What keeps you up at night? For me, it's the optimum training volume and frequency for maximum neuromuscular development. How often and how much should we train every muscle group for maximum strength gains and maximum size gains?
Fortunately for my sleep, we have a new meta analysis that analyzed the results of 67 studies to come up with new answers. Higher training frequencies clearly improved strength development. This effect was quite clear and quite strong.
There were diminishing returns, though. Going from a frequency of once per week to two times per week has very significant benefits, but as you can see in the graph here, going over three times per week the effects became a lot less strong. However, there was no clear evidence of a plateau effect.
So you could argue that for strength development you basically want to train a muscle group as often as possible. In this study researchers used a fractional volume counting approach. This means that they count up the volume for the bench press fully when the outcome was bench press strength.
And this is great because of course, doing bench pressing is the best thing you can do for your bench press. Strength is highly specific. However, we also want to count, say, the dumbbell bench press or push ups, and then we want to count flys and triceps extensions a lot less.
And we could quibble about the categorization that the researchers used. I have some remarks about it, but overall, I think the research did a great job. And their analysis also shows that their fractional volume counting approach improved the results, so improve the fit with the data showing that the best thing you can do when you're counting your training volume and your frequency in your programs is assigning fractional volumes.
For example, you count the bench press fully for strength development of the bench press, but you don't count something as triceps extensions towards your bench press volume. For most people training a muscle group or an exercise 2 to 3 times per week is probably ideal for strength development. The issue with training and exercise more than three times per week, especially with the powerlifts, for most individuals is injury sensitivity.
Doing squats more than three times per week or bench presses more than three times per week, you really have to be super careful with the intensity or the volume and at some point you have to start wondering if it's even worth the time doing an extra session that's so light, because otherwise you're going to injure your elbow, for example. So in my experience, training an exercise 2 times per week is a good rule of thumb for many individuals, and 3 times per week works really well if you want to really focus on a specific exercise. For example, if you're a powerlifter and you want to maximize strength development in that particular exercise.
Based on these results you can even make a strong argument that, specifically for powerlifting or for strength in a specific movement, you want to train that muscle group and even that exercise as frequently as possible as you can recover from. Because there were continued benefits with higher frequencies with no clear plateau effect. For muscle growth, higher training frequencies also seem to be positive but the effect was a lot smaller and less clear.
Specifically, researchers found a 91% probability that higher training frequencies in general are positive for muscle growth independent of training volume. So we're not looking at are you going to the gym two times a week versus are you going to the gym three times per week, which usually increases training volume by about 50%. This is independent of training volume.
So we're looking at, you have a certain number of sets, how are you going to distribute that across the week. And in this sense training frequency functions a lot like your rest interval. In fact, you can think of a higher training frequency as simply a longer rest interval.
If you do ten sets of bench presses on Monday, and now you're going to put five of those sets on Wednesday or Thursday it's like you're increasing your rest interval from minutes to days for the remaining sets. And what we see in practice is that when you do this you increase your training volume. You can do more repetitions even for the same number of sets.
If I take five of your bench press sets, move them to a different day, you're going to be more fresh, more recovered for those sets on that day. So your repetitions are going to be higher, or you can lift more weight for the same number of reps. And when we specifically look at those types of studies, based on prior research, we see more clear effects.
A great study by Nevis et al. from 2022 shows that when we equate the volume, which many studies do, and therefore research probably underestimates the effect of training frequency, we don't see any benefits. Like, if you do the exact same number of repetitions then it doesn't matter how you spread the volume across the week in most circumstances.
However, when we do allow the volume to go up we do see a trend towards benefits. It's still not super clear, but in general, just like with rest intervals, I believe you will get greater gains. And there are multiple studies, especially in trained individuals that find benefits.
In untrained individuals it probably doesn't matter yet. Your newbie gains are very easy to realize. We see that in powerlifters and Olympic weightlifters we do have multiple studies showing benefits of higher training frequencies independent of training volume, both for strength development and for muscle growth.
So that probably explains the great inconsistency we see here. Because this analysis did not separate between trained and untrained individuals, it did not separate between how volume was counted in terms of repetitions versus sets. The only use sets with their fractional sets volume counting method.
And again, this is a great method and we just need more research to determine exactly for whom higher training frequencies and when they are likely beneficial. For example, an unofficial meta analysis by James Krieger found that higher training frequencies are only beneficial when we're looking at set volumes over six sets per session. And think that's a good rule of thumb not to do a bro split where you have like 10 sets per muscle group in one session.
You're probably better off spreading that a bit more across the week, with a good rule of thumb being not to do more than 6 sets per muscle group per session. You're probably better off moving that to a separate day. Overall though, it's clear that for muscle growth training frequency is of strictly secondary importance to training volume.
Most of the benefits of higher training frequencies are mediated by being able to do higher training volume. So let's talk about volume. In line with multiple previous meta analyzes and studies, higher training volumes generally led to greater results.
For strength development, though, there were very sharp diminishing returns. In fact, above 5 sets per muscle group per week the results became unclear. As you can see in the graph here, though, generally there was an upward trend, but between 5 and 10 sets per muscle group the effects became very unclear, and we pretty much have a plateau after 10sets per muscle group per week.
Now again, this per muscle group for strength development is a little bit iffy. It might depends on the exercise. For example, we have some research showing that for squats, even 16 sets of squats per week were still better than 8.
Squats are a very technical exercise so it might be that those types of exercises, compound exercises that are very technical and take a lot more time to master, they benefit from more volume than, say, biceps curls or leg extensions, because a lot of studies actually look at leg extension strength. I mean, you don't need a lot of skill to do a leg extension. Moreover, think these results understate the importance of training volume for strength development because most studies are short term in nature.
In fact, the median study length in this analysis was, I believe, 10 weeks and we see that in that short time frame strength gains are very much neural in nature. Strength is a skill. It's movement specific and it refers, in large part, to how your body and specifically the motor cortex in your brain can coordinate your muscle mass.
So in the short term we mainly see benefits for strength development in cases where it improves neuromuscular coordination. It increases muscle activation for example. However, in the long term we see very clear correlations between strength and muscle growth.
For example, when we look at powerlifters, which is like the epitome of strength, not size. Actually, when we put those guys in a DEXA scanner their rankings are almost identical to their competition rankings because the correlation between strength and muscle growth becomes extremely strong in the long term. The only way you can maximize strength development is not just mastering a movement, but also increasing the size of the engine.
Like the muscle mass for for the bench press, for example, meaning the size of your pecs, your delts, your triceps, then you can maximize long term strength development. So in the short term, the benefits or training volume are not so clear because the neural development is not as dependent on training volume. Like, your body gets the hint.
In fact, just 1 set per week per muscle group on average led to strength development in this study. But we know from previous research that it's about 4 sets per exercise in powerlifters to continue gaining any strength. So again there's an effect of training status.
It might depends on the movement and in the long term you'll probably benefit from higher volumes because they increase muscle growth. Which brings us to training volume for muscle growth. If you like this video, you're probably a serious lifter that appreciates science just like me.
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Check out the link in the description for more information. I hope you'll enjoy it. For size gains, training volume is the #1 determinant.
In line with multiple previous analysis, your training volume is like the training equivalent of your energy intake for your diet. It is the foundation. So if you look at the graph here, you can see that the training volume quite strongly impacted muscle growth.
There were diminishing returns, but there was no clear evidence of a plateau effect and, in fact, there was also no clear evidence of an inverted U, which is the general hypothesis that at some point excess training volume becomes detrimental. Now, that is most likely true because we know from multiple previous studies that sometimes higher training volumes do lead to worse size gains and especially strength gains, but even size gains and that's likely due to recovery capacity. So these results have to be taken into consideration in light of someone's recovery capacity.
Usually people in these studies are not in energy deficit. That's a big consideration. And they are college aged.
So they don't have a family, a full time job, you know, three kids that make them not be able to sleep at night. All of these things impact recovery capacity. And when we look at older data together, we know that recovery capacity for many people is a limiting factor.
Based purely on these results, if you don't take that into account, you would say that the benefits of training volume increase for most individuals 43 sets per muscle group per week, and, even at that point, the data simply became unclear. There was no hard evidence of any negative results of higher training volumes. Overall, in the analysis, the more volume people did, the more muscle they gained.
In practice, though, again, people will get injured. They simply don't have the willpower, they don't have the time or they don't have the recovery capacity to sustain those levels of volume. 43 sets per muscle group per week is a whole lot of volume.
Try making a training program and see how much you have to do. Most people end up more in the 10 to 20 sets per week range, but I do think this analysis is very informative to show that if you have a recovery capacity, you can work up to very high training volumes, maybe for certain periods of time, and still get really good gains. However, again, on the flip side, it's worth noting that the minimum effective volume was only 4 sets per muscle group per week, so you can also make do with lower volumes, especially if you train very hard you can get great results with just a few sets per week per muscle group.
It should be noted that this analysis has not yet been peer reviewed, it's still in the pre-print stage. However, I personally know multiple of the researchers involved in this study and they are top tier. So I don't expect major changes.
In fact, most of the concern about preprints are from people that did Research 101 class. They're not actual exercise scientists and they think that peer review is some magical process by which every study suddenly takes its final form and completely changes. In reality, what peer review is, is just a bunch of other researchers that look at your results and, depending on how much time they have, they may give it a glance, they might give it a good look.
Sometimes you get good feedback, sometimes you get terrible feedback. When we have a study in peer review we often joke about how they're going to make the study worse, because sometimes you get really bad feedback and actually you have to do things in a study or state things a different way, even if you don't agree with that, but you want to get it published. So I'm not that enthralled with the magic of peer review.
It's a good process, though, to weed out the worst of the studies and it's certainly better than, say, the Instagram comments on the study. But overall, I wouldn't expect major changes and I think these results are very legit. I hope this video helps you optimize your training program so you can make better strength gains and gain more muscle.
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