Did high-volume training just get debunked? [2 New studies]

Chapters:

00:00 Intro

00:11 Study 1: 18 vs 4 sets a week

05:41 MH Physique App

06:06 Study 2: Fatigue, not volume, drives muscle growth?

09:46 Conclusion

Transcript:

This new research changes everything. Okay, that’s not actually how science works, but nevertheless, these are two very interesting studies on the training volume debate with quite surprising findings.

In the first study the researchers had strength trained individuals and 87 of them, no less, complete a strength training program with either a low or a high training volume. They did either 3-6 or 18 sets per muscle group per week. On average, the fractional volume per week per muscle group for the arms and the thighs, so biceps, triceps, hamstrings, and quads was 4.1 versus 18. And the quick note here: I’ve seen many other content creators discuss this as a comparison of 12 vs 36 sets per week per muscle group, but that is inaccurate. That is the total volume for the arms and the thighs, but that is not how you should count training volume.

Most people don’t have a clear systematic way of how they count training volume, and it’s actually very important because it’s one of the most important variables in your program. What you should do is count for every individual muscle group, for every exercise, how much does this exercise strain this muscle group, and then you count all of that together, you add all of it up together to get the total weekly fractional volume per muscle group. This is the method that I teach my students in my PT course and the method that my app uses. It’s also what the researchers used, albeit with some simplification, namely that “indirect” exercises like rows and presses only train the arms 50% as a general rule, which is a little bit crude but actually quite accurate, I would say, especially for this particular study.

So this was basically a comparison of 4.1 sets versus 18 sets per week per muscle group. Both groups trained in the 7 to 10 rep range using reverse pyramids were needed because they trained to true momentary failure. This research group is actually renowned for having individuals actually train to true failure, meaning momentary muscle failure. They literally fail the rep like Yates/Mentzer style. So this was a true HIT style, high intensity training comparison versus more high volume “science based”, if you will, training. So this study essentially compared HIT style, high intensity training versus higher volume training. Both groups trained 3x a week.

After 12 weeks total muscle growth as estimated by cross-sectional area, basically muscle growth, was statistically equivalent in both groups. So case closed. Low volume training, high volume training, equally effective. One hard set per exercise to true failure is basically enough, right?

Well, there are a lot of serious limitations to this study. The most obvious limitation is that muscle growth, cross-sectional area specifically, was estimated via skin fold calipers and circumference tape, not something gold standard like magnetic resonance imaging, MRI. The measurement error here is compounded by the fact that measurements took place across 22 different gyms. That means that 22 different people, at least, were doing skinfold measurements and tape measurements on individuals, which introduces very high error rates. The researchers did all they could statistically to make this as accurate and reliable as possible, but there’s only so much statistical wizardry you can do to make this super reliable. The large sample size really helps, although I would note that there was a 22% dropout rate, which is quite high for a pure training intervention.

It should also be noted that this study is still in pre-print, meaning it is still subject to formal peer review. However, this is a very high quality research team, so I don’t expect major changes to occur in the study. The final limitation is that this was a study on seriously trained lifters. Why on earth is this a limitation? I know most of you strongly prefer research on trained lifters versus untrained lifters. And I generally share that sentiment, but there is a huge downside to studying trained individuals, and that’s that they don’t grow much.

So if you have a short term study, which almost all studies are due to logistical constraints, you just get a very small effect size of muscle growth, and then in the other group you also get a very small effect size and then you have to say, is this small one better than this small one? And that’s very hard because a comparison between 0 and 0 is always zero. Based on a formal power analysis the researchers concluded that most exercise science studies are woefully underpowered, literally their words, to detect small differences in muscle growth.

So, statistical wizardry aside, if we just look at the amount of muscle growth that took place the effect size was in fact higher in the high volume group, but it was pretty marginal. If we look at the absolute amount of muscle growth, based on my own calculations, I back-calculated the actual amount of muscle growth, this is subject to some error or specification of which exact methods you use because of the skin fold issue and how you treat missing data and the like, but regardless, I saw indeed that the effect size both for the arms and for the thighs favored the high volume group. And if you look at the actual increase in muscle growth, if we take these as given, assuming that because of the large sample size the absolute means are accurate, then you get about 15% faster muscle growth in the high volume group. And that’s probably not an unfair total finding.

This is clearly a lot of extra training volume that’s required to progress only 15% faster. This means that if you are making good progress on a low volume training program and you’re happy with that, then the benefits of going with a higher volume are very marginal.

However, due to the limitations of this study and single studies in general, the best answer to the question of how much volume we need for maximum muscle growth is still the latest meta analysis, which I’ve discussed many times on this channel already, but it shows quite clearly that most people do get considerably more muscle growth with 18 than 4 sets per week. The gains taper off a lot more after 10 sets per week, and overall it is very clear that there are strong diminishing returns. Before I explain how I prescribe training volume in my app to my students and with my coaching clients, we should look at a second new study on training volume.

The second new study makes a case that training volume is not really what we should be looking at. We should be looking at fatigue. The researchers argued that when you hold fatigue constant, training volume has no impact on muscle growth. It is actually fatigue that drives muscle growth.

Now, the study design here has kind of Elon Musk vibes where you’re not sure if genius or just weird. The researchers had a group of strength trained men with a 1.4x bodyweight squat perform either a low, moderate or high training volume. The program was a squat specialization program with a very weird design. It was supposedly matched for total fatigue by having the high volume groups rest very long in between their repetitions. Effectively, the higher volume groups rested longer and longer between repetitions, so that the idea was the total fatigue was equated and the lower volume groups did their sets more like one actual set, although effectively all the groups were doing one very extended cluster set, doing one repetition, 10s or more at rest, one repetition, etc.

Here you can see the total design. And you can see that the total volumes were actually not that crazy, but the sets did take a long time. After eight weeks there were no significant differences between the groups in estimated 1 rep max on their squat or in muscle volume or cross-sectional area. Most growth was 7 to 10% in all the groups.

To me, the even bigger shock than the lack of a difference in any gains with a 6.5x difference in training volume is that these groups made any gains in the first place, especially the low volume group, which was basically doing two sub maximal sets per week, most of which likely never got within five reps to failure. So one thing this study shows is that the effective reps model, or at least a strict interpretation of the idea that only the last 5 repetitions of your set, the last 5 repetitions to failure, counts towards muscle growth. That is most likely false.

This and multiple other studies have shown that you can in fact gain muscle, at least some individuals, without ever getting within 5 reps to failure, or almost never getting there. In that sense, the general interpretation that fatigue may be more important than training volume is also a bit of a reach, because none of these groups, by serious lifter standers, experienced much fatigue to begin with.

And if you look at the general findings in the literature we see that there are a lot of ways that you can increase your fatigue without actually increasing your gains. Two of the clearest examples of a mismatch between fatigue and additional muscle growth are rest intervals and training to failure. In the research on training to failure we see minimal effects of actually reaching true momentary muscle failure, especially that last repetition, which is not even one full repetition, precisely because it is minimal extra training volume. So we see that the extra training volume helps, but whether you reach failure or not does not help. In contrast, fatigue increases very much when you actually train to failure. Measures of fatigue, including recovery from the workout are substantially delayed or increased in the case of fatigue when you train to true failure versus when you stay a bit further away from failure. So there is clearly worse stimulus to fatigue ratio when you get very close to failure or actually go to failure.

In the case of rest intervals we even see that shorter rest intervals increase fatigue while reducing muscle growth and strength development because you get less training volume. So overall, I think the case is quite strong for training volume being much more important than fatigue. And if anything, you should pay attention to stimulus to fatigue ratio, especially in high volume training programs, to make sure that your training volume actually helps without just incurring a lot of extra fatigue, which is now often called “junk volume”.

Mechanistic research also very clearly favors that mechanical tension, time under tension and total tension, are the dominant factors that drive muscle hypertrophy, whereas fatigue is just a byproduct. Nevertheless, setting aside for the moment that the second study is one of the weirder studies I’ve read in a while, it’s clear that these are two data points in favor of low volume training, as opposed to higher volume training. It’s very clear that if you train with a low training volume, especially if you train with very high effort, you can only make very good gains and you get very limited additional gains from doing more volume.

So one of the key variables is whether it’s worth it for you to have higher training volumes. And I think here one of the key determinants is whether are you are making good gains right now. If you are making good gains on a low training volume and you are happy with that, then the gains from doing more volume, the risk reward, the cost benefit is very poor. However, if you look at your photos from last year and you really don’t look appreciably differently, then you’re probably not making excellent gains and something has to change. Training volume can be one of those things.

So the thing with all of these comparisons between this and that, and we see that there’s maybe 15% extra growth with high volume versus low volume, if you are making good gains then 15% extra gains is quite trivial. But if you are not making gains and that extra little bit of volume or other program optimization makes the difference between not gaining and gaining, then 15% is misleading because it’s literally the difference between progress and no progress, which compounds substantially over time.

More generally, the method I teach my students and what my app uses is that your total training volume should be set based on your preference and your total recovery capacity. Your total recovery capacity is determined in large part by your training status, so how advanced you are, with more advanced trainees typically tolerating higher training volumes, and your recovery capacity in the more direct sense like how good is your sleep, how high are your stress levels, is your nutrition in check… These variables together determine how much volume you can productively recover from and therefore use in your program if you really want to maximize muscle hypertrophy.

If you’re interested in my app or my online PT certification you can check the links in the description. And if you’re interested in more free content check out my other videos on how best to set up your training program for maximum gains.