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Differential effects of attentional focus strategies during long-term resistance training



The purpose of this study was to investigate the effects of using an internal versus external focus of attention during resistance training on muscular adaptations. Thirty untrained college-aged men were randomly assigned to an internal focus group (INTERNAL) that focused on contracting the target muscle during training (n = 15) or an external focus group (EXTERNAL) that focused on the outcome of the lift (n = 15). Training for both routines consisted of 3 weekly sessions performed on non-consecutive days for 8 weeks. Subjects performed 4 sets of 8–12 repetitions per exercise. Changes in strength were assessed by six repetition maximum in the biceps curl and isometric maximal voluntary contraction in knee extension and elbow flexion. Changes in muscle thickness for the elbow flexors and quadriceps were assessed by ultrasound. Results show significantly greater increases in elbow flexor thickness in INTERNAL versus EXTERNAL (12.4% vs. 6.9%, respectively); similar changes were noted in quadriceps thickness. Isometric elbow flexion strength was greater for INTERNAL while isometric knee extension strength was greater for EXTERNAL, although neither reached statistical significance. The findings lend support to the use of a mind–muscle connection to enhance muscle hypertrophy.
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European Journal of Sport Science
ISSN: 1746-1391 (Print) 1536-7290 (Online) Journal homepage:
Differential effects of attentional focus strategies
during long-term resistance training
Brad Jon Schoenfeld, Andrew Vigotsky, Bret Contreras, Sheona Golden,
Andrew Alto, Rachel Larson, Nick Winkelman & Antonio Paoli
To cite this article: Brad Jon Schoenfeld, Andrew Vigotsky, Bret Contreras, Sheona Golden,
Andrew Alto, Rachel Larson, Nick Winkelman & Antonio Paoli (2018): Differential effects of
attentional focus strategies during long-term resistance training, European Journal of Sport
Science, DOI: 10.1080/17461391.2018.1447020
To link to this article:
Published online: 13 Mar 2018.
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Differential effects of attentional focus strategies during long-term
resistance training
Department of Health Sciences, CUNY Lehman College, Bronx, NY, USA;
Department of Biomedical Engineering,
Northwestern University, Evanston, IL, USA;
Sport Performance Research Institute, AUT University, Auckland, New
Department of Exercise Science & Health Promotion, Arizona State University, Phoenix, AZ, USA;
Irish Rugby
Football Union, Dublin, Ireland &
Department of Biomedical Sciences, University of Padova, Padova, Italy
The purpose of this study was to investigate the effects of using an internal versus external focus of attention during resistance
training on muscular adaptations. Thirty untrained college-aged men were randomly assigned to an internal focus group
(INTERNAL) that focused on contracting the target muscle during training (n= 15) or an external focus group
(EXTERNAL) that focused on the outcome of the lift (n= 15). Training for both routines consisted of 3 weekly sessions
performed on non-consecutive days for 8 weeks. Subjects performed 4 sets of 812 repetitions per exercise. Changes in
strength were assessed by six repetition maximum in the biceps curl and isometric maximal voluntary contraction in knee
extension and elbow flexion. Changes in muscle thickness for the elbow flexors and quadriceps were assessed by
ultrasound. Results show significantly greater increases in elbow flexor thickness in INTERNAL versus EXTERNAL
(12.4% vs. 6.9%, respectively); similar changes were noted in quadriceps thickness. Isometric elbow flexion strength was
greater for INTERNAL while isometric knee extension strength was greater for EXTERNAL, although neither
reached statistical significance. The findings lend support to the use of a mindmuscle connection to enhance muscle
Keywords: Mind-muscle connection,cueing,muscle hypertrophy
.An internal focus enhances hypertrophy of the elbow flexors during single joint elbow flexion, conceivably by increasing
activation of the musculature.
.Attentional focus did not affect hypertrophy of the quadriceps during single joint knee extension; this may be due to a
reduced ability for untrained individuals to develop a mind-muscle connection with the lower body musculature.
.It is not clear how adopting an internal versus external focus during resistance training over time affects maximal isometric
strength when testing is carried out under neutral attentional focus conditions.
Attentional focus is a well-established concept of
motor learning, and its use has potentially important
implications for promoting exercise-induced muscu-
lar adaptations (Schoenfeld & Contreras, 2016).
Attentional focus can be operationally defined as
what an individual thinks about when performing a
given activity (Schoenfeld & Contreras, 2016). The
topic can be sub-classified into two primary focus-
related strategies: internal focus and external focus.
An internal attentional focus involves thinking
about bodily movements when performing an
activity; for example, directing an individual to
squeezetheir muscle. Conversely, an external
attentional focus involves visualizing the outcome
during the performance; for example, directing an
individual to move the weight.
© 2018 European College of Sport Science
Correspondence: Brad Jon Schoenfeld, Department of Health Sciences, CUNY Lehman College, Bronx, NY, USA. E-mail: brad@
European Journal of Sport Science, 2018
The body of the literature appears to indicate that
an external focus of attention optimizes the execution
of performance-oriented tasks. A recent review by
Wulf (2013) concluded that an external focus
showed better improvements in motor learning com-
pared to an internal focus in more than 90% of pub-
lished studies on the topic. Superior outcomes were
observed across an array of physical activities in a
variety of different populations, providing strong
support for the use of an external focus for enhancing
performance-related measures.
While a myriad of data on attentional focus exists
for performance-oriented tasks, research into the
use of attentional focus during resistance training
(RT) is in its infancy. Acutely, the external focus is
beneficial for force production, while internal focus
increases agonist and antagonist surface electromyo-
graphy (sEMG) amplitudes (Marchant, Greig, &
Scott, 2009). Although the more economical move-
ment patterns observed during external focus con-
ditions appear to enhance skill acquisition, they may
be suboptimal for hypertrophic adaptations. Indeed,
electromyographic (EMG) studies report greater
EMG amplitudes of the target musculature during
resistance exercise with the use of an internal focus
(Snyder & Fry, 2012; Snyder & Leech, 2009).
Thus, it has been speculated that an internal focus,
referred to as a mind-muscle connectionin body-
building circles, should be adopted when the goal is
to maximize muscle development (Schoenfeld &
Contreras, 2016). However, drawing inferences con-
cerning adaptation from previous studies should not
be met without scrutiny. First, previous acute
studies that employ isoinertial loading do not
control for relative loading; effort differed between
conditions because the same absolute external load
was used, while one cue produces more economi-
calmovement than another. This means partici-
pants may have been utilizing a different percentage
of maximum for each condition, which is supported
by isokinetic data (Marchant et al., 2009). Second,
drawing inferences from acute measures, such as
sEMG, has recently been a topic of criticism, and a
call has been made for more longitudinal research
to draw more definitive conclusions (Halperin, Vig-
otsky, Foster, & Pyne, 2017).
Currently, there is a paucity of data investigating
the effects of attentional focus during RT on long-
term changes in strength. Moreover, to the authors
knowledge, no study to date has compared RT-
induced hypertrophic outcomes when employing
different attentional focus strategies, as is needed
for training recommendations. Thus, the purpose of
this study was to investigate the effects of using an
internal versus external focus during RT on muscular
adaptations. We hypothesized that the internal focus
would lead to greater increases in muscle hypertrophy
while the external focus would result in greater
strength gains.
Materials and methods
Subjects were 30 male volunteers (age = 21.7 ± 3.7
years; height = 176.3 ± 9.1 cm; mass = 78.2 ±
18.4 kg)recruited from a university population. Sub-
jects were between the ages of 1835, had no existing
cardiorespiratory or musculoskeletal disorders,
claimed to be free from consumption of anabolic
steroids or any other legal or illegal agents known to
increase muscle size currently and for the previous
year, and had not performed any regimented RT
for at least the past year. Table I provides anthropo-
metric data for each group.
Participants were pair-matched according to base-
line muscle thickness (MT) (a composite of values of
the elbow flexors and quadriceps) and then randomly
assigned to one of two experimental groups using
online software ( an internal focus
group (INTERNAL) that focused on contracting
the target muscle during training (n= 15) or an exter-
nal focus group (EXTERNAL) that focused on the
outcome of the lift during training (n= 15). Approval
for the study was obtained from the college Insti-
tutional Review Board. Informed consent was
obtained from all participants prior to beginning the
Experimental design
The investigation was carried out over a period of 10
weeks, with 8 weeks dedicated to the RT programme
and 2 weeks allocated for testing. Pre-study testing
was carried out in week 1 and post-study testing
was carried out in week 10. A supervised progressive
RT was performed between weeks 29.
RT procedures
The RT protocol consisted of two exercises: Standing
barbell curl and machine leg extension. These exer-
cises were chosen because it is easier to direct focus
internally during the performance of single-joint move-
ments, therefore helping to preserve internal validity.
Subjects were instructed to refrain from performing
any additional resistance-type or high-intensity
anaerobic training for the duration of the study.
Training for both conditions consisted of 3 weekly
sessions performed on non-consecutive days for 8
weeks. All routines were directly supervised by the
2B.J. Schoenfeld et al.
research team, which included a National Strength
and Conditioning Association Certified Strength and
Conditioning Specialist and certified personal trainers,
to ensure proper performance of the respective rou-
tines. Subjects performed 4 sets of 812 repetitions
per exercise. The supervising research staff member
provided relevant cues to subjects on each repetition
to reinforce the given focus of attention. For
INTERNAL, subjects were cued to squeeze the
muscle!on each repetition; for EXTERNAL, sub-
jects were cued to get the weight up!on each rep-
etition. All sets were carried out to the point of
momentary concentric muscular failure, operationally
defined as the inability to perform another concentric
repetition while maintaining proper form. Cadence of
the concentric portion of repetitions was carried out in
a fashion that allowed subjects to best achieve the given
attentional focus; eccentric actions were performed at
a2 second tempo to ensure controlled lowering of
weights. Subjects were afforded 2 min rest between
sets. The loads were adjusted for each exercise as
needed on successive sets to ensure that subjects
achieved failure in the target repetition range.
Attempts were made to progressively increase the
loads lifted each week within the confines of maintain-
ing the target repetition range. Prior to training, sub-
jects underwent 10-repetition maximum (RM)
testing to determine individual initial training loads
for each exercise. The RM testing was consistent
with recognized guidelines as established by the
National Strength and Conditioning Association
(Baechle & Earle, 2008).
Dietary adherence
To avoid potential dietary confounding of results,
subjects were advised to maintain their customary
nutritional regimen and avoid taking any sup-
plements other than that provided in the course of
the study. Dietary adherence was assessed by self-
reported 5-day food records using MyFitnessPal.-
com (, which were col-
lected twice during the study: 1 week before the first
training session (i.e. baseline) and during the final
week of the training protocol. Subjects were
instructed on how to properly record all food items
and their respective portion sizes consumed for the
designated period of interest. Each item of food
was individually entered into the programme, and
the programme provided relevant information as to
total energy consumption, as well as the amount of
energy derived from proteins, fats, and carbo-
hydrates for each time period analysed. To help
ensure that protein needs were met for anabolism,
subjects were supplied with a supplement on training
days containing 25 g protein and 1 g carbohydrate
(Iso100 Hydrolyzed Whey Protein Isolate, Dymatize
Nutrition, Dallas, TX) immediately following the
RT session (Aragon & Schoenfeld, 2013).
Body composition and anthropometry. Participants
height was measured using a Detecto Physicians
Scale (Cardinal Scale Manufacturing Company,
Webb City, MO). Assessment of fat mass, fat-free
mass, and skeletal muscle mass was carried out
using an InBody 770 multi-frequency bioelectrical
impedance device (Biospace Co. Ltd., Seoul,
Korea) according to the manufacturers instructions.
Subjects were told to refrain from eating for 12 h
prior to testing, eliminate alcohol consumption for
24 h, abstain from strenuous exercise for 24 h, and
void immediately before the test. Prior to each
measurement, the subjects palms and soles were
cleaned with an electrolyte tissue. Subjects then
stood on the InBody 770, placing the soles of their
feet on the electrodes. The instrument derived the
subjects body mass, and their age and sex subject
were manually entered into the display by the
researcher. Subjects then grasped the handles of the
unit ensuring that the palm and fingers of each hand
made direct contact with the electrodes. Arms were
fully extended and abducted approximately 20°.
Analysis of body composition was determined by the
unit with subjects remaining as motionless as possible.
Muscle thickness. Ultrasound imaging was used to
obtain measurements of MT. A trained technician
performed all testing using a B-mode ultrasound
imaging unit (ECO3, Chison Medical Imaging,
Ltd, Jiang Su Province, China). The technician
applied a water-soluble transmission gel (Aquasonic
100 Ultrasound Transmission gel, Parker Labora-
tories Inc., Fairfield, NJ) to each measurement site,
and a 5 MHz ultrasound probe was placed parallel
Table I. Participant demographics.
nAge (years) Stature (cm) Mass (kg)
INTERNAL 14 21.7 ± 3.7 175.8 ± 9.3 75.9 ± 20.1
EXTERNAL 13 21.8 ± 3.1 176.8 ± 9.1 81.0 ± 16.6
Combined 27 21.5 ± 3.3 176.3 ± 9.1 78.2 ± 18.4
Differential effects of attentional focus strategies during long-term resistance training 3
to the tissue interface without depressing the skin.
When the quality of the image was deemed to be sat-
isfactory, the technician saved the image to a hard
drive and obtained MT dimensions by measuring
the distance from the subcutaneous adipose tissue-
muscle interface to the muscle-bone interface, as
described previously (Abe, DeHoyos, Pollock, &
Garzarella, 2000). Measurements were taken on the
right side of the body at three sites: (1) elbow
flexors, (2) mid-thigh (a composite of the rectus
femoris and vastus intermedius), and (3) lateral
thigh (a composite of the vastus lateralis and vastus
intermedius). For the anterior upper arm, measure-
ments were taken 60% distal between the lateral epi-
condyle of the humerus and the acromion process of
the scapula; for the mid- and lateral thigh, measure-
ments were taken 50% between the lateral condyle
of the femur and greater trochanter for the quadriceps
femoris. In an effort to ensure that swelling in the
muscles from training did not obscure results,
images were obtained 4872 h before commence-
ment of the study, as well as after the final training
session. This is consistent with research showing
that acute increases in MT return to baseline within
48 h following a RT session (Ogasawara, Thiebaud,
Loenneke, Loftin, & Abe, 2012). To further ensure
the accuracy of measurements, three images were
obtained for each site and then averaged to obtain a
final value.
Isometric muscle strength. Strength assessments were
carried out using isometric dynamometry testing
(Biodex System 4; Biodex Medical Systems, Inc.
Shirley, NY, USA). After familiarization with the
dynamometer and protocol, subjects were seated in
the chair and performed isometric actions of the knee
extensors and elbow flexors. All isometric testing was
carried out on the subjectsdominant limbs.
During knee extension trials, subjects sat with their
backs flush against the seat back pad and maintained
hip joint angles of 85° with the centre of their lateral
femoral condyles aligned with the axis of rotation of
the dynamometer. The dynamometer arm length
was adjusted for each subject to allow the shin pad
to be secured with straps proximal to the medial mal-
leoli. Subjects were instructed to hold onto handles
for stability and were also strapped in across the ipsi-
lateral thigh, hips, and torso to help prevent
extraneous movement during performance. Testing
was carried out at a knee joint angle of 70° (Knapik,
Wright, Mawdsley, & Braun, 1983).
During elbow flexion trials, subjects were seated
with the dominant arm flexed to 30° and supported
in the sagittal plane to eliminate the effects of
gravity. The dominant forearm was strapped into
the upper extremity attachment, and the wrist was
placed in a supinated position. The hip and knee
joint angles were maintained at 85° and 90°, respect-
ively. The non-dominant arm was kept pinned to the
left side of the trunk with the forearm on the
abdomen. Subjects were strapped in by crossover
shoulder harnesses and an abdominal belt to help
prevent extraneous movement during performance.
Testing was carried out at an elbow joint angle of
90° (Knapik et al., 1983).
Each maximum voluntary contraction trial lasted
5 s, followed by 30 s rest, for a total of three to four
trials in each position (if a participants net joint
moment continued to increase in the third trial, then
a fourth trial was performed). Participants were verb-
ally encouraged to produce maximal force throughout
each bout. The highest peak net extension moment
from each of the three trials for each maximum volun-
tary contraction position was used for analysis.
Statistical analyses
Data were imported into Jamovi (version,
Jamovi team) for statistical analysis. Before carrying
out analyses, equality of variances (homogeneity) was
ensured using Levenes test. Rather than comparing
baseline values statistically, using independent t-tests,
baseline values were used as covariates in analyses of
covariance (ANCOVA), from which the differences
in the magnitude of changes from baseline were com-
pared (de Boer, Waterlander, Kuijper, Steenhuis, &
Twisk, 2015; Vickers & Altman, 2001). No within-
group comparisons from baseline were made (Bland
&Altman,2011,2015). Effect sizes were calculated
using partial eta squared (
p), which represents the
variance in the model accounted for by the difference
between groups. Because this model is analogous to a
multiple regression or partial correlation (Vickers &
Altman, 2001),
pcan be interpreted as the square
of a Pearsonsreffect size. As such, the correlation
coefficient interpretations as defined by Hopkins
(Hopkins, 2002) were adapted (squared) for qualitat-
ive interpretation: 0
p< 0.01 is trivial; 0.01
0.09 is small; 0.09
p< 0.25 is moderate;
p< 0.49 is large; 0.49
p<0.81 is very
large; 0.81
p< 1 is nearly perfect; and
p=1 is
perfect. Alpha was set apriorito 0.05 for determining
statistical differences between groups.
Of the 30 initial participants, 27 ultimately completed
the study; 2 subjects dropped out for personal reasons
and data for another subject were discarded due to
lack of compliance. Demographics of the included
4B.J. Schoenfeld et al.
participants can be found in Table I. Adherence to
the protocol was good for both INTERNAL and
EXTERNAL groups, with a mean attendance of
93% and 92% of sessions, respectively.
Of the three muscles that were measured, only elbow
flexor hypertrophy differed statistically between
groups, with a large effect size favouring the internal
focus condition (F
p= 0.307; p=
0.003). Small and trivial effect sizes favouring external
and internal focus were observed for rectus femoris
and vastus lateralis, respectively (F
0.030; p= 0.418 and F
p0; p= 0.999)
(Table II).
No statistical differences between groups were found
for any of the strength measures. Small effect sizes
favouring the external focus condition were observed
for isometric knee extension strength (F
= 1.50;
p= 0.064; p= 0.234), while a moderate effect size
favouring internal focus was observed for isometric
elbow flexion strength (F
= 2.82;
p= 0.114; p=
0.107) (Table II).
Body composition
No statistical differences between groups were found
for any body composition measures. Small and trivial
effect sizes favouring internal focus were noted for
increases in body fat and body weight, respectively
= 0.618;
p= 0.025; p= 0.439 and F
p= 0.007; p= 0.676). A small effect size
favouring external focus was noted for increases in
skeletal muscle mass (F
= 0.288;
p= 0.012; p=
0.596) (Table II).
Nutritional intake
Despite attempts to counsel subjects on how to prop-
erly log nutritional information, analysis of the food
diaries indicated gross misreporting of data. We
thus were unable to determine if/how changes in
dietary practices may have impacted results.
This is the first study to investigate the effects of differ-
ent attentional focus strategies on long-term muscular
adaptations. The study produced several novel and
notable findings. First, an internal focus elicited
superior hypertrophic increases in the elbow flexors
compared to an external focus, but MT in the quadri-
ceps was unaffected by attentional focus strategy. The
differences in changes in elbow flexor size between
INTERNAL and EXTERNAL (12.4% vs. 6.9%,
respectively) translated into a large magnitude of
effect favouring the INTERNAL condition (
0.307). These findings partially support the common
bodybuilding claim that a mindmuscle connection
enhances muscle growth. Although we did not
attempt to determine mechanistic reasons for discre-
pant findings between the upper and lower limbs, it
can be speculated that subjects found it easier to
focus on the elbow flexor muscles compared to the
thighs a sentiment that was anecdotally expressed
by several participants in the INTERNAL group. Pos-
tulations regarding the mechanisms of this phenom-
enon can be deduced from motor control and
neuroplasticity perspectives. First, neuromuscular
reeducation, at least following tendon transfer,
appears to be more prevalent in upper compared to
lower extremities (Sperry, 1945), suggesting that the
nervous system is better able to alter muscle recruit-
ment patterns of the upper extremity. Second, individ-
uals have greater force control of their elbow flexors
than their knee extensors (Tracy, Mehoudar, &
Ortega, 2007). Indeed, this may relate to why individ-
uals have better control of and coordination with their
upper extremities when compared to their lower extre-
mities (Kauranen & Vanharanta, 1996). Practically
speaking, Gordon and Ferris (Gordon & Ferris,
If there are inherent differences in efferent control
between any muscle groups, it would seem likely
that lower limb muscles might be the least accurate.
Humans rarely perform fine motor tasks with their
lower limbs, instead relying on them for gross
power output during locomotion.
Such sentiments do not preclude one from being able
to learn how to effectively utilize an internal focus of
attention. That is, such a phenomenon may be
related to the subjectsuntrained statuses, as individ-
uals with RT experience have been shown to be able
to increase quadriceps EMG amplitude when
directed to focus on the thigh musculature during
knee extension exercise (Marchant & Greig, 2017),
and recent evidence suggests that training status-
dependent control may indeed be muscle-specific
(Calatayud et al., 2016). If true, this would suggest
that trained individuals may be able to enhance quad-
riceps hypertrophy by adopting an internal focus
during lower body RT. Perhaps differences in this
regard would have been borne out with a longer inter-
vention period. Further investigation is needed to test
the validity of this hypothesis.
Differential effects of attentional focus strategies during long-term resistance training 5
Table II. Within- and between-group changes following 8 weeks of strength training with either internal or external focus of attention.
Internal focus External focus Between-group difference
Pre Post Change Pre Post Change Absolute
Effect size
p) Interpretation
Elbow flexor thickness
39.62 ± 8.07 44.55 ± 8.15 4.93 ± 1.73 40.22 ± 6.53 42.98 ± 6.40 2.77 ± 1.63 2.14 (0.853.43) 0.307 Large 0.003
Rectus femoris
thickness (mm)
55.10 ± 11.57 57.82 ± 10.99 2.72 ± 2.62 55.09 ± 5.90 58.69 ± 5.74 3.60 ± 2.87 0.88 (2.981.22) 0.030 Small 0.418
Vastus lateralis
thickness (mm)
51.81 ± 11.03 55.10 ± 10.80 3.29 ± 2.94 53.82 ± 5.47 56.99 ± 6.09 3.17 ± 3.37 0.00 (2.412.41) 0.000 Trivial 0.999
Isometric elbow flexion
(N m)
57.46 ± 12.96 66.78 ± 17.87 9.32 ± 10.88 62.45 ± 14.56 64.06 ± 11.55 1.61 ± 9.21 6.90 (1.1614.96) 0.114 Moderate 0.107
Isometric knee
extension (N m)
286.99 ± 70.04 316.08 ± 68.82 29.09 ± 55.04 280.99 ± 60.90 338.33 ± 55.38 57.34 ± 52.66 12.80 (33.387.78) 0.064 Small 0.234
Body mass (kg) 76.46 ± 20.60 77.90 ± 20.58 1.44 ± 1.24 80.89 ± 16.60 81.85 ± 15.18 0.95 ± 2.64 0.16 ± (0.580.90) 0.007 Trivial 0.676
Skeletal muscle mass
33.66 ± 6.90 34.26 ± 6.78 0.60 ± 0.63 34.55 ± 4.42 35.25 ± 4.33 0.71 ± 0.58 0.06 (0.290.17) 0.012 Small 0.596
Body fat (%) 20.02 ± 10.54 20.36 ± 10.01 0.34 ± 1.46 23.17 ± 8.88 22.82 ± 8.64 0.35 ± 2.01 0.52 (0.771.81) 0.025 Small 0.439
Notes: Pre, post, and change scores are presented as mean ± SD. Between-group, absolute differences are presented as mean (95% CI), with a positive value being in favour of (i.e. a greater or more
positive change score) internal focus, and are corrected for baseline values.
6B.J. Schoenfeld et al.
Attentional focus had markedly different effects
specific to the upper versus lower limbs. With
respect to peak isometric elbow flexion strength,
INTERNAL resulted in a 16.2% increase versus a
2.6% in EXTERNAL, translating into an ES of a
moderate magnitude of effect (
p= 0.114). These
potential findings are in contrast to acute studies,
wherein an external focus of attention is often
found to result in greater strength performance than
an internal focus of attention (Marchant et al.,
2009); therefore, it is important to note that partici-
pants were not encouraged to utilize specific atten-
tional foci during strength testing. Although
potential mechanisms for these non-statistical differ-
ences in isometric elbow flexion strength were not
studied, two often-proposed mechanisms of strength
gain include peripheral (i.e. muscle hypertrophy and
normalized muscle force) and neural (i.e. neural
drive and excitation) changes (Erskine, Jones, Wil-
liams, Stewart, & Degens, 2010). To explore
muscle size as a potential contributor, an additional
ANCOVA was carried out post hoc, using the
change in elbow flexor thickness as a covariate.
After accounting for the change in elbow flexor thick-
ness, the magnitude of the group effect decreased
substantially, from moderate (
p= 0.114) to trivial
p= 0.006). In contrast to recent criticisms of the
theory that hypertrophy is related to changes in
strength (Buckner et al., 2016), it appears that, in
this study, differences in hypertrophy accounted for
potential differences in strength between groups.
As opposed to isometric elbow flexion strength,
peak isometric knee extension strength favoured
EXTERNAL versus INTERNAL (20.4% vs.
10.1%, respectively), with the ES indicating a small
magnitude of effect (
p= 0.064). Although the
observed effect size was small and did not reach the
a priori alpha, in the interest of consistency, another
post hoc ANCOVA was carried out, utilizing both
changes in vastus lateralis and rectus femoris thick-
ness as covariates, but unlike elbow flexion strength,
the change in magnitude of the effect size was minus-
cule (
p= 0.052).
The study had several notable limitations. First,
the exercise protocol employed a moderate repetition
range and thus the results cannot necessarily be
extrapolated to training with heavier or lighter
loads, especially because the acute effects of internal
cueing are load-dependent (Calatayud et al., 2016).
Second, although we provided explicit instructions
on the focus of attention and supplemented the
instructions with cueing throughout each set, there
is no way to be sure that subjects were actually focus-
ing as directed. It remains possible that some subjects
did not adhere to the proper focus in at least some of
the sets, which in turn may have altered results. That
said, the marked between-group differences in elbow
flexor muscle growth favouring the internal focus
condition provides strong evidence that cueing strat-
egies affect hypertrophic outcomes. Third, MT was
measured only at the mid-portion of the muscles.
Although this region is widely considered to be
indicative of overall muscle growth, some studies
report that hypertrophy manifests in a regional-
specific manner, with greater adaptations seen proxi-
mally and/or distally (Wakahara et al., 2012; Waka-
hara, Fukutani, Kawakami, & Yanai, 2013). Thus,
we cannot discount the prospect that greater proxi-
mal or distal increases in MT occurred in one proto-
col versus the other. Fourth, we were not able to
obtain accurate reporting on dietary practices
throughout the study and thus cannot rule out the
possibility that differences in nutritional intake
unduly confounded results. Finally, the findings are
specific to untrained subjects; future research is
needed to determine the strength- and hypertrophy-
related effects of different attentional focus strategies
on those with previous RT experience.
Our findings indicate that an internal focus of atten-
tion is superior to an external focus of attention
when the goal is to maximize hypertrophy of the
elbow flexors. Attentional focus does not seem to
affect lower extremity hypertrophy, which may be
due to the difficulty for untrained individuals to
establish a mind-muscle connectionin the thigh
musculature during resistive exercise.
The authors gratefully acknowledge the contributions
of the research assistants who facilitated data collec-
tion and without whom this project could not have
been carried out: Harold Belen, Jesus Martinez,
Audrey Rivera, Alyssa Dumlao, Ezenwa Emerjuru,
Anthony Masner, Lauren Colenso-Semple, Mario
Rosario, Sussan Soto, Chris Morrison, Anthony
Rambarran, Denise Flores, Teshawna Smith,
Andrea Mene, Ronnie Guerra, Miguel Melendez,
Kyron Slater, Bryan Taveras, Greg Andronico, and
Leila Nasr. We also would like to express our grati-
tude to Dymatize Nutrition for providing the
protein supplements used in this study. The authors
declare no conflicts of interest.
Disclosure statement
No potential conflict of interest was reported by the authors.
Differential effects of attentional focus strategies during long-term resistance training 7
This study was supported by a grant from Dymatize Nutrition.
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8B.J. Schoenfeld et al.
... As personal training encompasses numerous potential avenues for resistance exercise, the authors decided to focus on the six most common patterns of movements that make up many resistance training programs (Table 3) (12, 13,17,18,19,37). These normally include a horizontal row and press, vertical pull and press, squat, and hip hinge pattern (3,8,11). Along with providing the personal trainer with a rudimentary way to classify movement, these patterns also recruit most of the major muscle groups of the body. ...
... There are several factors that promote healthy body composition from consuming plant-based foods, including higher fiber intake, reduced caloric intake, and increased energy expenditure. Plant-based foods contain considerable amounts of fiber, which not only improves gut microbiota, heart health, and colon health, but also induces satiety and contributes to reduced caloric intake (3,8). Plant-based diets also contribute to increased mitochondrial number and activity, resulting in elevated fat metabolism as well as increased energy expenditure following meals (27). ...
... In essence, if a client does not "feel ready," regardless of their physical readiness (e.g., muscle soreness), additional rest is required. Mental preparedness allows for a greater focus on movement technique and muscle contraction; this is referred to as the "mind muscle connection" and has been shown to improve exercise performance and adaptations (8). Therefore, the ideal recovery interval is long enough to substantially decrease heart rate, eliminate local muscle fatigue, and restore mental focus. ...
This article written for NSCA's Personal Training Quarterly provides personal trainers with facts about low back pain and how to train clients with low back pain based on the current body of evidence as well as author experiences and provides a practical guide to doing so.
... Studies show that an IF elicits a greater electromyographic activation in the target muscle compared to an EF (Calatayud et al., 2016;Snyder & Fry, 2012;Snyder & Leech, 2009). Moreover, an IF has been shown to promote superior increases in muscle thickness of the biceps brachii when compared to an EF over an 8-week resistance training intervention, although no hypertrophic differences were observed between conditions for the quadriceps (Schoenfeld et al., 2018). ...
... Effects of IF and EF on hypertrophic measures have been evaluated directly by ultrasound (Schoenfeld et al., 2018), who reported greater muscle thickness changes of the elbow flexors in favor of an IF versus EF following an 8-week training intervention (12.4% vs. 6.9% respectively). Alternatively, no significant between-group differences were observed in the quadriceps. ...
... Consequently, there are no clear data because it´s easier to direct focus internally during single-joint movements. Additionally, it should be noted that the favorable hypertrophic benefits of IF shown by Schoenfeld et al. (Schoenfeld et al., 2018) were exclusive to upper body exercises (biceps curl). Alternatively, changes in muscle thickness were similar irrespective of attentional focus in the lower body musculature, despite the fact that an isolated exercise was used (leg extension). ...
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The aim of this study was to investigate the effect of internal focus (IF) and external focus (EF) on lactate production and the perception of perceived exertion in the squat in strength trained-men. Methods: Thirteen men with experience in strength training (age =22.61 ± 1.19 years; height = 180 ± 6.55 cm; body mass = 79.38 ± 5.57 kg; BMI = 24.56 ± 2.11 kg·m-2; Squat = 129 ± 20 kg) performed two sessions, separated by one week, comprising 3 sets of 10 repetitions of the back squat with one minute of rest between sets. During the IF protocol participants were instructed to focus on tightening the quads during all repetitions, while participants in the EF were instructed to focus on lifting the barbell. Blood lactate samples were collected before and at immediately after each of the 3 sets, as well as 15 minutes after the last set. Additionally, the rating of perceived exertion (RPE) was evaluated using the OMNI-RES scale immediately after the completion of each session. Results: Significant increases were found in the IF protocol at the end of each of the 3 sets, with significant effect sizes (1ª set, P= .000, d= 2.66; 2ª set, P= .000; d= 3.14; 3ª set, P= .000, d= 3.50), as in the EF protocol (1ª set, P= .001, d= 2.24; 2ª set, P= .000, d= 3.35; 3ª set, P= .000; d= 3.67). However, there were no significant inter-group differences between pre and any set (1ª set, P=0.951, d=0.03; 2ª set, P=0.239, d=0.47; 3ª set, P=0.435, d=0.31, respectively). Additionally, the perceptions on the RPE scale were higher in the FI (P= 0.032; d = 0.47). Conclusions: Findings suggest that the application of IF may indirectly contribute to muscle hypertrophy in multi-joint lower limb exercises, due to the increase in RPE values and the existing correlation with lactate production. Keywords: Mind-muscle, muscle hypertrophy, internal focus, mind-muscle connection, resistance training
... In other words, muscle efficiency decreases [27], albeit this might not be a problem when searching for an enhancement of the hypertrophic stimulus, the main purpose of practitioners that use the attentional internal focus. To check for the truthfulness of this assumption deriving from the practice, only one study has compared to date the effects of an internal versus external focus systematically used during an 8-week resistance training protocol [83]. Two muscle/movement couples were examined: biceps brachii for biceps curl and quadriceps for knee extension, and both strength and hypertrophic changes were recorded [83]. ...
... To check for the truthfulness of this assumption deriving from the practice, only one study has compared to date the effects of an internal versus external focus systematically used during an 8-week resistance training protocol [83]. Two muscle/movement couples were examined: biceps brachii for biceps curl and quadriceps for knee extension, and both strength and hypertrophic changes were recorded [83]. While strength gains were similar between the internal and external focus in both exercises, the hypertrophic gains in biceps brachii were more pronounced with the internal focus, while no between-focus difference was found in quadriceps [83]. ...
... Two muscle/movement couples were examined: biceps brachii for biceps curl and quadriceps for knee extension, and both strength and hypertrophic changes were recorded [83]. While strength gains were similar between the internal and external focus in both exercises, the hypertrophic gains in biceps brachii were more pronounced with the internal focus, while no between-focus difference was found in quadriceps [83]. On these bases, considering the possible acute and chronic differences between the internal versus external focus, the attentional strategy should be always reported. ...
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Manipulating resistance training variables is crucial to plan the induced stimuli correctly. When reporting the exercise variables in resistance training protocols, sports scientists and practitioners often refer to the load lifted and the total number of repetitions. The present conceptual review explores all within-exercise variables that may influence the strength and hypertrophic gains, and the changes in muscle architecture. Together with the (1) load and (2) the number of repetitions, (3) performing repetitions to failure or not to failure, (4) the displacement of the load or the range of movement (full or partial), (5) the portion of the partial movement to identify the muscle length at which the exercise is performed, (6) the total time under tension, the duration of each phase and the position of the two isometric phases, (7) whether the concentric, eccentric or concentric-eccentric phase is performed, (8) the use of internal or external focus and (9) the inter-set rest may all have repercussions on the adaptations induced by each resistance exercise. Manipulating one or more variable allows to increase, equalize or decrease the stimuli related to each exercise. Sports scientists and practitioners are invited to list all aforementioned variables for each exercise when reporting resistance training protocols.
... When training for hypertrophy, it is important not only to perceive the efferent sensation of muscle contraction, but also to be centripetally conscious of the target muscle that is being recruited (Gandevia et al. 1992;Proske and Gandevia et al. 2009). However, fatigue has been reported to disturb the perception of the sensation of muscle contraction (Fortier and Basset et al. 2012), and a discrepancy in the perception between efferent sensations and centripetal consciousness decreases muscle activity and hypertrophy (Fujita et al. 2020;Paoli et al. 2019;Schoenfeld et al. 2018). Therefore, the implementation of a training motion that is less likely to impair the perception of muscle contraction in a state of fatigue enhances the training effect. ...
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Purpose We investigated the effect of the hip flexion angle (HFA) on the longitudinal muscle activity of the rectus femoris (RF) during leg extension exercise (LEE). Methods We conducted an acute study in a specific population. Nine male bodybuilders performed isotonic LEE using a leg extension machine at three different HFAs: 0°, 40°, and 80°. Participants extended their knees from 90° to 0° at each HFA setting for four sets of ten repetitions at 70% of the one-repetition maximum. The transverse relaxation time (T2) of the RF was measured before and after LEE using magnetic resonance imaging. We analyzed the rate of change in the T2 value in the proximal, middle, and distal regions of the RF. The subjective sensation of muscle contraction of the quadriceps was measured using a numerical rating scale (NRS) and compared with the T2 value which was the objective index. Results At 80°, the T2 value in the middle RF was lower than that in the distal RF (p < 0.05). The T2 values at 0° and 40° HFA were higher than those at 80° HFA in the proximal (p < 0.05, p < 0.01) and middle RF (p < 0.01, p < 0.01). The NRS scores were inconsistent with the objective index. Conclusion These results suggest that the 40° HFA is practical for region-specific strengthening of the proximal RF, and subjective sensation alone as an indication of training may not activate the proximal RF. We conclude that activation of each longitudinal section of the RF is possible depending on the hip joint angle.
... 46 In addition, focusing on maximal contraction of a muscle group (e.g., internal focus) during strength exercise has been reported to be superior to increase muscle thickness than external focus (or simply moving the load during strength exercise). 47 In contrast, external focus or distraction manoeuvres using dual tasks have been reported to improve muscular endurance. [48][49][50] Future studies are needed to investigate the effects of these cognitive variables on muscle strength and PWH functionality. ...
Introduction: Although strength exercise is often prescribed for people with haemophilia (PWH), it remains unknown how exercise variables and pain thresholds are used to prescribe strength training in PWH. Aim: To analyse how strength exercise variables and pain thresholds have been used to prescribe strength training in PWH. Methods: A systematic search was conducted in PubMed, Embase, Web of Science, CENTRAL and CINAHL databases from inception to 7 September 2022. Studies whose intervention included strengthening training in adults with haemophilia were included. Two independent reviewers were involved in study selection, data extraction and risk of bias assessment. Results: Eighteen studies were included. The least reported variables among the studies were: prophylactic factor coverage (11.1%), pain threshold/tolerability (5.6%), intensity (50%), total or partial range of motion (27.8%), time under tension (27.8%), attentional focus modality (0%), therapist experience in haemophilia (33.3%) and adherence assessment (50%). In contrast, weekly frequency (94.4%), duration (weeks) (100%), number of sets/repetitions (88.9%), repetitions to failure/not to failure (77.8%), types of contraction (77.8%), rest duration (55.6%), progression (55.6%), supervision (77.8%), exercise equipment (72.2%) and adverse event record (77.8%) had a higher percentage of reported (>50% of studies). Conclusion: Future research on strength training for PWH should improve information on pain threshold and other important variables such as prophylactic factor coverage, intensity, range of motion, time under tension, attentional focus modality, therapist experience in haemophilia and adherence assessment. This could improve clinical practice and comparison of different protocols.
... On one hand, an external focus appears to be superior in a variety of isometric and dynamic tasks, showing higher strength production [9][10][11] and neuromuscular efficiency [11][12][13][14][15]; on the other, an internal focus condition induces a greater advantage in electromyographic activity during both upper-and lower-body muscular strength exercises [11,16]. These findings support the notion of promoting both attentional focus strategies for a better "mind-muscle" connection during resistance training exercises [17]. ...
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This pilot study compared the effects of two attentional focus strategies on fitness parameters and body composition in outpatients with obesity. This was a randomized, controlled study that enrolled 94 obese individuals and allocated them into an internal focus group (IF) or an external focus group (EF) while performing six weeks of a home-based training program. The home-based exercise program was the same for both groups except for the instructions that shifted the attention to an external or an internal condition. At the beginning and after the intervention period, participants were assessed for functional performance using the Functional Movement Screen (FMS), body balance using the Modified Balance Error Scoring System (M-BESS) and muscular strength with the Handgrip Strength Test (HST) and the Five-Repetition Sit-To-Stand (FRSTS) test. Concerning body composition and anthropometric parameters, the body mass index (BMI) and fat mass percentage (FM%) were calculated. Significant improvements, main interactions and effects of time and groups were highlighted in the EF group as compared to the IF group in FMS (35% vs. 21%), M-BESS (42% vs. 18%), HST (13% vs. 7%) and FRSTS (23% vs. 12%) measures, while FM% (5%) and BMI (6% vs. 5%) showed a similar improvement overtime (p < 0.001). In conclusion, our findings provide initial evidence that a 6-week training program performed following external focus instruction is able to promote significant enhancements in movement efficiency, balance and muscular strength as compared to an internal focus cue. Fitness coaches and therapists might consider integrating a specific attentional focus strategy when designing rehabilitation programs in subjects with obesity.
... Internal cues may acutely direct focus to a single muscle group or movement when training with submaximal loads (5). Longitudinally, the superiority of internal cueing for muscular hypertrophy is equivocal (61). ...
The landmine row is an upper-body pulling exercise using a barbell as a lever. This column provides the strength and conditioning coach with a summary of trained musculature, technique descriptions for common landmine row variations, suggested instructional cues for improving technique and performance, an overview of unique exercise biomechanics, and programming recommendations.
Several devices (e.g., linear transducers) have been used for predicting resistance training intensity. However, subjective scales, such as rating of perceived exertion (RPE), are proposed as reliable and easier-to-use tools for monitoring intensity during resistance training. Accordingly, different perceptive scales have been presented in previous research for monitoring intensity during resistance training with elastic bands. The aim was to assess the accuracy and reliability of RPE for quantifying the potential maximal repetitions that could be performed at a given RPE (from 2 to 8 of 10) obtained in the first repetition. For this purpose, 13 recreationally active participants (age: 26.33 [6.52] years, body mass index: 24.97 [5.08] kg/m2) were involved in two familiarization and two experimental sessions. In each session, participants randomly performed one set at each intensity of the first repetition from 2/10 to 8/10 until volitional failure in three different exercises (fly, military press, and push-press). An individual grip width of the elastic band was chosen in each set. The number of repetitions and heart rate were assessed. Significance level was set at p < .05. Repetitions decreased when intensity increased (p < .01) and heart rate was higher in the global exercise (i.e., push-press; p < .05), but nonsignificant differences between intensities were reported. The level of experience influenced the number of repetitions performed (p < .05). Intersession reliability was set from good to excellent (range: 0.64-0.91). Therefore, the RPE of the first repetition is a relevant and reliable parameter related to the total number of repetitions performed for each RPE value in trained participants enrolled in elastic bands resistance training. Keywords: dosage prescription; exercise; human physical conditioning; intensity monitoring; musculoskeletal and neural physiological phenomena; physical fitness; resistance training.
Although researchers have highlighted the benefits of adopting an external focus of attention for rehabilitation, studies have consistently revealed low external focus use by physiotherapists. Consequently, the purpose of this research was to explore factors influencing physiotherapists’ focus of attention use and to gain insight into the barriers, and potential solutions, related to effective external focus use. Eight physiotherapists, working with musculoskeletal rehabilitation clients, first completed the Therapists’ Perceptions of Motor Learning Principles Questionnaire and then participated in virtual one-on-one interviews. The interviews followed a semistructured interview guide and were analyzed using a total quality framework approach to qualitative content analysis. Data showed that physiotherapists’ focus of attention use was influenced by physiotherapist, client, and task characteristics/experiences, as well as focus of attention statement provision strategies. Furthermore, the main barriers discussed related to educational experiences, reinforcement of internal focus of attention statement use and aspects related to research. Solutions presented to these barriers included the incorporation of focus of attention content into both the Canadian physiotherapy curriculum and continued education. Overall, these results advance our knowledge of factors underlying physiotherapists’ focus of attention use and barriers that must be overcome to successfully translate the focus of attention research into physiotherapy.
Although researchers have consistently demonstrated the potential benefit of an external focus of attention for rehabilitation, research has shown that this finding has yet to be translated into Canadian physiotherapy. Further, specific barriers to external focus use have been reported by Canadian physiotherapists, and as a solution toward increasing physiotherapists’ use of external focus, these same physiotherapists recommended the development of an educational workshop on focus of attention. Considering this, described herein is the process of developing such a workshop, which involved (a) gathering input from physiotherapists concerning content and format via one-on-one interviews and (b) engaging in discussion about content with focus of attention researchers. Analysis of the interview data featured key content for the workshop, the types of activities to include, and a recommended sequencing for the activities: specifically, sharing didactic information on focus of attention research, then providing instruction and demonstration of external focus use, and finally, finishing with opportunities for generating and delivering external focus statements. This input, along with that of the researchers, led to the development of a two-component focus of attention workshop, which includes an asynchronous component, featuring seven self-directed learning modules and a synchronous component, which consists of a virtual group session.
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Exercise and sport sciences continue to grow as a collective set of disciplines by investigating a broad array of basic and applied research questions. Despite the progress, there is room for improvement. A number of problems pertaining to reliability and validity of research practices hinder advancement and the potential impact of the field. These problems include: 1) inadequate validation of surrogate outcomes, 2) too few longitudinal and 3) replication studies, 4) limited reporting of null or trivial results, and 5) insufficient scientific transparency. The purpose of this review is to discuss these problems as they pertain to exercise and sport sciences based on their treatment in other disciplines, namely psychology and medicine, and propose a number of solutions and recommendations.
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Purpose: This study evaluates whether focusing on using specific muscles during bench press can selectively activate these muscles. Methods: Altogether 18 resistance-trained men participated. Subjects were familiarized with the procedure and performed one-maximum repetition (1RM) test during the first session. In the second session, 3 different bench press conditions were performed with intensities of 20, 40, 50, 60 and 80 % of the pre-determined 1RM: regular bench press, and bench press focusing on selectively using the pectoralis major and triceps brachii, respectively. Surface electromyography (EMG) signals were recorded for the triceps brachii and pectoralis major muscles. Subsequently, peak EMG of the filtered signals were normalized to maximum maximorum EMG of each muscle. Results: In both muscles, focusing on using the respective muscles increased muscle activity at relative loads between 20 and 60 %, but not at 80 % of 1RM. Overall, a threshold between 60 and 80 % rather than a linear decrease in selective activation with increasing intensity appeared to exist. The increased activity did not occur at the expense of decreased activity of the other muscle, e.g. when focusing on activating the triceps muscle the activity of the pectoralis muscle did not decrease. On the contrary, focusing on using the triceps muscle also increased pectoralis EMG at 50 and 60 % of 1RM. Conclusion: Resistance-trained individuals can increase triceps brachii or pectarilis major muscle activity during the bench press when focusing on using the specific muscle at intensities up to 60 % of 1RM. A threshold between 60 and 80 % appeared to exist.
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Background: According to the CONSORT statement, significance testing of baseline differences in randomized controlled trials should not be performed. In fact, this practice has been discouraged by numerous authors throughout the last forty years. During that time span, reporting of baseline differences has substantially decreased in the leading general medical journals. Our own experience in the field of nutrition behavior research however, is that co-authors, reviewers and even editors are still very persistent in their demand for these tests. The aim of this paper is therefore to negate this demand by providing clear evidence as to why testing for baseline differences between intervention groups statistically is superfluous and why such results should not be published. Discussion: Testing for baseline differences is often propagated because of the belief that it shows whether randomization was successful and it identifies real or important differences between treatment arms that should be accounted for in the statistical analyses. Especially the latter argument is flawed, because it ignores the fact that the prognostic strength of a variable is also important when the interest is in adjustment for confounding. In addition, including prognostic variables as covariates can increase the precision of the effect estimate. This means that choosing covariates based on significance tests for baseline differences might lead to omissions of important covariates and, less importantly, to inclusion of irrelevant covariates in the analysis. We used data from four supermarket trials on the effects of pricing strategies on fruit and vegetables purchases, to show that results from fully adjusted analyses sometimes do appreciably differ from results from analyses adjusted for significant baseline differences only. We propose to adjust for known or anticipated important prognostic variables. These could or should be pre-specified in trial protocols. Subsequently, authors should report results from the fully adjusted as well as crude analyses, especially for dichotomous and time to event data. Based on our arguments, which were illustrated by our findings, we propose that journals in and outside the field of nutrition behavior actively adopt the CONSORT 2010 statement on this topic by not publishing significance tests for baseline differences anymore.
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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.
The attentional focus emphasised in verbal instruction influences movement and muscle recruitment characteristics, with an external focus (onto movement effects) typically benefiting performance. However, contrasting findings suggest either a selective isolation or spreading activation effect on associated muscles as a result of internally focused instruction (movement characteristics). In the present experiment, participants completed maximal isokinetic concentric leg extension exercise using internally (muscle specific: vastus medialis oblique) or externally (outcome specific) focused instructions. Integrated Electromyography (iEMG) of the vastus lateralis, vastus medialis oblique and rectus femoris muscles was obtained in addition to knee extensor torque. There were no differences in torque production between conditions. Externally focused instruction produced significantly lower iEMG magnitude across muscles, whereas an internal focus produced the greatest activity but with no evidence of a selective isolation effect of the vastus medialis oblique. The muscle-specific internal focus of attention resulted in a spreading activation effect, such that activity is elevated in muscles not within the focus of attention. Whilst an external focus did not improve performance, force was produced with lower muscular activity reflecting increased efficiency. The resultant noise in the motor system associated with an internal focus inhibits movement economy and attempts at selective activation.
In this paper we revisit a topic originally discussed in 1955, namely the lack of direct evidence that muscle hypertrophy from exercise plays an important role in increasing strength. To this day, long-term adaptations in strength are thought to be primarily contingent on changes in muscle size. Given this assumption, there has been considerable attention placed on programs designed to allow for maximization of both muscle size and strength. However, the conclusion that a change in muscle size affects a change in strength is surprisingly based on little evidence. We suggest that these changes may be completely separate phenomena based on: (1) the weak correlation between the change in muscle size and the change in muscle strength after training; (2) the loss of muscle mass with detraining, yet a maintenance of muscle strength; and (3) the similar muscle growth between low-load and high-load resistance training, yet divergent results in strength. Muscle Nerve, 2016.
Researchers often analyze randomized trials and other comparative studies by separate analysis of changes from baseline in each parallel group. This may be the only analysis presented or it may be in addition to the direct comparison of allocated groups. We illustrate this by reference to 3 recently published nutritional trials. We show why this method of analysis may be highly misleading and may produce type I errors far greater than the 5% that we expect. We recommend direct comparison of means between groups with the use of baseline as a covariate if required.
Over the past 15 years, research on focus of attention has consistently demonstrated that an external focus (i.e., on the movement effect) enhances motor performance and learning relative to an internal focus (i.e., on body movements). This article provides a comprehensive review of the extant literature. Findings show that the performance and learning advantages through instructions or feedback inducing an external focus extend across different types of tasks, skill levels, and age groups. Benefits are seen in movement effectiveness (e.g., accuracy, consistency, balance) as well as efficiency (e.g., muscular activity, force production, cardiovascular responses). Methodological issues that have arisen in the literature are discussed. Finally, our current understanding of the underlying mechanisms of the attentional focus effect is outlined, and directions for future research are suggested.
Purpose: Muscle hypertrophy in response to resistance training has been reported to occur nonuniformly along the length of the muscle. The purpose of the present study was to examine whether the regional difference in muscle hypertrophy induced by a training intervention corresponds to the regional difference in muscle activation in the training session. Methods: Twelve young men participated in a training intervention program for the elbow extensors with a multijoint resistance exercise for 12 wk (3 d · wk(-1)). Before and after the intervention, cross-sectional areas of the triceps brachii along its length were measured with magnetic resonance images. A series of transverse relaxation time (T2)-weighted magnetic resonance images was recorded before and immediately after the first session of training intervention. The T2 was calculated for each pixel within the triceps brachii. In the images recorded after the session, the number of pixels with a T2 greater than the threshold (mean + 1 SD of T2 before the session) was expressed as the ratio to the whole number of pixels within the muscle and used as an index of muscle activation (percent activated area). Results: The percent activated area of the triceps brachii in the first session was significantly higher in the middle regions than that in the most proximal region. Similarly, the relative change in cross-sectional area induced by the training intervention was also significantly greater in the middle regions than the most proximal region. Conclusion: The results suggest that nonuniform muscle hypertrophy after training intervention is due to the region-specific muscle activation during the training session.