Understanding training volume, fatigue and how to properly manage the two.

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 as well as how to utilize it in a practical way in your 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 Load

One way volume can be defined is Sets x Reps x Load, which is referred to as "tonnage" or more recently "volume load". 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 volume load 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, because volume load increasing over time is a great indication that you're making progress towards getting stronger and bigger.

One major downside to this method, however, is that it can lead to some incorrect assumptions. Some exercises may be much easier to perform extremely high volume loads as opposed to other movements that target the same muscle groups, but won't necessarily increase hypertrophic stimulus. For example, you can load up a leg press with ridiculous amounts of weights and perform a set that is equally as difficult as a barbell back squat loaded with far less weight, but hypertrophy will likely be equal for both, despite the leg press being a much higher total volume load. This means that volume load should only be used to track progress on each individual exercise and not a way to compare one exercise to another to compare hypertrophic stimulus.


Total Hard Sets

A more modern approach to defining volume 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, because hypertrophy has been found to have a very strong dose-response relationship with the total number of sets performed.

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 volume load levels. In other words, regardless of which set and rep scheme equals more total volume load, 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 volume load 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. Adding sets past a certain point will result in overreaching and potential recovery issues between training sessions. Because of this, you will eventually need to add reps or weight to push your volume load up instead of adding additional sets. You could then even decrease the amount of sets you're doing, but increase weight and/or reps to increase the intensity of your sets. Then, from that point, you could begin increasing sets again. This can be repeated over and over and is a great way to progress.


Volume Concepts Applied

Both methods will elicit strength and muscle growth because they are both tools used to achieve progressive overload. It is probably a good idea to use the hard set definition of volume for the bulk of your training if your goal is hypertrophy, while using volume load to track long term progress. Most well planned routines will utilize the hard set definition of volume by having increases and decreases in sets done as part of its periodization process, but like with all routines, the overall focus is on increasing volume load over time by adding weight to the bar or performing more reps over time in order to maintain the proper intensity of effort required to make muscle and strength adaptations.

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 and/or reps performed before beginning to add sets again. This way you're utilizing both increases in sets done to make sure you're doing enough sets to elicit optimal hypertrophy, while also utilizing volume load increases to keep each set in the correct intensity zone. You can also adjust load on the bar or repetitions performed at the same time as increasing sets in order to maintain intensity when a load becomes too light, this way you avoid performing a [junk volume].

Week 1:
Bench Press 3x6 @ 225 lbs
Barbell Curls 3x12 @ 80 lbs

Week 2:
Bench Press 4x6 @ 225 lbs
Barbell Curls 4x12 @ 80 lbs

Week 3:
Bench Press 5x6 @ 225 lbs
Barbell Curls 5x12 @ 80 lbs

Week 4:
Bench Press 3x6 @ 230 lbs
Barbell Curls 3x12 @ 85 lbs


Understanding Training Fatigue

The same stimulus required for the body to adapt and improve also causes training fatigue. There are two major types of training fatigue. One is local fatigue, which is fatigue in the local area a muscle was trained. This type of fatigue usually manifests itself as a muscle feeling sore or weak due to muscle damage. The other type of fatigue is systemic fatigue, which is general fatigue across the entire body, but especially the central nervous system. This type of fatigue can manifest in many ways, but generally will show itself in the form of a loss in performance in the gym, lethargy, and just feeling overall unprepared to enter the gym and train hard.

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. Some compound movements are much more fatiguing than others as well. The deadlift and squat will cause much more fatigue than the bench press, for example.

Training fatigue, once accumulated over time, will result in degradation of performance. So when fatigue accumulation gets too high, you have to get rid of this fatigue before you can continue to make progress. It's important to understand how fatigue occurs and what you can do to manage it.

Aside from exercise selection, two major variables determine how much training fatigue you will accumulate when training. The first is the proximity to failure of each set you perform. The second is how many total sets (volume) you perform. So the closer to failure you train or the more sets you perform, the more fatigue you will accumulate. This leads us to two very important concepts that can help you manage fatigue.


Reps In Reserve

The harder a set is, the more fatigue that set will generate. This is where the concept of RIR comes into play. In my article Should You Train To Failure? An Intro To RIR, 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. 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, otherwise performance falls and thus the stimulus you can generate next workout suffers. If you were to train to failure on the bench press on multiple sets, 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 reducing 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 large decrease in performance and you'd be able to perform more total weekly volume with ease, resulting in more overall hypertrophy.


Minimally Effective Volume (MEV), Maximum Adaptable Volume (MAV) & Maximum Recoverable Volume (MRV)

MEV, MAV and MRV are concepts that utilize the "total hard sets" definition of volume and are tools that help you find and maintain optimal volume levels. These terms were coined by Dr. Mike Israetel.

MEV is 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 your muscle.

MAV is the most amount of volume you're actually able to benefit from and adapt to. This is thought to be more of a range as opposed to a specific amount of sets. This is where you'll want to train in order to maximize stimulus. Doing more than this amount will not facilitate more stimulus, even if you are able to do so without recovery issues. If your MAV is 20-22 sets, then doing 23 sets would not cause more hypertrophy than doing 22 sets. Your training would be optimized by staying within the 20-22 set range.

MRV is the maximum amount of volume (sets) that you can do and still recover from. Doing any more than this amount means that you will be under recovering and eventually burn out and no longer make progress, or even begin to regress and perform worse until you reduce volume and/or intensity to allow recovery.  It is noteworthy to mention that there could be a gap between your MAV range and your MRV. In other words, your MAV could be 20-22 sets, while your MRV is 26 sets. This means that there is a grey area of 23-25 sets where you won't have trouble recovering from this amount of volume but you'll gain no benefits over just doing 20-22 sets. On the other hand, it is not uncommon for your MAV and MRV to overlap and be the same amount of volume (as in our example below).

The goal should be to train within the range of your MAV, but without going over your MRV. This can be better visualized by looking at the graph below. As sets increase, so does hypertrophy, but only up until a certain point. There are both diminishing returns when increasing volume, as well as hypertrophy decreases when volume is taken too far.

A good way to think of this is filling a cup with water (fatigue + stimulus). The cup can only hold so much water until any 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 see that the hypothetical MRV 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, don't expect these numbers to be accurate for you as an individual.

Must-read takeaway: While these concepts are very important to understand and can revolutionize your training, the examples above use very specific set numbers -- the vast majority of the time this is not how it will play out in the real world, nor should you expect it to. Volume requirements vary greatly between individuals, and may likely even fluctuate within each individual depending on many factors. Use these concepts as as rough guide on how to manage volume levels.


Key takeaways.

Training volume refers to how much work you do in a given period. There are two major ways to track training volume. The first is called "volume load" and is tracked by multiplying Sets x Reps x Weight. The second is to count the total number of "hard sets" that you perform. Both have their uses in tracking volume, but their applications are slightly different.

Volume load is better used to track long term trends of individual exercises while counting total hard sets is a better way to track short term volume for individual muscle groups. Counting total hard sets is likely a more practical approach to tracking volume for hypertrophy, while tracking volume load can still be beneficial to hypertrophy, it has slightly more application for strength training. Either way you go, volume load should always be trending up over the long term to guarantee progress.

The more volume you do, the more training stimulus you'll generate. However, the same training that generates a growth stimulus will also generate training fatigue, so there's only so much volume you can perform consistently before you're doing too much, resulting in subpar progress. Each muscle can only recover from so much volume on a consistent basis. In addition, there is only so much volume your body itself can handle, regardless of which muscle group(s) is the focus of said volume. This means you must learn how much volume you as an individual can handle and make intelligent programming decisions based on this knowledge.

In addition to volume, proximity to failure of each set will also determine training stimulus and fatigue. The closer to failure you train, the stronger the strength stimulus but the more fatigue will be generated. This means that in addition to managing volume properly, you should also manage how close to failure you train. Research suggests training at least 4 repetitions from failure or closer for optimal progress, but training all the way to failure will likely cause far more fatigue than it does training stimulus, so should be avoided.


Supporting Studies

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