Are you making fake gains due to junk volume?

Chapters:

00:00 Intro

00:14 Latest meta-analysis

01:05 Are the gains from higher volumes all just swelling?

02:14 The repeated bout effect

02:53 Studies in trained individuals

07:10 My Online PT Course

07:40 Contribution of swelling at the time of measurement

08:58 Volume vs Hypertrophy

09:44 Volume vs Strength development

10:15 Size vs Strength

11:39 Neurological influence on strength

13:19 Practical implications

14:13 Outro

Transcript:

What is the optimal training volume for muscle growth and strength development? According to the latest meta-analysis of studies that looked at this, the training volume that maximizes strength development seems to be a lot lower than the training volume that maximizes muscle hypertrophy.

For strength development there seem to be minimal benefits to doing more than 10 sets per week per exercise, including exercises that overlap with the exercise that you want to get stronger at. So in this study, for example, leg extensions would be counted as half in terms of volume for squats because – yes, they make your quads bigger, but they don’t directly train squats. For muscle growth, however, the number of sets per week that we have to do to maximize our gains seems to be well over 20, probably over 30, and possibly even over 40. There was no clear evidence of a true plateau, and especially no evidence of detrimental effects of higher training volumes.

But if higher training volumes are so effective at increasing muscle growth, how come strength development is not increasing proportionately in these studies? More contractile mass should logically increase force production. So muscle growth should improve strength development. Why is it then that we don’t see this in this study? One trending explanation for this divergence between strength and size gains is that the additional hypertrophy from higher training volumes is just swelling. It’s water retention. It’s edema from muscle damage that takes place when you do higher volume workouts. While there is no direct evidence that higher trading volumes increase edema, it is very likely because higher training volumes induce more muscle damage, and it’s the muscle damage that causes the water retention and the edema.

In exercise science studies muscle growth is usually measured 48 to 72 hours after the last workout. At this point, if you do an ultrasound or an MRI scan, it is possible that you’re just picking up edema. The muscles might still be swollen from the last workout. If this is the case – that most exercise science studies are completely confounded by muscle swelling – it’s hard to overestimate just how big the implications of this are. Not just for training volume, but in general for which exercise science studies hold any weight at all. And indeed, there are plenty of studies which show that edema takes more than 48 to 72 hours to subside back to pre-workout levels after a high training volume workout.

However, the vast majority of these studies are in untrained individuals. Untrained individuals are by definition doing a workouts that they are not familiar with. And there is this nice little phenomenon called “The repeated bout effect” which protects muscles from doing a workout that they are accustomed to. This is also why the first time you do a workout, even if it’s not really strength training, it might be surfing, it might be a yoga session, you can get crazy sore the first time, but over time you get less and less sore, and we also see that muscle damage decreases more and more. Repeated bout effect is quite dramatic. It’s so strong and long lasting that we see that if individuals do a workout, they get very sore, they repeat that workout months later without training in between, they still get substantially less sore and have substantially lower indicators of muscle damage, and they recover faster after that workout the second time around.

So if that’s the effect on an untrained individual doing a workout one time, what do we see in trained individuals doing their habitual workout many, many times during a program? In most exercise science studies individuals do the work out for at least 8 weeks. This is plenty of time for the repeated bout effect to massively decrease the amount of muscle damage that takes place from those workouts. Indeed, if we look at studies on how long it takes for edema to subside after a workout, and we look specifically at trained individuals doing workouts with exercises that they are presumably familiar with, like barbell bench presses, leg extensions, or squats, then we see that the duration of edema is generally 24 to 72 hours, exactly in line with researchers recommendation to measure muscle growth 2 to 3 days after a workout. I typically recommend that exercise scientists increase this duration to 4 days, but based on these studies it is clear that edema is no longer a major confounding factor after 2 to 3 days.

Concretely, studies by Gordon et al. and Ferreira at al. looked at how long it takes for edema to subside after 8 sets of about 10 reps of leg extensions, dumbbell bench presses, and barbell bench presses. They found that measured both via ultrasound and MRI scans edema had subsided within 24 hours back to baseline levels. There was no longer a statistically significant increase in muscle swelling after just one day. This finding was replicated in middle aged adults, showing that it’s also applicable to somewhat older lifters.

Two more studies by Ferreira et al. and Trindade et al. found slightly longer durations of muscle edema after 8 to 10 sets of barbell bench presses to failure, but after 72 hours there was again no longer a significant difference from baseline levels. The researchers also looked at whether it mattered if you paused in the bottom position of the bench press and it didn’t. Most of the swelling had in fact subsided within 24 hours, and looking at the triceps measurements instead of the pec measurements we could see that just 24 hours after the workout there was indeed no longer a significant increase in muscle size.

A similar study by Bartolomei looked at 8 sets of squats performed close to failure. Here we could see that measurements of muscle thickness at just 24 hours after the workout were no longer significantly elevated. For a muscle cross-sectional area the increase was still evident at 24 hours, but no longer significant at 48 hours. Moreover, another group doing the same workout at 90% instead of 70% of 1RM found that just 24 hours after the workout, both muscle thickness and cross-sectional area were no longer significantly elevated, meaning there was very little edema taking place at all when doing lower rep workouts. This is in line with most research and is completely counter to the prevailing idea in bodybuilding and powerlifting circles that low rep workouts wreck your CNS and cause a lot of recovery time. That is not the case. It might be true for connective tissues, but muscular tissue heals much more quickly and gets much less damaged from doing heavier workouts. It’s paradoxical, but exercise science very clearly shows that this is the case.

Importantly, in all of these studies, the researchers just got a bunch of strength trained individuals together, had them do the workout, and then tested how long it took for muscle swelling to subside afterwards. In exercise science studies, participants typically do a given workout for about 8 weeks or ideally longer. This means that in most of the high volume studies the participants had a lot of time to habituate to that exact workout. Most lifters don’t do 8 to 10 sets of squats or bench presses to failure in their normal workouts. So it makes sense that they get a lot more muscle damage from a workout like that when they’re not habituated to it. After the end of, say, a German volume training program you’ll likely get a lot less damage from that same workout. And this is the condition that we see in most studies. So the acute studies likely significantly overestimate the duration of swelling after a given workout that people are familiar with.

Indeed, we had one study by Refalo et al. which directly measured if their measurements of muscle hypertrophy after the study work confounded by edema. Over the last four weeks of the study they have increased their training volume by 20%. At the last workout they were doing some 5 to 9 sets per muscle group. Three days after that measurements of muscle size were conducted and then 2 to 3 days after that measurements of muscle size were repeated. This allowed the researchers to see if the measurements of muscle size subsided after the first measurement, which would indicate that they were confounded by edema. This did not occur. In fact, the measurements were not lower at all, suggesting that the growth was real growth, not just edema. Or at least that whatever growth was there, was there to stay. It’s possible that some measurements of swelling occur at first, and they later make way for actual contractile muscle growth.

The fact that most swelling subsided within 24 hours and is almost completely gone within 72 hours in trained individuals is completely in line with most research on how long it takes to recover from a workout, and how long muscle protein synthesis stays elevated after a workout. So all of these findings largely converge to the finding that 72 hours should be ample for researchers to measure muscle size after workout without a big confounding effect of swelling from that last workout. The total amount of muscle growth that takes place might be this, the swelling that we see after workout might be somewhere here, and then we look at the effect of the additional effect, which is completely speculative, of the higher volume – We’re just looking at a very small possible contribution to the total amount of muscle growth that we see in research. So even if there are still some swelling in a study at the time point that they measure muscle hypertrophy, it’s just not enough to explain the full difference in muscle growth that we see between a higher volume and a lower volume group.

On a technical note, you might argue that the swelling studies are statistically underpowered to detect the duration of swelling. However, that would also apply to the studies of muscle hypertrophy. So if we do see significant muscle hypertrophy, then by definition, if there wasn’t significant swelling, it’s very unlikely that the swelling could explain the totality of the muscle growth difference. The lack of statistical power goes both ways. An additional finding in research that does not align with the idea that higher training volumes just cause more edema instead of actual further contractile muscle growth. Is that the relationship between training volume and muscle hypertrophy strengthens over time. This makes perfect sense if you assume that muscle hypertrophy is indeed greater with higher training volumes. The longer the study goes, the more clear it becomes that there is indeed a difference between the groups.

However, if most of the muscle hypertrophy difference from higher volumes versus lower volumes was explained by edema, you would expect that in a shorter study the difference would be magnified, because we see that the amount of muscle damage that individuals occur during a given training program goes down over time. So the fact that the relationship between volume and muscle hypertrophy strengthens over time is counter to the idea that it’s confounded by swelling.

Okay, so if higher training volumes do indeed cause more contractile muscle hypertrophy, how come they’re not increasing strength development? Well, they probably are, we’re just not seeing it in the studies. For one, Greg Nuckols has unofficially reanalyzed the results of this meta analysis, looking specifically at strength development and muscle growth in the same study versus looking at across studies, which is a better measure to do it. So the way Greg Nuckols did it, looking at within a study is a better measure when you really want to answer the question of how size and strength relate to one another in the same individual. And there we see that the relationship is a lot stronger.

Moreover, we see that the relationship between strength and size increases massively over time. In the short term, strength and size seem to be very different things. In the long term, strength and size correlate very strongly. I’ve often remarked on the irony that in research we see that powerlifters rankings are almost the same as their rankings in a DEXA scan. So if you just put powerlifters in a DEXA scanner, you measure their fat free mass and you rank them from most muscular to least muscular, then you see that that ranking is almost exactly the same as their powerlifting scores. And this is the population that is supposed to be training the most purely for strength instead of size. However, we clearly see that more muscle mass increases total force output potential, therefore allowing the bigger powerlifters to outperform the smaller powerlifters.

Now in a shorter study you might not see this effect, because even if we assume that the relationship between size and strength is linear, that would mean that a 10% increase in muscle size would be needed to increase strength by 10%. In an eight week study, which is the typical exercise science study duration, you’re not going to get a 10% increase in muscle size generally. Even if you do, that is still smaller than the increase in muscle strength that you’re likely to get.

You can easily get a 20% increase in muscle strength over an eight week period, especially if the subjects were not rigorously implementing progressive overload before or they were not completely familiar with the exercise. I typically lose about 20% of strength on an exercise if I haven’t done it for a while, even if I’ve done substitute exercises. So the first 20% of strength gains are mostly just neurological.

Strength is influenced very heavily, not just by muscle size and other morphological factors, but also very strongly by neurological elements. In particular, the coordination of the movement. Your motor cortex, the part of the brain that governs movement learns to coordinate muscles better, and it has things like intermuscular coordination, even some intramuscular coordination that improve as you learn an exercise. It’s like riding a bicycle. The body learns how to perform the movement, and that makes you a lot better at it, even if you’re not getting more muscular. An analogy I often use is that you can think of strength as the speed a race car drives at. You can make the race car go faster by increasing the size of the engine, which is making the muscles bigger, or you can increase the speed of the race car by having a better driver. That would be a more efficient nervous system.

Moreover, in many studies it’s logical that strength and size don’t correlate that well, at least not in a very short term, in span of weeks, because you measure different things. If, for example, a study has muscle growth measured by a quadriceps training volume, and you’re doing squats and leg extensions, and strength is measured as squad strength, how much do you really expect the leg extensions over such a short period of time to contribute to your squad strength? Not very much.

Now, if you’re only doing squats, the relationship will be a lot stronger. So strength development is highly influenced by exercise selection in addition to things like training proximity to failure, technical mastery, whether you’re doing speed work, and importantly – training intensity. How your training intensities reliably improve strength development but not muscle hypertrophy due to higher levels of muscle activation and better neurological learning. So we just can’t realistically expect, over the span of a few weeks to find very strong correlations between muscle size and strength, but we actually do see them in some of the better controlled studies. So overall I would say that strength or size do correlate. And in the best controlled research, within individuals over time, over long periods of time, we reliably see this.

The practical implication of all of this is massive. If higher training volumes just cause more edema and not more strength development or contractile growth, then it would be the case that we should look mostly at the literature on strength development to guide training volume recommendations, and that would mean – 10 sets or so, low volume – is the way to go. In fact, we see that higher training volumes most likely do lead to actually more contractile muscle growth, and also more strength development in the long run. This means that both for strength development and for muscle hypertrophy we should be erring on the side of higher training volumes if we really want to maximize muscle hypertrophy. There’s a strong risk-reward here and a cost-benefit, but for individuals that really want to maximize their gains, they should be pushing their volume up to their limits. And the practical limit for most individuals is not some arbitrary number from research, but it’s mostly what they can recover from in practice. As long as you can still recover from additional volume, you’ll likely increase your gains with additional volume.

So in one of my next videos I’m going to tell you how to increase your maximum tolerable training volume, because I know for many people that have tried high volume workouts – they just get injured, they burn out, it’s not sustainable. So if you’re interested in that video and more evidence based fitness content in general, I’d be honored if you like and subscribe. And if you want to know everything there is about maximizing strength development, muscle hypertrophy, and achieving your maximum muscular potential and your lowest sustainable body fat percentage – check out my online PT course. It will teach you absolutely everything you need to know.

Ciao-ciao!

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