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The principle of progressive overload must be adhered to for individuals to continually increase muscle size with resistance training. While the majority of trained individuals adhere to this principle by increasing the number of sets performed per exercise session, this does not appear to be an effective method for increasing muscle size once a given threshold is surpassed. Opposite the numerous studies examining differences in training loads and sets of exercise performed, a few studies have assessed the importance of training frequency with respect to muscle growth, none of which have tested very high frequencies of training (e.g., 7 days a week). The lack of studies examining such frequencies may be related to the American College of Sports Medicine recommendation that trained individuals use split routines allowing at least 48 h of rest between exercises that stress the same muscle groups. Given the attenuated muscle protein synthetic response to resistance exercise present in trained individuals, it can be hypothesized that increasing the training frequency would allow for more frequent elevations in muscle protein synthesis and more time spent in a positive net protein balance. We hypothesize that increasing the training frequency, as opposed to the training load or sets performed, may be a more appropriate strategy for trained individuals to progress a resistance exercise program aimed at increasing muscle size.
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CURRENT OPINION
Frequency: The Overlooked Resistance Training Variable
for Inducing Muscle Hypertrophy?
Scott J. Dankel
1
Kevin T. Mattocks
1
Matthew B. Jessee
1
Samuel L. Buckner
1
J. Grant Mouser
1
Brittany R. Counts
1
Gilberto C. Laurentino
1
Jeremy P. Loenneke
1
ÓSpringer International Publishing Switzerland 2016
Abstract The principle of progressive overload must be
adhered to for individuals to continually increase muscle
size with resistance training. While the majority of trained
individuals adhere to this principle by increasing the
number of sets performed per exercise session, this does
not appear to be an effective method for increasing muscle
size once a given threshold is surpassed. Opposite the
numerous studies examining differences in training loads
and sets of exercise performed, a few studies have assessed
the importance of training frequency with respect to muscle
growth, none of which have tested very high frequencies of
training (e.g., 7 days a week). The lack of studies exam-
ining such frequencies may be related to the American
College of Sports Medicine recommendation that trained
individuals use split routines allowing at least 48 h of rest
between exercises that stress the same muscle groups.
Given the attenuated muscle protein synthetic response to
resistance exercise present in trained individuals, it can be
hypothesized that increasing the training frequency would
allow for more frequent elevations in muscle protein syn-
thesis and more time spent in a positive net protein balance.
We hypothesize that increasing the training frequency, as
opposed to the training load or sets performed, may be a
more appropriate strategy for trained individuals to pro-
gress a resistance exercise program aimed at increasing
muscle size.
Key Points
Individuals are likely completing a volume of
resistance exercise above that which is beneficial for
muscle hypertrophy.
The muscle protein synthetic response to resistance
exercise would seemingly favor higher frequencies
of exercise.
Reducing the training volume and increasing the
frequency may be beneficial for muscle hypertrophy.
1 Introduction
The American College of Sports Medicine recommends
that individuals looking to increase muscle size perform
two to four sets of exercise targeting each muscle group
two to three times per week [1]. It is also recommended
that individuals perform between 8 and 12 repetitions per
set using a load corresponding to C70 % of the individual’s
one-repetition maximum (1RM) [1]. As individuals
become trained and start to adapt to resistance exercise, an
increased stress must be placed on the musculature to allow
the possibility for further muscle growth. This principle of
progressive overload can be adhered to by undertaking one
or more of the following three modifications: (1) increasing
the absolute training load performed for a set number of
repetitions, (2) increasing the number of sets, and/or (3)
increasing the frequency of exercise. It is well known that
increases in muscle size are attenuated with training [25],
with *70 % of muscle growth proposed to occur within
the first several weeks [6]. While part of the attenuated
&Jeremy P. Loenneke
jploenne@olemiss.edu
1
Department of Health, Exercise Science, and Recreation
Management, Kevser Ermin Applied Physiology Laboratory,
The University of Mississippi, P.O. Box 1848, University,
MS 38677, USA
123
Sports Med
DOI 10.1007/s40279-016-0640-8
muscle growth can be attributed to individuals approaching
their genetic potential (i.e., the finite amount of muscle
they can accrue), it may also be partially due to an
increased difficulty of providing a more effective stimulus.
Herein we discuss the current literature examining different
methods of progressive overload and explain why, in our
opinion, increasing the training frequency may be the most
effective way for trained individuals to progress a resis-
tance training program aimed at increasing muscle size.
2 Increasing the Absolute Load
One strategy by which an individual can progress a muscle
hypertrophy-focused training program is to increase the
absolute training load that is lifted for a set number of
repetitions (or maintain a constant absolute training load
and perform more repetitions per set). However, increasing
the absolute training load will become more difficult as
strength gains are attenuated with continued training [7].
Once an individual can no longer increase the absolute
training load while maintaining a similar repetition range,
they must adhere to the principle of progressive overload to
further increase muscle size. This can be done by either
increasing the number of sets performed for each muscle
group or increasing the frequency at which each muscle
group is trained.
3 Increasing the Sets
Individuals can progress a resistance training program by
increasing the number of sets performed for a given muscle
group. While this is commonly referred to as exercise
volume, the reporting of exercise volume has notable lim-
itations in that it is entirely dependent on the absolute and
relative load used. Briefly, muscle growth appears to be
highly dependent on fatiguing the muscle, whereby the
muscle is brought to a point at or near contractile failure to
increase motor unit recruitment/activation [8]. Low-load
protocols require substantially more repetitions to elicit
contractile failure, thus requiring more volume to produce
similar elevations in muscle protein synthesis [9,10] and
muscle hypertrophy [11]. Given that the level of effort to
reach volitional failure, as opposed to fatigue per se,
appears to be primarily driving muscle hypertrophy [8], we
refer to ‘sets of exercise’ rather than ‘exercise volume’ to
account for negligible differences in the reporting of
exercise volume (i.e., lower loads require greater absolute
volume to reach contractile failure [11]).
The American College of Sports Medicine recommends
that more advanced lifters use split routines training one to
three muscle groups per workout to allow for more sets per
muscle group to be completed within a given training
session [1]. In support of this recommendation, the
majority of bodybuilders perform around four sets per
exercise, while performing four different exercises target-
ing each muscle group, thus totaling 16 sets of exercise
targeting a specific muscle group within a single training
session [12]. While increasing the number of sets per-
formed in a given session would adhere to the principle of
progressive overload, there appears to be a point where no
additive benefit (with respect to muscle hypertrophy) is
seen from performing additional sets of exercise within a
given training session. The point at which the anabolic
response is maximized would also appear to be much lower
than what is typically performed by trained individuals
[12]. For example, one acute (short-term) study found no
difference in muscle protein synthesis after performing
three or six sets of resistance exercise [13], and this is
supported by a training study illustrating similar increases
in muscle size upon completing either four sets or eight sets
per training session [14]. Although both of these studies
were performed in untrained individuals [13,14], similar
increases in muscle size have been observed comparing
one, two, or four sets of exercise per training session over
10 weeks in trained individuals [15].
Although a meta-analysis supports the efficacy of
greater exercise volume [16], considerable heterogeneity
was present in the studies included for analysis [17], and
the only significant difference was observed when com-
paring one set with three sets. Even if a small difference
exists between one and three sets of exercise, there is likely
a threshold whereby increasing the sets of exercise per-
formed per muscle group within a given training session
does not necessarily provide greater muscle growth [18].
Specifically, this point of diminishing returns would likely
be much lower than what is typically performed by trained
individuals looking to increase muscle size (16 sets) [12].
This may be analogous to protein consumption where 10 g
of protein may be better than 5 g for muscle growth, but
consuming 80 g is not necessarily better for muscle growth
than consuming 40 g [19]. For this reason, increasing the
number of sets performed in a given training session may
simply prolong fatigue without providing a greater increase
in muscle size.
4 The Case for Frequency
Few studies have examined the efficacy of high-frequency
training, which may be in part related to the American
College of Sports Medicine’s recommendation that indi-
viduals rest at least 48 h between training similar muscle
groups [1]. This recommendation may also explain why
68 % of bodybuilders report only training a specific muscle
S. J. Dankel et al.
123
group once per week [12], and none of the 127 that were
sampled reported training a specific muscle group more
than twice per week [12]. It is also likely that the longer
recovery periods are necessary to allow sufficient recovery
from the previous bout of exercise, given that the average
bodybuilder performs 16 sets of exercise targeting a
specific muscle group within a given training session [12].
In response to resistance exercise, individuals undergo
an elevated muscle protein synthetic response that lasts at
least 24 [20], 36 [21], or 48 [22] h post-exercise. The
magnitude and duration of the elevated protein synthetic
response appears to be blunted in trained individuals [23].
Therefore, given that a relatively low number of sets (i.e.,
four sets to volitional failure) may be sufficient to elicit a
large increase in protein synthesis for up to 24 h post-
exercise [20], performing fewer sets may be more effective
at reducing prolonged fatigue and allowing the same
muscle group to be trained more frequently. The more
repetitive stimuli would hypothetically result in a greater
time spent in a net-positive protein balance, and it can
therefore be hypothesized that trained individuals may see
greater benefits in muscle growth by keeping the same
number of sets performed per week but simply dispersing
them over a greater number of training sessions (Fig. 1).
This would allow for the avoidance of ‘wasted sets’ in
terms of muscle hypertrophy, while also allowing for a
hypothetical refractory period to pass before additional
exercise is performed. While hypothetical, this refractory
period may work in a similar manner to that of nutrition-
induced muscle protein synthesis [24], whereby a certain
time period must elapse before the muscle protein synthetic
response from resistance exercise can be re-stimulated.
However, this refractory period may be relatively short and
may even be overcome within a 24-h window [25].
Increasing the training frequency may be somewhat less
effective for untrained individuals given the longer dura-
tion for which muscle protein synthesis is elevated post-
exercise (Fig. 2). Nonetheless, for trained individuals, it
would likely be beneficial to progressively increase the
training frequency from one to two times a week to two to
three times a week in which the same muscle groups are
stressed. As individuals become accustomed to training the
same muscle group at higher frequencies, it may be ben-
eficial to perform full-body routines daily, or every other
day, depending on how individuals recover from exercise.
5 Previous Studies Assessing Training Frequency
A review paper demonstrated that the increase in muscle
size per training session (*0.15 %) does not differ
depending on whether high or low frequencies are
employed [26]. Therefore, individuals who train more
frequently would likely observe larger increases in muscle
mass over the same time period given that more training
sessions can be performed. However, this review [26] was
not designed to examine the importance of training fre-
quency as all other training variables were not held con-
stant. Another recent meta-analysis concluded that volume-
equated resistance training dispersed over two sessions per
week was more effective than performing a larger volume
in one session [27]; however, the analysis included insuf-
ficient studies to enable evaluation of training frequencies
greater than twice per week. To our knowledge, only three
studies have set out to directly assess the importance of
training frequency while using a direct measure of muscle
size. One study assessed trained individuals targeting the
same muscle groups once versus three times per week [28]
and noted a general trend toward greater muscle growth
among those training three times a week. However, the
results from this study were somewhat inconclusive as the
only significant difference was noted in a muscle group that
was not directly trained (i.e., biceps brachii). Another study
assessing female athletes illustrated greater increases in
muscle size when the total resistance training volume was
split into two sessions per day as opposed to one [25]. It
was likely that the group training twice a day avoided
performing ‘wasted sets’ as described in Fig. 1and was
able to re-stimulate muscle protein synthesis after it
quickly returned to baseline, as is the case in trained
individuals. A similar study comparing the same training
volume over one or two sessions per week found no dif-
ferences in muscle size [29]; however, this study assessed
untrained males, and may differ for reasons mentioned in
Fig. 2. Despite two of these studies supporting our
hypothesis, the vast majority of studies assessing training
frequency have focused specifically on strength adapta-
tions, whereas those providing a measure of muscle size
have been limited to indirect measures of total lean mass
(e.g., skinfold measurements, whole body dual-energy
X-ray absorptiometry) [3034].
6 Decreasing the Training Frequency
Although increasing the training frequency may provide
greater muscle growth, it may be difficult to increase the
training frequency beyond a certain point. We propose that
once an individual has been training at a higher frequency
for a sufficient duration (e.g., 16 weeks), it may then be
beneficial to decrease the training frequency for a period of
time (e.g., 24 weeks). A previous study [35] demonstrated
that the muscle mass gained following 16 weeks of training
(nine sets per session three times per week) was maintained
after drastically reducing the exercise stimulus for an
additional 32 weeks (three sets per session once per week).
Frequency of Training for Muscle Hypertrophy
123
Therefore, once an individual increases the training fre-
quency and hypothetically increases muscle mass over a
period of time, he/she may then be able to reduce the
training frequency while still maintaining the added muscle
mass. While also hypothetical, this may allow for the
down-regulation of metabolic brakes [36] and the re-sen-
sitization of the muscle to the anabolic stimulus [37],
whereby an individual may then benefit from increasing the
training frequency again for reasons previously mentioned.
Some support for this hypothesis may exist in that the
rebounding of muscle hypertrophy following detraining is
such that no differences were observed when comparing
24 weeks of continuous training with another group per-
forming cycles of 6 weeks of training followed by 3 weeks
of detraining [38]. Even if this hypothesis is correct, there
would inevitably come a point where an individual can no
longer increase muscle mass as he/she has reached his/her
genetic ceiling.
7 Limitations of this Hypothesis
While increasing the training frequency would hypotheti-
cally allow for more frequent elevations in muscle protein
synthesis, the body would likely adapt, forcing a further
increase in training frequency to produce greater muscle
growth. Even so, many trained individuals are not training
the same muscle groups at high frequencies [12]; thus, this
Fig. 1 a Hypothetical protein
synthetic response to two
different exercise protocols with
the same number of sets
performed per week.
Performing fewer sets per
session at a higher frequency
will likely be sufficient for
increasing muscle size while
also limiting fatigue to allow for
higher frequencies and thus
more frequent stimulations of
muscle protein synthesis.
Performing more sets per
session while using a lower
training frequency may reduce
the time spent in a positive net
protein balance because the
large number of sets performed
within a given session may
exceed the ‘anabolic limit’,
resulting in wasted sets.
Additionally, performing more
sets within a given session
requires greater recovery time,
causing muscle protein
synthesis to return to basal
levels until re-stimulated again
during another training session.
bDemonstration of the greater
anabolic potential during each
protocol. No shading in the area
under the curve illustrates a
similar anabolic potential
between both frequencies. The
difference in the area under the
curve between protocols can be
attributed to the ‘wasted sets’
completed above the volume
threshold during the twice-
weekly protocol. AUC area
under the curve
S. J. Dankel et al.
123
would likely be the most beneficial way to further progress
a training program aimed at increasing muscle size.
Additionally, this hypothesis is based largely on the muscle
protein synthetic response to resistance exercise, which
does not always correlate well with long-term changes in
muscle size [39], nor does it take into account changes in
muscle protein breakdown. Even so, acute changes in
muscle protein synthesis would appear to be the primary
driver of muscle growth from resistance training in humans
[40,41], and the lack of a correlation between muscle
protein synthesis and muscle size may simply be due to the
‘snapshot’-specific nature of how muscle protein synthesis
is measured (i.e., muscle biopsies). Nonetheless, an
increase in muscle size would need to occur through the
accretion of new proteins, and would likely correlate well
with muscle growth if measured over time [42], making the
acute marker of muscle protein synthesis at least somewhat
indicative of the efficacy of a resistance exercise protocol.
8 Future Research Questions
The hypothesis that increasing training frequency, rather
than training load or sets performed, may be a more
effective strategy for trained individuals to increase muscle
size opens an avenue for future research to test whether
increased training frequency does indeed result in greater
muscle hypertrophy. Future studies may seek to compare
two groups of trained individuals performing at markedly
different training frequencies (e.g., 1 vs. 6 days per week)
while equating the total number of sets performed to
volitional failure. While this type of study design would
oppose the recommendation of resting at least 48 h
between exercises of the same muscle group [1], we have
unpublished data suggesting that even three sets of exercise
per day, for 21 straight days, elicited no signs of over-
training in previously trained individuals. By using a direct
measure of muscle size (e.g., ultrasound, magnetic
Fig. 2 Hypothetical depiction of muscle anabolism illustrating why
increasing the training frequency may be more beneficial in trained
individuals. aTrained and untrained individuals performing the same
frequency of exercise. (b) Depiction of where the area under the curve
favors trained or untrained individuals. No shading illustrates a
similar anabolic potential between trained and untrained individuals.
Notably, untrained individuals demonstrate longer durations in which
the muscle is primed for anabolism. cUntrained individuals training
the same muscle groups with different frequencies. dDepiction of
where the area under the curve favors higher frequency. No shading
under the curve illustrates similar anabolic potential between low and
high frequencies. Increasing the training frequency is of less
importance in untrained individuals because the muscle is still primed
for greater anabolism as a result of the previous bout. AUC area under
the curve
Frequency of Training for Muscle Hypertrophy
123
resonance imaging), the two groups can then be compared
and any differences in muscle size could be attributed to
differences in training frequencies. To test whether a
muscle could then be re-sensitized to the anabolic stimulus,
the high-frequency group could then be split into two
groups, one of which continues training at a high frequency
while the other reduces the frequency for a short period in
an attempt to sensitize the muscle to the reintroduction of
high-frequency training.
Future studies may also be designed to compare differ-
ent exercise volumes to more closely detail the specific
point at which the anabolic potential of a given training
session has been reached. While a previous meta-analysis
was only able to assess one set versus three sets [16],
previous research in trained individuals found no differ-
ence between performing one, two, or four sets [15]of
exercise within a single training session. Thus, the specific
point at which performing more volume is not more
advantageous for muscle growth has not been determined
and may be exercise specific. For example, compound
movements may require additional sets to fully activate the
muscles of interest (e.g., bench press vs. triceps
extensions).
9 Conclusion
While the majority of studies within the resistance training
literature focus on increasing the sets of exercise to pro-
duce greater adaptations in muscle size, it is our opinion
that it is likely more beneficial to increase the training
frequency. Contrary to the American College of Sports
Medicine recommendations that trained individuals use
split routines to perform more sets of exercise within a
given training session [1], we feel that trained individuals
should train similar muscle groups more frequently while
reducing the number of sets performed in a given training
session. This hypothesis is made based on previous
research demonstrating that (1) increasing the number of
sets beyond a certain point has negligible effects on muscle
hypertrophy given the relatively low volume that appears
to maximally stimulate muscle protein synthesis; and (2)
the duration of the time period when muscle protein syn-
thesis is elevated in trained individuals appears to be
shortened.
Compliance with Ethical Standards
Funding No sources of funding were used to assist in the preparation
of this article.
Conflict of interest Scott Dankel, Kevin Mattocks, Matthew Jessee,
Samuel Buckner, J. Grant Mouser, Brittany Counts, Gilberto
Laurentino, and Jeremy Loenneke have no conflicts of interest rele-
vant to the content of this review.
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Frequency of Training for Muscle Hypertrophy
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... Training frequency is an often overlooked variable of exercise prescription [23]. While studies and systematic reviews have been conducted on RT frequency [24][25][26][27][28], current recommendations for improving muscular adaptation are based on inferences from a limited body of evidence with inherent major limitations that makes the interpretation and applicability of results difficult to implement, such as small sample sizes [26,27,29]. ...
... Additionally, the use of MQ as a main outcome measure of analysis, rather than just strictly muscle strength and/or mass, is an asset given the lack of overall attention and results to this important predictor of function in young populations in previous research [1]. Finally, the presentation of training frequency as an important variable of the exercise prescription is a strength given the fact that this variable has been previously recognized as an often overlooked component of the RT prescription [23]. ...
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Previous research has established the role of resistance training (RT) on muscle function in adolescents, but a lack of evidence to optimize RT for enhancing muscle quality (MQ) exists. This study examined whether RT frequency is associated with MQ in a nationally representative adolescent cohort. A total of 605 adolescents (12–15 year) in NHANES were stratified based on RT frequency. MQ was calculated as combined handgrip strength divided by arm lean mass (via dual-energy X-ray absorptiometry). Analysis of covariance was adjusted for sex, race/ethnicity, and arm fat percentage; p < 0.05 was considered significant. RT frequency was associated with MQ for 2–7 day/week but not 1 day/week. When no RT was compared to 1–2 and 3–7 day/week, associations were present for 3–7 day/week but not 1–2 day/week. When comparing no RT to 1–4 and 5–7 days/week, associations existed for 5–7 day/week but not 1–4 day/week. Next, no RT was compared to 1, 2–3, and 4–7 day/week; associations were found for 4–7 day/week, while 2–3 days/wk had a borderline association (p = 0.06); there were no associations for 1 day/week. Finally, no RT was compared to 1, 2, 3, 4, and 5–7 day/week; associations were present for all except 1 and 3 day/week. These prospective data suggest a minimum RT frequency of 2 day/week is associated with MQ in adolescents as indicated by the lack of differences in MQ between 1 day/week RT versus no RT.
... For FB, weekly training volume ranged from 22,771 (20,855,24,687) kg to 31,348 (29,433, 33,265), with the lowest training volume noted during week 1 and the highest in week 7. For SPLIT, weekly training volume ranged from 23,543 (21,345,25,741) kg to 32,215 (30,017,34,412) kg, with the lowest training volume noted during week 1 and the highest in week 8. Figure 3 provides a complete illustration of weekly training volume throughout the intervention. ...
... Conceivably, training frequency may become more important when people gain experience in resistance training. Second, it is possible that a longer intervention with a higher total training volume could have resulted in different findings [34]. Usually, split-routines is a strategy to increase weekly training volume [5,6], and it is conceivable that the volume we employed was insufficient to achieve desired benefits. ...
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Background The aim of this study was to assess the efficacy of a 12-week upper/lower split- versus a full-body resistance training program on maximal strength, muscle mass and explosive characteristics. Fifty resistance untrained women were pair-matched according to baseline strength and randomized to either a full-body (FB) routine that trained all of the major muscle groups in one session twice per week, or a split-body program (SPLIT) that performed 4 weekly sessions (2 upper body and 2 lower body). Both groups performed the same exercises and weekly number of sets and repetitions. Each exercise was performed with three sets and 8–12 repetition maximum (RM) loading. Study outcomes included maximal strength, muscle mass, jump height and maximal power output. Results No between-group differences were found in any of the variables. However, both FB and SPLIT increased mean 1-RM from pre- to post-test in the bench press by 25.5% versus 30.0%, lat pulldown by 27.2% versus 26.0% and leg press by 29.2% versus 28.3%, respectively. Moreover, both FB and SPLIT increased jump height by 12.5% versus 12.5%, upper-body power by 20.3% versus 16.7% and muscle mass by 1.9% versus 1.7%, p < 0.01, respectively. Conclusions This study did not show any benefits for split-body resistance-training program compared to full-body resistance training program on measures of maximal- and explosive muscle strength, and muscle mass. Trial registration : ISRCTN81548172, registered 15. February 2022.
... The initial hypothesis was based on the idea that long periods without variation in training loads can result in fatigue and stagnation in training adaptations (12,39). Therefore, as the individual adapts to the training stimulus, an increase in stress must be provided to allow the optimization of adaptations (8). The principle of progressive overload, which will generate an increase in training stress, can be achieved in three ways (8): by increasing the training session volume (number of sets or repetitions); an increase in weekly frequency of exercises; or by increasing the load intensity for a training volume. ...
... Therefore, as the individual adapts to the training stimulus, an increase in stress must be provided to allow the optimization of adaptations (8). The principle of progressive overload, which will generate an increase in training stress, can be achieved in three ways (8): by increasing the training session volume (number of sets or repetitions); an increase in weekly frequency of exercises; or by increasing the load intensity for a training volume. In the present study, the progression of the training load occurred by increasing the load intensity, providing a greater variation in training stimuli, which may lead to greater adaptations. ...
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The purpose of this study was to compare a periodized versus a non-periodized protocol of kettlebell (KTB) swings over six weeks on strength, power, and muscular endurance. Twenty-eight high intensity functional training (HIFT) practitioners were assigned to non-periodized (NPG = 11), periodized (PG = 11), or control groups (CG = 6). NPG used the same load (20 kg) throughout the training period while the PG used a step loading progression (with an added four kilograms every two weeks). Measures of strength and muscular endurance in the deadlift exercise, and power in the countermovement jump were assessed before and after six weeks. A two-way ANOVA was used to verify pre-to post-test differences in strength, power, and muscular endurance. An analysis of the effect size was also incorporated. For strength and power, statistical differences from pre-to post-test were found for both the NPG (p < 0.001; 1-RM improvement = 8.7%; jump height improvement = 8.7%) and PG (p < 0.001; 1-RM improvement = 7.8%; jump height improvement = 10.1%), with no difference between groups. For muscular endurance, only the PG showed significant differences from pre-to post-test (p = 0.013; muscular endurance improvement = 23.8%). In conclusion, when the goal is to increase strength and power performances in HIFT practitioners, periodized and non-periodized KTB models appear to be equally effective, and this can simplify the strength coach's practice in programming KTB swing training periods. For muscular endurance, the addition of KTB swing on a periodized basis seems to be a more effective strategy.
... Generally, RT-frequency refers to how many times a given muscle is stimulated on a weekly basis (52). Increasing training frequency is usually adopted to accumulate a large VL for a specific muscle group, which, in turn, would induce higher magnitudes of strength and hypertrophy adaptations (26). Although a meaningful number of studies has investigated the effects of manipulating RT-frequency, specific recommendations regarding this variable must be done with some caution, especially because of methodological differences between them. ...
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International Journal of Exercise Science 15(4): 910-933, 2022. The regular practice of resistance training (RT) has been shown to induce relevant increases in both muscle strength and size. In order to maximize these adaptations, the proper manipulation of RT variables is warranted. In this sense, the aim of the present study was to review the available literature that has examined the application of the acute training variables and their influence on strength and morphological adaptations of healthy young adults. The information presented in this study may represent a relevant approach to proper training design. Therefore, strength and conditioning coaches may acquire a fundamental understanding of RT-variables and the relevance of their practical application within exercise prescription.
... Generally, RT-frequency refers to how many times a given muscle is stimulated on a weekly basis (52). Increasing training frequency is usually adopted to accumulate a large VL for a specific muscle group, which, in turn, would induce higher magnitudes of strength and hypertrophy adaptations (26). Although a meaningful number of studies has investigated the effects of manipulating RT-frequency, specific recommendations regarding this variable must be done with some caution, especially because of methodological differences between them. ...
Article
Full-text available
International Journal of Exercise Science 15(4): X-Y, 2022. The regular practice of resistance training (RT) has been shown to induce relevant increases in both muscle strength and size. In order to maximize these adaptations, the proper manipulation of RT variables is warranted. In this sense, the aim of the present study was to review the available literature that has examined the application of the acute training variables and their influence on strength and morphological adaptations of healthy young adults. The information presented in this study may represent a relevant approach to proper training design. Therefore, strength and conditioning coaches may acquire a fundamental understanding of RT-variables and the relevance of their practical application within exercise prescription.
... Increases in both muscle strength and size (i.e. hypertrophy) are considered specific adaptations of resistance training (RT), which may be enhanced by the proper manipulation of training variables, such as training frequency [1]. Generally, RT frequency refers to the number of sessions performed during a specific period, usually described on a weekly basis. ...
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The purpose of this study was to investigate the chronic effects of training each muscle group through a split-body routine on 2 versus 3 days per week on muscle strength and morphological adaptations in recreationally resistance-trained men with the number of sets per muscle group equated between conditions. Twenty healthy men (28.8 ± 6.1 years [range 19 to 37 years]; 172.8 ± 5.1 cm; total body mass = 70.2 ± 7.4 kg; RT experience = 3.5 ± 0.8 years [range 2 to 5 years]; RT frequency = 4.4 ± 0.5 session·wk-1) volunteered to participate in this study. Subjects were randomly assigned into 2 experimental groups: 2 sessions·wk-1 per muscle (G2x, n = 10), in which every muscle was trained twice a week with 9 sets/session, or 3 sessions·wk-1 per muscle (G3x, n = 10), in which every muscle was trained thrice a week with 6 sets/session. All other variables were held constant over the 8-week study period (training intensity: 8-12 maximum repetitions; rest intervals: 60 seconds between sets). No significant difference between conditions was observed for maximal strength in the back squat (G2x: ∆ = 51.5%; G3x: ∆ = 56.3%, p = 0.337) and bench press (G2x: ∆ = 15.4%; G3x: ∆ = 20.5%, p = 0.756), muscle thickness of the biceps brachii (G2x: ∆ = 6.9%; G3x: ∆ = 8.9%, p = 0.495), triceps brachii (G2x: ∆ = 8.4%; G3x: ∆ = 15.7%, p = 0.186), vastus lateralis (G2x: ∆ = 11.2%; G3x: ∆ = 5.0%, p = 0.082 and anterior quadriceps (rectus femoris and vastus intermedius) (G2x: ∆ = 12.1%; G3x: ∆ = 21.0%, p = 0.102). In conclusion, both G2x and G3x can result in significant increases in muscle strength and size in recreationally trained men.
... Thus, the advantages of higher training frequencies may increase with training status. Further, it has been suggested that distributing training volume across several days may reduce fatigue during the sessions (Dankel et al., 2016) and reduce recovery time between sessions (Pareja-Blanco et al., 2020). This may allow for greater training loads, potentially resulting in superior muscular adaptations to resistance training. ...
Article
Background: Postural balance represents a fundamental movement skill for the successful performance of everyday and sport-related activities. There is ample evidence on the effectiveness of balance training on balance performance in athletic and non-athletic population. However, less is known on potential transfer effects of other training types, such as plyometric jump training (PJT) on measures of balance. Given that PJT is a highly dynamic exercise mode with various forms of jump-landing tasks, high levels of postural control are needed to successfully perform PJT exercises. Accordingly, PJT has the potential to not only improve measures of muscle strength and power but also balance. Objective: To systematically review and synthetize evidence from randomized and non-randomized controlled trials regarding the effects of PJT on measures of balance in apparently healthy participants. Methods: Systematic literature searches were performed in the electronic databases PubMed, Web of Science, and SCOPUS. A PICOS approach was applied to define inclusion criteria, (i) apparently healthy participants, with no restrictions on their fitness level, sex, or age, (ii) a PJT program, (iii) active controls (any sport-related activity) or specific active controls (a specific exercise type such as balance training), (iv) assessment of dynamic, static balance pre- and post-PJT, (v) randomized controlled trials and controlled trials. The methodological quality of studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. This meta-analysis was computed using the inverse variance random-effects model. The significance level was set at p < 0.05. Results: The initial search retrieved 8,251 plus 23 records identified through other sources. Forty-two articles met our inclusion criteria for qualitative and 38 for quantitative analysis (1,806 participants [990 males, 816 females], age range 9–63 years). PJT interventions lasted between 4 and 36 weeks. The median PEDro score was 6 and no study had low methodological quality (�3). The analysis revealed significant small effects of PJT on overall (dynamic and static) balance (ES = 0.46; 95% CI = 0.32–0.61; p < 0.001), dynamic (e.g., Y-balance test) balance (ES = 0.50; 95% CI = 0.30–0.71; p < 0.001), and static (e.g., flamingo balance test) balance (ES = 0.49; 95% CI = 0.31–0.67; p<0.001). The moderator analyses revealed that sex and/or age did not moderate balance performance outcomes. When PJT was compared to specific active controls (i.e., participants undergoing balance training, whole body vibration training, resistance training), both PJT and alternative training methods showed similar effects on overall (dynamic and static) balance (p = 0.534). Specifically, when PJT was compared to balance training, both training types showed similar effects on overall (dynamic and static) balance (p = 0.514). Conclusion: Compared to active controls, PJT showed small effects on overall balance, dynamic and static balance. Additionally, PJT produced similar balance improvements compared to other training types (i.e., balance training). Although PJT is widely used in athletic and recreational sport settings to improve athletes’ physical fitness (e.g., jumping; sprinting), our systematic review with meta-analysis is novel in as much as it indicates that PJT also improves balance performance. The observed PJT-related balance enhancements were irrespective of sex and participants’ age. Therefore, PJT appears to be an adequate training regime to improve balance in both, athletic and recreational settings.
... Thus, the advantages of higher training frequencies may increase with training status. Further, it has been suggested that distributing training volume across several days may reduce fatigue during the sessions (Dankel et al., 2016) and reduce recovery time between sessions (Pareja-Blanco et al., 2020). This may allow for greater training loads, potentially resulting in superior muscular adaptations to resistance training. ...
Article
Studies comparing children and adolescents from different periods have shown that physical activity and fitness decreased in the last decades, which might have important adverse health consequences such as body fat gain and poor metabolic health. The purpose of the current article is to present the benefits of high-intensity multimodal training (HIMT), such as CrossFit, to young people, with a critical discussion about its potential benefits and concerns. During HIMT, exercise professionals might have an opportunity to promote positive changes in physical function and body composition in children and adolescents, as well as to promote improvements in mental health and psychosocial aspects. Moreover, this might serve as an opportunity to educate them about the benefits of a healthy lifestyle and overcome the perceived barriers for being physically active. In technical terms, the characteristics of HIMT, such as, the simultaneous development of many physical capacities and diversity of movement skills and exercise modalities might be particularly interesting for training young people. Many concerns like an increased risk of injury and insufficient recovery might be easily addressed and not become a relevant problem for this group.
... It was already proved that power production in stable conditions is different from the power that is produced in unstable conditions [58]. Plus, training in unstable conditions result in a load decrement compared to training in stable conditions [59] and, for this reason, the back squat is a good exercise to apply the progressive overload principle to continually increase muscle size with resistance training [60]. Moreover, the back squat is an exercise that is performed in the sagittal plane while the act of skating is performed more on the frontal plane and there must be a specific strength program regarding the movement patterns that must be developed to notice any force-vector transference effect. ...
Article
Objectives The purposes of this review are: (i) to summarize the scientific literature regarding the anthropometric profile of artistic roller and figure skaters by skating discipline, skating level and gender; (ii) to summarize the scientific literature regarding the physical qualities of artistic roller and figure skaters by skating discipline, skating level and gender to provide relevant recommendations for both coaches and practitioners. News The analysis of the current literature demonstrates that elite skaters have high levels of aerobic power, agility, and strength compared to their non-elite counterparts. Moreover, elite skaters have significant asymmetries between limbs that might result in future injuries. Male skaters that participate in pairs disciplines have greater anthropometric measurements such as body mass, body height and arm span compared to those that participate in single disciplines. Freestyle skaters jump higher and have better levels of agility than synchronized skaters. Freestyle skaters and pairs skaters are amongst those who have better levels of flexibility. Prospects and projects This study is a narrative review which analyzed studies that investigated how body composition and physical qualities affect sports performance in artistic roller and figure skaters, based on their skating level and skating discipline. Conclusion This review can be a useful tool for coaches because it can help them to identify athletes with relevant morphological characteristics for any discipline of the artistic roller and figure skating. Furthermore, this review can help coaches build specific strength and conditioning programs for artistic skaters bearing in mind the athletes’ discipline and their level.
Article
The purpose of this study was to calculate the effects of exercise programs on phase angle (PhA) in older people. A systematic review was undertaken in multiple electronic databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement guidelines for the purposes of selecting randomized controlled trials that measured the effects of the exercise programs on PhA in older adults on 31 March 2022. We carried out a random-effect meta-analysis for the effects of exercise programs on PhA. Additionally, we analysed the differences between subgroups in terms of weekly frequency, number of sets and repetitions, and duration of interventions. Studies were methodological assessed through the PEDro scale where one had excellent, ten had good, and three had poor methodological quality. For the purposes of the study, fourteen studies met the criteria for inclusion. However, four studies did not have enough information to be included in the quantitative analysis. The remaining ten articles revealed moderate effects on PhA in favour of intervention groups (p=0.009, SMD=0.72 [0.46–0.99], I²=54%). The meta-analysis also showed that interventions lasting twelve weeks are more successful in generating positive effects on PhA as opposed to eight weeks (SMD's=0.79 vs. 0.64, respectively). These results indicate that resistance training (RT) is an effective and safe to improve PhA in the older people, especially through RT programs lasting from eight to twelve weeks. A novel finding of this study was that RT is the most used type of exercise by authors when assessing the PhA in older adults.
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Background A number of resistance training (RT) program variables can be manipulated to maximize muscular hypertrophy. One variable of primary interest in this regard is RT frequency. Frequency can refer to the number of resistance training sessions performed in a given period of time, as well as to the number of times a specific muscle group is trained over a given period of time. Objective We conducted a systematic review and meta-analysis to determine the effects of resistance training frequency on hypertrophic outcomes. Methods Studies were deemed eligible for inclusion if they met the following criteria: (1) were an experimental trial published in an English-language refereed journal; (2) directly compared different weekly resistance training frequencies in traditional dynamic exercise using coupled concentric and eccentric actions; (3) measured morphologic changes via biopsy, imaging, circumference, and/or densitometry; (4) had a minimum duration of 4 weeks; and (5) used human participants without chronic disease or injury. A total of ten studies were identified that investigated RT frequency in accordance with the criteria outlined. Results Analysis using binary frequency as a predictor variable revealed a significant impact of training frequency on hypertrophy effect size (P = 0.002), with higher frequency being associated with a greater effect size than lower frequency (0.49 ± 0.08 vs. 0.30 ± 0.07, respectively). Statistical analyses of studies investigating training session frequency when groups are matched for frequency of training per muscle group could not be carried out and reliable estimates could not be generated due to inadequate sample size. Conclusions When comparing studies that investigated training muscle groups between 1 to 3 days per week on a volume-equated basis, the current body of evidence indicates that frequencies of training twice a week promote superior hypertrophic outcomes to once a week. It can therefore be inferred that the major muscle groups should be trained at least twice a week to maximize muscle growth; whether training a muscle group three times per week is superior to a twice-per-week protocol remains to be determined.
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Skeletal muscle mass is regulated by a balance between muscle protein synthesis (MPS) and muscle protein breakdown (MPB). In healthy humans, MPS is more sensitive (varying 4-5 times more than MPB) to changes in protein feeding and loading rendering it the primary locus determining gains in muscle mass. Performing resistance exercise (RE) followed by the consumption of protein results in an augmentation of MPS and, over time, can lead to muscle hypertrophy. The magnitude of the RE-induced increase in MPS is dictated by a variety of factors including: the dose of protein, source of protein, and possibly the distribution and timing of post-exercise protein ingestion. In addition, RE variables such as frequency of sessions, time under tension, volume, and training status play roles in regulating MPS. This review provides a brief overview of our current understanding of how RE and protein ingestion can influence gains in skeletal muscle mass in young, healthy individuals. It is the goal of this review to provide nutritional recommendations for optimal skeletal muscle adaptation. Specifically, we will focus on how the manipulation of protein intake during the recovery period following RE augments the adaptive response.
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Resistance exercise training (RET) is widely used to increase muscle mass in athletes and also aged/cachectic populations. However, the time course and metabolic and molecular control of hypertrophy remain poorly defined. Using newly developed deuterium oxide (D2O)-tracer techniques, we investigated the relationship between long-term muscle protein synthesis (MPS) and hypertrophic responses to RET. A total of 10 men (2361 yr) undertook 6 wk of unilateral (1-legged) RET [6 x 8 repetitions, 75% 1 repetition maximum (1-RM) 3/wk], rendering 1 leg untrained (UT) and the contralateral, trained (T). After baseline bilateral vastus lateralis (VL) muscle biopsies, subjects consumed 150 ml D2O (70 atom percentage; thereafter 50 ml/wk) with regular body water monitoring in saliva via high-temperature conversion elemental analyzer:isotope ratio mass spectrometer. Further bilateral VL muscle biopsies were taken at 3 and 6 wk to temporally quantify MPS via gas chromatography: pyrolysis: isotope ratio mass spectrometer. Expectedly, only the T leg exhibited marked increases in function [i.e., 1-RM/maximal voluntary contraction (60 degrees)] and VL thickness (peaking at 3 wk). Critically, whereas MPS remained unchanged in the UT leg (e.g., similar to 1.35 +/- 0.08%/d), the T leg exhibited increased MPS at 0-3wk(1.6 +/- 0.01%/d), but not at3-6wk(1.29 +/- 0.11%/d); this was reflected by dampened acute mechanistic target of rapamycin complex 1 signaling responses to RET, beyond 3 wk. Therefore, hypertrophic remodeling is most active during the early stages of RET, reflecting longer-term MPS. Moreover, D2O heralds promise for coupling MPS and muscle mass and providing insight into the control of hypertrophy and efficacy of anabolic interventions.
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The purpose of this study was to investigate the effects of training muscle groups 1 day per week using a split-body routine versus 3 days per week using a total-body routine on muscular adaptations in well-trained men. Subjects were 20 male volunteers (height = 1.76 ± 0.05 m; body mass = 78.0 ± 10.7 kg; age = 23.5 ± 2.9 years) recruited from a university population. Participants were pair-matched according to baseline strength and then randomly assigned to 1 of 2 experimental groups: a split-body routine (SPLIT) where multiple exercises were performed for a specific muscle group in a session with 2-3 muscle groups trained per session (n = 10), or; a total-body routine (TOTAL), where 1 exercise was performed per muscle group in a session with all muscle groups trained in each session (n = 10). Subjects were tested pre- and post-study for 1 repetition maximum strength in the bench press and squat, and muscle thickness of forearm flexors, forearm extensors, and vastus lateralis. Results showed significantly greater increases in forearm flexor muscle thickness for TOTAL compared to SPLIT. No significant differences were noted in maximal strength measures. The findings suggest a potentially superior hypertrophic benefit to higher weekly resistance training frequencies.
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Muscle protein synthesis (MPS) is stimulated by resistance exercise (RE) and is further stimulated by protein ingestion. The summation of periods of RE-induced increases in MPS can induce hypertrophy chronically. As such, studying the response of MPS with resistance training (RT) is informative, as adaptations in this process can modulate muscle mass gain. Previous studies have shown that the amplitude and duration of increases in MPS after an acute bout of RE are modulated by an individual's training status. Nevertheless, it has been shown that the initial responses of MPS to RE and nutrition are not correlated with subsequent hypertrophy. Thus, early acute responses of MPS in the hours after RE, in an untrained state, do not capture how MPS can affect RE-induced muscle hypertrophy. The purpose of this review is provide an in-depth understanding of the dynamic process of muscle hypertrophy throughout RT by examining all of the available data on MPS after RE and in different phases of an RT programme. Analysis of the time course and the overall response of MPS is critical to determine the potential protein accretion after an RE bout. Exercise-induced increases in MPS are shorter lived and peak earlier in the trained state than in the untrained state, resulting in a smaller overall muscle protein synthetic response in the trained state. Thus, RT induces a dampening of the MPS response, potentially limiting protein accretion, but when this occurs remains unknown.
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The goal of the current work was to profile positive (mTORC1 activation, autocrine/paracrine growth factors) and negative [AMPK, unfolded protein response (UPR)] pathways that might regulate overload-induced mTORC1 activation with the hypothesis that a number of negative regulators of mTORC1 will be engaged during a supra-physiological model of hypertrophy. To achieve this, mTORC1-IRS1/2 signaling, BiP/CHOP/IRE1α, and AMPK activation were determined in rat plantaris muscle following synergist ablation (SA). SA resulted in significant increases in muscle mass of ~4% per day throughout the 21 days of the experiment. The expression of the insulin-like growth factors were high throughout the 21d of overload. However, IGF signaling was limited since IRS1 and 2 were undetectable in the overloaded muscle from day 3 to day 9. The decreases in IRS1/2 protein were paralleled by increases in GRB10(Ser501/503) and S6K1(Thr389) phosphorylation, two mTORC1 targets that can destabilize IRS proteins. PKB(Ser473) phosphorylation was higher from 3-6 days and this was associated with increased TSC2(Thr939) phosphorylation. The phosphorylation of TSC2(Thr1345) (an AMPK site) was also elevated whereas phosphorylation at the other PKB site, Thr(1462), was unchanged at 6d. In agreement with the phosphorylation of Thr(1345), synergist ablation led to activation of α1-AMPK during the initial growth phase, lasting the first 9 days before returning to baseline by day 12. The UPR markers CHOP and BiP were elevated over the first 12 days following ablation, whereas IRE1α levels decreased. These data suggest that during supra-physiological muscle loading, at least three potential molecular brakes engage to down-regulate mTORC1.
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Aim: The purpose of the present study was to compare the effects of equal-volume resistance training (RT) performed once or twice a week on muscle mass and strength of the elbow flexors in untrained young men. Methods: Thirty men (23 ± 3 years) without previous resistance training experience were divided into two groups: Group 1 (G1) trained each muscle group only once a week and group 2 (G2) trained each muscle twice a week during 10 weeks. Baseline and 10 weeks post-test elbow flexors muscle thickness (MT) were measured using a B-Mode ultrasound. Peak torque (PT) was assessed by an isokinetic dynamometer before and after the training program. Results: Elbow flexors MT increased significantly (P<0.05) from 31.70 ± 3.31 to 33.43 ± 3.46 mm in G1, and from 32.78 ± 4.03 to 35.09 ± 3.55 mm in G2. Elbow flexors PT also increased (P<0.05) from 50.77 ± 9.26 to 54.15 ± 10.79 N.m in G1, and from 48.99 ± 11.52 to 55.29 ± 10.24 N.m in G2. The results of ANOVA did not reveal group by time interactions for any variable, indicating no difference between groups for the changes in MT or PT. Conclusion: The results from the present study suggest that untrained men experience similar gains in muscle mass and strength with equal volume RT performed one or two days per week.
Article
The purpose of this study was to determine the effect strength training frequency has on improvements in lean mass and strength. Participants were 7 women and 12 men, age (χ̄= 34.64 years ± 6.91 years), with strength training experience, training age (χ̄= 51.16 months ± 39.02 months). Participants were assigned to one of two groups to equal baseline group demographics. High frequency training group (HFT) trained each muscle group as the agonist, 3 times per week, exercising with 3 sets per muscle group per session (3 total body workouts). Low frequency training group (LFT) trained each muscle group as the agonist one time per week, completing all 9 sets during that one workout. LFT consisted of a routine split over three days: 1) pectoralis, deltoids, and triceps; 2) upper back and biceps; 3) quadriceps, hamstrings, calves, and abdominals. Following eight weeks of training, HFT increased lean mass by 1.06 kg ± 1.78 kg, (1.9%), and LFT increased lean mass by .99 kg ± 1.31 kg, (2.0%). HFT strength improvements on the chest press was 9.07 kg ± 6.33 kg, (11%), and hack squat 20.16 kg ± 11.59 kg, (21%). LFT strength improvements on chest press was 5.80kg ± 4.26 kg, (7.0%), and hack squat 21.83 kg ± 11.17 kg, (24 %). No mean differences between groups were significant. These results suggest that HFT and LFT of equal set totals result in similar improvements in lean mass and strength, following 8 weeks of strength training.