. Without these factors, the hypertrophy process is significantly weakened, and maintaining already achieved results becomes challenging. Mechanical tension also plays an important role in activating satellite cells, which are essential for the repair and growth of muscle fibers.

The Impact of Metabolic Stress on Hypertrophy. As mentioned above, according to scientific literature, metabolic stress is one of the primary activators of muscle hypertrophy. It occurs during high-intensity exercise when metabolites such as lactate, inorganic phosphate, and hydrogen ions accumulate in the muscles. In response, the body initiates a cascade of physiological reactions that include the activation of intracellular signaling pathways, enhancement of the hormonal response, and stimulation of anabolic processes. Ultimately, these mechanisms contribute to muscle mass growth. Schoenfeld [27, 28, 29] asserts that metabolic stress plays a significant role in muscle growth by activating anabolic signaling pathways such as mTOR and AKT (also known as Protein Kinase B). Various authors have studied the effects of metabolic stress on satellite cells and have found that high blood lactate levels promote the proliferation and differentiation of myosatellites, which play an important role in muscle hypertrophy. Takarada et al. [30, 31] demonstrated that occlusive exercises (with restricted blood flow) produce significant metabolic stress, promoting hypertrophy even when using low loads (20–30% of 1RM). Goto et al. [14, 15] confirmed that a combination of high and low-intensity exercises with short rest intervals creates strong metabolic stress, contributing to muscle growth. Wernbom et al. [34] conducted a meta-analysis and determined that workout regimes characterized by high metabolite concentrations lead to greater hypertrophy than those focusing solely on mechanical tension. Schoenfeld and Krieger [29] compared different training programs and found that methods focused on increasing metabolic stress produced better results than traditional strength movement. Dankel et al. [10, 11] determined that a high level of metabolic stress increases the permeability of muscle fiber membranes, facilitating the entry of anabolic factors and promoting muscle tissue growth. Mitchell et al. [22], who investigated the mechanisms of metabolic stress, found that its effect on hypertrophy is due to increased intramuscular pressure and enhanced secretion of anabolic hormones. Lasevicius et al. [18, 19] confirmed that workout with moderate loads (30–50% of 1RM) and high metabolic demand leads to significant increases in muscle mass despite relatively low levels of mechanical stress. Fujita et al. [12] examined the effects of hypoxic exercises and found that oxygen deficiency enhances metabolic stress and stimulates the production of myogenic factors necessary for muscle growth.

The Hormonal Response and Its Impact on Hypertrophy. The hormonal response to physical load plays a significant role, as it affects protein synthesis, the activation of satellite cells, and intracellular signaling pathways. Testosterone, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and cortisol are key regulators of muscle growth. Schoenfeld [27, 28] states that the post-exercise hormonal response significantly influences muscle growth, particularly through the secretion of testosterone and IGF-1. These hormones activate the mTOR signaling pathway, which promotes protein synthesis. West and Phillips [35] found that short-term increases in testosterone levels after exercise correlate with increases in muscle mass, although its long-term effect depends on other factors such as mechanical tension and metabolic stress. Kraemer and Ratamess [17] showed that intensive strength movement with short rest periods increases the levels of growth hormone and testosterone, promoting anabolic processes. Ahtiainen et al. [2, 3] determined that complex exercises with high training volume increase the levels of anabolic hormones and, consequently, stimulate muscle hypertrophy. Crewther et al. [7, 8] note that training programs that induce a strong hormonal response are more effective for increasing muscle mass compared to low-intensity methods. Vingren et al. [33] indicate that testosterone enhances protein synthesis and activates androgen receptors in muscle tissue, accelerating hypertrophy. Morton et al. [23] confirmed that high testosterone levels contribute to muscle recovery and increased strength. McCall et al. [21] noted that an increase in testosterone concentration in the blood after workout improves amino acid transport, thereby enhancing protein synthesis. Adams and Haddad [1] demonstrated that IGF-1 stimulates muscle hypertrophy by activating the AKT/mTOR signaling pathways and promoting the proliferation of satellite cells. Bamman et al. [4] confirmed that exercises that significantly increase IGF-1 levels promote greater muscle hypertrophy. Rennie et al. [26] also noted that IGF-1 plays a key role in the repair and regeneration of muscle fibers. Kraemer et al. [17] showed that complex exercises and moderate rest periods (30–60 seconds) ensure maximal growth hormone secretion.

Discussion

The analysis of the presented scientific studies clearly demonstrates that mechanical tension, metabolic stress, and hormonal response act in a complex and interconnected manner in the process of muscle hypertrophy. Although the role of each mechanism is distinct, their combined effect determines maximal muscle mass growth. Their interaction is illustrated in Figure 1.

Figure 1. The influence of mechanical tension, metabolic stress, and hormonal response

Mechanical tension is considered one of the most important factors, as it directly leads to the formation of microtraumas in muscle fibers, which in turn activates anabolic reactions in the body. According to data presented in the literature [27, 28, 29, 34], to achieve optimal mechanical tension, it is recommended to perform 6–12 repetitions with a load of 65–85% of 1RM, which ensures effective anabolic stimulation. On the other hand, metabolic stress also plays an important role in stimulating hypertrophy. High metabolic stress, expressed by the accumulation of lactate, hydrogen ions, and inorganic phosphate, activates intracellular signaling pathways that further enhance anabolic processes [14, 29]. Studies indicate that to achieve maximal metabolic stress, moderate loads (30–50% of 1RM) with a high number of repetitions (15–25) and short rest intervals [31] are recommended.

The hormonal response, particularly the secretion of testosterone, IGF-1, and growth hormone, should also be considered significant. According to the presented studies [17, 35], the duration of strength movements directly affects the intensity of anabolic hormone secretion, which in turn promotes the activation of protein synthesis and the proliferation of satellite cells. Research confirms that complex exercises performed with short rest periods (30–60 seconds) and moderate loads provide maximal hormonal stimulation [2, 7].  The analysis of studies shows that performing strength movements for 30–60 seconds most effectively combines the necessary stimuli (mechanical tension and metabolic stress) required for achieving muscle hypertrophy. For example, Schoenfeld et al. [27, 28, 29] demonstrated in several studies that exercises with a moderate number of repetitions (6–12) and a total set duration of 30–60 seconds lead to maximal hypertrophy. Schoenfeld notes that excessively long sets (>70 seconds) reduce working weights, negatively affecting mechanical tension. Burd et al. [5] mention that slow-tempo strength movements increase metabolic stress; however, excessively prolonged duration (>70 seconds) reduces overall intensity, limiting hypertrophy. Lasevicius et al. [18, 19] compared traditional sets (6–12 repetitions) and slow sets (3–5 repetitions with a prolonged eccentric phase) and found that increasing set duration without increasing working load may be ineffective. Campos et al. [6] examined the effects of low (3–5), moderate (9–11), and high (20–28) repetition ranges on hypertrophy and determined that muscle mass increases most with a moderate number of repetitions. Tanimoto and Ishii [32] showed that a slow tempo (4-0-4) activates more muscle fibers but reduces overall working load. The meta-analysis by Wernbom et al. [34] revealed that the optimal repetition range for hypertrophy is 6–12, and the duration of strength movements should be 30–60 seconds. Henselmans and Schoenfeld [16] confirmed that eccentric loading (prolonged descending phase) is more effective for muscle growth during strength movements. Dankel et al. [10, 11] determined that the total duration of strength movements is a more important factor than the specific number of repetitions per set. Other authors also confirm that performing strength movements with a moderate number of repetitions and moderate intensity is the most effective approach for muscle growth. The meta-analysis by Grgic et al. [28] shows that moderate weights and medium-duration sets have the most positive effect on hypertrophy. Phillips et al. [35] studied the impact of various strength movement durations on protein synthesis and determined that the strongest effect is achieved with strength movements lasting 30–60 seconds. Schoenfeld and Grgic [28] confirmed that medium-duration sets (30–60 seconds) are the most effective for muscle growth. The effect of resistance movement duration on hypertrophy is shown in detail in Figure 2.

Figure 2. The effect of strength movement duration on muscle hypertrophy

Conclusion

This review study demonstrates that the optimal stimulation of muscle hypertrophy is achieved through the proper management of the interaction between mechanical tension, metabolic stress, and hormonal response. Mechanical tension is critically important for activating microtraumas in muscle fibers and initiating subsequent anabolic processes, while metabolic stress promotes protein synthesis by stimulating intracellular signaling pathways. Hormonal response, particularly testosterone, IGF-1, and growth hormone, represents significant regulators of muscle growth.

Based on scientific data, it can be concluded that the optimal duration of strength movements for achieving muscle hypertrophy is 30–60 seconds. This time interval provides a balance between mechanical tension and metabolic stress, facilitating the adaptation of muscle fibers. Research confirms that workout within this duration, using moderate repetitions (6–12) and moderate loads (65–85% of 1RM), yields the best results. Longer sets (>70 seconds) reduce mechanical tension and exercise intensity, while overly short sets (<30 seconds) may fail to provide sufficient metabolic stress.

However, despite the existence of general recommendations, it is important to consider individual adaptation. For different individuals, periodic modifications of the training program may be necessary to maximize the effect of supercompensation. It is also essential to consider the ratio of type I and type II muscle fibers in specific muscles. All of this highlights the need for continued research in this area in the future.

*По запросу Роскомнадзора сообщаем, что иностранное лицо, владеющее информационными ресурсами Google, является нарушителем законодательства Российской Федерации — прим. ред.

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