More volume = more muscle… or just swelling? [New study]

Chapters:

00:00 Intro

00:18 Training volume – Muscle damage – Edema

00:56 Study – Alvarez et al.

02:50 Study – Varovic et al.

03:37 Untrained individuals, repeated bout effect and soreness

04:49 My Online PT Course

05:09 Perceived recovery

06:48 Conclusion

Transcript:

Higher training volumes generally lead to greater increases in muscle size. The latest meta-analysis of the literature found no clear end-point beyond which greater training volumes no longer contributed to additional muscle hypertrophy. However, critics argue that size isn’t everything. – It is! Critics also argue that the increases in muscle size may not reflect contractile muscle mass. They may instead simply be temporary swelling; edema from the muscle damage that is caused by higher training volumes.

The idea is that since muscle hypertrophy is generally only measured some 48 to 72 hours after the last workout, and higher training volumes cause greater muscle damage, the measurements, instead of picking up on actual contractile muscle growth, they pick up on a lot of temporary swelling from the last workout in the higher volume conditions. So the higher the training volume, the more muscle damage, the more muscle swelling, and that confounds the relationship we see in research between training volume and muscle hypertrophy.

A new study for the first time directly investigated if this is true. The researchers had a group of well trained men complete a grueling leg workout with 7, 14, or 21 sets for their quads. The participants’ 10 rep max was almost three plates, so these were seriously train lifters. The workout consisted of squats, leg presses, and leg extensions at approximately 10 rep max loads, and they were completed with… “MAXIMUM EFFORT”. So these were seriously high volume workouts. Even the lowest volume workout was a very serious leg day. The main conclusion was that: “Muscle swelling, measured by changes in muscle thickness and echo-intensity as a proxy for edema, returned to baseline values after 24 hours.” – with no notable effect of training volume at all.

A notable caveat is that muscle hypertrophy was measured in the middle of the quads, so it measured basically the rectus femoris and the vastus intermediates. This, in my opinion, was not a very good choice because squats and leg presses don’t train the rectus femoris particularly well. The rectus femoris is a bi-articulate muscle, and it cannot effectively contribute force during an exercise where you have both hip extension and knee extension. Because the rectus femoris would be helping you at the knee trying to extend the knee, but it will also be pulling yourself deeper back into the bottom position by flexing at the hip. However, even if we take the rather extreme position that squats and leg presses don’t train the rectus femoris at all, and therefore the additional volume was zero for these exercises for the rectus femoris, they still train the vastus intermediates, and leg extensions, which also had an increase in training volume in the different groups; do train the rectus femoris.

So overall this is still compelling evidence that muscles swelling is not a considerable confounder in well trained individuals, even when they are doing very high volume training. The vast majority of studies measure muscle size 48 to 72 hours after the last workout, and in this case we saw that the swelling had basically completely returned to baseline within 24 hours.

Another new study came to a similar conclusion using different methods. They measured muscle hypertrophy some 70 to 120 hours after last workout, which was six weeks after the start of their training program, after completing five sets of leg extensions to failure, and then they measure muscle size again a day later. If muscle swelling was indeed a big contributing factor. You would expect that a day later some of the swelling had subsided and the measurements were no longer as inflated as before, so muscle size should return to a lower level. It didn’t. Therefore, it seems that measurements of muscle size taken some 72 hours after the last workout of the training program are quite robust and are not significantly inflated by edema and muscle swelling.

This conclusion is in line with what I personally hypothesized in my last video on this topic, based on the available evidence at that time.

The primary reason that the confounding effect of muscle swelling is debated is because there are many studies showing that swelling actually persists more than three days after a workout. However, what most of these studies have in common is that they look at untrained individuals doing a, by definition as untrained individuals, unfamiliar workouts. These individuals do not benefit from what is called the repeated bout effect. The repeated bout effect is a protective mechanism by which trained lifters become much, much, much more tolerant of muscle damage. The increase in muscle damage after a familiar workout is dramatically less than after a novel workout.

This also correlates with soreness. Soreness is typically extremely high after you do a workout for the first time. After you go skiing or snowboarding, or do any sport for the first time, even if you’re a well trained lifter you might get hella sore. However, many well trained lifters never get sore at all from their regular workouts.

What the new studys have in common is that they look at train lifters doing a workout with familiar exercises, presumably at least in the new study, because squats, leg presses, and leg extensions are quite common exercises and therefore they benefit from repeated bout effect. These new findings are therefore much more relevant for trained lifters, which by definition is what all the participants in studies on training volume are after the study.

Another very interesting finding of this new study is that how recovered the lifters felt was not in line with their objective recovery at all. This is in line with multiple previous studies that I’ve posted about on this channel. Perceived recovery status, as it’s formerly called, basically didn’t correlate at all with objective strength recovery. Objective strength recovery is usually defined as loss fatigue. Fatigue is defined as the loss of force production. So when force production is stable, or in this case, even at a trend for an increase, measured on the ten rep max on their squat, there is no objective fatigue anymore. In contrast, the lifters definitely didn’t feel recovered after their leg days with 7, 14 or 21 sets, even 72 hours after the lowest volume workouts.

Perceived recovery status, so how recovered lifters felt, had not returned to baseline, meaning the lifters still didn’t feel fully recovered three days after the workout. However, they actually were. 10 rep max on th squat was not significantly lower than at the start. There was actually evidence of a learning effect, which confounds the results a little bit, that the 10 rep max was higher after 72, and especially after 24 hours compared to the first time. While this learning effect slightly confounds the results of this particular study, it’s in line with multiple previous studies that how recovered you feel is a very poor indicator of how recovered your muscles actually are.

Our feelings are influenced by many more factors than how recovered the slab of meat of our muscles actually is. Actual physical recovery is a very basic process. However, our feelings are influenced by how well rested do we feel, what are our expectations, how well did we sleep tonight, how stressed are we… Many, many factors can influence how we feel, but there are not so many factors that influence how recovered we actually are in the neuromuscular sense.

Overall, these two new studies give us two concrete take home messages. First – higher training volumes do in fact cause greater muscle hypertrophy, and this is not just edema or swelling. It actually is robust contractile muscle growth based on the best available evidence. Second – how recovered we feel is not a reliable measurement of how recovered our muscles actually are. Most lifters can recover from a lot more volume than they think. Now, this doesn’t mean you have to train with high training volumes. You can make excellent gains on low training volumes, but let’s not kid ourselves that hard work doesn’t pay off. Low volume programs are all the rage right now, and it’s an easy sell. You get more with less, but you don’t get more. You just get good gains, which might be satisfactory, but you don’t get maximum gains. For maximum gains hard work does pay off.

If you’re interested in more of this evidence based fitness content, I’d be honored if you like and subscribe. And if you’re interested in a deep dive in everything related to muscle growth, check out my online course. The link is in the description.