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Low-Load Bench Press Training to Fatigue Results in Muscle Hypertrophy Similar to High-Load Bench Press Training

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The purpose of this study was to determine whether the training responses observed with low-load resistance exercise to volitional fatigue translates into significant muscle hypertrophy, and compare that response to high-load resistance training. Nine previously untrained men (aged 25 [SD 3] years at the beginning of the study, standing height 1.73 [SD 0.07] m, body mass 68.9 [SD 8.1] kg) completed 6-week of high load-resistance training (HL-RT) (75% of one repetition maximal [1RM], 3-sets, 3x/wk) followed by 12 months of detraining. Following this, subjects completed 6 weeks of low load-resistance training (LL-RT) to volitional fatigue (30% 1 RM, 4 sets, 3x/wk). Increases (p < 0.05) in magnetic resonance imaging-measured triceps brachii and pectorals major muscle cross-sectional areas were similar for both HL-RT (11.9% and 17.6%, respectively) and LL-RT (9.8% and 21.1%, respectively). In addition, both groups increased (p < 0.05) 1RM and maximal elbow extension strength following training; however, the percent increases in 1RM (8.6% vs. 21.0%) and elbow extension strength (6.5% vs. 13.9%) were significantly (p < 0.05) lower with LL-RT. Both protocols elicited similar increases in muscle cross-sectional area, however differences were observed in strength. An explanation of the smaller relative increases in strength may be due to the fact that detraining after HL-RT did not cause strength values to return to baseline levels thereby producing smaller changes in strength. In addition, the results may also suggest that the consistent practice of lifting a heavy load is necessary to maximize gains in muscular strength of the trained movement. These results demonstrate that significant muscle hypertrophy can occur without high-load resistance training and suggests that the focus on percentage of external load as the important deciding factor on muscle hypertrophy is too simplistic and inappropriate.
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International Journal of Clinical Medicine, 2013, 4, 114-121
http://dx.doi.org/10.4236/ijcm.2013.42022 Published Online February 2013 (http://www.scirp.org/journal/ijcm)
Low-Load Bench Press Training to Fatigue Results in
Muscle Hypertrophy Similar to High-Load Bench Press
Training
Riki Ogasawara1,2, Jeremy P. Loenneke3, Robert S. Thiebaud3, Takashi Abe1,4
1Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Japan; 2College of Sport and Health Science, Ritsumeikan
University, Kusatsu, Japan; 3Department of Health and Exercise Science, University of Oklahoma, Norman, USA; 4Department of
Health, Exercise Science, & Recreation Management, University of Mississippi, Oxford, USA.
Email: t12abe@gmail.com
Received December 20th, 2012; revised January 20th, 2013; accepted January 27th, 2013
ABSTRACT
The purpose of this study was to determine whether the training responses observed with low-load resistance exercise to
volitional fatigue translates into significant muscle hypertrophy, and compare that response to high-load resistance
training. Nine previously untrained men (aged 25 [SD 3] years at the beginning of the study, standing height 1.73 [SD
0.07] m, body mass 68.9 [SD 8.1] kg) completed 6 weeks of high load-resistance training (HL-RT) (75% of one repeti-
tion maximal [1RM], 3-sets, 3x/wk) followed by 12 months of detraining. Following this, subjects completed 6 weeks
of low load-resistance training (LL-RT) to volitional fatigue (30% 1 RM, 4 sets, 3x/wk). Increases (p < 0.05) in mag-
netic resonance imaging-measured triceps brachii and pectoralis major muscle cross-sectional areas were similar for
both HL-RT (11.9% and 17.6%, respectively) and LL-RT (9.8% and 21.1%, respectively). In addition, both groups in-
creased (p < 0.05) 1RM and maximal elbow extension strength following training; however, the percent increases in
1RM (8.6% vs. 21.0%) and elbow extension strength (6.5% vs. 13.9%) were significantly (p < 0.05) lower with LL-RT.
Both protocols elicited similar increases in muscle cross-sectional area, however differences were observed in strength.
An explanation of the smaller relative increases in strength may be due to the fact that detraining after HL-RT did not
cause strength values to return to baseline levels thereby producing smaller changes in strength. In addition, the results
may also suggest that the consistent practice of lifting a heavy load is necessary to maximize gains in muscular strength
of the trained movement. These results demonstrate that significant muscle hypertrophy can occur without high-load
resistance training and suggests that the focus on percentage of external load as the important deciding factor on muscle
hypertrophy is too simplistic and inappropriate.
Keywords: Bench Press; Training Intensity; Muscle CSA; MRI; Strength
1. Introduction
As a muscle is overloaded from increased mechanical
work, the added stress increases skeletal muscle amino
acid transporter expression [1], which in turn enhances
the synthesis of the contractile proteins, actin and myosin
[2]. These acute positive balances between muscle protein
synthesis (MPS) and muscle protein breakdown (MPB)
lead to skeletal muscle hypertrophy over time which oc-
curs from both an increase in the thickness and number
of myofibrils [see molecular pathway review by Adams
[3]. Although skeletal muscle hypertrophy occurs in both
slow twitch (ST) and fast twitch (FT) fibers, the latter has
the greatest potential for growth [4]. Therefore it is been
hypothesized that skeletal muscle hypertrophy can occur
independent of exercise load, as long as FT fibers are
activated [5,6].
Conventional thought is that at least 70% of one’s
repetition maximum (1 RM) must be lifted repeatedly to
observe a meaningful increase in muscular size [7]. How-
ever, acute molecular research indicates that external
exercise load may be of less importance when adequate
volume of resistance exercise is completed. To illustrate,
when four sets of resistance exercise was performed at
30% 1 RM to volitional fatigue, myofibril MPS was ele-
vated to the same level as 90% 1 RM to volitional fatigue
(not work matched) [8]. This is contrary to what has
commonly been reported in the literature which states
that training to volitional fatigue is not an effective
stimulus unless a sufficient external load as defined by
percentage of 1 RM (~80% 1 RM) is lifted. The common
thought has always been that higher repetition training
Copyright © 2013 SciRes. IJCM
Low-Load Bench Press Training to Fatigue Results in Muscle Hypertrophy Similar to High-Load Bench Press Training 115
cannot produce a stress that is adequate enough to recruit
and fatigue the highest threshold motor units [9].
Interestingly, Campos et al. [10] provide the only evi-
dence to date that resistance exercise to volitional fatigue
at higher loads is more effective than training at lower
loads for skeletal muscle hypertrophy (4 sets 3 - 4 RM vs.
2 sets 20 - 28 RM). However, using the identical meth-
ods of Campos et al. [10], Leger et al. [11] observed sig-
nificant increases in muscle hypertrophy, muscular strength,
and endurance independent of the external load lifted.
One possible reason for the difference could be due to
the older less active subjects used in latter study (36 vs
22 yrs). In addition, the volume of exercise (2 sets) may
have been inadequate to recruit the higher threshold mo-
tor units in the younger more active subjects used in the
Campos et al. [10] paper.
The aforementioned evidence has led to the formation
of the metabolite/volume threshold theory [5]. This the-
ory states that, assuming an adequate exercise volume is
achieved, the recruitment of FT fibers appears to be the
large driving force of skeletal muscle hypertrophy where-
as the external load lifted and systemic endogenous hor-
mone elevations may not be as important as previously
thought [12,13]. Much of this theory was based on acute
myofibril MPS and it is acknowledged that although
these acute studies are hypothesized to be predictive of
chronic adaptations, they are not definitive as incongru-
ences may exist between the acute and chronic changes
following resistance training [14,15]. Therefore, the pur-
pose of this study was to determine whether the training
responses observed with low-load resistance exercise to
volitional fatigue translates into significant muscle hy-
pertrophy, and compare that response to high-load resis-
tance training. Low load knee extensor exercise to fa-
tigue has shown that muscle hypertrophy (whole muscle
and fiber level) occurs at levels similar to higher loads
[16], however it is currently unknown whether this is
also true for upper body resistance exercise. Bench press
is one of the major exercises for developing the upper
body, however, very few studies report muscle size
changes in the chest and upper arm following a single
mode of high-load bench press training [17,18]. In the
present study, a within subject experimental design was
chosen to reduce biological variability. Further, due to
possible differences in systemic endogenous hormones
with each loading scheme and the cross-training neural
adaptations associated with a unilateral training model
[19], each subject completed both exercise protocols sep-
arated by over a year (12 months). All subjects began
with high-load resistance training as this design also al-
lowed us to investigate the muscle size and strength
changes to one year of detraining with traditional high
load exercise. Although the order of training was not
randomized, it increased our statistical power to investi-
gate at least one of our purposes with the possibility of a
poor attrition rate with such a long investigation. We
hypothesized that similar increases in muscle hypertro-
phy would be observed with both protocols, independent
of the external load lifted.
2. Material and Methods
2.1. Subjects
Nine previously untrained young men (aged 25 [SD 3]
years at the beginning of the study) volunteered to par-
ticipate in two different 6-week resistance training pro-
tocols separated by 12 months (Table 1). In the first
training protocol, all subjects performed high-load (75%
of 1 RM) resistance exercise. Twelve months after the
end of the first training protocol, the subjects performed
the second resistance training program with low-loads
(30% of 1 RM). None of the subjects performed resis-
tance training as well as aerobic-type training for at least
9 months prior to the start of the second training protocol.
Subjects were instructed to maintain their usual dietary
regimen throughout the study. All subjects were in-
formed of the procedures, risks, and benefits and signed
an informed consent document. The study was conducted
according to the Declaration of Helsinki and was ap-
proved by the Ethics Committee for Human Experiments
at The University of Tokyo, Japan.
2.2. Resistance Training Protocol
Free-weight bench press exercise was performed 3 days
per week (Monday, Wednesday, Friday) in both the
high-load (HL-RT) as well as the low-load (LL-RT) re-
sistance training protocol. The exercise session in the
HL-RT consisted of 3 sets (3 min rest between sets) of 10
reps at 75% of 1RM, while the exercise session with LL-
RT consisted of 4 sets (3 min rest between sets) of bench
press exercise until volitional fatigue at 30% of 1 RM.
During HL-RT and LL-RT exercise sessions, the veloci-
ties of the eccentric and concentric movements were
standardized to approximately 2-second (eccentric ~1 s,
concentric ~1 s) using a metronome. During the latter
repetitions for the HL-RT, velocity decreased to ~2
Table 1. Physical characteristics of the subjects.
Height Body mass Body mass index
(m) (kg) (kg/m2)
HL-RT pre (0.07) 1.73 68.9 (8.1) 23.0 (2.8)
HL-RT post 69.5 (8.5)* 23.2 (2.8)
LL-RT pre (0.07) 1.74 68.8 (8.0) 22.9 (2.8)
LL-RT post 69.4 (7.9)* 23.1 (2.5)
HL-RT, high-load resistance training; LL-RT, low-load resistance training;
*p < 0.05, pre vs. post.
Copyright © 2013 SciRes. IJCM
Low-Load Bench Press Training to Fatigue Results in Muscle Hypertrophy Similar to High-Load Bench Press Training
116
sec per muscle action. Training load was adjusted to the
new 1RM determined at 3 weeks in both training proto-
cols. For the HL-RT, if subjects were able to perform 12
repetitions or more during a training session, the training
load was increased ~5% for the next training session. To
ensure adequate training load, all training sessions were
surveyed and supervised by trained personnel. All sub-
jects successfully completed every training session.
2.3. Measurements Schedule
Subjects testing took place before the start of the study
(pre) and 3 - 4 days after (post) the 6-week training pe-
riod. The magnetic resonance imaging (MRI) measure-
ment was obtained between 16:00 and 19:00 hours. The
strength measurement was determined on the same day or
the following day after the MRI measurement. All meas-
urements were balanced for the time of day.
2.4. Strength Measurement
All subjects completed 2 - 3 familiarization sessions to
receive instruction on proper technique and to practice
the 1 RM and maximal voluntary isometric strength
(MVC) tests. The 1RM was assessed with the free-
weight bench press exercise. The 1 RM was determined
by progressively increasing the weight lifted until the
subject failed to lift the weight through a complete range
of motion. Usually 5 trials were required to complete a 1
RM test. Adequate amount of recovery time was permit-
ted between 1RM trials (3 - 5 min) [20]. MVC of the
elbow extensors (right arm) was measured by using an
isokinetic dynamometer (Biodex System 3, Biodex Me-
dical Systems Inc., Shirley, NY, USA). The subjects
were comfortably seated on a chair and the arm was po-
sitioned on a firm and stable table at chest level with an
elbow joint angle of 90˚ (0˚ at full extension). The upper
arm was maintained in the horizontal plane while the
subject’s wrist was fixed at the end of the lever arm in a
position halfway between supination and pronation. The
elbow extensor force was measured with a transducer,
while a diagonal strap was secured over the elbow to
maintain a stationary position during the MVC. Subjects
were instructed to contract as fast and forcefully as pos-
sible. MVC was measured twice. If MVC torque for the
first two MVCs varied by >5%, up to two additional
MVCs were performed. Each effort was held for ~5 s.
The coefficient of variation (CV) for this measurement
from test to retest was 3.1% [21]. Both MVC and 1RM
tests (same day and about 20 min apart between two tests)
were performed before training and after 3 and 6 weeks
of training.
2.5. Muscle Size Measurements
Multi-slice MRI images of the upper arm and chest were
obtained using a MRI scanner (General Electric Yokoga-
wa Signa 0.2-T, Milwaukee, WI, USA). A T1-weighted,
spin-echo, axial plane sequence was performed with a
520 ms repetition time and a 20 ms echo time. Subjects
rested quietly in the magnet bore in a supine position
with their arms extended. The lateral epicondyle of the
humerus was used as the origin point, and continuous
transverse images with 1.0 cm slice thickness (0.2 cm
interslice gap) were obtained from the lateral epicondyle
of the humerus to the acromial process of the scapula for
each subject (Figure 1). All MRI data were transferred to
a personal computer for analysis using specially designed
image analysis software (TomoVision Inc., Montreal,
Canada). For each slice, skeletal muscle tissue cross-
sectional area (CSA) was digitized. Triceps brachii (TB)
and pectoralis major (PM) muscle CSA of 3 continuous
slices for the muscle belly were averaged to represent a
single data point for statistical analysis, respectively. We
have previously determined that the CV of this meas-
urement was less than 1% [21].
2.6. Statistical Analysis
All values are expressed as mean [SD]. TB and PM mus-
cle CSA, 1RM, MVC data were analyzed using two-way
ANOVA with repeated measures (group × time). Post
hoc testing was performed using Tukey-Kramer when
appropriate. Pre-training values of each training protocol
were compared using a paired t-test. Pearson product-
moment correlation coefficients determined the associa-
tion between high-load and low-load hypertrophy changes
in TB and PM muscle CSA. Significance was set at p <
0.05. All analyses were performed using JMP statistical
software version 8.0 (SAS Institute, Cary, NC, USA).
Figure 1. Typical magnetic resonance imaging image show-
ing transverse scan of the chest.
Copyright © 2013 SciRes. IJCM
Low-Load Bench Press Training to Fatigue Results in Muscle Hypertrophy Similar to High-Load Bench Press Training
Copyright © 2013 SciRes. IJCM
117
3. Results
There was no difference in body weight at pre-training
between HL-RT (68.9 [8.1] kg) and LL-RT (68.8 [8.0]
kg). After 6-week of training, body weight increased (p <
0.05) by 0.6 kg in the HL-RT and 0.6 kg in the LL-RT.
During the LL-RT protocol, the average total number of
repetitions for each exercise session was 141 [14].
Following 6 weeks of training, 1 RM and MVC
strength increased (p < 0.05) significantly in both HL-RT
and LL-RT protocols. However, the percent increases in
strength were lower (p < 0.05) in the LL-RT (1 RM 8.6
[2.9]%, MVC 6.5 [4.9]%) than in the HL-RT (1 RM 21.0
[5.9]%, MVC 13.9 [7.5]%) (Figure 2). Before the start
of the LL-RT, 1-RM and MVC strength had not returned
to pre-training HL-RT 1-RM and MVC strength levels
(Figure 2).
At the start of training, muscle CSA in the PM was the
same between the HL-RT and LL-RT protocols, whereas
muscle CSA in the TB was 2.2% higher (p = 0.03) in
LL-RT than in HL-RT. The TB muscle CSA increased (p
< 0.01) following LL-RT and HL-RT and the percent
increase in muscle CSA was similar between the two
training protocols (LL-RT 9.8 [4.6]%, HL-RT 11.9
[2.6]%) (Figure 3(a)). Similarly, absolute and relative
increases (p < 0.01) in PM muscle CSA were similar
between HL-RT and LL-RT (Figure 3B). A significant
correlation was observed between percent increase in
muscle CSA following HL-RT and LL-RT in the TB and
PM muscles (Figure 4).
HL-RT LL-RT HL-RT LL-RT
H
L
-RT LL-RT
HL-RT LL-RT
30
20
10
0
Change (%)
25
20
15
10
5
0
50
40
30
20
10
0
MVC (Nm)
100
80
60
40
20
0
Bench press IRM (kg)
(a) (b)
Pre Pre Pre Pre
wk3
wk3 wk3 wk3
Pos
t
Post Post
Post
(a) (b)
Figure 2. Changes in maximum dynamic (bench press one repetition maximum) and isometric (elbow extension) strength
following 6 weeks of high-load (HL-RT) and low-load (LL-RT) resistance training. Pre, before training; wk3, after 3 weeks;
Post, after 6 weeks. *p < 0.05 vs. pre- training, p < 0.05 vs. HL-RT.
HL-RT LL-RT HL-RT LL-RT
H
L
-RT LL-RT
H
L
-RT LL-RT
30
20
10
0
Change (%)
20
15
10
5
0 50
40
30
20
10
0
40
30
20
10
0
Muscle CSA (cm
2
)
(a) (b)
Pre
Post
Change (%)
TB PM
Muscle CSA (cm
2
)
Pre
Pre
Pre Post Post Post
(a) (b)
Figure 3. Changes in muscle cross-sectional area (CSA) in the triceps brachii (TB) and pectoralis major (PM) muscles fol-
lowing 6 weeks of high-load (HL-RT) and low-load (LL-RT) resistance training. Pre, before training; Post, after 6 weeks. *p <
0.05 vs. pre-training, p < 0.05 vs. HL-RT.
Low-Load Bench Press Training to Fatigue Results in Muscle Hypertrophy Similar to High-Load Bench Press Training
118
0 5 10 15 20
40
30
20
10
0
20
15
10
5
0
Low-load training (% change)
PM
r = 0.75
P = 0.020
TB
0 10 20 30 40
r = 0.76
P = 0.017
Low-load training (% change)
High-load training (% change) High-load training (% change)
Figure 4. Relationship between percent increase in muscle cross-sectional area following 6 weeks of high-load (HL-RT) and
low-load (LL-RT) resistance training in the triceps brachii (TB) and pectoralis major (PM) muscles.
4. Discussion
This study found that 1) LL-RT to volitional fatigue and
HL-RT results in similar levels of skeletal muscle hyper-
trophy in the upper body and 2) significant correlations
in the degree of muscle hypertrophy between LL-RT to
volitional fatigue and HL-RT. This data suggests that
skeletal muscle hypertrophy can occur independent of a
higher load in the upper body as long as there is adequate
exercise volume. In addition, one year of detraining from
HL-RT results in a complete loss of muscle size, how-
ever muscle strength was decreased but still elevated
above the pre-training level.
4.1. Muscle Hypertrophy
Six weeks of high-load (75% 1 RM) resistance training
resulted in significant skeletal muscle hypertrophy. In-
terestingly, after 12 months of detraining the same sub-
jects then performed low-load resistance training to voli-
tional fatigue and found similar increases in skeletal
muscle hypertrophy compared to that observed with
high-load training. This is contrary to previous research
[9,10] and recommendations [7] that report higher-loads
to be superior. However, the research in which those
recommendations were largely based were matched for
work and it appears that in order for low-loads to in-
crease muscle hypertrophy to levels similar to high-loads,
exercise must be taken to volitional fatigue [5].
This study confirms acute research from Burd et al. [8]
who found similar increases in myofibril MPS inde-
pendent of exercise load when exercise was taken to vo-
litional fatigue. This might be related to the significant
increase in muscle time under tension when repetitions
are taken to volitional fatigue as this has recently been
found to be an important variable in the synthetic re-
sponse [2]. In addition, MPS from resistance training
occurs primarily from the activation of signaling proteins,
primarily S6K1, which are approximately 3 to 4-fold
higher in FT fibers compared to ST [22]. Furthermore,
phosphorylation of this signaling protein has shown to be
predictive of skeletal muscle hypertrophy [23]. This
suggests that skeletal muscle hypertrophy occurs inde-
pendent of a higher exercise load, as long as FT fibers
are activated from sufficient exercise volume [5,6]. It is
acknowledged that the protein degradation response to
low-load resistance training to volitional fatigue is not
known, as research is typically completed under the as-
sumption that synthesis rates and not degradation rates
are more responsive to resistance exercise in healthy
humans [24]. The similar levels of muscle hypertrophy
between protocols suggest that this assumption is likely
true for the upper body. This also supports recent re-
search completed in the lower body, which found sig-
nificant muscle hypertrophy with low load (30% 1 RM)
knee extensor exercise to fatigue [16].
Interestingly, it should be mentioned that rodent data
suggest that the myonuclei gained from resistance train-
ing are not lost following 3 months of detraining [25].
This has led some to speculate that this retention of
myonuclei is important in the “muscle memory” response
to exercise. Therefore, if one is trained following the
cessation of training, it might be possible that the re-
bound in muscle hypertrophy is due to the myonuclei that
were added with training and maintained through muscle
atrophy. It is currently unknown how this translates to
humans or how long this effect lasts, but we cannot rule
out the possibility that this may be playing some role in
the equal response between variables.
The percentage increases in muscle hypertrophy for
the TB and PM were larger than what has been previ-
ously reported for the lower body. Unfortunately, the
molecular mechanisms for upper body muscle hypertro-
phy are currently under studied when compared with
what is known for the lower body. However, the results
of the present investigation suggest that heavy resistance
exercise induced activation of muscle protein metabolism
may be more responsive in the upper body compared to
the lower body. To illustrate, Seynnes et al. [26] ob-
served a 7% increase in quadriceps femoris CSA follow-
ing 35 days of lower body bilateral knee extensions. In
Copyright © 2013 SciRes. IJCM
Low-Load Bench Press Training to Fatigue Results in Muscle Hypertrophy Similar to High-Load Bench Press Training 119
addition, Abe et al. [20] observed after a 6 week total
body workout (70% 1 RM), that the quadriceps muscle
thickness increased 5%, however the PM and TB in-
creased 13% and 9%, respectively. Furthermore, using a
MRI, muscle CSA increased 16% in the PM and 10% in
the TB following 18 days of bench press training (75%
1RM) [27]. Yasuda et al. [28] also observed that 18 days
of bench press training (75% 1 RM) resulted in an 18%
increase in PM and a 10% increase in the TB. The cur-
rent findings are in agreement with the previous research
in the upper body which suggests that the upper body
may have a higher capacity for muscle hypertrophy than
the lower body.
4.2. Muscular Strength
Changes in strength between the LL-RT and HL-RT are
another interesting finding from this study. Both groups
had significant increases in strength following training;
however, the percent increases in strength were signifi-
cantly lower in the LL-RT protocol. An explanation of
the smaller relative increases in strength may be due to
the fact that detraining after HL-RT did not cause
strength values to return to baseline levels thereby pro-
ducing smaller changes in strength. Although subjects
were told to return back to their pre-training lifestyle, it is
possible that subjects maintained a level of activity high
enough to maintain strength but not muscle mass. Further,
it is possible that the neural adaptation to resistance exer-
cise is longer lasting than the hypertrophic response. In-
deed, there is evidence to support the finding that
strength does not return to baseline levels despite de-
training. In young women who did 20 weeks of strength
training and then detrained for 30 - 32 weeks, strength
levels significantly decreased but did not return to pre-
training levels [29]. In addition, Bickel et al. [30] found
that after 16 weeks of lower body training and 32 weeks
of detraining that strength significantly decreased by 7%
but remained 23% above baseline. Another study in older
adults found that 2 years of training followed by 3 years
of detraining produced significant decreases in dynamic
strength but levels remained slightly above baseline val-
ues and significantly higher than control subjects [31].
Although the reasons for this maintenance of strength are
unknown from the present investigation, it is possible
that following detraining there was a partial maintenance
of the increased volitional drive from the supraspinal
center which may have maintained part of the increased
muscle activation likely gained from HL-RT [32]. There-
fore, the lower amounts of strength observed in the
LL-RT group compared to the HL-RT may be more a
function of the training effect rather than the intervention
itself. Also, all subjects began training with high-load
resistance training and finished with low-load training,
therefore it remains unknown if the same strength effects
would be observed if the protocols were reversed. Lastly,
an alternative explanation is that the specificity of train-
ing may dictate the overall maximal gains in strength.
For example, the results may suggest that the consistent
practice of lifting a heavy load is necessary to maximize
gains in muscular strength of the trained movement.
5. Conclusion
This study verifies that similar degrees of muscle hyper-
trophy can occur in the upper body independent of a high
external load, provided enough muscular work is com-
pleted. This data seems to support that the acute myofi-
bril MPS responses previously observed with LL-RT to
fatigue do translate to chronic training adaptation. These
results demonstrate that significant muscle hypertrophy
can occur without high-load resistance training and sug-
gests that the focus on percentage of external load as the
important deciding factor on muscle adaptation (i.e.
muscle hypertrophy) is too simplistic and inappropriate.
6. Acknowledgements
The authors thank the students who participated in this
study. None of the authors had financial or personal con-
flict of interest with regard to this study. No sources of
funding were used to assist in the preparation of this
manuscript.
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... Swallowing exercises are often used in rehabilitation during CRT to increase muscle strength and prevent muscle atrophy. In general, muscle training is a well-established intervention for muscle strengthening, as it is believed to produce muscle hypertrophy effects and changes in the firing threshold and discharge rate of motor units (MUs), in addition to increasing the muscle output power [7,8]. Muscle strength evaluation using high-density surface electromyography (HD-sEMG) can provide detailed information about MUs. ...
... Swallowing exercises are often used in rehabilitation during CRT to increase muscle strength and prevent muscle atrophy. In general, muscle training is a well-established in tervention for muscle strengthening, as it is believed to produce muscle hypertrophy ef fects and changes in the firing threshold and discharge rate of motor units (MUs), in ad dition to increasing the muscle output power [7,8]. Muscle strength evaluation using high density surface electromyography (HD-sEMG) can provide detailed information abou MUs. ...
... The RMS reflects the muscle activation quantification of the MU, whereas the CoV indicates the spatial distribution of the muscle activity [10,17,18]. Muscle-strengthening exercises are thought to increase muscle strength by stimulating hypertrophy of the muscle fibers, lowering the recruitment threshold, and increasing the discharge rate [7,8], which has been proven in actual clinical practice [18]. ...
Article
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Background and Objectives: Muscle strength evaluation using high-density surface electromyography (HD-sEMG) was recently developed for the detailed analysis of the motor unit (MU). Detection of the spatial distribution of sEMG can detect changes in MU recruitment patterns resulting from muscle-strengthening exercises. We conducted a prospective study in 2022 to evaluate the safety and feasibility of transcutaneous electrical sensory stimulation (TESS) therapy using an interferential current device (IFCD) in patients with head and neck squamous cell carcinoma (HNSCC) undergoing chemoradiotherapy (CRT), and reported the safety and feasibility of TESS. We evaluated the efficacy of swallowing exercises in patients with HNSCC undergoing CRT and determined the significance of sEMG in evaluating swallowing function. Materials and Methods: In this supplementary study, the patients performed muscle-strengthening exercises five days a week. The association of the effects of the exercises with body mass index, skeletal muscle mass index, HD-sEMG, tongue muscle strength, and tongue pressure were evaluated. Results: We found significant correlations between the rate of weight loss and skeletal muscle mass index reduction and the rate of change in the recruitment of the MU of the suprahyoid muscle group measured using HD-sEMG. Conclusions: We believe that nutritional supplementation is necessary in addition to muscle strengthening during CRT.
... For example, if the change score (pre-to postintervention) in any given measurement does not differ from that of the time-matched nonexercise control group, then it would not be appropriate to conclude that such a change reflects any physiological adaptation(s) from training (4,11,20). Yet, despite the known importance of control groups in experimental work (12,43), they are rarely included in studies on resistance-trained individuals (7), which could be related to the possibility that resistance-trained individuals who stop training may lose skeletal muscle size (10,37) and would thus not serve the purpose of a control group. Be that as it may, it becomes difficult to determine whether an exercise intervention truly had an effect without the inclusion of a control group (4,20). ...
... Two studies (3,25) randomly assigned individuals who had previous resistance training experience to nonexercise control groups, and 2 others (2,29) assigned individuals to a control group but did not note whether it was a nonexercise control group. The first 2 study designs (3,25) become limited because of the greater difficulty of subject recruitment (i.e., having resistance-trained individuals stop training altogether to enroll in a study) and the possibility that a detraining effect influenced (or even decreased) the mean change in the control group (i.e., the possibility that resistance-trained individuals who stop training may lose skeletal muscle size and/or strength) (10,37). In addition, those designs may be limited by the possibility that some resistance-trained individuals adhered to their assignment (i.e., to stop exercising), whereas other individuals did not, which in turn inflated the variability of the change score (i.e., SD) in the control group. ...
Article
The applicability of training effects from experimental research depends on the ability to quantify the degree of measurement error accurately over time, which can be accounted for by including a time-matched nonexercise control group. Yet, control groups are rarely included in studies on resistance-trained individuals. Many authors instead report short term relative or absolute measures of reliability for the interpretation of statistical tests and the size or meaning of effects observed and assume that good short-term reliability justifies the lack of a control group. In this article, we offer some potential alternatives for employing control groups in research studies on resistance-trained individuals. We wish to suggest researchers consider using a “time-matched training group” (i.e., resistance-trained individuals who keep an exercise log, continue their normal training, and perform the pre- and posttest measures spanning the same duration as that of the exercise group or groups) and/or a time-matched nonexercise control group (i.e., non resistance-trained individuals who perform only the pre- and posttest measures spanning the same duration as that of the exercise training group or groups). If it is not feasible (e.g., researchers do not wish to randomly assign individuals to a time-matched training group or include a time-matched nonexercise control group) to employ such designs, or relevant, then an alternative approach might be to include a run-in (i.e., control) period that spans the same duration as the exercise training intervention. Our hope is that this article can help strengthen future research designs conducted on resistance-trained individuals.
... Untrained participants demonstrate significant skeletal muscle hypertrophy from less than four weeks of RT (8,10,26,32). Specifically, upper body lean mass improves significantly during the early weeks of RT (17,20,27). Diverse training volumes result in lean mass and CSA improvements in untrained participants (1,3,11,18,29). ...
... , all of them showed similar increases in muscle hypertrophy in the groups with high and low loads of training, but 10 studies showed a higher increase in muscle strength in the group with high loads of training(Au et al., 2017;Fink et al., 2016;Jenkins et al., 2016;Jenkins et al., 2017;Jessee et al., 2018;Lasevicius et al., 2018;Lasevicius et al., 2022;Mitchell et al., 2012;Ogasawara et al., 2013;Van Roie et al., 2013b).Au et al. (2017) studied 46 young, healthy, trained male participants undergoing a 12-week training program and found that ...
Article
INTRODUCTION: Traditionally, it has been proposed that strength gains and muscle hypertrophy required distinct characteristics to be achieved with resistance training. However, current evidence shows that the obtaining of improvements of strength and hypertrophy can be obtained with a single resistance training protocol. The purpose of this systematic review was to examine the existing body of literature pertaining to association between load during resistance training and their effects on strength gains and muscle hypertrophy. METHODOLOGY: Searches were conducted on Web of Science, PubMed/Medline, and Embase with no year restriction applied to the search strategy. Selected studies met the following inclusion criteria: (a) studies that included a combination of young and old males and females, with no known medical conditions or injuries; (b) including a resistance training with high-loads (≥60% of one-repetition maximum, 1RM) or low-loads (<60% 1RM); (c) the duration and frequency of the resistance training protocols was equal; (d) measurement of hypertrophy and/or strength gains induced by the training; (e) in English and published in peer-reviewed journals. RESULTS: A total of 24 studies were included in the review. Overall, the increase in muscle mass were similar for both high-load and low-load resistance training protocols. However, in 10 out of 24 studies, the gains in strength were significantly higher with the high-load resistance training when compared to the low-load protocol. CONCLUSIONS: The use of loads above ≥60% of 1RM during a resistance training induces higher gains in muscle strength while muscle hypertrophy is similar to resistance training with lower loads. This suggests that the use of high loads is recommended during resistance training with the aim of maximizing training adaptations.
... This protocol was used in the first BFR studies (Takarada et al., 2000(Takarada et al., , 2002. It is also common that sets may be performed to concentric failure during BFR-RE Ogasawara et al., 2013;Takarada et al., 2002). ...
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Intermittent Claudication (IC) is a common and debilitating symptom of peripheral arterial disease (PAD) resulting in significant reduction in exercise performance and quality of life. Supervised exercise programmes are part of first-line treatment for IC proving highly effective for improving exercise performance and alleviating symptoms. Despite this, supervised exercise programmes have poor adherence in part to patients’ inability to tolerate IC related pain during walking exercise highlighting the need for alternative exercise modes. Blood flow restriction resistance exercise (BFR-RE) is a technique that facilitates local muscle hypoxia during resistance exercise to induce hypertrophy, strength, and muscular endurance. BFR-RE presents an exciting alternative modality to improve exercise performance in IC patients though requires research on safety, feasibility, and efficacy. This research explored the acute perceptual, affective, and physiological responses to resistance exercises performed at low-load with BFR (LL-BFR), low-load (LL) and moderate-load (ML) in healthy young and older adults; examined the inter-day reliability of a physical function test battery in IC patients sought to determine suitability of the test battery and smallest worthwhile change for each measure; and conducted a randomised controlled trial to evaluate the safety, feasibility, and efficacy of an 8-week LL-BFR resistance exercise programme in IC patients. No adverse events were recorded during this body of work that was attributed to the protocols or procedures administered. LL-BFR was shown to be more demanding than LL and ML predominately through increased pain (p ≤ 0.024, d = 0.8 – 1.4). However, this did not lead to decrements in affective response and fatigue post exercise. Excellent reliability (≥ 0.92 ICC) of the physical function test battery was observed in IC patients and the minimum likely change (76% chance) was calculated for each measure. The feasibility trial observed high adherence (LL-BFR = 78.3%, LL = 83.8%) and completion rates (LL-BFR = 93%, LL = 87%). Significant clinical improvement (>35 m) in the six-minute walk test (6MWT) was achieved in 86% of patients in LL-BFR but only 46% of patients in LL. Additionally, time to claudication pain during 6MWT was likely increased (44.7 s [20.8, 68.6]) for LL-BFR and likely unchanged (4.4 s [-32.4, 23.6]) for LL. This thesis supports BFR-RE as a safe, feasible and potentially effective exercise mode for IC patients.
... Las recomendaciones generales para el trabajo de fuerza e hipertrofia muscular rondan entre el 65 % al 85 % de la 1RM (American College of Sports Medicine, 2009), aunque se ha demostrado que, tanto intensidades moderadas a bajas (<60 % 1RM), como intensidades altas (>80 % RM), son eficaces para influir sobre la hipertrofia, siempre y cuando, las series sean programadas cercanas al fallo muscular (Lasevicius et al., 2018;Ogasawara et al., 2013;Schoenfeld, 2017b). Arazi et al. (2021) ocuparon un rango de intensidad del 65 % al 95 % de la 1RM para ambos grupos, (cluster y entrenamiento de fuerza tradicional), durante su intervención. ...
Article
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Objetivo: El objetivo de la presente revisión sistemática fue determinar los efectos del entrenamiento cluster sobre la hipertrofia muscular. Metodología: Se realizó una búsqueda bibliográfica en las bases de datos electrónicas Pubmed, Scopus y Web of Science, utilizando las siguientes palabras clave: 'cluster training', 'rest Interval', 'rest pause', 'hypertrophy', 'resistance training' y 'cross sectional area'. Se incluyeron ensayos clínicos que utilizaron el entrenamiento cluster como intervención en personas mayores de 18 años de ambos sexos. Resultados: La revisión sistemática obtenida durante la búsqueda de las bases de datos consultadas arrojó un total de 23 artículos, potencialmente elegibles, de los cuales se tomó una muestra de 9, con los que se podían obtener resultados que respondían al objetivo de esta revisión. La cantidad de participantes de los 9 artículos elegibles fue de 172 sujetos. Los entrenamientos cluster permiten aumentar el volumen de entrenamiento y la intensidad sin provocar elevados niveles de fatiga, favoreciendo así el desarrollo de la hipertrofia muscular. Conclusiones: Los resultados de esta revisión sistemática sugieren que los entrenamientos cluster pueden ser una herramienta eficaz para el desarrollo de la hipertrofia muscular.
... The American College of Sports Medicine recommends strength training with a resistance of at least 70% of one's one-repetition maximum (1RM) to induce muscular growth 5 . However, it has been demonstrated that exercises performed to volitional fatigue display similar hypertrophy when utilizing high loads and low loads 6,7 . Utilizing low loads to fatigue may become tedious for patients to complete due to the high number of repetitions required. ...
Article
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The use of blood flow restriction is becoming more common and requires the use of individualized pressures in order to remain a safe and effective rehabilitation modality. Measuring limb occlusion pressure (LOP) allows the practitioner to set the restriction pressure so that full occlusion does not occur. Objective: Compare a research-grade clinical vascular doppler and a consumer-grade vascular doppler in the measurement of LOP. Design: A randomized crossover design measuring LOP in the upper and lower body. Methods: 20 participants (men=10) visited the laboratory on one occasion. Limb circumference in the arm and thigh was measured. Following 10 min of supine rest, LOP was measured either in the arm, using a 5 cm wide inelastic cuff, or in the leg, using a 10 cm wide inelastic cuff. Measurements were repeated at 5 min intervals until LOP had been measured in both limbs with both dopplers. Results: Bland-Altman analysis showed agreement between the two dopplers in both the upper body (mean bias: 0.6 (-1.3 – 2.4) mmHg) and lower body (mean bias: -1.5 (-4.4 – 1.4) mmHg). Two one-sided tests of equivalence determined that both dopplers measured a statistically equivalent LOP in the upper body (p = .547) and lower body (p = .288). Conclusions: In a healthy, young population, the consumer-grade vascular doppler measured LOP equally as well as the research-grade clinical doppler.
Article
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Range of motion in exercises is one of the foundations for greater activation of a muscle group. The objective of this investigation was to compare the structural and functional capacity of the triceps brachii between three groups with different angles (90°, 110°, and 130°) in a unilateral elbow extension exercise. The sample consisted of 25 subjects with a mean age of 24.12 ± 3.83 years, mean height of 1.78 ± 0.10 m and mean body weight of 78.01 ± 15.70 kg. The following variables were collected pre-and post-intervention: triceps brachii circumference, one repetition maximum, and electromyography during dynamic exercise. Over eight weeks, subjects performed this exercise, performing 3 sets of 12 repetitions for each arm, with days of rest in between. The results showed that the 110° angle provided greater muscle activation compared to the other angles. There was no difference between the triceps brachii circumference and the root mean square (RMS) between the groups. It was concluded that, although the 110º angle showed a tendency for greater muscle activation, the RMS and arm perimeter data did not show significant differences between all the angles evaluated (90º, 110º, 130º). 446 AIMS Biophysics Volume 11, Issue 4, 445−454.
Article
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Background Osteoarthritis (OA) is the most common and prevalent musculoskeletal disease associated with population aging, negatively impacting function and quality of life. A consequence of knee OA is quadriceps muscle weakness. Musculoskeletal rehabilitation using low load exercises, associated with Blood Flow Restriction (BFR) may be a useful alternative to high load exercises when those cannot be tolerated. Several systematic reviews have reported inconclusive results due to discrepancies in study findings, heterogeneity of results, evaluated time points, and research questions explored. Objective To perform an overview of systematic reviews with meta-analyses, synthesizing the most recent evidence on the effects of muscle strength training with BFR for knee OA. Methodology Systematic reviews that include primary controlled and randomized clinical trials will be considered for inclusion. Articles will be considered only if they present a clear and reproducible methodological structure, and when they clearly demonstrate that a critical analysis of the evidence was carried out using instrumented analysis. Narrative reviews, other types of review, overviews of systematic reviews, and diagnostic, prognostic and economic evaluation studies will be excluded. Studies must include adults aged 40 years and older with a diagnosis of knee OA. Two authors will perform an electronic search with guidance from an experienced librarian. The following databases will be searched: PubMed via MEDLINE, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), PEDro, Cumulative Index to Nursing and Allied Health Literature (CINAHL) via EBSCO host, Web of Science, and the gray literature. The search strategy used in the databases will follow the acronym PICOS (population, intervention, comparison, outcome, and study design). Screening (i.e., titles and abstracts) of studies identified by the search strategy will be selected using Rayyan (http://rayyan.qcri.org). The quality assessment will be performed using the “Assessment of Multiple Systematic Reviews” (AMSTAR-2) tool. Systematic Review Registration PROSPERO, CRD42022367209.
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The purpose of this study was to investigate the time course of hypertrophic adaptations in both the upper arm and trunk muscles following high-intensity bench press training. Seven previously untrained young men (aged 25 ± 3 years) performed free-weight bench press training 3 days (Monday, Wednesday and Friday) per week for 24 weeks. Training intensity and volume were set at 75% of one repetition maximum (1-RM) and 30 repetitions (3 sets of 10 repetitions, with 2-3 min of rest between sets), respectively. Muscle thickness (MTH) was measured using B-mode ultrasound at three sites: the biceps and triceps brachii and the pectoralis major. Measurements were taken a week prior to the start of training, before the training session on every Monday and 3 days after the final training session. Pairwise comparisons from baseline revealed that pectoralis major MTH significantly increased after week-1 (p = 0.002), triceps MTH increased after week-5 (p = 0.001) and 1-RM strength increased after week-3 (p = 0.001) while no changes were observed in the biceps MTH from baseline. Significant muscle hypertrophy was observed earlier in the chest compared to that of the triceps. Our results indicate that the time course of the muscle hypertrophic response differs between the upper arm and chest.
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To compare the effects of a periodic resistance training (PTR) program with those of a continuous resistance training (CTR) program on muscle size and function, 14 young men were randomly divided into a CTR group and a PTR group. Both groups performed high-intensity bench press exercise training [75 % of one repetition maximum (1-RM); 3 sets of 10 reps] for 3 days per week. The CTR group trained continuously over a 24-week period, whereas the PTR group performed three cycles of 6-week training (or retraining), with 3-week detraining periods between training cycles. After an initial 6 weeks of training, increases in cross-sectional area (CSA) of the triceps brachii and pectoralis major muscles and maximum isometric voluntary contraction of the elbow extensors and 1-RM were similar between the two groups. In the CTR group, muscle CSA and strength gradually increased during the initial 6 weeks of training. However, the rate of increase in muscle CSA and 1-RM decreased gradually after that. In the PTR group, increase in muscle CSA and strength during the first 3-week detraining/6-week retraining cycle were similar to that in the CTR group during the corresponding period. However, increase in muscle CSA and strength during the second 3-week detraining/6-week retraining cycle were significantly higher in the PTR group than in the CTR group. Thus, overall improvements in muscle CSA and strength were similar between the groups. The results indicate that 3-week detraining/6-week retraining cycles result in muscle hypertrophy similar to that occurring with continuous resistance training after 24 weeks.
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The purpose of this study was to investigate associations between acute exercise-induced hormone responses and adaptations to high intensity resistance training in a large cohort (n = 56) of young men. Acute post-exercise serum growth hormone (GH), free testosterone (fT), insulin-like growth factor (IGF-1) and cortisol responses were determined following an acute intense leg resistance exercise routine at the midpoint of a 12-week resistance exercise training study. Acute hormonal responses were correlated with gains in lean body mass (LBM), muscle fibre cross-sectional area (CSA) and leg press strength. There were no significant correlations between the exercise-induced elevations (area under the curve—AUC) of GH, fT and IGF-1 and gains in LBM or leg press strength. Significant correlations were found for cortisol, usually assumed to be a hormone indicative of catabolic drive, AUC with change in LBM (r = 0.29, P < 0.05) and type II fibre CSA (r = 0.35, P < 0.01) as well as GH AUC and gain in fibre area (type I: r = 0.36, P = 0.006; type II: r = 0.28, P = 0.04, but not lean mass). No correlations with strength were observed. We report that the acute exercise-induced systemic hormonal responses of cortisol and GH are weakly correlated with resistance training-induced changes in fibre CSA and LBM (cortisol only), but not with changes in strength. Electronic supplementary material The online version of this article (doi:10.1007/s00421-011-2246-z) contains supplementary material, which is available to authorized users.
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