Back in 2018, the publication of a new study on training volume and muscle growth led to a collective Roger Moore-esque raising of eyebrows [1].
It reports, amongst other things, that a whopping 45 sets per muscle group per week led to muscle being built more quickly than 9 sets or 27 sets.
When I first heard about the study, I was expecting to see such a high volume of training lead to stagnation or even regression.
But it didn’t.
On average, the guys who did the most sets were the ones who built the most muscle.
So, what’s going on? Should you be ramping up your training volume? Or will all those sets leave you overtrained and burned out?
First, a bit of background.
How Many Sets Per Muscle Group Do You Need to Build Muscle?
Back in the 1970’s, Arthur Jones, the inventor of the Nautilus range of exercise machines, ruffled more than a few feathers when he claimed that bodybuilders were wasting their time training for two hours a day, six days week.
In his view, a couple of hours a week would have done the job just as well.
Ever since, debates have raged about the number of sets required to maximize gains in both size and strength.
When a team of US researchers pulled together all the relevant research on training volume and muscle growth, they found a “dose-response” relationship between the number of sets you do for a muscle and the speed at which that muscle grows [2].
Ten or more sets per muscle group per week worked better than 5-9 sets. And 5-9 sets worked better than four sets or less.
However, the number of studies to look at the impact of more than 10 weekly sets were few and far between. There wasn’t enough research to draw any solid conclusions as to what the effect of higher training volumes might be.
And it was this gap in the research that the authors of this new study set out to fill.
The Research: What They Did
The study looked at the effect of three different training volumes – low, medium and high. The low volume group did one set per exercise, the medium volume group did three sets, while the high volume group did five sets.
All three groups trained three days a week on non-consecutive days (i.e. Monday, Wednesday and Friday). Here’s what the training program looked like:
Chest press
Shoulder press
Lat pulldown
Seated row
Squat
Leg press
Leg extension
Subjects in all three groups did 8-12 reps per set, with all the sets carried out to (or at least close to) muscular failure.
The result?
Across all the muscles studied – biceps, triceps, and two of the muscles that make up your quadriceps (vastus lateralis and rectus femoris) – the high volume group saw the biggest gains in muscle thickness, followed by the medium and then the low volume group.
In the outer thigh, for example, there were increases of 5%, 8%, and 14% for the 1, 3, and 5-set groups, respectively. That’s almost three times faster gains with five versus one set per exercise.
So, what to make of it all?
First, these are the results from just one study. You can’t come to a strong conclusion about anything based on the results of one study.
What little research there is on the subject of high volume training and muscle growth shows that gains in muscle size tend to flatten out at around 10-20 sets per muscle group per week [3, 4].
That’s not to say higher volumes won’t lead to faster gains. But there is a point of diminishing returns, where you end up expending a lot of extra time and effort, as well as exposing yourself to a greater risk of injury, for a relatively small benefit.
In fact, subjects doing just one set per exercise still saw their quads grow by around five percent. That’s not too bad, especially considering that the men had moved beyond the beginner stages of training, and their workouts lasted less than 15 minutes.
Training Volume, Stress and Recovery
You also need to consider what else is going on in your life.
A high volume of training performed against the background of a low-stress lifestyle will produce very different results to that same volume of training paired with a high-stress lifestyle.
That’s because non-training stressors have the potential to slow the rate at which you recover from and adapt to your workouts.
Researchers have found that when you’re “under stress,” you recover more slowly after training [5, 6].
In one study, subjects with lower stress scores saw greater gains in the bench press and squat after 12 weeks of training compared to subjects with higher stress scores [7].
“When athletes are subjected to elevated non-training stressors, physiological training adaptations will inevitably be compromised,” writes John Kiely, former Head of Strength and Conditioning for UK Athletics.
“This will occur regardless of the origin of that stress: whether it be anxiety due to loss of form, exam pressure, relationship turbulence, poor sleep, or corrosive environmental conditions.”
Christie Aschwanden, author of Good to Go: What the Athlete in All of Us Can Learn from the Strange Science of Recovery, makes a similar point:
“To our bodies, physical and emotional stress are both similarly taxing. A good recovery plan takes both kinds of stress into account. one of the most common mistakes athletes make is to discount the stress that their jobs and busy lives place on their bodies. To fully recover, you have to not just take a break from training, you have to find ways to reduce those other stressors too.”
What’s more, the subjects taking part in the study were young men. You’re not going to see the same results in your 40’s, 50’s and beyond.
How Many Sets per Workout?
The number of weekly sets you need to maximize muscle growth also depends on how often a particular muscle is trained.
That is, doing 16 sets once a week will produce different results to 8 sets twice a week.
That’s because there’s an upper limit on the amount of stimulation your muscles can respond to in any given workout [9]. And the closer you get to this ceiling, the smaller the return on your investment of time and effort becomes.
As an example, let’s say that doing 4 sets rather than 2 sets per muscle group speeds up growth by 50%. But going from 4 sets to 6 sets might increase growth by 25%. A further increase from 6 sets to 8 sets might accelerate growth by just 10%.
In other words, the gains become progressively smaller as the number of sets increases.
This is something that’s shown up in animal studies as well. Research in rats, for example, shows that muscle protein synthesis plateaus after around 10 sets (see figure below), with no further increase after 20 sets [10].
Continue adding sets, and eventually your rate of growth will flatten out, and you may well end up going backwards if you do too much.
Blitzing your muscles with lots of exercises gives you much more of a pump, as well as generating a high level of post-exercise muscle soreness.
But while getting a pump and feeling sore for days after a workout might feel satisfying, it’s no guarantee that muscle is going to be built any faster.
Training Volume and Joint Health
As well as the impact that training volume has on your muscles, you also need to consider what it’s doing to your joints, which are often the limiting factor when it comes to the number of sets you can handle in the gym.
The benefit of any increase in training volume has to be weighed against the potential negative effect it can have on connective tissue.
This is especially true if you do a lot of heavy lifting with the various compound exercises, such as the squat, bench press and so on. While these exercises are great for building muscle, they’re not always the most “joint friendly” options available.
The last thing you want is to be constantly nagged by various aches and pains in your knees, elbows, shoulders or back.
Pushing your body to the limit can deliver impressive results in the short term. But, in the long run, chances are you’re going to end up getting injured.
Some folks can handle it.
If you have great genetics, age on your side, you’re benefiting from some pharmaceutical assistance, or you’ve spent many years training your body to handle high training volumes, you can get away with it.
Most, however, will be better off with a training volume that’s slightly below what is “optimal” for muscle growth, but one that leaves you feeling fresh, motivated, and free from pain.
What Happens After Eight Weeks?
Here’s something else that’s very important.
A study lasting eight weeks doesn’t tell you what’s going to happen after 16 or 32 weeks.
As Brad Schoenfeld, one of the study authors, points out:
“[T]he study duration was relatively short, comprising eight weeks of regimented training. The human body is very resilient and handles high levels of stress well in the short-term. When these stressors are properly managed, there is a positive adaptive response; in the case of a high resistance training volumes, the upshot is greater muscle growth. However, persistent exposure to such stressors ultimately overtaxes the body’s ability to respond, leading to an overtrained state.”
In real life, over a longer time frame, things are going to play out differently. Very few people can tolerate such a high volume of training for extended periods of time.
When you factor in deloads, as well as periods where you train with fewer sets – which your body will need to recover from all that volume – you may well end up in the exact same place as someone who’s used a lower volume of training all year round.
Had the study lasted, say 4-6 months, my guess is that guys in the lower volume group would have continued to make progress, while the higher volume group would end up stagnating, and may have gone backwards.
Even 27 sets a week for your quads is a lot. Most people will struggle to sustain that amount of work.
How Hard Are You Training?
One feature of this study is that all the subjects supposedly trained to failure. To quote the researchers directly:
“Sets consisted of 8 to 12 repetitions carried out to the point of momentary concentric failure, that is, the inability to perform another concentric repetition while maintaining proper form. The cadence of repetitions was carried out in a controlled fashion, with a concentric action of approximately 1 second and an eccentric action of approximately 2 seconds.”
Training your legs is hard work. Doing multiple sets to failure on exercises like squats and leg press is harder still. Doing 15 sets for your legs, taking every set to failure, then doing the same thing again a couple of days later is brutal.
Personally, I’m not convinced they were training to failure. There’s a big difference between terminating a set simply because it’s getting a bit hard, and genuinely pushing yourself to the point where you’re no longer able to complete another rep.
If you know you’ve got fourteen sets to come, you’re not going to push yourself as hard in that first set. You’re going to back off and leave a few reps in the tank.
That matters, because the number of sets you need to maximize growth also depends on how hard you train.
Specifically, I’m talking about the number of reps you have left in the tank at the end of each set. If you finish each set with 3-4 reps in reserve, chances are you’ll need more sets to produce the same amount of growth than someone who pushes each set to, or very close to, muscular failure.
Just because a training program involves a large number of sets doesn’t mean that all of those sets are effective at stimulating growth.
While building muscle doesn’t require taking each set to failure, you do need to train hard and push yourself.
A training program can involve a large number of sets, but if each set is cut short with a large number of reps in the tank, the strength of the “make me bigger” signal being sent to your muscles will be relatively small.
You’re better off doing fewer sets, but pushing yourself hard in each one, rather than doing lots of sets with a lower level of effort.
Training for Hardgainers
For slow-responders – the so-called “hardgainers” of this world – increasing your training volume may be just what you need to get your muscles growing.
I’m not saying you should be doing 45 sets per muscle group per week. But, as long as your overall training program is set up properly, gradually ramping up your training volume over time may well deliver better gains than going in the other direction and doing less.
This has been seen in research on endurance exercise, where low responders to a particular exercise program see better results when they switch to a higher volume of training.
In one study, subjects who saw little or no gains in cardiovascular fitness following a six-week low-volume training protocol made much better improvements when they upped the dose of training [8].
In fact, none of the participants were classified as “non responders” after the higher volume of exercise.
In much the same way, higher training volumes may help slow responders see a more “normal” muscle-building response to lifting weights.
A practical way to do so is with the use of short specialization cycles, where you bump up the amount of work you do for certain muscles to make them grow faster.
If you tried to do it for all muscles at the same time, the overall training stress would be too much.
For 1-2 muscle groups at a time, it’s doable. But not for your whole body.
Final Thoughts
There’s a theoretical “optimal” number of sets per muscle group, above and below which gains in muscle size will be slower than they otherwise would be.
The precise location of this “sweet spot” will depend on your genetics, the length of time you’ve been training, your age, the exercises you’re doing, the muscle group in question, your diet, how much effort you’re putting into each set, as well as other sources of stress, be they physical or psychological, that you have going on in your life.
The challenge comes when deciding exactly where that sweet spot is.
Chances are you’re going to see better results with at least 10 sets per muscle group per week than you will with 5-9 sets. For some people and in some muscle groups, even higher training volumes may be useful.
But I can’t tell you exactly how many sets to do. Nor can anyone else. Research can guide your decisions, but it only tells you the average response in a group of people.
That’s why it’s important to experiment. And the way to do so is to start out with a lower training volume and gradually work your way up.
Starting at lower volumes and then ramping it up over time will let you see if the increase in sets makes enough of a difference to justify the time and effort involved in doing so.
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ABOUT THE AUTHOR
Christian Finn is an exercise scientist and former “trainer to the trainers” based in the UK. He holds a masters degree in exercise science, and has been featured in or contributed to major media on two continents, including the BBC and Sunday Times in the U.K. and Men’s Health and Men’s Fitness in the U.S.