Hypertrophy training manual an evidence based guide to maximise muscle growth (2nd edition)

CREATED BY

FLOW HIGH PERFORMANCE

2ND EDITION

HYPERTROPHY
TRAINING MANUAL
AN EVIDENCE-BASED GUIDE TO MAXIMISE MUSCLE GROWTH


HYPERTROPHY TRAINING MANUAL (2ND EDITION)

CONTENTS
PROXIMITY TO FAILURE

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QUANTIFYING PROXIMITY TO FAILURE

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ACCURACY

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TECHNIQUE

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SET BY SET

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‘ALL OR NOTHING’ PRINCIPLE -

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SIZE PRINCIPLE

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MOTOR UNIT RECRUITMENT

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PROXIMITY TO FAILURE & HYPERTROPHY
FAILURE VS NON-FAILURE

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REP RANGES & LOAD -

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EXERCISE SELECTION -

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MOTOR UNIT RECRUITMENT

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TOO LIGHT & TOO HEAVY -

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COMPOUND VS ISOLATION LIFTS -

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JOINT HEALTH

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VOLUME LOAD

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NUMBER OF SETS

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VOLUME & HYPERTROPHY -

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INDIVIDUAL RESPONSE

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JOINT TOLERANCE

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SYSTEMIC FATIGUE

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PRACTICALITY -

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VOLUME

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QUANTIFYING VOLUME

LIMITING FACTORS -

VOLUME ALLOCATION

FREQUENCY
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FREQUENCY & VOLUME

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DIRECT VS INDIRECT TRAINING

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FREQUENCY & HYPERTROPHY

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INDIRECT INFLUENCE

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VOLUME

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LIFTING PERFORMANCE

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INJURY RISK

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EXERCISE SELECTION

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ANATOMY & BIOMECHANICS

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COMPOUND VS ISOLATION LIFTS -

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COMPOUND LIFTS

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ISOLATION LIFTS

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STIMULUS-TO-FATIGUE RATIO
STIMULUS

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FATIGUE

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MUSCLE RANGE OF MOTION

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MUSCLE LENGTH

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EXERCISE ORDER & HYPERTROPHY

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COMPOUND VS ISOLATION LIFTS

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LARGE VS SMALL MUSCLES

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PRE-EXHAUSTION

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LIFTING PERFORMANCE

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JOINT STRESS -

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STRENGTH GAINS

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TENSION CURVES

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PERSONAL PREFERENCE

EXERCISE ORDER
ACUTE EFFECTS

INDIRECT EFFECTS -

INTERSET REST

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ACUTE EFFECTS

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INTERSET REST & HYPERTROPHY -

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LIFTING PERFORMANCE

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METABOLIC STRESS

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ANABOLIC HORMONES

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PRACTICAL CONSIDERATIONS

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TIME EFFICIENCY

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JOINT STRESS -

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EXERCISE SELECTION -

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REFERENCES

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PROXIMITY TO FAILURE

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QUANTIFYING PROXIMITY TO FAILURE
Proximity to failure in the simplest sense refers to how close a set is taken to failure. This
can be quantified using the Reps in Reserve (RIR) or Rate of Perceived Exertion (RPE)
scales (Table 1.1). These are subjective scales that require trainees to judge how many
reps they could have performed before failure. Therefore, it is a subjective estimation of
proximity to failure and may be influenced by many individual factors. Both scales quantify
proximity to failure in the same way, they are just different numerical systems.
RATE OF PERCEIVED EXERTION (RPE)

REPS IN RESERVE (RIR)

MEANING

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NO MORE REPS COULD HAVE BEEN
PERFORMED

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2 MORE REP COULD HAVE BEEN
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3 MORE REP COULD HAVE BEEN
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4 MORE REP COULD HAVE BEEN
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6 MORE REP COULD HAVE BEEN
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7 MORE REP COULD HAVE BEEN
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PERFORMED

TABLE 1.1: RPE & RIR SCALES

ACCURACY
Several studies have investigated the validity of these scales with all studies finding
positive results. This study (Zourdos et al., 2021) found that when performing the
squat with 70% 1RM to failure, trainees were accurately able to predict repetition
in reserve using the RPE scale. It was also found that as trainees got closer to failure,
repetition in reserve predictions were more accurate. There also seemed to be some

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individual variation in how accurate trainees were able to judge proximity to failure,
which was not related to training experience.
Furthermore, this study (Helms et al., 2017) explored the accuracy of using the
RPE scale in powerlifters performing the squat, bench press, and deadlift. Overall,
trainees could accurately self-select loads to meet a prescribed RPE. It was also
found that the accuracy of these predictions was increased when sets were taken
closer to failure, and when trainees had been using the scale for multiple successive
weeks.
Therefore, the RIR and RPE scales seem to be valid tools to assess proximity to
failure. It also seems that estimations are more accurate as sets are taken closer to
failure, and as trainees accumulate experience using the scales.
TECHNIQUE

Proximity to failure also depends on lifting technique. For hypertrophy training,
trainees generally want to use a technique that maximally stresses the target
muscle, not necessarily the technique that allows us to lift the most weight.
Therefore, if technique deviates, trainees can probably perform more reps or load
compared with strict technique. For example, when a trainee is getting close to
failure in a set of biceps curls with strict form, if they start to swing the weight using
momentum, then they can probably perform more reps than if they kept the
technique strict. This has implications for proximity to failure as it is relative to the
technique used. In other words, trainees should never break their form at the
expense of increasing reps performed.
SET BY SET
Proximity to failure is also independent of each set. This is because workouts are
not performed in a ‘vacuum’ so to speak. One set will induce fatigue, which will
impact the following sets and following exercises. Therefore, performance will likely
decrease from set to set, and throughout the course of a workout.
For example, let’s say a trainee performs three sets of bench press with a load of
70kg and takes each set to a proximity to failure of two reps in reserve. In their first
set, 10 reps may be performed in a fresh state. In the second set, 9 reps may be
performed with the same load with two reps in reserve. In the third set, they may
only perform 8 reps with the same load and same proximity to failure. As the trainee
becomes more fatigued with each set, performance starts to decline (Table 1.2). If
this trainee were to perform 10 reps on each set, they would end up training at a
closer proximity to failure with each successive set.

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TABLE 1.2: PERFORMANCE DECLINE WITH SUBSEQUENT SETS

MOTOR UNIT RECRUITMENT
‘Motor unit’ is a collective term to describe a motor neuron and the muscle fibres that it
innervates. Each muscle generally has multiple thousand muscle fibres and hundreds of
motor neurons. Each motor neuron is responsible for the control and contraction of the
specific muscle fibres that it innervates.
Some muscle fibres are larger and stronger which are often referred to as ‘fast-twitch’ or
‘type 2’ fibres. Other fibres are smaller and weaker but have greater endurance capacity,
which are often referred to as ‘slow-twitch’ or ‘type 1’ fibres. Fast-twitch fibres and their
associated motor neurons are referred to as ‘high-threshold’ motor units, while slow-twitch
fibres and their associated motor neurons are referred to as ‘low-threshold’ motor units.
‘ALL OR NOTHING’ PRINCIPLE
Motor units are recruited based on force requirements. Greater force demands
require more motor units to be innervated, while lower force demands require fewer
motor units to be innervated. The strength of the neural impulse does not change
with the magnitude of force requirements, rather the number of motor units recruited
will be adjusted. This is known as the ‘all or nothing’ principle of motor unit
recruitment.
This has implications for resistance training and hypertrophy adaptations. When a
lighter load is used, a smaller portion of motor units will be recruited since force
demands are lower. When a heavier load is used, a larger portion of motor units will
be recruited since force demands are greater. Therefore, fewer muscle fibres are
initially trained using lighter loads, while more muscle fibres are initially trained using
heavier loads.

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SIZE PRINCIPLE
The order of motor unit recruitment follows what is known as ‘Henneman’s Size
Principle’. According to this research review (Mendell, 2005), the size principle
suggests that low-threshold motor units are always recruited first, while highthreshold motor units are only recruited when required. Therefore, if a submaximal
exercise is performed until exhaustion, only low-threshold motor units will be
recruited initially, and high-threshold motor units will contribute more as the exercise
nears exhaustion. By the end of the exercise bout, all motor units will be recruited
to contribute to force production (Figure 1.1).

FIGURE 1.1: HENNEMAN’S SIZE PRINCIPLE

Concerning resistance training, this determines the amount and type of muscle
fibres that are trained. According to this research review (Duchateau et al., 2006),
all motor units are recruited from the first repetition with loads of approximately
85% 1RM and greater, although this varies between muscles. This means that when
loads are lighter than this approximate threshold, not all muscle fibres will be
involved from the start of the set.
However, this study (Morton et al., 2019) showed similar type-2 muscle activation
when performing leg extension with 30% or 80% 1RM, when sets were taken to
failure. This suggests that although heavier loads will recruit more muscle fibres
initially, all muscle fibres will eventually be recruited and trained when sets are taken
close enough to failure.

PROXIMITY TO FAILURE & HYPERTROPHY
There is no ‘optimal’ proximity to failure trainees should aim to achieve, rather it depends
on several factors.

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FAILURE VS NON-FAILURE
First, is a simple binary decision: should we take sets to complete failure, or should
we leave reps in reserve? This meta-analysis (Grgic et al., 2021) found no
significant difference in muscle growth when comparing training to failure versus
non-failure. Although these results were non-significant, there did seem to be a
slight benefit in favour of training to failure on a set-by-set basis.
When all other variables are equated, training to failure seems to be more
hypertrophic than non-failure training. However, in practice, trainees generally
perform an entire workout in the gym rather than a single exercise. Therefore, the
indirect influence of training to failure on muscle growth should also be considered.
Frequent or inappropriate training to failure may result in excessive fatigue. For
example, training to failure with exercises performed at the beginning of the session
may carry fatigue into the rest of the workout. This may lead to a less productive
training session and may inhibit the performance of subsequent sessions.
REP RANGES & LOAD
How close a set is taken to failure will also depend on the rep ranges and loads
used. According to the principles of motor unit recruitment, heavier loads will involve
more muscle fibres earlier in the set, while lighter loads will only recruit slow-twitch
muscle fibres initially. However, to maximise hypertrophy, all muscle fibres need to
be recruited and trained to induce adaption.
This study (Lasevicius et al., 2019) compared performing leg extensions with
different loads and different proximities to failure. Subjects trained one limb to failure

and the other limb with approximately 3-4 repetitions in reserve. One group of
subjects used a load of 30% 1RM and another group used a load of 80% 1RM. It
was found that training to failure with either load resulted in similar hypertrophy.
Similar hypertrophy was also seen between the limbs using 80% 1RM despite the
difference in proximity to failure. However, the limb training to failure using 30%
1RM saw significantly greater muscle growth than the limb training further from
failure (Figure 1.2). It therefore seems that when training with heavier loads, sets
do not need to be taken as close to failure to elicit significant muscle hypertrophy.
Alternatively, lighter loads probably need to be taken closer to failure to ensure all
muscle fibres are stressed, thus maximising hypertrophy adaptations.

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FIGURE 1.2: CHANGE IN QUADRICEPS CROSS-SECTIONAL AREA (LASEVICIUS ET AL., 2019)

As a result of such outcomes, this research review (Schoenfeld & Grgic, 2019)
suggests that when training in the approximate 6-12 rep range, stopping several
reps before failure doesn’t seem to compromise muscle growth compared with
training to failure. However, when training with lighter loads in the 12-20+ rep
range, sets should be taken between 0-2 reps in reserve to ensure the highest
threshold motor units are recruited.
EXERCISE SELECTION
Certain exercises may be more suited to different proximity to failure ranges. This is
more of a practical consideration, rather than a scientifically based theory.
It is probably more appropriate to train further from failure with heavy, compound,

free-weight lifts that are highly centrally fatiguing. Exercises like squat variations,
weighted pull-ups, military press, and deadlift variations involve many accessory and
stabiliser muscles. This will be more taxing on the cardiovascular and respiratory
systems, and fatigue accessory and stabiliser muscles resulting in greater total
fatigue with each set. Consequently, if sets are taken very close to failure, the
performance of subsequent sets and subsequent exercises may be compromised.
Furthermore, these exercises are generally performed with lower rep ranges and
heavier loads, which means the hypertrophic effect will be similar, even if several
repetitions are left in the tank. For these reasons, it seems more appropriate to train
slightly further from failure with heavy, free-weight, compound exercises.

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In opposition, it seems more appropriate to perform lighter isolation lifts closer to
failure. This is because isolation lifts involve movement of only one joint, and only
one primary muscle is being trained. Therefore, fatigue is localised to the target
muscle, while central fatigue is minimal. Consequently, the target muscle will almost
always be the limiting factor to performance. Furthermore, isolation lifts are generally
performed with higher rep ranges and lighter loads. This means that sets need to
be taken closer to failure to maximise the hypertrophic stimulus. For these reasons,
it seems more appropriate to train slightly closer to failure with lighter isolation
exercises.

PRACTICAL GUIDELINES

• When training in the 6-12 rep range, sets should mostly be taken around 1-3
reps in reserve.
• When training with greater than 12 reps, sets should mostly be taken to around
0-2 reps in reserve.
• Only a small portion of a trainee’s total number of sets should be taken to
failure. These sets should be performed at the end of the session to prevent
reductions in training quality for the rest of the session.
• Training to failure should be mainly performed in isolation exercises rather than
compound lifts, to avoid excessive systemic fatigue.

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REP RANGES & LOAD

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The rep ranges used will determine what loads are used and vice versa. This is because
there is an inverse relationship between the load used and how many reps can be
performed (Figure 2.1). In other words, lighter loads allow higher rep ranges to be used,
while heavier loads limit rep performance potential.

FIGURE 2.1: RELATIONSHIP BETWEEN LOAD LIFTED & REPETITION PERFORMANCE

MOTOR UNIT RECRUITMENT
As previously discussed, motor unit recruitment follows the size principle, where low
threshold muscle fibres are recruited first, and high threshold muscle fibres are recruited
last (see ‘Proximity to Failure’ chapter). It was also established that heavier loads recruit
a higher number of muscle fibres from the start of the set, while lighter loads only exhaust
the high threshold motor units by the end of the set.
With this principle in mind, it seems that a large spectrum of rep ranges can be used for
hypertrophy training since all rep ranges will eventually train all muscle fibres if taken close
enough to failure. This meta-analysis (Schoenfeld et al., 2017) showed that hypertrophy

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can be equally achieved using a spectrum of different rep ranges and loading zones when
sets were taken very close to failure.

TOO LIGHT & TOO HEAVY
It has been established that hypertrophy can be achieved using a large spectrum of rep
ranges and loads, however, is it possible for loads to be too light or too heavy for optimal
hypertrophy gains?
This study (Lasevicius et al., 2018) showed that training with loads of 20% 1RM was not
as effective for muscle growth as heavier loads. However, the subjects who used loads of
20% 1RM performed around 60-70 reps per set on average, making it very impractical to

perform anyway. Therefore, it seems that very light loads may be inferior for muscle growth
compared with moderate and heavier loads.
While it seems that loads can be too light to maximise hypertrophy adaptations, can loads
also be too heavy? This study (Schoenfeld et al., 2016) compared the effects of training
in the 2-4 rep range compared with the traditional 8-12 rep range on hypertrophy
outcomes. With the total number of sets equated, the group training in the 8-12 rep range
saw superior muscle growth. Therefore, it seems that if loads are too heavy, hypertrophy
adaptations may also not be ideal. This could theoretically be because very low rep ranges
may not provide enough total mechanical tension and metabolic stress to fully exhaust the
muscles being trained.

COMPOUND VS ISOLATION LIFTS
The nature of the lift should also be considered when selecting rep ranges and loads.
Compound lifts involve movement of multiple joints and require active contraction of more
total musculature. This increases the likelihood of other systems limiting performance
before the target muscle. The cardiorespiratory system, or accessory and stabiliser muscles
may fatigue before the target muscle. Since higher rep ranges require sets to be taken
close to failure, this may not be achieved with compound lifts. However, during isolation
lifts, the target muscle will almost always be the limiting factor regardless of the rep ranges
employed. This is because there are minimal other muscle groups involved, and the
cardiorespiratory system will not be significantly fatigued. Furthermore, it may be advisable
to limit the load used on isolation lifts because stress will be concentrated on a single joint,
which may increase the risk of pain or irritation over time. Therefore, compound lifts may
be better suited to lower rep ranges, while isolation lifts may be better suited to higher rep
ranges.

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JOINT HEALTH
Another consideration when selecting loads and rep ranges is their effect on joint health.
Anecdotally, heavier loads generally tax the joints to a more significant degree than lighter
loads, meaning that high volumes of heavy load training may cause joint irritation over
time. This is probably due to the higher force demands incurred when using heavier loads,
resulting in greater joint stress. It is therefore important from a longevity standpoint, to
avoid excessive training with heavy loads.

PRACTICAL GUIDELINES

• Train within the rep ranges of around 6-20 with challenging loads to maximise
muscle hypertrophy (Table 2.1).
• Compound lifts may be better suited to the 6-12 rep range, while isolation lifts
may be better suited to the 10-20+ rep range.
• Avoid excessive training with heavy loads to minimise joint stress.

TABLE 2.1: REP RANGES FOR HYPERTROPHY

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VOLUME

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The next variable that will be discussed is training volume. More specifically, the influence
of volume on hypertrophy adaptations will be discussed, and how much volume may be
best to maximise muscle growth.

QUANTIFYING VOLUME
First, volume needs to be defined and quantified. Volume for resistance training is a
measure of how much work we perform over a given period. This is usually measured over
the time course of one microcycle because this is the shortest repeatable cycle in a training
plan. In most cases, the microcycle is one week long, which means volume is generally
measured over the time frame of one week. Two primary methods can be used to quantify
volume for resistance training which we will now cover.
VOLUME LOAD
Volume load is the most accurate definition of work performed and is calculated by
multiplying reps x sets x load x distance that the weight has moved. Volume load
might be a somewhat useful metric for strength training; however, it is probably not
the most useful method to quantify volume for hypertrophy training. This is because
it is clear from scientific research, that hypertrophy can be equally achieved across
a spectrum of different rep ranges and loads, different exercises, and different
techniques. Therefore, volume load won’t provide a metric that can be used to
compare different training strategies, it can only be used to compare the same
training style with itself.
NUMBER OF SETS
It is understood that muscle hypertrophy can be equally achieved using a variety of

training styles. This has led to the development of using number of sets as a method
to quantify volume for hypertrophy training. This systematic review (Baz-Valle et al.,
2021) concluded this is certainly a viable method when sets are taken close to
failure within the 6-20 rep range. Trainees can therefore use the number of sets
performed per muscle group per week as a method to quantify volume. This allows
trainees to compare and manipulate volume using different styles of hypertrophy
training. Therefore, for the rest of this book, volume will refer to the number of sets
performed per muscle group per week.

VOLUME & HYPERTROPHY
The volume-hypertrophy relationship is not completely clear, and more research is required
to further understand how volume influences muscle growth. The most comprehensive
evidence exploring the influence of volume on hypertrophy is this meta-analysis
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(Schoenfeld et al., 2017). This meta-analysis demonstrates a dose-response relationship
between training volume and muscle growth. In other words, the more volume that was
performed, the more muscle growth that was induced. However, this analysis grouped
studies into categories of 5, 5-9, 9+ and 10+ sets per muscle group per week. From a
practical perspective, 10 sets per muscle group per week is generally not considered a
very high training volume in most hypertrophy-based training communities. Therefore, it
should be considered if training with more volume than this would continue this doseresponse relationship.
Since that meta-analysis was published, further research explored the effects of much
higher training volumes. This study (Brigatto et al., 2019) compared the hypertrophic
effects of training with 16, 24, and 32 sets per muscle group per week (Figure 3.1). Like

the initial meta-analysis, a dose-response relationship was found, where more volume
resulted in greater growth at all sites measured.

FIGURE 3.1: CHANGE IN MUSCLE THICKNESS (BRIGATTO ET AL., 2019)

Furthermore, this study (Schoenfeld et al., 2019) compared performing the same program
with different volumes. Subjects were allocated to one of three groups using a low-,
moderate- and high-volume program. In the group that trained with the highest volume,
some muscle groups were trained with up to 45 sets per week. Once again, the same
dose-response relationship was seen, where more volume even up to these extreme levels
resulted in greater muscle growth in all muscles measured.
From the current research, it certainly seems that hypertrophy can be achieved even with
very low volumes, although the more volume that is performed, the more muscle growth
we see.
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INDIVIDUAL RESPONSE
Another factor to consider is the individual response to training volume. While the
research on volume clearly shows that more volume results in greater growth, these
results are presented as average values. Therefore, it seems that the response to
different training volumes may be somewhat individual.
Going back to the study (Schoenfeld et al., 2019) using extremely high training
volumes of up to 45 sets per muscle group, the individual response of each trainee
was presented. In this figure (Figure 3.2) we can see the change in muscle
thickness for the biceps and triceps for each trainee. Each line shows the muscle

thickness from pre- to post-training, for each individual subject. Although we can
see that there are general trends, there is certainly some individual variation in the
growth response. Some trainees saw more growth than others with different
volumes, and some trainees saw decreases in muscle size. This data suggests that
there is likely to be some variation in the individual response to different training
volumes.

FIGURE 3.2: INDIVIDUAL CHANGES IN MUSCLE THICKNESS (SCHOENFELD ET AL., 2019)

One factor influencing this individual response may be the subjects training history.
This interesting study (Scarpelli et al., 2020) explored the effects of increasing
training volume with consideration for prior training history. The subjects performed
different volumes of leg extensions for each limb. One limb was assigned an arbitrary
22 sets per week, while the other limb was trained with an individualised training
volume. This volume was 20% more than whatever training volume they had
previously been training with for the quads. The arbitrary 22 sets were more volume
than some trainees had been previously training with and less for others. However,
for the individualised training limb, the volume performed was slightly more than

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they had been training with for every single individual. Although both training
interventions used a similar average volume, the individualised limb saw significantly
greater muscle growth than the arbitrary 22 sets. This indicates again that
increasing training volume seems to result in greater muscle growth, although

increasing volume relative to prior training history may be more effective.

LIMITING FACTORS
As it seems from the scientific research, more volume appears to result in greater growth,
especially when this increase is relative to training history. However, all these studies use
relatively short-term interventions. Most of them are between 4 to 8 weeks long, and at
maximum 12 weeks long. Furthermore, these results don’t include subjects that dropped
out or any negative consequences of the training intervention. Trainees need to manage
training volume for months and years on end, rather than looking at training in a vacuum
of 4-8 weeks. There are inevitably limitations to how much volume can be performed at
any given point in time.
JOINT TOLERANCE
Ultimately, there is a limit to how much stress each joint can handle over any given
time frame. Training with volumes beyond this threshold will result in joint pain or
irritation in the short term and may result in chronic injury if this stress persists. Joint
tolerance will vary between individuals and between different joints for the same
person based on factors such as anatomical structure, training history, injury history,
perception of pain, exercise selection, and external load.
Furthermore, the acute risk of injury is elevated when we experience sudden
changes in workload. This study (Hulin et al., 2014) found that cricket players who
experienced drastic increases in bowling load in a short timeframe were associated
with higher injury rates. This study (Hulin et al., 2016) found a similar result in
rugby players, where sudden spikes in running workload were associated with
increased injury risk. Furthermore, this same study (Hulin et al., 2016) found that
high chronic workloads were associated with greater resilience to injury. Therefore,
it seems that tissues can adapt over time to tolerate more stress.
Although these studies were not conducted in a resistance training context, the
principles of workload are likely universal to all forms of physical stress. From this
data, we can extrapolate some recommendations for resistance training. First,
trainees should avoid sudden changes in training volume over short timeframes as

this will increase the likelihood of joint pain. Second, tissues can adapt over time to
tolerate more volume. However, no matter how carefully volume is managed, there

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is ultimately a limit to how much stress each tissue can handle each week, and
trainees must stay below this threshold.
SYSTEMIC FATIGUE
The second factor which may limit total volume is systemic fatigue. Systemic fatigue
is a very vague and non-specific concept. This refers to the recovery capacity of the
entire organism, including all forms of stress. Like the principles of joint tolerance,
there is only a finite amount of stress individuals can handle at any given point in
time, and breaching this threshold will have negative health and performance
consequences. Breaching systemic capacity will increase the risk of illness, inhibit
lifting performance, and may have negative effects on hormone regulation and
essential bodily functions. Total workload is one contributor to systemic fatigue, but
other stressors include work stress, family and relationship stress, sleep (or lack
thereof), and other physical activity.
Inevitably, there is a threshold of how much volume each trainee can handle before
breaching this systemic threshold and experiencing negative outcomes. This is
generally something that accumulates over a chronic period rather than an acute
timeframe. This means trainees may be able to handle a certain level of stress for a
short time frame, but it may only result in negative effects after multiple weeks or
months. Like any other human system, our systemic capacity can likely increase
over time, allowing trainees to tolerate greater training stress. This may allow more

volume to be performed over time before breaching the systemic capacity. However,
there is ultimately still a threshold of what is too much and, trainees should avoid
performing so much volume that they breach this capacity.
PRACTICALITY
The last factor that could potentially limit training volume is practicality. This refers
to the constraints of each trainee’s lifestyle. This is influenced by factors such as
time available to train, willingness to train, participating in other forms of exercise,
and personal preference. These constraints may limit how much volume we can
perform in any given week. For example, a trainee may only be able to train 3 times
per week for around one hour due to their lifestyle and preference. Therefore, there
is only so much volume that that can be performed within these time constraints.

VOLUME ALLOCATION
As it is understood, more volume generally results in greater muscle growth, especially
when it is individualised based on training history. However, volume is likely to be limited
by one of three factors previously discussed. Ultimately, there is only a finite amount of
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volume each trainee can perform each week. Therefore, it is recommended that volume is
allocated based on preference. In other words, more volume should be allocated to muscle
groups that the trainee wants to specifically develop, and less volume to muscles that they
aren’t as concerned with developing. These preferences can also be changed over time
based on the individual’s specific goals and rate of progress. As more volume is allocated
to certain muscle groups, they are more likely to experience a faster rate of growth.

PRACTICAL GUIDELINES

• If the goal is to increase volume, trainees should very gradually increase this
over time, avoiding sudden spikes.
• There are multiple factors which are likely to limit our total weekly workload,
including joint tolerance, systemic fatigue, and practical limitations, and trainees
should maximise volume within their own personal constraints.
• Allocate volume based on personal preference, to emphasise certain muscle
groups over others.
• Continuously adjust training over time based on the individual response to
different volumes.

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FREQUENCY
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Training frequency refers to how often a muscle is trained. This is usually quantified as the
number of times a muscle is trained per week since most people follow the same training
split each week. Therefore, for the remainder of this chapter, frequency will refer to the

number of times a muscle is trained per week.

FREQUENCY & VOLUME
When discussing frequency, a major caveat needs to be clarified. When comparing different
training frequencies, it is assumed that volume is equated. More specifically, the total
number of sets must be equated between conditions. This is because it is quite clear that
volume has a significant influence on muscle growth, so changes in volume as a result of
changes in frequency will likely influence hypertrophy outcomes. Therefore, for the
remainder of this chapter, it is assumed that volume is equated between different
frequencies.

DIRECT VS INDIRECT TRAINING
When discussing frequency, it is generally applied to how many times a muscle group is
trained directly. However, it is often the case that muscles can be trained indirectly through
exercises in which the muscle is not a prime mover. The muscle will not be stressed to the
same extent as when it is trained directly, but it may still receive a slight hypertrophy
stimulus. While this is not a significantly important consideration, it should just be
understood that frequency is not a black and white topic. However, for this chapter
frequency will only refer to direct training for each muscle group.

FREQUENCY & HYPERTROPHY
Several studies have investigated the influence of frequency of muscle growth. The latest
meta-analysis on this topic (Schoenfeld et al., 2019) concluded that training frequency
had no significant influence on muscle growth. However, this was under the condition that
volume – as calculated by the number of sets per muscle group – was equated between
frequencies. Therefore it seems that if the same total weekly volume is performed, it
doesn’t make much difference how many times this is distributed throughout the week
(Figure 4.1).

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