Exercise volume is defined as the product of total repetitions, sets, and load performed in a training session. Higher-volume, multiple-set protocols have consistently proven superior over single set protocols when trying to stimulate muscle hypertrophy. It’s still not really known whether the superiority of higher-volume workloads is the product of greater total muscle tension, muscle damage, metabolic stress, or some combination of these factors.
Higher-volume, bodybuilding style programs that generate significant glycolytic activity have been consistently proven to elevate acute testosterone levels to a greater extent than low-volume routines. Some studies have demonstrated that testosterone did not significantly increase during squat performance until after completion of the fourth set, indicating a clear benefit of multi-set routines. Higher-volume programs also have been shown to mediate the acute release of GH, particularly in routines designed to heighten metabolic stress. Much research is showing multi-set routines elicit greater GH responses than single set workouts.
It’s also been shown that split body routines, where multiple exercises are performed for a specific muscle group in a session, may also help to maximize the hypertrophic response. Compared to full body routines, a split routine allows total weekly training volume to be maintained with fewer sets performed per training session and greater recovery afforded between sessions. This may enable the use of heavier daily training loads and thus generate greater muscular tension. Moreover, split routines can serve to increase muscular metabolic stress by prolonging the training stimulus within a given muscle group, potentially heightening acute anabolic hormonal secretions.
To maximize hypertrophy, evidence exists that volume should be progressively increased over a given periodized cycle, culminating in a brief period of overreaching. Overreaching can be defined as a planned, short-term increase in volume and/or intensity intended to improve performance. Improvements are thought to be obtained by initiating a ‘‘rebound effect’’ where an initial decrease in anabolic drive causes the body to supercompensate by significantly increasing accretion of body proteins. Training status has been shown to affect the overreaching response, with reduced detrimental effects to the endocrine system seen in those with more than 1 year of experience.
To ensure optimal supercompensation, the period of overreaching should be followed by a brief taper or cessation from training. Prolonged periods of overreaching, however, can rapidly lead to an overtrained state. Overtraining has catabolic effects on muscle tissue, and is characterized by chronically decreased concentrations of testosterone and luteinizing hormone, as well as increasing cortisol levels.
Studies are showing that overtraining is a result of excessive volume rather than intensity. Given that recuperative abilities are highly variable between individuals, it is essential to be aware of your training status and adjust volume accordingly to avoid a negative effect on protein accretion. Furthermore, the quest to train with a high volume must be balanced with performance decrements arising from lengthy exercise sessions. Long workouts tend to be associated with reduced intensity of effort, decreased motivation, and alterations in immune response. Accordingly, it has been proposed that intense workouts should not last longer than one hour to ensure maximal training capacity throughout the session.