Training Volume and Hypertrophy: Why is Volume Important?

Hypertrophy as you all know refers to the process of gain in muscle mass as a result of training or exercising. Some athletes/ professionals take up resistance training with the sole purpose of bulking up, and for some it is just an added benefit. Irrespective there is a lot of noise around the need to gain muscles, however the extent to which one wants to bulk up is subjective. Like many other things in life, building muscles requires some serious effort and dedication. In addition there is a load of confusion in respect to what are the basic principles on which one should build a routine that leads to maximum hypertrophy.

Professionals across the world are split amongst various beliefs, which makes it difficult for an individual to figure out the ideal training routine for them. But a look at various research and logic professed by experts can show you a way out of the confusion.

One of the topics which has been debated upon a lot is ‘the hypertrophy range’. We have already concurred that the hypertrophy range in question is more wide spread that initially assumed, in the article here. Then the next hot topic of debate in reference to hypertrophy is the volume of training. Again there are split opinions when it comes to what is the best volume to train for hypertrophy. Or even what is the best way to quantify training volume. While some believe that training with extremely high volume is the way to go, there are many who refute these claims or somehow have differing opinions on the matter.

Key Points:

  • Whenever we exert any sort of pressure on our muscles, the nervous system initially recruits smaller motor units/ muscles. And with an increase in effort requirement, larger muscles come to play. This mechanism is essential for hypertrophy.
  • Volume is defined as the total workload over a given period of time. This effort made leads to fatigue which ultimately triggers hypertrophy. Hence training volume is detrimental in ensuring hypertrophy.
  • The formulation set*reps*weight is the generally accepted way to measure volume. But research and experience show that total number of sets that are taken to failure are the way to measure actual effective volume.

Through this article we aim to first assess how training volume actually comes to affect hypertrophy and concur the best way to quantify the said volume. This will answer questions as to what is going wrong for athletes who are training at high volumes, but aren’t showing expected results. Let’s begin with a few basics that are essential to understanding the relationship between hypertrophy and volume.

The mechanics behind what makes the muscles grow?

The basic motive of this discussion is to figure out the ideal conditions for optimum hypertrophy in a training routine. So it is important for us understand how training leads to muscle growth in the first place. That is, what actually is going on in the human body?

Let’s begin with what happens at the basic physiological level in terms muscle recruitment. The process though critical, is quite straightforward. When a set is taken to failure, the nervous system initially recruits smaller or slower motor units. Note that this initial recruitment response holds true for most exercises or regular activities any human undertakes (and happens well before failure). In training then, as a set progresses towards failure, the CNS recruits larger and faster motor units. This continues until the force requirements are met, or in case of failure- the force requirements cannot be met any further [1]. This is termed as the size principle.

To further understand the use of size principle in hypertrophy, we need to look at what happens as a result of the motor units/ muscles recruitment. When a muscle contracts (that is, is recruited during resistance training), the muscle fibers experience some level of fatigue by the way of being worked for lifting weights etc. This fatiguing process is said to have some sort of signaling mechanism which causes hypertrophy to take place [2]. The level of fatigue or mechanical tension the muscle fibers experience is determined by two factors- one is whether the fibers are activated (employed) or not, and the other is the speed at which the muscle fiber shortens.

In keeping with the size principle and the above statement, we can conclude that if we want our muscles to grow, we must exert them and lead them to experience fatigue while activating all required muscle fibers. Even though we may not know in definite terms an exact threshold of pressure needed, we now know that the exercise must be attuned to exert a maximum viable effort. But the question still remains- how does volume fit into the picture and how to determine the ideal required training volume?

What is Volume? Why is it so important when it comes to hypertrophy? Why some professionals show lacking results even when training with enough volume?

Now that we know how muscle recruitment in training leads to hypertrophy, let’s discuss how ‘training volume’ fits into the picture. To begin with, the most common definition of volume in resistance training is- the total amount of work an individual does over a given period of time. Or, to state more formally- total training volume is the total workload per exercise, per session and per week [3]. These definitions give us peek into why volume is one of the important factors determining the amount of effort made, fatigue experienced and ultimately muscle growth experienced. However, mere qualitative definitions do not solve our purpose, we need to figure out how to best quantify training volume.

Well, a formula that is accepted across the boards for this purpose is a multiplication of sets to reps and load. That is- sets*reps*weight. This means maintaining/ altering volume, whether it is by the way of number of sets performed or load lifted, controls effort made and hence the extent of hypertrophic response within our muscles.

But then why are there so many people claiming that even when they maintain volume as per expert suggestions, they still don’t show expected muscle gains. Does this mean that what we think of volume and hypertrophy is wrong?

Definitely not. Time and again, studies and experience both have shown that training volume is important when it comes to hypertrophy. How much volume is required or what are the limits is something we will discuss down the line, but the fact remains that volume is important. Schoenfeld et al. conducted a study that was aimed to evaluate muscular adaptations between low, moderate and high volume resistance training in trained men. As per the results of the study, volume and muscle hypertrophy follow a dose-response relationship. That is, higher training volumes result in increasingly greater gains in muscle growth [4]. Think of it like this then, volume is a way to measure the size of the dose of the training program whose purpose is hypertrophy.

Another review article/ meta-analysis by Schoenfeld analyzed 15 studies to access the relationship between weekly volume and hypertrophy [5]. The findings again showed graded dose-response relationship wherein an increase in RT volume leads to greater gains in muscle hypertrophy.  There is no doubt then that there is a strong relationship between training volume and muscle hypertrophy. So what is going wrong for professionals who equate volume as per required standards and still don’t grow? Or what are the athletes that grow muscular even with comparatively lower levels of volume doing right?

The answer to this is not that difficult to figure out. According to experts at 3DMJ while being focused on volume, many usually forget all about proximity to failure and load. So while volume is in fact detrimental in hypertrophy, there are some co-factors that make the volume effective. And this is where most of trouble lies. This is a major reason as to why people working with the ideal/ extensively high volume do not produce expected results.

In this context Brad Loomis from 3DMJ states that we must consider ‘effective volume’, when discussing hypertrophy and training volume [6]. According to Brad, many ‘high volume’ programs may actually be made up of a lot of sets that are far from failure, or a few sets that are taken close to failure but in a bad form. And these lead to a lot of un-effective volume which does not do the job of activating the muscle or triggering hypertrophy.

This means that while the number of sets are of the best ways of determining training volume, we also have to be careful of the quality of those sets. Because only the sets which exert enough stimulus and fatigue on muscle fibers are effective in terms of hypertrophy.

In more specific terms, it seems that total number of sets to failure or at least close to is an adequate way to measure or quantify training volume [7], when considering muscular hypertrophy. In fact both the study and the review by Schoenfeld mentioned above have taken sets taken to failure into account when conducting analysis. Another study, conducted by Radaelli et al. demonstrated the dose-response for number of sets performed per exercise and a superiority of multiple sets as against single sets for muscle hypertrophy along with other affects [8].


The discussion above clarifies how training volume is important for hypertrophy. The studies indicate that higher training volume results in greater muscle gains. However, we must be cautious of how we calculate or quantify the volume we are pursuing. While set*reps*weights is the general formula for doing so, it is dependent on taking the sets to failure. Working at high volumes without making sure the sets are effective and create enough stimulus is not productive.


Share this post

Share on facebook
Share on twitter
Share on linkedin
Share on pinterest
Share on print
Share on email