Within the fitness world, there seem to
be diverse opinions on how many sets a person should perform to build muscle optimally. On one end of the spectrum, some believe a
low number of sets are sufficient, with some even proposing 1 set of repetitions to failure
per exercise is all you need to build muscle. On the other end of the spectrum,
others suggest that so long as you can successfully recover from
it, more sets mean more stimulus, thus the higher number of sets you can
perform the better for muscle growth. However, what does scientific research say? Before exploring the research, it's useful to get
some definitions and technical points out the way. In this video, a set is defined as a
bout of repetitions between 8 and 12, performed 3 or fewer repetitions
from the point of failure. This is what pretty much all the research
we'll explore in this video used as a set. Furthermore, in this video,
we'll actually be exploring how many weekly sets you may want to
be performing for each muscle group. Any exercise that involves a muscle group as a prime mover will count towards
that muscles group's weekly sets. For example, in a compound
exercise like the bench press, the chest, triceps, and deltoid muscles are
prime movers. Thus, one set on the bench press will count towards 1 set for the chest, 1 set
for the triceps, and 1 set for the deltoids. Also, any isolation exercises
that target a specific muscle group will of course count towards
that muscle group's weekly set count. For instance, 1 set on the triceps skull crusher
will count towards 1 set for your triceps. Okay, let us now explore the research on
how many weekly sets you should perform per muscle group to maximize muscle hypertrophy. Kicking things off, the results from a
meta-analysis by Schoenfeld et al. seem to indicate that the more sets performed for a
muscle group per week, the more muscle growth. Based on data from 15 studies, each additional weekly set was associated
with an 0.37% increase in muscle size. Furthermore, performing 9 or more weekly
sets for a muscle group produced more muscle hypertrophy than fewer than 9 weekly sets. However, there are two important
considerations with this meta-analysis. Firstly, the majority of the studies included did not have subjects perform more than
9-12 weekly sets for a muscle group. Secondly, the majority of the studies were also
conducted on previously untrained individuals. As a result, probably the most accurate
takeaway from this analysis is that for beginners, performing 9-12 weekly sets per
muscle group is likely better than fewer. This is probably a solid takeaway for beginners. 9-12 weekly sets is probably an
ideal amount of work for them. We know that beginners gain the
fastest rate of muscle and strength, but they also experience the most muscle
damage and longest recovery durations. Thus, performing more than 9-12 weekly
sets may not be necessary for them. However, what about once a beginner
gains a good degree of experience, and what about individuals with
numerous training years of experience? Could performing more than 9-12 weekly sets for
trained individuals benefit muscle hypertrophy? As far as I'm aware, there have
been 6 studies exploring this. 3 of them essentially indicate the more sets the
better, while the other 3 suggest there's a point where further weekly sets provide no further
benefit or even regression for hypertrophy. Let us briefly examine these
6 studies in hope of finding reasons that could explain
the overall mixed results. We'll first examine the 3 studies
that find more sets to be better. Brigatto et al. had 27 men with an
average of 3.5 years of training experience either train their muscle
groups with 16, 24, or 32 weekly sets. All groups distributed their sets
over two non-consecutive days a week, and training lasted 8 weeks. 50% of the weekly sets for a muscle
group were from compound exercises, with the remaining 50% coming
from isolation exercises. Also, 60-second rest intervals were
used between sets in a session. Increases in biceps, triceps, and vastus
lateralis thickness were greatest for the subjects performing 32 weekly
sets for their muscle groups. Radaelli et al. had 48 men with
previous calisthenics experience train their biceps with either 6,
18, or 30 weekly sets. Moreover, subjects either trained their triceps
with 9, 27, or 45 weekly sets. All groups distributed their sets over
three non-consecutive days a week, and training lasted 6 months. For their biceps, 50% of the weekly
sets were from compound exercises, while the remaining 50% was
from isolation exercises. For the triceps, 2/3 of the sets
were from compound exercises, while 1/3 were from isolation exercises. Also, 90-120 seconds of rest was
given between sets in a session. Increases in biceps and triceps thickness favored
performing the highest number of weekly sets. Schoenfeld et al. had 34 men with an average of
4.4 years of training experience perform either 6, 18, or 30 weekly sets for
their biceps and triceps. Moreover, subjects either trained their
quadriceps with 9, 27, or 45 weekly sets. All groups distributed their sets over
three non-consecutive days a week, and training lasted for 8 weeks. For the biceps and triceps, 100% of the
weekly sets were from compound exercises. For the quadriceps, 2/3 of the
weekly sets were from compound exercises, with the remaining
1/3 from isolation exercises. Also, 90 seconds of rest was
given between sets in a session. Increases in biceps, triceps, rectus femoris, and lateral thigh thickness favored
performing the highest number of weekly sets. So, these three studies we've just
overviewed indicate between 30-45 weekly sets for a muscle group are
beneficial for muscle hypertrophy. Let us now briefly detail the 3
other studies that oppose this, and then figure out why this could be. Heaselgrave et al. had 49 men
with at least 1 year of training experience train their biceps with
either 9, 18, or 27 weekly sets. The subjects that performed 9 weekly
sets performed this all in one session, while the subjects that performed
18 or 27 weekly sets distributed it over two non-consecutive days
a week. Training lasted 6 weeks. 2/3 of the weekly sets were from compound
exercises, with the rest from isolation exercises. Also, 3 minutes of rest between
sets was used in a session. Increases in biceps thickness seem to favor the
group performing 18 weekly sets for the biceps, suggesting this is an optimal
number of weekly sets. Ostrowski et al. had 35 men with between
1-4 years of training experience train their triceps with either
7, 14, or 28 weekly sets. All subjects distributed their weekly sets
over two non-consecutive days per week, and training lasted 10 weeks. 70% of the weekly sets were
from compound exercises, with the remaining 30% from isolation exercises. Also, 3 minutes of rest between
sets was used in a session. Increases in triceps thickness were similar
between the subjects performing 14 and 28 weekly sets, and both were greater than the
subjects performing 7 weekly sets. Therefore, this data suggest 14 weekly sets is sufficient,
with extra sets providing no further benefit. Finally, Aube et al. had 35 men
with at least 3 years of training experience train their quadriceps
with either 12, 18, or 24 weekly sets. All subjects distributed their weekly sets
over two non-consecutive days per week, and training lasted 8 weeks. 100% of the weekly sets were
from compound exercises. Also, 2 minutes of rest between
sets was used in a session. Increases in anterior thigh thickness at two
regions were statistically similar between all three weekly set groups. Indicating
that 12 weekly sets may be sufficient. So, these three studies collectively indicate
that between 12-18 weekly sets may be sufficient, or perhaps even optimal (in the case of the
Heaselgrave et al. study), for building muscle. Why might these 3 studies conflict
with the other 3 studies that suggest more weekly sets result in
more muscle hypertrophy? There are three potential
hypotheses I can think of. Firstly, perhaps individual differences
explain the conflicting results. More specifically, the optimal number of
weekly sets may be highly individualized. The 3 studies that found more sets to be better
might have predominantly recruited subjects that respond favorably to a high number of weekly
sets, while the other 3 studies may not have. To some degree, I think part of this hypothesis
is true. That is, it's probably very likely that certain individuals respond better to a high or
lower number of weekly sets for a muscle group. However, this might not be
the only thing going on, as we'll see with the second and third hypotheses. The second hypothesis, relating to rest intervals, might actually be a very strong hypothesis
that could explain the divergent results. More precisely, the 3 studies that
found more sets to be better seemed to predominantly have subjects rest 60-90
seconds between their sets in a session. Put differently, they used short rest intervals. In contrast, the 3 studies that found 12-18
weekly sets per muscle group to be sufficient or optimal had subjects rest 2-3
minutes between sets in a session. In other words, they used long rest intervals. The reason this is potentially significant
is that the research seems to indicate using long rest intervals makes each set
more effective for building muscle. We've explored this in-depth
in our rest interval video. However, let us briefly detail a study by Longo et
al. that demonstrates this concept extremely well. They found that when performing 3 sets of
repetitions to failure with an 80% one-rep max load on a leg press, resting for 3
minutes between sets produced greater increases in quadriceps cross-sectional area
versus resting for 1 minute between sets. However, when subjects performed 4 to
5 sets of repetitions to failure with an 80% one-rep max load and used
1 minute of rest between sets, quadriceps cross-sectional area increases were
similar to performing 3 sets of repetitions to failure with an 80% one-rep max load and
using 3 minutes of rest between sets. Therefore, this study nicely demonstrates
that longer rest intervals make each set more effective for building muscle. If you
use shorter rest intervals between sets, you have to perform more sets to receive
similar growth to using longer rest intervals. Now, it should be noted that a leg press, a
compound exercise, was used in this study. This conclusion we've just made seems to
be only relevant to compound exercises, the research on rest intervals with
isolation exercises is far from clear. Nevertheless, many compound exercises were
used in the studies explored in this video, and perhaps this logic explains the results. Given longer rest intervals
make each set more effective, it perhaps makes sense that the
3 studies that used longer rest intervals found 12-18 weekly sets per
muscle group to be sufficient or optimal. Conversely, given shorter rest intervals
require you to perform a higher number of sets to receive the equivalent muscle
growth to using longer rest intervals, it makes sense that the three studies that used
short rest intervals found that up to 30 to 45 weekly sets per muscle group provided
more benefit for muscle hypertrophy. Of course, it's important to
recognize this is only a hypothesis. However, I personally believe it's a pretty strong
hypothesis and may indeed explain the results. However, the third hypothesis, relating to training frequency, adds a further
twist to our interpretation of the evidence. The 3 studies that found 12-18 weekly sets to
be sufficient or optimal for building muscle all had subjects distribute their weekly sets
for a muscle group over only 2 days a week. It's possible there could exist a limit
to the number of sets you can perform for a muscle group per session, meaning that the
highest number of set groups in these studies, which we know performed around 24-28 weekly
sets per muscle group, might have experienced more muscle growth if they distributed their
weekly sets across more than two days a week. However, does a limit to the number of sets you can perform for a muscle group
each session actually exist? One factor we might have to consider here is the
one we've just mentioned: rest interval durations. It's likely that if a limit to the number
of sets you can perform per session exists, it would be lower when using longer rest interval
durations compared to using short rest intervals durations, because as we've mentioned, longer
rest intervals make each set more effective. In the three studies that found 30-45 weekly sets
per muscle group produced more muscle growth, we know they used short rest intervals. Moreover, they had subjects distribute their
weekly sets over two to three days each week. In essence, this meant that the subjects
performing 30-45 weekly sets per muscle group were performing 15-16 sets
for a muscle group each session. As the subjects that did this experienced the most
growth compared to others performing fewer sets, we can potentially conclude that performing
15-16 sets per muscle group each session is within any potential limit to the
number of sets you can perform per session for a muscle group when
using shorter rest intervals. However, this information fails
to help us understand what the limit could be when using longer rest intervals. Unfortunately, there are no direct
studies that can help us here. But, there are two studies that
may somewhat give us clues. A study by Ogasawara et al. subjected the
gastrocnemius of rats to sets of 10 electrically induced muscle contractions, using 3 minutes of
rest between sets (which is a long rest interval). They found that muscle protein
synthesis progressively increased up to performing 10 sets of this per session. However, muscle protein synthesis was
less when performing 20 sets per session. As a result, this data potentially suggests
that the limit the number of sets you can perform per muscle group each session when using
longer rest intervals lies between 10-20 sets. Of course, two important limitations of this study
are that rats were used, and only acute muscle protein synthesis measurements, not long-term
muscle growth measurements, were explored. Another study by Damas et al., conducted on
humans, provides potential further insight. They found that when performing 12
sets for the quadriceps in one session, muscle protein synthesis increases seemed to have
only been slightly greater compared to performing 8 sets for the quadriceps in one session.
They used 2-minute rest intervals between sets in this study (which is probably just
about what we'd call a long rest interval). As a result, this data potentially implies, when
using longer rest intervals, performing 12 or more sets per muscle group each session may not result
in much further benefit, indicating this could be near or at the limit to the number of sets
you can perform per muscle group each session. Of course, a limitation is that only acute
muscle protein synthesis measurements, not long-term muscle growth
measurements, were assessed. Nevertheless, returning to the 3 studies that
found 12-18 weekly sets to be sufficient or optimal for building muscle, and used longer rest
intervals, we know that the highest set groups in these studies, performing 24-28 weekly sets,
distributed their sets across 2 days a week. This means they performed roughly 12-14 sets
for a muscle group each session, and this number is potentially at or past the potential limit
indicated by the Ogasawara and Damas studies. Thus, perhaps if they distributed their weekly
sets across 3 or more days a week, they would have experienced more muscle growth than the
other groups performing fewer weekly sets. Of course, it's important to recognize
this is a hypothesis based on limited data. Ultimately, future direct research would be
needed to truly prove if this is correct. Before moving on to the
final section of this video, let us briefly summarize our current
conclusions to make everything crystal clear. For beginners, 9-12 weekly sets per muscle
group is probably near-ideal for them. In more trained individuals, if you
use longer rest intervals between sets (2 or more minutes), the current research
potentially indicates between 12-18 weekly sets could be sufficient for muscle hypertrophy.
However, there remains a possibility that more weekly sets could be better if you distribute
your weekly sets across 3 or more days per week, but this remains a tentative conclusion until
more direct future research explores this. If you use shorter rest intervals between sets
(90 seconds or less), it seems performing up to 30-45 weekly sets per muscle group could be
beneficial, so long as you probably spread this volume across two or more days per week. However,
I'm not too sure how practical this will actually be for most people. Performing 30-45 weekly sets
for your muscle groups is likely going to require a substantial amount of training time. Moreover,
due to the short rest intervals and numerous sets, doing this is likely going to be subjectively
more fatiguing and tiring versus using longer rest intervals and performing fewer sets. If you think
you can handle this, and it's something you'd like to try, go for it. Otherwise, it's probably
best to use longer rest intervals and fewer sets. Moving on to the final section of this
video, for the majority of the viewers that are currently training, there's
a good chance that you probably don't have to change your training based on
the research recommendations presented. Regardless of whether you are above, within,
or below the weekly set recommendations, if you're making progress with
your current training program, there's probably no need to change things. On the other hand, and this is probably one
of the more important sections of this video, if in the future (or now itself) you
experience a plateau in muscle hypertrophy, or you're minimally responding
to your program hypertrophy-wise, you may want to modestly increase the number
of sets you perform for your muscle groups. The reason I say this is because
two studies demonstrate that increasing the number of sets you
perform can probably be effective for spurring on more muscle hypertrophy in
plateaued or low responding individuals. A study by Aube et al., which is one study
we've already overviewed in this video, demonstrates this. As we noted, this study found in men with
at least 3 years of training experience, there was no statistical difference in
anterior thigh growth between performing 12, 18, or 24 weekly sets for the quadriceps. However, after the study, the researchers
did something quite interesting. They split the subjects, based on their results,
into one of three groups: a low responder group, which contained subjects that grew the anterior
thigh the least, a high responder group which contained subjects that grew the anterior thigh
the most, and a moderate responder group which contained subjets that grew the anterior thigh
to an extent between the other two groups. Remember, the subjects of this study had at least 3 years of training experience and were
training before the study took place. Fascinatingly, it seems that those
that grew their anterior thigh the most in the high responder group had
increased their weekly sets by the greatest number relative to what
they were doing before the study. Specifically, they were performing an
average of 6 more weekly sets for the quads. For the moderate responders, they
were performing an average of 4 more sets relative to what they were before
the study, and for the low responders, they were only performing around 1-2 more sets
than what they were doing before the study. Therefore, this study indicates
increasing the number of sets you perform can help further enhance
the muscle growth you experience, and perhaps may be a useful tool to get
past plateaus or aid low responders. Now, in this study, the subjects
experienced the most benefit by increasing the number of sets for a
muscle group by roughly 6 per week. However, larger jumps than this
might not actually be better. Scarpelli et al. illustrates this. They recruited 16 men with at least 2
years of training experience and had them train the unilateral (one-leg)
leg extension and leg press. With one leg, each subject individually performed 20% more weekly sets for their quadriceps
than what they were doing before the study. While with their other leg, all subjects
performed a prescribed number of weekly sets for their quadriceps (this ended
up being roughly 22 weekly sets). After an 8-week training duration, increases
in vastus lateralis cross-sectional area (were significantly greater for the leg that performed
20% more weekly sets for their quadriceps. Put differently, a progressive
increase in weekly sets (20%) seems to be beneficial for muscle growth. Now, here's an important point,
for 8 out of 16 of the subjects, the prescribed number of weekly sets (again,
roughly 22 weekly sets) was actually MORE than 20% of the weekly sets they had been performing
for their quadriceps prior to the study (it ranged from being 30% to 120% more
weekly sets than usual for these subjects). Yet, results still favored the
leg that was only performing 20% more weekly sets. This finding emphasizes
that larger jumps (30-120%) in weekly sets are not necessarily better than more modest 20%
increases in weekly sets for muscle hypertrophy. So, to summarize this final section of the video, if you consider yourself a low responder or
you have plateaued, modestly increasing the number of weekly sets you perform for a muscle
group (perhaps by 20%) may be of great benefit. However, although this conclusion probably
applies to many people, there are likely some individuals out there who contrastingly experience
greater adaptations with lower weekly set numbers. This study had 16 men and 18 women train
the unilateral leg press and leg extension, with a 7-10 rep max load, three
times per week for 12 weeks. With one-leg, subjects trained
each exercise with only one set, resulting in a total of 6 weekly sets for the
quadriceps. With the other leg, they trained each exercise with three sets, resulting in
a total of 18 weekly sets for the quadriceps. Cross-sectional area of the quadriceps
was measured before and after the study. The graph on the screen shows the
individual responses for each participant, with the Y-axis showing the cross-sectional
area increases for the leg that trained each exercise with 3 sets, and the X-axis showing the cross-sectional area increases for the
leg that trained each exercise with 1 set. Quite a few participants demonstrated better
gains when performing 3 sets per exercise, as you'd expect based on the research provided
in this video. However, there were still a few subjects that responded slightly better
with performing one set per exercise. This study nicely underscores the idea that
individual differences without a doubt exist. That brings us to the end of the
video, let us summarize the video into a few key takeaway points
to make everything crystal clear. For beginners, 9-12 weekly sets per muscle group
is probably sufficient for building muscle. In more trained individuals, if you
use long rest intervals between sets (2 or more minutes), 12-18 weekly sets
per muscle group might be sufficient. However, although very tentative at this time,
performing more than this could provide more muscle growth if you distribute your weekly
sets across three or more days per week. If you use short rest intervals between sets
(90 seconds or less), up to 30-45 weekly sets per muscle group could be beneficial for muscle
hypertrophy, provided these sets are distributed across 2 or more days per week. However, this
is probably not practical or sustainable for most people, so perhaps you'd simply want to opt
for using longer rest intervals with fewer sets. For many individuals watching this that
are currently training, so long as you are making progress, you definitely do not
have to change anything based on this video. However, once you hit a plateau, or if
you consider yourself a low responder, you may wish to modestly increase the number
of sets you perform per muscle group each week (probably by 20%), as this could be beneficial. Finally, it's worth remembering
individual differences are real. Some individuals out there might
actually experience better muscle hypertrophy when performing a lower
number of sets per muscle group.