Understanding Volume & Fatigue

Posted by Shaun LaFleur on

You have probably seen the term “volume” used a lot in regards to resistance training and have probably even noticed that depending on who uses the term, it seems to have a slightly different meaning. In this article I am going to explain the different ways volume can be defined, and how to utilize it in a practical way in your workout programming to optimize progress. I'll also touch on training fatigue, how it occurs and how to properly manage it. Understanding proper volume and fatigue management is a key concept to training intelligently and optimizing your progress.

So What Is Training Volume?

Training volume, put simply, is the total amount of work you do in a given time period, most commonly used to refer to total work done in a given workout or a given weekly period. Depending on the sport or individual coach or trainer, volume may be defined in a couple different ways. Each method of calculating volume has its benefits and drawbacks, but both can help in ensuring progressive overload takes place by giving you an objective metric of your training to monitor and adjust. Below are the most common ways that training volume is defined.

Sets x Reps x Weight

One way volume can be defined is Sets x Reps x Weight, which is referred to as "tonnage". For example, 3 sets of 10 with 100 lbs would be 3,000 lbs of tonnage (3x10x100). This method is one of the oldest and most commonly used methods of defining volume. There are three ways you can increase volume using this method. You can add sets, add reps or add weight to the bar. Each will increase tonnage done and is a form of progressive overload. This method is great for being able to track how much volume you're doing over time, and whether or not you're improving overall from training cycle to training cycle.

While tonnage increasing over time is a great indication that you're making progress towards getting stronger, increasing tonnage is not always correlated with increases in hypertrophy and thus is better used in the context of strength training and strength progression than bodybuilding.

Another downside to this method is that if you're most often increasing your tonnage by increasing reps or weight on the bar rather than adding sets, increasing tonnage can become a relatively slow process because of how slow strength gains occur when you’re past the beginner phases of training. This means that the faster and easier method of increasing total volume would be adding more sets, which leads us to the next way of defining total volume.

Total Hard Sets

Modern research suggests another method of defining volume, which is by  counting the total amount of “hard sets” you perform. A "hard set" would be any set that is taken near failure - typically 4 or less reps from failure. This method, in my opinion, is the most practical and useful method of defining total volume and is heavily supported by recent research as being the best predictor of hypertrophy.

Research has shown that when comparing different rep ranges, loading schemes and controlling for total amount of sets done, hypertrophy is relatively equal across the board, even across different tonnage levels. In other words, regardless of which set and rep scheme equals more total tonnage, the set and rep scheme that includes more total sets will always cause more hypertrophy. This means that perhaps total hard sets is a better metric to track than tonnage for hypertrophy focused approaches, as it is more directly correlated to how much muscle is being built.

The downside to this method, however, is that you can't simply add sets forever, and adding sets past a certain point will result in overreaching and potential recovery issues between training sessions. Because of this, you will then need to add reps or weight (get stronger) to push your tonnage up and force progress. This will allow you to reduce the total amount of sets you're doing while still increasing volume in terms of tonnage by adding weight and/or reps, which can then be followed by slowly adding  sets again, further increasing volume in terms of both tonnage and total sets. This is a common method of cycling volume and intensity and can be repeated infinitum.

Progressive Overload

Both methods will elicit strength and muscle progress because they are both forms of progressive overload. Even if you were to maintain the same amount of sets and reps, but add weight to the bar during those sets, you’d still be placing a novel stimulus on the body which will elicit progress. 

It is probably a good idea to use the hard set definition of volume for the bulk of your training, while keeping in mind that it can also be defined as total tonnage. Most well planned routines will have increases and decreases in sets done as part of its periodization process, but like with all routines, the overall focus is on adding weight to the bar over time.

Both methods need to be utilized in the right way. If your main goal is hypertrophy, slowly increase your total sets done over the weeks. Once you hit your limits for how many sets you can perform, reduce the amount of sets, but increase the weight you're using on the bar before beginning to add sets again. This way you're utilizing both increases in sets done and tonnage to continually progress.

Understanding Training Stress & Fatigue

When resistance training or performing any intense exercise, you are placing stress on the body which causes training fatigue to accumulate. It is the repeated build up and recovery from this training fatigue that causes the body to become stronger and better. Training fatigue can be muscle specific or general fatigue, which is just overall fatigue on the body’s systems, especially the central nervous system (CNS). For example, performing the bench press will create fatigue in the pecs, shoulders and other muscles used in the movement, but because it's a movement that uses a large percentage of the body's total muscles, it also contributes to general training fatigue.

Most exercises contribute to an accumulation of both types of fatigue, with the bigger compound movements such as the bench, squat and deadlift contributing more to general fatigue than smaller movements like barbell curls or tricep pushdowns. This is why if you want to get in more volume on a specific body part, it's important to get that extra volume in using smaller accessory movements rather than adding more additional compound movements on top of the ones you're already doing for that body part. This way you can contribute to more overall volume in a particular area you want to bring up without causing too much fatigue. Some compound movements are much more fatiguing than others as well. The deadlift will cause much more fatigue than the squat and bench press, for example, and typically can't be done with volume levels as high as what you should be able to handle on the bench and squat.

On top of this, fatigue accumulation will be higher for sets taken closer to failure. In my article Should You Train To Failure?, I explain the concept of RIR (Reps in Reserve) and how the closer to failure you take a given set, the more progress you'll make, but also the more fatigue you will accumulate. To sum it the article: going to failure will cause slightly more hypertrophy, but much more fatigue. Because of this, it's typically not worth taking many sets to failure.

In order to continue making progress you must recover from the fatigue built up by your previous training sessions. If you were to train to failure on the bench press on multiple sets for example, this would cause a tremendous amount of fatigue in the muscles used for the bench press, and if you were to go back into the gym in 24-48 hours, you likely wouldn’t be fully recovered and your bench press performance would be severely impacted, ultimately impacting the amount of stimulus you can get from your workout on that day. However, if you were to train with a reasonable amount of volume and intensity, you should be able to recover in roughly 24-48 hours and be ready to perform the same movements again without a decrease in performance and you'd be able to perform more total weekly volume this way, resulting in more overall hypertrophy.


Minimally Effective Volume (MEV) & Maximum Recoverable Volume (MRV)

MEV and MRV are concepts that utilize the the "total hard sets" definition of volume and are tools that help you find and maintain optimal total set ranges.

MEV is simply the minimum amount of volume (sets) that will cause a muscle to grow. If you did this amount of total work per week, you would progress but at the slowest rate possible; anything less would simply be maintaining said muscle.

MRV is the maximum amount of volume (sets) that you can do and still recover and make progress with. Doing any more than this amount means that you will be under recovering and you will eventually burn out and no longer make progress, or even begin to regress and perform worse until you take a deload or reduce your volume.

The goal is to train as close to your MRV as possible, without going over this amount. It can be better visualized by looking at this graph. As sets increase, so does hypertrophy, but only up until a certain point. 

A good way to think of this is filling a cup with water. The cup can only hold so much water until any more water added to it simply overflows and does not contribute to filling the cup anymore, because it is already at capacity. The only way to continue filling it with water again is to remove some of the water (fatigue) by pouring some out (recovery).

By looking at the graph above, we can deduce that your MRV (the maximum amount of volume you can actually benefit from before you're unable to recover) is somewhere around 21-25 sets. We know this because this is the point at which hypertrophy hits its peak, and performing more sets than this results in a gradual decrease in hypertrophy. These numbers are only used as an example to help you understand the concepts of volume and recovery better.


Tying It All Together

With this understanding of volume and fatigue in mind, it’s important to note that properly managing the two are the foundation of any good routine. While volume is directly correlated with progress, it's also correlated with the build up of fatigue. The more volume you do the more progress you make, but the more fatigue you accumulate as well. Past a certain point, any increase in volume will result in more fatigue than you are capable of recovering from within a reasonable time frame, and thus not only can progress stall, but it can regress.

After performing a reasonable amount of volume in a given workout, it typically takes a muscle group 24-48 hours to fully recover; some muscles may recover slower and others faster. Typically smaller muscle groups such as the biceps and calves can recover extremely fast, while larger muscle groups like the pecs, lats and quads may require more time to recover. It’s also important to remember general fatigue as well, as all heavy exercises will cause an accumulation in CNS fatigue. Because of this, many routines will have a deload week programmed into them after several weeks of hard training in order to facilitate full recovery and adaptation to the training stimulus.

The amount of volume a person can do and still recover will vary from person to person and will even vary within the same individual at different times, due to many factors both in and outside of the gym. There’s no practical way to perfectly estimate the amount of volume a person can handle at any given period in any given muscle group, but there are practical ways to go about training and signs to watch out for, such as mood changes, feeling generally tired or low energy, degradation of performance, stalling and other similar factors.

The idea is that in order to maximize progress you need to do as much volume as possible while still being able to recover. Any less than this amount and your progress won’t be maximized, but any more than this amount and you will simply not be able to recover and will eventually burn out and your performance will regress until you allow yourself to recover.

This requires a lot of trial and error. This is why it’s a good idea to slowly increase your volume until you feel as though you may be nearing your MRV. It’s usually not a good idea to jump straight into a high volume protocol before having some idea of how much volume your body can handle. It can become a recipe for disaster and cause you to start off training above your MRV, accumulating too much fatigue early on in your training cycle and affecting your overall performance, and requiring you to deload prematurely, meaning you're wasting valuable time trying to recover from an unnecessarily hard training week.


Practical Application

So let's say that through trial and error you have discovered that you can perform 15-20 sets per week on the bench press and make great progress while recovering just fine. You can then program 15-20 sets of the bench press in multiple different ways depending on what type of routine you enjoy and how often you want to train the bench press. Let's use an upper/lower split as an example, where you will be training bench press twice a week. First off, I recommend training in multiple rep ranges and to never neglect strength work, so having a light, heavy and/or moderate day works well, but for this example we'll have one heavy and one light. You would then split up 15-20 sets of the bench press (and it's variations) between the two upper body days. One way you could do this is as so:

Upper Body Day 1: 
Bench Press 4x3
Close Grip Bench Press 5x5

Upper Body Day 2:
Bench Press 3x8
Floor Press 5x10

This would result in a total volume of 17 sets over the week for the bench press with a mixture of heavy and light sets. While performing 17 total sets in any rep range will build muscle, by performing 8 of those 17 sets in the lighter rep ranges, you will improve your recovery between sessions and build up far less fatigue than if you attempted to perform all 17 sets in the heavier rep ranges.

You can program all lifts and/or body parts this way, which will allow you to monitor how much work you're doing overall while being able to adjust accordingly to make sure you're always progressing. It's also important to monitor overall CNS fatigue as well, not just each muscle group on it's own.

You could continue to progress this way and even add more sets over the following weeks. Once you reach a point where you feel as though you may be under recovering, you would take a deload. After the deload, you would reduce the amount of working sets back down closer to your MEV (Minimal Effective Volume), but increase the weight on the bar so that your tonnage is higher for this cycle than your last. From there, repeat the process of adding sets until you begin to under recover/overreach, taking a deload and then again reducing sets, but adding weight to the bar to increase tonnage above your last cycle's. This is a great method of properly managing recovery and utilizing both definitions of volume to your advantage.

Supporting Studies

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