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The purpose of the present study was to compare changes in muscle strength and hypertrophy between volume-equated resistance training (RT) performed 2 versus 3 times per week in trained men. Thirty-six resistance-trained men were randomly assigned to one of the two experimental groups: a split-body training routine (SPLIT) with muscle groups trained twice per week (n = 18) over four weekly sessions, or a total-body routine (TOTAL), with muscle groups being trained three times per week (n = 18) over three weekly sessions. The training intervention lasted 10 weeks. Testing was carried out pre- and post-study to assess maximal muscular strength in the back squat and bench press, and hypertrophic adaptations were assessed by measuring muscle thickness of the elbow flexors, elbow extensors, and quadriceps femoris. Twenty-eight subjects completed the study. Significant pre-to-post intervention increases in upper and lower-body muscular strength occurred in both groups with no significant between-group differences. Furthermore, significant pre-to-post intervention increases in muscle size of the elbow extensors and quadriceps femoris occurred in both groups with no significant between-group differences. No significant pre-to-post changes were observed for the muscle size of elbow flexors both in the SPLIT or TOTAL group. In conclusion, a training frequency of 2 versus 3 days per week produces similar increases in muscular adaptations in trained men over a 10-week training period. However, effect size differences favored SPLIT for all hypertrophy measures, indicating a potential benefit for training two versus three days a week when the goal is to maximize gains in muscle mass.
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Journal of Human Kinetics volume 68/2019, 135-143 DOI: 10.2478/hukin-2019-0062 135
Strength & Power
1 - Department of Sport, School of Physical Education and Sport, University of São Paulo, São Paulo, SP, Brazil.
2 - Health Sciences Department, CUNY Lehman College, Bronx, NY, USA.
3 - Institute for Health and Sport (IHES)Victoria University, Melbourne, Australia.
Authors submitted their contribution to the article to the editorial board.
Accepted for printing in the Journal of Human Kinetics vol. 68/2019 in August 2019.
Similar Muscular Adaptations in Resistance Training Performed
Two Versus Three Days Per Week
by
Thiago Lasevicius1, Brad Jon Schoenfeld2, Jozo Grgic3, Gilberto Laurentino1,
Lucas Duarte Tavares1, Valmor Tricoli1
The purpose of the present study was to compare changes in muscle strength and hypertrophy between volume-
equated resistance training (RT) performed 2 versus 3 times per week in trained men. Thirty-six resistance-trained men
were randomly assigned to one of the two experimental groups: a split-body training routine (SPLIT) with muscle groups
trained twice per week (n = 18) over four weekly sessions, or a total-body routine (TOTAL), with muscle groups being
trained three times per week (n = 18) over three weekly sessions. The training intervention lasted 10 weeks. Testing was
carried out pre- and post-study to assess maximal muscular strength in the back squat and bench press, and hypertrophic
adaptations were assessed by measuring muscle thickness of the elbow flexors, elbow extensors, and quadriceps femoris.
Twenty-eight subjects completed the study. Significant pre-to-post intervention increases in upper and lower-body
muscular strength occurred in both groups with no significant between-group differences. Furthermore, significant pre-
to-post intervention increases in muscle size of the elbow extensors and quadriceps femoris occurred in both groups with
no significant between-group differences. No significant pre-to-post changes were observed for the muscle size of elbow
flexors both in the SPLIT or TOTAL group. In conclusion, a training frequency of 2 versus 3 days per week produces
similar increases in muscular adaptations in trained men over a 10-week training period. Nonetheless, effect size
differences favored SPLIT for all hypertrophy measures, indicating a potential benefit for training two versus three days
a week when the goal is to maximize gains in muscle mass.
Key words: frequency, strength training, hypertrophy, volume.
Introduction
The manipulation of resistance training (RT)
variables is thought to be paramount for
maximizing muscular adaptations in humans
(Kraemer and Ratamess, 2004). The American
College of Sports Medicine (2009) recommends
that resistance trained individuals should perform
a majority of repetitions with a load corresponding
to 6-12 repetition maximum (RM), using a
movement tempo of 1-2 seconds per muscle action
(i.e. concentric and eccentric phase), and taking 1 to
2 minutes rest between sets. Furthermore,
individuals should perform at least 10 sets per
week per muscle group to maximize muscular
adaptations (Schoenfeld et al., 2017). However,
research is somewhat limited as to the effects of
manipulating RT frequency. RT frequency can be
defined as the number of weekly RT sessions.
Frequency can also be characterized as how many
times a given muscle group is worked each week –
a definition that is more relevant to bodybuilders
and others seeking to maximize muscle growth
(Hackett et al., 2013).
The acute post-exercise muscle protein
synthesis (MPS) response to RT lasts ~48 hours in
untrained individuals (Phillips et al., 1997) and
there is evidence that this response is attenuated in
those acclimated to RT, whereby the time course is
136 Resistance training two vs. three days per week
Journal of Human Kinetics - volume 68/2019 http://www.johk.pl
reduced to ~36 hours or less (MacDougall et al.,
1995; Tang et al., 2008). Based on this attenuated
MPS response in trained individuals, some have
speculated that an increased RT frequency would
sustain elevations in MPS over time, thereby
maximizing the area under the curve and, in
theory, result in a greater muscle protein accretion
(Dankel et al., 2017). Consistent with motor
learning theory, it also can be surmised that
performing a given exercise more frequently over
time would elicit superior increases in strength,
conceivably through heightened improvements in
neural efficiency (Shea et al., 2000). However, the
hypothesis that greater RT frequencies enhance
muscular adaptations remains speculative. Such
inferences can only be gleaned from longitudinal
studies that directly compare different RT
frequencies while controlling all other variables.
A recent meta-analysis of longitudinal studies
on the topic of RT frequency found that training a
muscle group twice per week produced superior
gains in muscle mass as compared to a RT
frequency of once per week (Schoenfeld et al.,
2016). However, there were insufficient data to
determine whether even higher frequencies of
training would further enhance the hypertrophic
response. In addition, only two out of 10 studies
included in the meta-analysis involved resistance-
trained individuals, and both studies compared
training muscle groups once versus three times per
week (McLester et al., 2000; Schoenfeld et al., 2015).
Moreover, all of the studies that investigated
training frequencies of two versus three days per
week employed whole body measures of muscle
mass (e.g., dual-energy X-ray absorptiometry),
which are not as sensitive for detecting subtle
changes over time as site-specific measures such as
ultrasound or magnetic resonance imaging (Levine
et al., 2000; Maden-Wilkinson et al., 2013). It is
evident that there is a paucity of research
investigating the potential benefits of training
muscle groups at frequencies of two or more days
per week while using site-specific measures of
muscle growth and performed in those with
previous RT experience. Therefore, in an effort to
fill important gaps in the current literature, the
purpose of this paper was to compare changes in
muscular strength and hypertrophy between RT
performed two versus three days per week in a
group of resistance-trained men. In order to control
for potential confounding factors, the total weekly
RT volume (sets x repetitions x load) was equated
between groups as research shows that there is a
direct dose-response relationship between volume
and gains in both muscular strength and muscle
mass (Ralston et al., 2017; Schoenfeld et al., 2017).
Our hypothesis was that training muscle groups
three times per week would promote greater
muscular adaptations compared to a weekly
training frequency of twice per week.
Methods
Participants
The participants were 36 apparently healthy
male volunteers (age = 21.0 ± 3.0 yrs; body mass =
78.7 ± 9.8 kg; body height = 178.5 ± 6.0 cm; RT
experience = 3.2 ± 1.1 yrs); the sample size was
justified by a power analysis with the outcome
being vastus lateralis muscle thickness (MT) with
an effect size (ES) difference of 0.40, p = .05 and
power of 0.80 while factoring in the possibility of
six dropouts. Participants were considered to be
resistance-trained, defined as having a minimum
consistent RT experience of at least three days-per-
week (on most weeks) for one year. All participants
employed the bench press and squat exercises in
their usual training routines. Based on the baseline
strength and MT, the participants were pair-
matched and then randomly assigned to a split-
body routine (SPLIT) whereby muscle groups were
trained twice per week (n = 18) over four weekly
sessions, or a total-body routine (TOTAL), where
muscle groups were trained three times per week
(n = 18) over three weekly sessions. The University
of São Paulo Institutional Review Board approved
the research protocol, and all participants signed
an informed consent form.
Resistance training procedures
During the 10-week training period, the
participants were instructed not to do any
additional (i.e., external) RT. The specific protocols
for SPLIT and TOTAL routines are outlined in
Table 1. The number of repetitions per set was 8-
12, with sets carried out to the point of momentary
concentric muscular failure. The rest interval
between sets was 90 s. The cadence of repetitions
for concentric and eccentric actions was 2:2. All
training sessions were supervised by research
personnel experienced in RT performance. Before
the training program started, the participants were
tested for their 10 repetition maximum (RM) in all
of the exercises employed during the intervention.
The 10RM data were used to determine
by Thiago Lasevicius et al. 137
© Editorial Committee of Journal of Human Kinetics
participants’ initial training loads. During the
course of the study, we attempted to progressively
increase the external load by 2.5% when
participants performed more than 12 repetitions
for a given set of an exercise; alternatively, loads
were decreased by 2.5% when they performed
fewer than 8 repetitions for a given set of an
exercise.
Dietary adherence
The participants were advised to maintain
their usual and customary nutritional habits and to
avoid consuming any muscle-building
supplements during the study period. The
MyFitnessPal.com (http://www.myfitnesspal.com)
software was used for the collection of food
records. The food records were self-reported by the
participants twice: the first time was seven days
before the training program started and the second
time was in week ten of the intervention. The
participants were instructed by the research staff
on how to use the software and how to report their
food items. Total values of protein, carbohydrates,
and fats were recorded for further analysis.
Muscle thickness
B-mode ultrasound was used for the
assessment of MT (imaging unit: SonoAce R3,
Samsung-Medison, Gangwon-do, South Korea).
The assessment of MT was performed by an
experienced technician. Following the application
of water-soluble transmission gel (Aquasonic 100
Ultrasound Transmission gel, Parker Laboratories
Inc., Fairfield, NJ), the technician used a five MHz
ultrasound probe, which was placed
perpendicularly to the tissue interface with caution
been taken not to depress the skin. Upon obtaining
a satisfactory quality image, the image was saved
to hard drive. MT was measured according to the
protocol utilized by Abe et al. (2000).
Measurements were taken at two sites for the
upper-body (elbow flexors and elbow extensors)
and at two sites for the lower-body (rectus femoris
and vastus lateralis). For the upper-body,
assessment of MT was done at a site located 60%
distal between the humerus lateral epicondyle and
the acromion process of the scapula. For the lower-
body, the assessment was done at a site located
50% between the greater trochanter and the lateral
condyle of the femur. In order to reduce the
confounding impact of training-induced edema,
the assessment of MT was carried out 48-72 hours
after the final training session (Ogasawara et al.,
2012). The typical error (TE) and the coefficient of
variation for MT measurements of the elbow
flexor, elbow extensor, rectus femoris and vastus
lateralis were 0.8 mm (CV: 2.17%), 0.6 mm (CV:
2.13%), 1.0 mm (CV: 3.85%), and 1.0 mm (CV:
3.95%), respectively.
Muscle strength
Lower-body muscular strength was evaluated
using the 1RM Smith squat test (1RMSQUAT), while
upper-body muscular strength was assessed using
the 1RM barbell bench press test (1RMBENCH). For
testing at baseline and post-RT intervention, the
participants reported to the lab having refrained
from any exercise for at least 48 hours. Upon
arriving at the lab, the participants performed a
warm-up which consisted of light cardiovascular
exercise (~10 min). The first set of a given exercise
was carried out at a load of ~50% of the 1RM for
five repetitions. The second and third sets were
performed with two-three repetitions at a load
corresponding to ~60-80% of the 1RM. The
following sets were carried out with one repetition
while increasing weight for the 1RM determination
and resting from 3 to 5 minutes between each
successive attempt. All 1RM determinations were
made within 5 attempts. The participants’ thighs
were required to reach parallel in the 1RMSQUAT for
the attempt to be considered successful as
determined by the research assistants. Successful
1RMBENCH was achieved if the participant
displayed a 5-point body contact position (head,
upper back, and buttocks firmly on the bench with
both feet flat on the floor) and executed a full lock
out of the limbs. 1RMBENCH testing was conducted
first in the sequence; the 1RMSQUAT test was carried
out following a 5-min rest period. Hand and foot
placement during the muscular strength tests were
recorded at baseline, and the same positions were
reused for post-study performance.
The 10RM test was performed in the
following order: Smith squat, bench press, leg
press 45º, lat pulldown, leg extension, triceps
pushdown and biceps curl. The exercises were
selected because of their extensive use in RT
programs and ease of execution. Standardized
instructions were provided to participants prior to
the test. Final values were obtained within 3
attempts, with 3- to 5-min rest intervals afforded
between attempts. After obtaining the load in a
given exercise, recovery intervals of no less than 5
min were provided before proceeding to test 10RM
138 Resistance training two vs. three days per week
Journal of Human Kinetics - volume 68/2019 http://www.johk.pl
for the ensuing exercise.
10RM testing for the bench press and
Smith squat exercises followed the same
procedures as employed for the 1RM test.
Procedures for the other exercises were as follows:
1) Leg press 45º: the footplate of the unit
was divided into 10 x 10 cm squares with adhesive
tape to facilitate annotation of the feet positioning
on a sheet of paper and thus ensure reproducibility
in all testing sessions. Thereafter, the range of
motion for each repetition was determined by
having participants perform an unloaded
repetition, starting with the complete extension of
the knees up to 90º of flexion; a goniometer was
used to confirm the degree of flexion. A plastic
marker was then placed on the side column of the
leg press 45º to mark the knee flexion point. A
measuring tape was also glued onto the side
column of the apparatus to ensure reproducibility
of marker positioning.
2) Lat pulldown: participants sat on the
bench of the lat pulldown machine with the trunk
slightly inclined and knees semi-flexed. They
grasped the bar using a shoulder-width grip in full
elbow extension, and then pulled the bar down to
the chest by simultaneously adducting at the
shoulder joint and flexing at the elbow.
3) Leg extension: participants sat upright
with the trunk fully supported on the backrest of
extensor chair and knees at a 90º angle. Movement
was initiated by extending the knees until reaching
full extension and then flexing them back to the
initial position.
4) Triceps pushdown: participants
assumed a shoulder-width stance, knees semi-
flexed, elbows flexed at a 90º angle, and hands
holding the bar in a pronated position. Movement
entailed pushing down on the bar until achieving
complete elbow extension.
5) Biceps curl: participants assumed a
shoulder-width stance, knees semi-flexed, elbows
extended and hands holding the bar in a supinated
position. Movement entailed curling the bar until
achieving complete elbow flexion.
After obtaining the maximum loads in the
10RM test, participants rested for 48 hours and
were reevaluated to obtain the reproducibility of
the test (test and retest). The load established on
both days, a difference of less than 5% was
considered as the 10RM. In the intervals between
testing sessions, participants were instructed not to
perform any type of resistive exercise. The initial
loads used in the experimental conditions were the
highest obtained during pre-testing. The intraclass
correlation coefficients (ICC) for the tests were as
follows: Smith squat: ICC = 0.98; bench press: ICC
= 0.99; leg press 45º: ICC = 1.00; lat pulldown: ICC
= 0.99; leg extension: ICC = 0.99; triceps pushdown:
ICC = 0.97; biceps curl ICC = 0.99.
Statistical analysis
Initially, the data were analyzed
quantitatively and visually to verify their
normality (Shapiro-Wilk test) and existence of
outliers (box-plots). The TE of measurement was
used for measures of reliability, calculated as the
standard deviation of the difference between day
one and day two measurements / 2 and the
coefficient of variation calculated as the (TE of the
difference between day one and day two / means
of the day one and day two values) * 100. A one-
way ANOVA was performed to compare
differences between groups in the volume load and
dietary intake. A mixed model analysis was
performed for each dependent variable (MT and
1RM), with groups (TOTAL and SPLIT) and time
(pre- and post-intervention) as fixed factors, and
participants as a random factor. For each outcome,
an ES was calculated as proposed by Morris (2008).
The ES magnitude was classified as follows: <0.20
was considered as trivial, 0.20-0.50 was considered
as small, 0.50-0.80 as moderate and >0.80 was
considered as being of large magnitude (Cohen,
1988). Pre- to post RT intervention percent changes
were also calculated for the muscular strength and
hypertrophy outcomes ([post-testing value – pre-
testing value] / pre-testing value * 100). The
statistical significance threshold was set at p < .05.
All analyses were performed using the statistical
software package SAS 9.2 (SAS, NC).
Results
Eight participants dropped out over the
course of the study (four from each group). The
participants dropped out due to personal reasons
(non-related to the RT intervention). Thus, a total
of 28 participants completed the study (14 in each
group). Attendance was 95.6% and 95.3% for the
TOTAL and SPLIT group, respectively.
Dietary analyses
There were no significant differences in
average caloric intake or consumption of protein,
carbohydrate or fat between the TOTAL and SPLIT
groups. Data of daily dietary intake are presented
by Thiago Lasevicius et al. 139
© Editorial Committee of Journal of Human Kinetics
in Table 2.
Volume load
Volume load was calculated as sets x
repetitions x load for all sets performed during the
entire study. There were no differences in the
volume load between groups for chest (p = .89; 95%
confidence interval [CI] = -20912.0, 18363.5), back
(p = .79; 95% CI = -13364.7, 17270.9), elbow flexors
(p = .25; 95% CI = -2600.9, 9489.2), elbow extensors
(p = .74; 95% CI= -24719.9, 17869.2) and anterior
thigh (p = .78; 95% CI = -74560.3, 100729.0). Results
are presented in Table 3.
Muscle thickness
MT of the rectus femoris increased from
baseline to post-study by 7.9% (p < .001) and 12.3%
(p < .001) for TOTAL and SPLIT groups,
respectively, with no statistical differences noted
between groups (p = .50; CI = -0.19, 0.09; ES
difference = 0.39) (Table 4).
MT of the vastus lateralis increased from
baseline to post-study by 12.2% (p < .001) and 16.9%
(p < .001) for TOTAL and SPLIT groups,
respectively, with no statistical differences noted
between groups (p = .54; 95% CI = -0.25, 0.13; ES
difference = 0.31) (Table 4).
There were no statistical differences noted for
time or between groups in MT of the elbow flexors
(p = .67; 95% CI = -0.22, 0.34; ES difference = 0.36)
(Table 4). The change from baseline to post-study
was 1.6% (p > .05) and 7.3% (p > .05) for TOTAL and
SPLIT groups, respectively.
MT of the elbow extensors increased from
baseline to post-study by 8.6% (p < .001) and 15.7%
(p < .001) for TOTAL and SPLIT groups,
respectively, with no statistical differences noted
between groups (p = .62; 95% CI = -0.45, 0.27; ES
difference = 0.35) (Table 4).
Muscle strength
There was a significant main effect of time for
the 1RMBENCH (p = .033) and 1RMSQUAT (p = .0001).
1RMBENCH increased from baseline to post-study by
10.2% (p = .034) and 11.8% (p = .03) for TOTAL and
SPLIT groups, respectively, with no differences
noted between groups (p = .47; 95% CI = -13.75,
6.54; ES difference = 0.09) (Table 4). 1RMSQUAT
increased from baseline to post-study by 17.7% (p
= .011) and 18.9% (p =.006) for TOTAL and SPLIT
groups, respectively, with no differences noted
between groups (p = .60; 95% CI = -21.54, 12.61; ES
difference = 0.09) (Table 4).
Discussion
The present study is the first to investigate the
effects of training muscle groups two versus three
days per week in men with previous RT experience
while equating total training volume between
conditions using site-specific measures of muscle
growth. The primary and novel finding of our
study is that both RT frequencies elicited similar
increases in muscular strength and hypertrophy
over a 10-week program. The results are not in
agreement with our hypothesis that the TOTAL
group would experience greater increases in
muscle size and strength, and appear to refute the
hypothesis that increasing the frequency of MPS
stimulation with RT necessarily leads to enhanced
muscle protein accretion over time.
Both TOTAL and SPLIT produced significant
gains in maximal strength with marked increases
noted in the 1RMBENCH (10.2% and 11.8%,
respectively) and 1RMSQUAT (17.7% and 18.9%,
respectively). No statistical differences were found
between conditions and the ES differences were
minimal for both strength outcomes. These results
seem to be in line with several recent studies that
compared RT frequency prescription and were
done in resistance-trained individuals. For
example, Yue et al. (2018) compared training a
muscle group two versus four times per week with
volume equated between conditions and observed
no significant differences in strength gains
between the two groups. Brigatto et al. (2018)
compared strength gains over an 8-week period
between groups training a muscle group once
versus twice per week on a volume-equated basis.
Both groups increased their levels of strength in the
bench press and squat exercise post-intervention;
however, no significant differences between the
training groups were found. Furthermore, our
results corroborate meta-analytical data which
reported that when training volume was equated,
no significant effect of RT frequency on strength
gains was observed (Grgic et al., 2018).
140 Resistance training two vs. three days per week
Journal of Human Kinetics - volume 68/2019 http://www.johk.pl
Table 1
Training protocols
Protocol Monday Tuesday Wednesday Thursday Friday
TOTAL
(n=14)
Smith squat (4
sets)
Leg press (4 sets)
Leg extension (4
sets)
Bench press (4
sets)
Lat pulldown (4
sets)
Triceps pushdown
(4 sets)
Biceps curl (4 sets)
OFF
Smith squat (4
sets)
Leg press (4 sets)
Leg extension (4
sets)
Bench press (4
sets)
Lat pulldown (4
sets)
Triceps pushdown
(4 sets)
Biceps curl (4 sets)
OFF
Smith squat (4
sets)
Leg press (4 sets)
Leg extension (4
sets)
Bench press (4
sets)
Lat pulldown (4
sets)
Triceps pushdown
(4 sets)
Biceps curl (4 sets)
SPLIT
(n=14)
Smith squat (6
sets)
Leg press (6 sets)
Leg extension (6
sets)
Bench press (6
sets)
Lat pulldown (6
sets)
Triceps
pushdown (6 sets)
Biceps curl (6 sets)
OFF
Smith squat (6
sets)
Leg press (6
sets)
Leg extension
(6 sets)
Bench press (6
sets)
Lat pulldown (6
sets)
Triceps pushdown
(6 sets)
Biceps curl (6 sets)
Table 2
Dietary measures
TOTAL Initial TOTAL Final SPLIT Initial SPLIT Final
Calories
Carbohydrate (g)
Fat (g)
Protein (g)
2857.1 ± 811.9
372.9 ± 121.3
70.9 ± 37.5
192.0 ± 113.7
2804.9 ± 801.2
362.4 ± 107.6
69.1 ± 34.7
192.6 ± 96.5
2970.4 ± 530.1
393.4 ± 146.5
67.6 ± 32.2
197.1 ± 104.6
2987.1 ±
480.1
386.2 ± 131.7
70.1 ± 29.5
199.2 ± 89.0
Data are reported as mean ± SD
Table 3
Total volume load by exercise (kg)
Data are reported as mean ± SD.
Muscle Group TOTAL SPLIT
Bench press 62154.6 ± 27848.0 63428.9 ± 27848.0
Lat pulldown 63444.5 ± 21597.2 61491.4 ± 17635.5
Biceps curl 34527.7 ± 7749.4 31083.6 ± 7812.0
Triceps pushdown 59001.4 ± 25613.2 62426.8 ± 29094.2
Smith Squat 185532.7 ± 92670.7 158611.2 ± 33466.6
Leg Press 45º 244459.2 ± 61992.5 237917.1 ± 50199.9
Leg Extension 81486.4 ± 20664.1 79305.5 ± 16733.3
by Thiago Lasevicius et al. 141
© Editorial Committee of Journal of Human Kinetics
Table 4
Pre- to Post-study outcome measures
Data are reported as mean ± SD. Asterisk (*) indicates a significant effect from baseline
values. ES = effect size
These findings are somewhat
counterintuitive, as motor learning theory dictates
that practicing a given exercise more frequently
over time leads to better skill acquisition,
conceivably through neural enhancements (Shea et
al., 2000). Given our results, it may be speculated
that training twice a week is sufficient to optimize
neural proficiency in strength-related tasks, and
thereafter, training volume (and not frequency)
becomes the predominant factor for maximizing
results. Alternatively, it is possible that there is not
a sufficient difference between two versus three
weekly RT sessions from a frequency standpoint,
and perhaps higher frequencies are required to
promote additional neural improvements. That
said, this idea remains speculative given that
Colquhoun et al. (2018) and Saric et al. (2018)
recently compared volume-equated training three
versus six times per week and observed
comparable strength gains between the two
training frequencies. Further research is required
to develop a better understanding of these
complexities.
With respect to gains in muscle mass,
while both groups increased MT of the elbow
extensors and quadriceps following 10 weeks of
training, no significant between-group differences
were seen in the upper- or lower-body. No
previous studies have endeavored to evaluate site-
specific changes in muscle size when training
muscle groups two versus three days per week.
However, several volume-equated investigations
of training frequency have employed whole-body
measures of muscle mass including girth
measurements (Arazi and Asadi, 2011), air
displacement plethysmography (Benton et al.,
2011), and dual x-ray absorptiometry (Candow
and Burke, 2007), with no significant between-
group differences reported in all of these studies.
Schoenfeld et al. (2015) found greater increases in
elbow flexor MT and a trend for greater increases
in vastus lateralis MT when comparing volume-
equated groups training muscle groups three times
versus once per week. Brigatto et al. (2018)
compared training once versus twice per week
(over an 8-week training period) and reported no
significant differences in muscle hypertrophy
between the training groups. Based on the current
body of evidence, it is possible that variables such
as training volume may have a more profound
effect on muscular hypertrophy as compared to RT
frequency (Schoenfeld et al., 2017; Schoenfeld et al.,
2019). It should be noted that small, but potentially
meaningful ES differences (ranging from 0.31 to
0.39) were observed in favor of training muscles
two versus three days per week for every
hypertrophy outcome measure studied. These
findings suggest a potential hypertrophic benefit to
the lower training frequency. That said, additional
studies using direct measures of
Measure Total-Pre Total-Post ES Split-Pre Split-Post ES
Rectus Femoris (mm) 22.7 ± 2.5 24.5 ± 2.7* 0.71 22.7 ± 2.6 25.5 ± 2.2* 1.10
Vastus Lateralis (mm) 21.2 ± 3.4 23.8 ± 3.9* 0.83 21.3 ± 2.9 24.9 ± 3.1* 1.14
Elbow Flexors (mm) 35.9 ± 5.3 36.5 ± 6.0 0.11 34.3 ± 5.3 36.8 ± 4.7 0.47
Elbow Extensor (mm) 30.0 ± 5.6 32.6 ± 8.1* 0.43 29.9 ± 6.5 34.6 ± 5.8* 0.78
1RM Squat (kg) 156.5 ± 26.5 184.3 ± 31.2* 1.03 159.7 ± 27.7 190.0 ± 29.3* 1.12
1RM Bench Press (kg) 78.1 ± 19.8 86.1 ± 21.6* 0.45 80.9 ± 15.6 90.5 ± 17.3* 0.54
142 Resistance training two vs. three days per week
Journal of Human Kinetics - volume 68/2019 http://www.johk.pl
hypertrophy (i.e., ultrasound, magnetic resonance
imaging or computed tomography) are warranted
to explore this topic further. Also, studies with
longer duration time courses are needed given that
the majority of the current studies were six to 10
weeks in duration.
One possible limitation of the present
study is that it might have been slightly
underpowered from a statistical standpoint. We
initially recruited a sample of 36 participants;
however, eight participants did not complete the
whole training program, which subsequently
might have impacted the statistical power of the
study. Additionally, the sample was comprised of
young. trained men which therefore limits the
generalizability of the results to those who are
untrained, older, and women. Finally, the training
program lasted 10 weeks; it is possible that the
results would be different over longer time
courses.
Conclusions
Based on our findings, we conclude that
training muscle groups either twice or three times
per week results in similar increases in muscular
strength and hypertrophy in young adult trained
men when volume is equated between the training
conditions. The TOTAL protocol employed in this
study required fewer weekly sessions, but more
training time per session compared to SPLIT.
Alternatively, the SPLIT protocol required a higher
total number of weekly sessions, but each session
was of shorter duration compared to TOTAL.
Given the larger ESs favoring the SPLIT training
routine noted for hypertrophic outcomes, it
remains possible that small, but potentially
meaningful improvements may be elicited by
employing a training frequency of twice per week
as compared to training three times per week.
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Corresponding author:
Brad Jon Schoenfeld
Health Sciences Department, CUNY Lehman College,
Bronx, NY, 250 Bedford Park Blvd West, Bronx, NY 10468,
Phone: 718-960-1999;
E-mail: bradschoenfeldphd@gmail.com
... However, studies comparing different RT frequencies in trained subjects, distributed into SPLIT versus full-body routines on a volume-equated basis (same number of sets per muscle group per week), have shown controversial results. Some of these studies reported no significant differences between higher (full-body) and lower frequencies (SPLIT) [5,6], while others demonstrated a potentially better hypertrophic effect for the full-body routine [2,7]. Indeed, systematic reviews with meta-analysis showed no significant difference between higher and lower frequency on a volume-equated basis for both muscle strength [8] and hypertrophy [9] outcomes. ...
... Although it is well established that both higher and lower frequencies can generate substantial increases in muscle strength and morphological outcomes, only 7 studies have investigated the effects of different RT frequencies on morphological adaptations in trained subjects, using validated diagnostic imaging methods (e.g. ultrasound) to assess changes in muscle size [2,6,7,[10][11][12][13]. Moreover, most of the studies that specifically investigated training frequencies of 2 versus 3 days per week employed whole body measures of muscle mass (e.g., dual-energy X-ray absorptiometry), which are not as sensitive for detecting subtle changes over time as site-specific measures, such as ultrasound or magnetic resonance imaging [14]. ...
... Moreover, most of the studies that specifically investigated training frequencies of 2 versus 3 days per week employed whole body measures of muscle mass (e.g., dual-energy X-ray absorptiometry), which are not as sensitive for detecting subtle changes over time as site-specific measures, such as ultrasound or magnetic resonance imaging [14]. To the authors' knowledge, only one study investigated the effects of training the same muscle group twice versus thrice a week in trained subjects using validated diagnostic imaging methods [6]. In this study, in which SPLIT (2 sessions·wk-1) versus full-body (3 sessions·wk-1) routines were compared, both frequencies produced similar increases in muscular adaptations over 10 weeks [6]. ...
Article
Full-text available
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.
... Prospective participants were considered eligible if they had less than 1 year of RT experience and no lower extremity injuries. The sample size was justified by a priori power analysis using G*Power software (Germany, Düsseldorf, version 3.1.9.7) based on an effect size (ES) of 0.40 for vastus lateralis (VL) MT, an alpha level of 0.05, and a power (1−β) of 0.80, consistent with findings by Lasevicius et al. [12]. Analysis showed the required sample size to achieve sufficient statistical power was 15 participants. ...
... The participants were instructed to refrain from any intensive physical activities (outside the study program) and to maintain their current eating habits for the duration of the study. The CONSORT flow diagram is presented in Figure 1. by Lasevicius et al. [12]. Analysis showed the required sample size to achieve sufficient statistical power was 15 participants. ...
Article
Full-text available
The study aimed to compare the effects of drop set resistance training (RT) versus traditional RT on markers of maximal muscle strength and regional hypertrophy of the quadriceps femoris. Sixteen recreationally active young men had one leg randomly assigned to the drop-set method (DS) and the other to training in a traditional manner (TRAD). Participants performed unilateral seated leg extensions using a periodized approach for eight weeks. Rectus femoris (RF) and vastus lateralis (VL) muscle thickness (MT), estimated one repetition maximum (RM) in the unilateral knee extension, and peak and average isokinetic knee extension torque at 60◦/s angular velocity were measured pre- and post-study. Both conditions increased muscle thickness of the RF and VL from preto post-intervention. DS showed statistically greater increases in the RF at 30% and 50% of muscle length, whereas no MT differences were detected at 70% muscle length nor at any aspect of the VL. Both DS and TRAD increased estimated one RM from pre- to post-study (+34.6% versus +32.0%, respectively) with no between-condition differences noted. Both conditions showed similar increases in peak torque (DS: +21.7%; TRAD: +22.5%) and average torque (DS: +23.6%; TRAD: +22.5%) from pre- to post-study. Our findings indicate a potential benefit of the drop-set method for inducing non-uniform hypertrophic gains in the RF muscle pursuant to leg extension training. The strategy did not promote an advantage in improving hypertrophy of the VL, nor in strength-related measures, compared to traditional training
... In general, the 1-RM improvements in this study were somewhat lower than strength gains in previous research using similar RT regimens. For example, Lasevicius et al. (2019) found an average increase in BP 1-RM of 8 and 9.6 kg following 10 weeks of split and total body RT respectively. Also, Colquhoun et al. (2018) found BP 1-RM mean improvements of 7.8 kg and 8.8 kg following a 6week RT intervention period with a training frequency of three and six sessions per week, respectively, but equal volume between groups. ...
... For this reason, the results by Colquhoun et al. (2018) could have been higher compared to those presented here, since, in contrast to this study, only untrained subjects participated. Lasevicius et al. (2019), however, only allowed trained individuals to participate, as was conducted here. The intervention period was 2 weeks longer than in the present study. ...
Article
Full-text available
The aim of this study was to investigate the effects of an 8‑week powerlifting-type bench press (BP) resistance training (RT) program, either without (RAW) or with using a supportive elastic bench press device (EBD) on one-repetition maximum (1-RM), body weight (BW), mid-upper arm and chest circumference, as well as visual analogue pain scale (VAS) of the shoulder, elbow, and wrist. For this purpose, a matched pair parallel design based on initial 1‑RM was used (BPD n = 16, age 24.4 ± 4 years, RT experience 3.75 ± 1.83 years; RAW n = 16, age 25 ± 2 years, RT experience 5.66 ± 3.00 years). Following two weeks of familiarization with the protocol , BP RT was carried out twice weekly. The EBD group completed more than half of their BP sets with elastic assistance and 10% higher training intensity than the RAW group. There was a significant time × group interaction in BW ( p = 0.008). Post hoc analysis showed a significant loss of 0.92 kg in the EBD group ( p = 0.049; effect size [ES] = −0.08; 95%CI [−1.80, 0.04]). A significant time effect for 1‑RM was observed ( p < 0.001). In both groups there was a significant change in 1‑RM of 5.00 kg ( p < 0.001; ES = 0.35; 95%CI [2.98, 7.02]). There was no significant change in any circumference or VAS measure. In conclusion, using an EBD leads to 1‑RM gains similar to conventional RAW BP training. However, more studies are required with highly trained individuals, in particular female athletes. Practitioners may implement EBD training for reasons of variation.
... Although the number of studies published is increasing, the total pool of studies is still limited. To the best of our knowledge, there are eight published studies that explore the effects of training frequencies on muscle adaptations on trained males under equal volume conditions (Brigatto et al., 2019;Colquhoun et al., 2018;Gentil et al., 2018;Gomes et al., 2019;Lasevicius et al., 2019;Mclester, Bishop & Guilliams, 2000;Saric et al., 2019;Schoenfeld et al., 2015). Several of these studies have focused on lower training frequencies, that is, three or lower. ...
... Both SPLIT and FULLBODY groups had a similar increase in strength from pretest to posttest in both 1RM SQUAT (13.25 and 12.27 kg, respectively) and 1RM BENCHPRESS (7.75 and 8.86 kg, respectively), which indicates that 8 weeks of training, regardless of frequency, will increase muscle strength, as long as the weekly training volume in the exercises, barbell back squat, and bench press are high enough. The result of this study follows the trends shown in other studies (Brigatto et al., 2019;Colquhoun et al., 2018;Gentil et al., 2018;Gomes et al., 2019;Lasevicius et al., 2019;Saric et al., 2019;Schoenfeld et al., 2015) on the topic, with the effect of an increase in frequency not yielding a significantly greater effect on maximal strength. Only Mclester, Bishop & Guilliams (2000) reported that a lower frequency group achieved only 2/3 of the increase in strength of the high-frequency group, but they compared one session per week with three sessions per week. ...
Article
Full-text available
Background In resistance training, the role of training frequency to increase maximal strength is often debated. However, the limited data available does not allow for clear training frequency “optimization” recommendations. The purpose of this study was to investigate the effects of training frequency on maximal muscular strength and rate of perceived exertion (RPE). The total weekly training volume was equally distributed between two and four sessions per muscle group. Methods Twenty-one experienced resistance-trained male subjects (height: 1.85 ± 0.06 m, body mass: 85.3 ± 12.3 kg, age: 27.6 ± 7.6 years) were tested prior to and after an 8-week training period in one-repetition maximum (1RM) barbell back squat and bench press. Subjects were randomly assigned to a SPLIT group ( n = 10), in which there were two training sessions of squats and lower-body exercises and two training sessions of bench press and upper-body exercises, or a FULLBODY group ( n = 11), in which four sessions with squats, bench press and supplementary exercises were conducted every session. In each session, the subjects rated their RPE after barbell back squat, bench press, and the full session. Results Both groups significantly increased 1RM strength in barbell back squat (SPLIT group: +13.25 kg; FULLBODY group: +14.31 kg) and bench press (SPLIT group: +7.75 kg; FULLBODY group: +8.86 kg) but training frequency did not affect this increase for squat ( p = 0.640) or bench press ( p = 0.431). Both groups showed a significant effect for time on RPE on all three measurements. The analyses showed only an interaction effect between groups on time for the RPE after the squat exercise ( p = 0.002). Conclusion We conclude that there are no additional benefits of increasing the training frequency from two to four sessions under volume-equated conditions, but it could be favorable to spread the total training volume into several training bouts through the week to avoid potential increases in RPE, especially after the squat exercise.
... As trained individuals are more likely to have greater training frequencies than less trained individuals, and the frequencies used are likely to be greater than those investigated in most studies (Strömbäck et al., 2018), a need for more research on this group has been expressed (Grgic et al., 2018;Ralston et al., 2018). To our knowledge, there are ten published studies on volume equated resistance training frequency in trained individuals published to date (McLester et al., 2000;Schoenfeld et al., 2015;Brigatto et al., 2018;Colquhoun et al., 2018;Gentil et al., 2018;Gomes et al., 2019;Lasevicius et al., 2019;Saric et al., 2019;Zaroni et al., 2019;Johnsen and van den Tillaar, 2021). Five of these studies have focused on higher frequencies than 3 days per week (Colquhoun et al., 2018;Gomes et al., 2019;Saric et al., 2019;Zaroni et al., 2019;Johnsen and van den Tillaar, 2021). ...
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.
... As trained individuals are more likely to have greater training frequencies than less trained individuals, and the frequencies used are likely to be greater than those investigated in most studies (Strömbäck et al., 2018), a need for more research on this group has been expressed (Grgic et al., 2018;Ralston et al., 2018). To our knowledge, there are ten published studies on volume equated resistance training frequency in trained individuals published to date (McLester et al., 2000;Schoenfeld et al., 2015;Brigatto et al., 2018;Colquhoun et al., 2018;Gentil et al., 2018;Gomes et al., 2019;Lasevicius et al., 2019;Saric et al., 2019;Zaroni et al., 2019;Johnsen and van den Tillaar, 2021). Five of these studies have focused on higher frequencies than 3 days per week (Colquhoun et al., 2018;Gomes et al., 2019;Saric et al., 2019;Zaroni et al., 2019;Johnsen and van den Tillaar, 2021). ...
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.
... As trained individuals are more likely to have greater training frequencies than less trained individuals, and the frequencies used are likely to be greater than those investigated in most studies (Strömbäck et al., 2018), a need for more research on this group has been expressed (Grgic et al., 2018;Ralston et al., 2018). To our knowledge, there are ten published studies on volume equated resistance training frequency in trained individuals published to date (McLester et al., 2000;Schoenfeld et al., 2015;Brigatto et al., 2018;Colquhoun et al., 2018;Gentil et al., 2018;Gomes et al., 2019;Lasevicius et al., 2019;Saric et al., 2019;Zaroni et al., 2019;Johnsen and van den Tillaar, 2021). Five of these studies have focused on higher frequencies than 3 days per week (Colquhoun et al., 2018;Gomes et al., 2019;Saric et al., 2019;Zaroni et al., 2019;Johnsen and van den Tillaar, 2021). ...
Article
Full-text available
The main goal of the current study was to compare the effects of volume-equated training frequency on gains in muscle mass and strength. In addition, we aimed to investigate whether the effect of training frequency was affected by the complexity, concerning the degrees of freedom, of an exercise. Participants were randomized to a moderate training frequency group (two weekly sessions) or high training frequency group (four weekly sessions). Twenty-one participants (male: 11, female: 10, age: 25.9 ± 4.0) completed the 9-week whole-body progressive heavy resistance training intervention with moderate ( n = 13) or high ( n = 8) training frequency. Whole-body and regional changes in lean mass were measured using dual-energy x-ray absorptiometry, while the vastus lateralis thickness was measured by ultrasound. Changes in muscle strength were measured as one repetition maximum for squat, hack squat, bench press, and chest press. No differences between groups were observed for any of the measures of muscle growth or muscle strength. Muscle strength increased to a greater extent in hack squat and chest press than squat and bench press for both moderate (50 and 21% vs. 19 and 14%, respectively) and high-frequency groups (63 and 31% vs. 19 and 16%, respectively), with no differences between groups. These results suggest that training frequency is less decisive when weekly training volume is equated. Further, familiarity with an exercise seems to be of greater importance for strength adaptations than the complexity of the exercise.
... In fact, the way of quantifying the total load shown in figure 2 was not shown in the manuscript. This equation is classic in literature and has been used in previous studies [8][9] . Thus, to facilitate clarifications for future readers, we will request the Brazilian Journal of Sports Medicine that this information can be inserted in the chapter of the study design, following the appropriate process. ...
... Lasevicius and colleagues (149) After 10 weeks of training, there was a significant increase rectus femoris, vastus lateralis and elbow extensor muscle thickness with no significant difference between the SPLIT and TOTAL groups for any of these measurements. Lasevicius and colleagues (149) concluded that their data showed that training a muscle group 2 or 3 times a week resulted in similar increases in muscular strength and hypertrophy in young adult resistance trained males. Nonetheless, they claimed that the small but potentially meaningful difference in effect sizes (0.31 to 0.39), which favored the SPLIT group, indicated a potential benefit of training muscle groups 2x/week versus 3x/week. ...
Article
Full-text available
Researchers have expressed concern recently for standardization of resistance training protocols so that valid comparisons of different training variables such as muscular fatigue, time under tension, pre-exhaust exercise and exercise order, pyramid and drop sets, amount of resistance (load), range of repetitions, frequency and volume of exercise, interset rest intervals, etc. can be more closely studied and compared. This Critical Commentary addresses some recent review articles and training studies specifically focused on the stimulus for muscle hypertrophy in participants with several years of resistance training experience. It reveals that many of the recommended resistance training protocols have their foundation in some long-held, self-described bias. Blinding of assessors and statisticians, self-plagiarism, authorship responsibility, and conflicts of interest are briefly discussed as well. The conclusion is that most of the published peer-reviewed resistance training literature failed to provide any compelling evidence that the manipulation of any one or combination of the aforementioned variables can significantly affect the degree of muscle hypertrophy, especially in well-trained participants. Although the specific stimulus for optimal gains in muscle mass is unknown, many authors are desperately clinging to their unsupported belief that a greater volume of exercise will produce superior muscle hypertrophy.
... Regarding muscle mass and strength gains, although no study investigated the effects of ST in these neuromuscular adaptations in older adults, it is possible to suggest that the gains are comparable to TRT. It has been suggested that performing RT to concentric muscle failure (Jenkins et al. 2015;Schoenfeld et al. 2015) can maximize gains in muscle strength (Rooney et al. 1994;Drinkwater et al. 2005) and hypertrophy (Schott et al. 1995), due to the increase in the muscle activation, regardless of training variables manipulation or methods (Souza et al. 2014;Barcelos et al. 2018;Nobrega et al. 2018;Damas et al. 2019;Lasevicius et al. 2019). In fact, it has been recently shown that manipulation of load, time under tension and number of repetitions during RT resulted in similar muscle activation when exercises were performed to concentric muscle failure (Morton et al. 2019). ...
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PurposeWe compared the effects of suspension training (ST) with traditional resistance training (TRT) on muscle mass, strength and functional performance in older adults.Methods Forty-two untrained older adults were randomized in TRT, ST (both performed 3 sets of whole body exercises to muscle failure) or control group (CON). Muscle thickness (MT) of biceps brachii (MTBB) and vastus lateralis (MTVL), maximal dynamic strength test (1RM) for biceps curl (1RMBC) and leg extension exercises (1RMLE), and functional performance tests (chair stand [CS], timed up and go [TUG] and maximal gait speed [MGS]) were performed before and after 12 weeks of training.ResultsMTBB increased significantly and similarly for all training groups (TRT 23.35%; ST 21.56%). MTVL increased significantly and similarly for all training groups (TRT 13.03%; ST 14.07%). 1RMBC increased significantly and similarly for all training groups (TRT 16.06%; ST 14.33%). 1RMLE increased significantly and similarly for all training groups (TRT 14.89%; ST 18.06%). MGS increased significantly and similarly for all groups (TRT 6.26%; ST 5.99%; CON 2.87%). CS decreased significantly and similarly for all training groups (TRT − 20.80%; ST − 15.73%). TUG decreased significantly and similarly for all training groups (TRT − 8.66%; ST − 9.16%).Conclusion Suspension training (ST) promotes similar muscle mass, strength and functional performance improvements compared to TRT in older adults.
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We examined the effects of resistance training (RT) frequency performed 3 times per week (RT3) versus RT performed 6 times per week (RT6) under volume-equated conditions in resistance-trained men. Twenty-seven men were randomly allocated to RT3 (n = 14) or RT6 (n = 13). The supervised training intervention lasted for 6-weeks. Upper and lower-body strength were assessed using the one-repetition maximum (1RM) test. Also, muscular endurance (60% 1RM performed to momentary failure), and muscle thickness (elbow flexors, elbow extensors, rectus femoris, and vastus intermedius) were measured pre and post-intervention. Pre-to-post intervention, both groups increased upper-body strength (RT3: +4%; RT6: +6%) and lower-body strength (RT3: +22%; RT6: +18%) with no significant between-group differences. No significant pre-to-post intervention increases in muscular endurance were seen in either of the training groups. Both groups increased elbow extensor thickness (RT3: +14%; RT6: +11%), rectus femoris thickness (RT3: +5%; RT6: +6%), and vastus intermedius thickness (RT3: +10%; RT6: +11%) with no significant between-group differences. Only the RT3 group significantly increased elbow flexor thickness from pre-to-post intervention (+7%). When training volume is equated, it seems that RT performed either 3 or 6 times per week can result in similar strength gains over a 6-week training period. Furthermore, under volume-equated conditions, comparable hypertrophy results may also be expected with both RT frequencies. Finally, no changes were seen in muscular endurance possibly because of the considerable inter-individual variability in the responses. The findings presented herein might be of interest to coaches, exercise practitioners, athletes, and recreational trainees.
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The purpose of this study was to investigate the chronic effects of training muscle groups 1 day per week vs. 2 days per week on neuromuscular performance and morphological adaptations in trained men with the number of sets per muscle group equated between conditions. Participants were randomly assigned in 2 experimental groups: 1 session·wk-1 per muscle group (G1, n = 10), where every muscle group was trained once a week with 16 sets or 2 sessions·wk-1 per muscle group (G2, n = 10), where every muscle group was trained twice a week with 8 sets per session. All other variables were held constant over the 8-week study period. No significant difference between conditions for maximal strength in the back squat or bench press, muscle thickness in the elbow extensors, elbow flexors, or quadriceps femoris, and muscle endurance in the back squat and bench press performed at 60% 1RM was detected. Effect size favored G2 for some outcome measurements, suggesting the potential of a slight benefit to the higher training frequency. In conclusion, both G1 and G2 significantly enhance neuromuscular adaptations, with a similar change noted between experimental conditions. Keywords: Split body routine; resistance training frequency; muscle hypertrophy; maximal strength.
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Background Current recommendations on resistance training (RT) frequency for gains in muscular strength are based on extrapolations from limited evidence on the topic, and thus their practical applicability remains questionable. Objective To elucidate this issue, we conducted a systematic review and meta-analysis of the studies that compared muscular strength outcomes with different RT frequencies. Methods To carry out this review, English-language literature searches of the PubMed/MEDLINE, Scopus, and SPORTDiscus databases were conducted. The meta-analysis was performed using a random-effects model. The meta-analysis models were generated with RT frequencies classified as a categorical variable as either 1, 2, 3, or 4+ times/week, or, if there were insufficient data in subgroup analyses, the training frequencies were categorized as 1, 2, or 3 times/week. Subgroup analyses were performed for potential moderators, including (1) training volume; (2) exercise selection for the 1 repetition maximum (RM) test (for both multi-joint and single-joint exercises); (3) upper and lower body strength gains; (4) training to muscular failure (for studies involving and not involving training to muscular failure); (5) age (for both middle-aged/older adults and young adults); and (6) sex (for men and for women). The methodological quality of studies was appraised using the modified Downs and Black checklist. Results A total of 22 studies were found to meet the inclusion criteria. The average score on the Downs and Black checklist was 18 (range 13–22 points). Four studies were classified as being of good methodological quality, while the rest were classified as being of moderate methodological quality. Results of the meta-analysis showed a significant effect (p = 0.003) of RT frequency on muscular strength gains. Effect sizes increased in magnitude from 0.74, 0.82, 0.93, and 1.08 for training 1, 2, 3, and 4+ times per week, respectively. A subgroup analysis of volume-equated studies showed no significant effect (p = 0.421) of RT frequency on muscular strength gains. The subgroup analysis for exercise selection for the 1RM test suggested a significant effect of RT frequency on multi-joint (p < 0.001), but not single-joint, 1RM test results (p = 0.324). The subgroup analysis for upper and lower body showed a significant effect of frequency (p = 0.004) for upper body, but not lower body, strength gains (p = 0.070). In the subgroup analysis for studies in which the training was and was not carried out to muscular failure, no significant effect of RT frequency was found. The subgroup analysis for the age groups suggested a significant effect of training frequency among young adults (p = 0.024), but not among middle-aged and older adults (p = 0.093). Finally, the subgroup analysis for sex indicated a significant effect of RT frequency on strength gains in women (p = 0.030), but not men (p = 0.190). Conclusions The results of the present systematic review and meta-analysis suggest a significant effect of RT frequency as higher training frequencies are translated into greater muscular strength gains. However, these effects seem to be primarily driven by training volume because when the volume is equated, there was no significant effect of RT frequency on muscular strength gains. Thus, from a practical standpoint, greater training frequencies can be used for additional RT volume, which is then likely to result in greater muscular strength gains. However, it remains unclear whether RT frequency on its own has significant effects on strength gain. It seems that higher RT frequencies result in greater gains in muscular strength on multi-joint exercises in the upper body and in women, and, finally, in contrast to older adults, young individuals seem to respond more positively to greater RT frequencies. More evidence among resistance-trained individuals is needed as most of the current studies were performed in untrained participants.
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Background Strength training set organisation and its relationship to the development of muscular strength have yet to be clearly defined. Current meta-analytical research suggests that different population groups have distinctive muscular adaptations, primarily due to the prescription of the strength training set dose. Objectives We conducted a meta-analysis with restrictive inclusion criteria and examined the potential effects of low (LWS), medium (MWS) or high weekly set (HWS) strength training on muscular strength per exercise. Secondly, we examined strength gain variations when performing multi-joint or isolation exercises, and probed for a potential relationship between weekly set number and stage of subjects’ training (trained versus untrained). Methods Computerised searches were performed on PubMed, MEDLINE, SWETSWISE, EMBASE and SPORTDiscus™ using the terms ‘strength training’, ‘resistance training’, ‘single sets’, ‘multiple sets’ and ‘volume’. As of September 2016, 6962 potentially relevant studies were identified. After review, nine studies were deemed eligible per pre-set inclusion criteria. Primary data were pooled using a random-effect model. Outcomes for strength gain, strength gain with multi-joint and isolation exercise were analysed for main effects. Sensitivity analyses were calculated for several subgroups by separating the data set and by calculation of separate analyses for each subgroup. Heterogeneity between studies was assessed using the Cochran Q and I2 statistics. ResultsPre- versus post-training strength analysis comprised 61 treatment groups from nine studies. For combined multi-joint and isolation exercises, pre- versus post- training strength gains were greater with HWS compared with LWS [mean effect size (ES) 0.18; 95% CI 0.06–0.30; p = 0.003]. The mean ES for LWS was 0.82 (95% CI 0.47–1.17). The mean ES for HWS was 1.01 (95% CI 0.70–1.32). Separate analysis of the effects of pre- versus post-training strength for LWS or MWS observed marginally greater strength gains with MWS compared with LWS (ES 0.15; 95% CI 0.01–0.30; p = 0.04). The mean ES for LWS was 0.83 (95% CI 0.53–1.13). The mean ES for MWS was 0.98 (95% CI 0.62–1.34). For multi-joint exercises, greater strength gains were observed with HWS compared with LWS (ES 0.18; 95% CI 0.01–0.34; p = 0.04). The mean ES for LWS was 0.81 (95% CI 0.65–0.97). The mean ES for HWS was 1.00 (95% CI 0.77–1.23). For isolation exercises, greater strength gains were observed with HWS compared with LWS (ES 0.23; 95% CI 0.06–0.40; p = 0.008). The mean ES for LWS was 0.95 (95% CI 0.30–1.60). The mean ES for HWS was 1.10 (95% CI 0.26–1.94). For multi-joint and isolation exercise-specific one repetition maximum (1 RM), marginally greater strength gains were observed with HWS compared with LWS (ES 0.14; 95% CI −0.01 to 0.29; p = 0.06). The mean ES for LWS was 0.80 (95% CI 0.47–1.13). The mean ES for HWS was 0.97 (95% CI 0.68–1.26). Conclusion This meta-analysis presents additional evidence regarding a graded dose–response relationship between weekly sets performed and strength gain. The use of MWS and HWS was more effective than LWS, with LWS producing the smallest pre- to post-training strength difference. For novice and intermediate male trainees, the findings suggest that LWSs do not lead to strength gains compared with MWS or HWS training. For those trainees in the middle ground, not a novice and not advanced, the existing data provide a relationship between weekly sets and strength gain as set configurations produced different pre- to post-training strength increases. For well trained individuals, the use of either MWS or HWS may be an appropriate dose to produce strength gains.
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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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The purpose of this paper was to systematically review the current literature and elucidate the effects of total weekly resistance training (RT) volume on changes in measures of muscle mass via meta-regression. The final analysis comprised 34 treatment groups from 15 studies. Outcomes for weekly sets as a continuous variable showed a significant effect of volume on changes in muscle size (P = 0.002). Each additional set was associated with an increase in effect size (ES) of 0.023 corresponding to an increase in the percentage gain by 0.37%. Outcomes for weekly sets categorised as lower or higher within each study showed a significant effect of volume on changes in muscle size (P = 0.03); the ES difference between higher and lower volumes was 0.241, which equated to a percentage gain difference of 3.9%. Outcomes for weekly sets as a three-level categorical variable (<5, 5-9 and 10+ per muscle) showed a trend for an effect of weekly sets (P = 0.074). The findings indicate a graded dose-response relationship whereby increases in RT volume produce greater gains in muscle hypertrophy.
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Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a systematic review and meta-analysis of experimental studies designed to investigate the effects of weekly training frequency on hypertrophic adaptations. Following a systematic search of PubMed/MEDLINE, Scoups, and SPORTDiscus databases, a total of 25 studies were deemed to meet inclusion criteria. Results showed no significant difference between higher and lower frequency on a volume-equated basis. Moreover, no significant differences were seen between frequencies of training across all categories when taking into account direct measures of growth, in those considered resistance-trained, and when segmenting into training for the upper body and lower body. Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference.
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Purpose: To compare the effects of a high- versus a moderate-training frequency on maximal strength and body composition. Methods: 28 young, healthy resistance-trained males were randomly assigned to either: 3x/week (3x; n=16) or 6x/week (6x; n=12). Dependent variables (DVs) assessed at baseline and after the 6-week training intervention included: squat 1RM (SQ1RM), bench press 1RM (BP1RM), deadlift 1RM (DL1RM), powerlifting total (PLT), Wilk's coefficient (WC), fat-free mass (FFM) and fat mass (FM). Data for each DV was analyzed via a 2x2 between-within factorial repeated measures ANOVA. Results: There was a main effect for time (p < 0.001) for SQ1RM (3x: + 16.8 kg; 6x: + 16.7 kg), BP1RM (3x: + 7.8 kg; 6x: + 8.8 kg), DL1RM (3x: + 19 kg; 6x: + 21 kg), PLT (3x: + 43.6 kg; 6x: + 46.5 kg), WC (3x: + 27; 6x: + 27.1), and FFM (3x: + 1.7 kg; 6x: + 2.6 kg). There were no group x time interactions or main effects for group. Conclusion: The primary finding was that 6-weeks of resistance training lead to significant increases in maximal strength and fat-free mass. Additionally, it appears that increased training frequency does not lead to additional strength improvements when volume and intensity are equated. Practical Application: High frequency (6x/wk) resistance training does not appear to offer additional strength and hypertrophy benefits over lower frequency (3x/wk), when volume and intensity are equated. Coaches and practitioners can therefore expect similar increases in strength and lean body mass with both 3- and 6-weekly sessions.
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The present study compared the effects of two weekly-equalized volume and relative load interventions on body composition, strength and power. Based on individual baseline maximal strength values, eighteen recreationally trained men were pair-matched and consequently randomly assigned to one of the following experimental groups: a low volume per session with a high frequency (LV-HF, n = 9) group who trained 4-days (Mondays, Tuesdays, Thursdays and Fridays) or a high volume per session and low frequency (HV-LF, n = 9) group who trained 2-days (Mondays and Thursdays). Both groups performed two different routines over 6 weeks. Participants were tested pre- and post- intervention for maximal strength, upper body power, fat-free mass, limb circumferences and muscle thickness. Compared to baseline values, both groups increased their fat-free mass (HV-LF +1.19 ± 1.94; LV-HF +1.36 ± 1.06 kg, p<0.05) and vastus medialis thickness (HV-LF +2.18±1.88, p<0.01; LV-HF +1.82±2.43 mm, p<0.05), but only the HV-LF group enhanced arm circumference (1.08±1.47cm, p<0.05), elbow flexors thickness (2.21±2.81 mm, P<0.01) values and decreased their fat mass (-2.41 ± 1.10, P<0.01). Both groups improved (p<0.01) the maximal loads lifted in the bench press (LV-HF +0.14 ± 0.01; HV-LF +0.14 ± 0.01 kg.body mass-1) and the squat (LV-HF +0.14 ± 0.06; HV-LF 0.17 ± 0.01 kg.body mass-1) exercises as well as in upper body power (LV-HF +0.22 ± 0.25; HV-LF +0.27 ± 0.22 watts.body mass-1) Although both training strategies improved performance and lower body muscle mass, only the HV-LF protocol increased upper body hypertrophy and improved body composition.