ArticlePDF Available

Abstract and Figures

Aim: Although comparison between multi and single joint exercises has been conducted, there is insufficient evidence that these exercises could lead to different muscle activations. The aim of this study was to compare deltoid muscle activation during multi and single joint exercises. Methods: Twelve male participants (23.4±1.6 years) with at least one year of strength training experience were assessed performing inclined lat pull-down, reverse peck deck and seated row exercises. Surface electromyography was used to measure activation of anterior, middle and posterior portions of deltoid muscle during each exercise. Deltoid activation was recorded during maximum voluntary isometric contraction (MVIC) and during dynamic isoinertial exercises of ten maximum repetitions for inclined lateral pull-down, reverse peck deck and seated row. Results: There was no difference in activation of the anterior portion of deltoid muscle for any of the three exercises (P=0.08). The middle portion presented greater activation during the reverse peck deck (P=0.03) and during the seated row (P=0.03) compared to the inclined lat pull-down. For the posterior portion of deltoid muscle there was greater activation during the reverse peck deck (P=0.001) compared to the seated row and to the inclined lat pull-down. Conclusion: Results indicate that reverse peck deck and seated row should be more appropriate for recruitment of the middle portion of the deltoid muscle than the inclined lat pull-down. Differently, the reverse peck deck should be primarily used rather than the seated row and the lat pull-down for recruitment of the posterior portion of the deltoid muscle.
Content may be subject to copyright.
714 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS July-August 2015
ed to move the humerus in relation to the scapula.
The anterior portion is a prime motor during exion
and horizontal adduction of the shoulder, while the
middle portion acts during abduction and horizon-
tal abduction and the posterior portion is recruited
during horizontal abduction.1, 2 Apart from hu-
merus motion, the deltoid resists to lower pulling
forces applied to the upper limb, improving joint
stability.3-5
An individual analysis of each portion of the del-
toid indicated that the anterior deltoid has the greatest
potential to joint destabilization.3 Traditional exer-
cises of strength training (e.g. bench press) have em-
phasis on the anterior deltoid by the predominance
of horizontal adduction movement of the shoulder,
which could provide a muscular imbalance between
individual portions of the deltoid and increase joint
instability. Therefore, strength training for the mid-
dle and posterior deltoid muscle could enhance its
role in gaining shoulder stabilization.
Strength training exercises have been assessed to
compare the use of single and multijoint exercises
and their effects in muscle recruitment.6-11 Informa-
tion gathered from these studies provided evidence
for improving strength training prescription and op-
timization of training programs.12, 13 The option for
multijoint exercises has been suggested for begin-
Aim. Although comparison between multi and single joint ex-
ercises has been conducted, there is insufcient evidence that
these exercises could lead to different muscle activations. The
aim of this study was to compare deltoid muscle activation
during multi and single joint exercises.
Methods. Twelve male participants (23.4±1.6 years) with at least
one year of strength training experience were assessed perform-
ing inclined lat pull-down, reverse peck deck and seated row ex-
ercises. Surface electromyography was used to measure activa-
tion of anterior, middle and posterior portions of deltoid muscle
during each exercise. Deltoid activation was recorded during
maximum voluntary isometric contraction (MVIC) and during
dynamic isoinertial exercises of ten maximum repetitions for
inclined lateral pull-down, reverse peck deck and seated row.
Results. There was no difference in activation of the ante-
rior portion of deltoid muscle for any of the three exercises
(P=0.08). The middle portion presented greater activation
during the reverse peck deck (P=0.03) and during the seated
row (P=0.03) compared to the inclined lat pull-down. For the
posterior portion of deltoid muscle there was greater activa-
tion during the reverse peck deck (P=0.001) compared to the
seated row and to the inclined lat pull-down.
Conclusion. Results indicate that reverse peck deck and
seated row should be more appropriate for recruitment of
the middle portion of the deltoid muscle than the inclined lat
pull-down. Differently, the reverse peck deck should be pri-
marily used rather than the seated row and the lat pull-down
for recruitment of the posterior portion of the deltoid muscle.
K : Electromyography - Resistance training - Shoul-
der - Deltoid muscle.
The deltoid is a pennated muscle that covers the
shoulder joint by three portions that are recruit-
Exercise Research Laboratory
School of Physical Education
Federal University of Rio Grande do Sul
Rio Grande do Sul, Brazil
J SPORTS MED PHYS FITNESS 2015;55:714-21
R. DE AZEVEDO FRANKE, C. EHLERS BOTTON, R. RODRIGUES, R. SILVEIRA PINTO, C. SILVEIRA LIMA
Analysis of anterior, middle and posterior deltoid
activation during single and multijoint exercises
Corresponding author: R. de Azevedo Franke, Exercise Research Lab-
oratory (LAPEX), Federal University of Rio Grande do Sul (UFRGS),
Rua Felizardo, 750 – Bairro Jardim Botânico, CEP: 90690-200, Porto
Alegre – RS, Brazil. E-mail: rodrigo_franke@hotmail.com
Anno: 2015
Mese: July-August
Volume: 55
No: 7-8
Rivista: THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS
Cod Rivista: J SPORTS MED PHYS FITNESS
Lavoro: 4828-JSM
titolo breve: ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DUR-
ING SINGLE
primo autore: DE AZEVEDO FRANKE
pagine: 714-21
MINERVA MEDICA
COPYRIGHT®
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies
(either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other
means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is
not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo,
or other proprietary information of the Publisher.
ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DURING SINGLE DE AZEVEDO FRANKE
Vol. 55 - No. 7-8 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS 715
Lavoro: 4828-JSM
titolo breve: ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DUR-
ING SINGLE
primo autore: DE AZEVEDO FRANKE
pagine: 714-21
three portions of the deltoid during single and multi-
joint exercises involving shoulder horizontal abduc-
tion. Thus, the purpose of this study was to compare
activation of the three portions of the deltoid muscle
(anterior, middle and posterior) during single and
multijoint shoulder horizontal abduction exercises.
Materials and methods
This study compared the electromyographic activ-
ity (EMG) of the three portions of the deltoid (an-
terior, middle and posterior) in three different ex-
ercises (inclined lateral pull down, seated row and
reverse peck deck). Participants performed tests of
maximal voluntary isometric contraction (MVIC)
and ten maximal repetitions. Then, the three exer-
cises were performed with simultaneous acquisition
of the EMG signals.
Twelve healthy male participants (23.4±1.6 years;
177.2±2.3 cm; 78.9±16.2 kg; 15.4±4.2 % body
fat) familiarized with strength training (at least six
months of training) without shoulder injury history
have taken part in the study. To asses these infor-
mations, the participants answered a questionnaire
applied provided by researchers. The study was ap-
proved by the University Ethics Committee in Hu-
man Research (2008006) and all participants signed
an informed consent to take part in the study.
Procedures
Data was collected during three sessions that were
separated by 48 hours. During the rst session, meth-
ods and procedures of the study were introduced to
participants. Anthropometrics were then collected
for participants’ characterization. After that, muscle
activation was collected using surface electromyo-
graphy during three MVIC in the established posi-
tions, separated by ve minutes of rest.
In the second session, participants performed ten
maximum repetitions testing to estimate the load for
each exercise (inclined lateral pull-down [Figure 1],
seated row [Figure 2] and reverse peck deck [Figure
3]). Testing order was randomly selected and a resting
interval of ve minutes between trials was enforced.
In the third session, participants performed the three
exercises with the ten maximum repetitions load and
simultaneous recording of muscle activation.
ners because they require greater inter-muscle coor-
dination compared to single joint motions.12, 14, 15
Although differences in neuromuscular coordina-
tion may be expected comparing multi to single joint
exercises, the literature shows inconclusive results
about muscle activation. Major attention has been
given to assess activation of lower limb muscles with
conicting ndings from these studies.6-8, 10 For the
upper limb, only two studies had focus on the assess-
ment of shoulder horizontal adductors (i.e. pectora-
lis major and anterior deltoid) with no differences
in activation of these muscles comparing single to
multijoint exercises.9, 11
Based on this scenario, it is very important to un-
derstand how different portions of the deltoid are
activated in different exercises to establish a more
grounded rehabilitation and conditioning program,
and to date, no studies compared activation of the
Figure 1.—Inclined lateral pull-down exercise.
MINERVA MEDICA
COPYRIGHT®
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies
(either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other
means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is
not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo,
or other proprietary information of the Publisher.
DE AZEVEDO FRANKE ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DURING SINGLE
716 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS July-August 2015
and to perform only the required movements, to try
to minimize the contribution of other muscle groups.
Participants were verbally motivated 16 (24) during
the three trials of ve seconds of each test and a ve
minutes resting interval was enforced to postpone fa-
tigue effects.17, 18
Ten maximum repetitions test
Participants performed a ten maximum repetitions
test to determine the load used in each exercise. Pri-
marily, all participants warmed up in the target exer-
cise with minimum self-selected load. The load for
the ten repetitions test was changed until participants
achieved exhaustion in the tenth repetition and was
dened using the maximum of three trials. If a fourth
trial of ten repetitions would be required, a new ses-
sion was scheduled with the participants to avoid
MVIC
MVIC were performed using a crossover exer-
cise machine (World, Porto Alegre, RS, Brazil) in-
strumented with a load cell (Miotec - Equipamentos
Biomédicos, Porto Alegre, RS, Brazil) in order to
collect force measurements with simultaneous EMG
records. Shoulder exion was used to record the
maximum force for the anterior portion of deltoid
with participants in upright position and the domi-
nant shoulder at 90° of exion. Shoulder horizontal
abduction was used to assess middle and posterior
portion of deltoid maximum force, when participants
were upright and the dominant shoulder were at 90°
of abduction. In both positions, participants were in-
structed to pull the machine cable with their hand
Figure 2.—Seated row exercise.
Figure 3.—Reverse peck deck exercise.
MINERVA MEDICA
COPYRIGHT®
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies
(either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other
means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is
not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo,
or other proprietary information of the Publisher.
ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DURING SINGLE DE AZEVEDO FRANKE
Vol. 55 - No. 7-8 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS 717
cises were computed for the second, fourth, sixth
and eighth trials during both the concentric and ec-
centric phases of motion. A an optic motion tracking
displacement sensor attached to the load cable of the
exercise machine (Miotec - Equipamentos Biomédi-
cos, Porto Alegre, RS, Brazil) was employed to de-
ne the start and end of each repetition and the con-
centric and eccentric phases of motion. An average
of four RMS values was computed for each muscle
during each exercise and converted to percentages of
the MIVC.23, 24
Statistical analysis
Normality and sphericity of data distribution was
assessed via Shapiro-Wilk and Mauchly tests, re-
spectively. Correction factors of Greenhouse-Geis-
ser were used whenever appropriate. A one-way
ANOVA for repeated measures was used to com-
pare deltoid muscle (anterior, middle and posterior
portions) activation across exercises (seated row vs.
inclined lateral pull-down vs. reverse peck deck).
When between factors or interactions were found,
a Bonferroni post-hoc analysis was performed. Re-
sults about participants’ characterization are pre-
sented in the text as mean ± standard deviations and
results about the load in ten maximum repetition
tests and muscle activation in exercises in the gures
as mean±standard errors. All statistical procedures
were conducted in a statistical package (SPSS 17.0
for Windows, SPSS Inc., Chicago, IL, USA) and sig-
nicance was assumed for P<0.05.
Results
The load for the ten maximum repetitions test was
signicantly greater for the seated row compared to
the inclined lateral pull-down (P=0.01) and to the
reverse peck deck (P<0.01). The load during the in-
clined lateral pull-down was signicantly greater than
during the reverse peck deck (P=0.002) (Figure 4).
Signicant differences in activation for the ante-
rior portion of the deltoid were not observed com-
paring the three exercises (P=0.08) (Figure 5).
The middle portion of deltoid presented increased
activation during the reverse peck deck and the seat-
ed row compared to the inclined lateral pull-down
(P=0.03; P=0.03).
fatigue effects in load denition. A ve minute rest
was enforced between each ten repetitions trial.
The nal loads obtained on the ten maximum rep-
etitions tests were used in the exercises execution
with the simultaneous acquisition of EMG signals.
Order for performing the ten maximum repetitions
tests and to record muscle activation during exercis-
es was randomized.19
Muscle activation acquisition and signal processing
Surface electromyography was employed to meas-
ure the activation of the three portions of the del-
toid muscle during maximum isometric contractions
and during the inclined lat pull-down, reverse peck
deck and seated row exercises. A four channel elec-
tromyography system (Miotool 400, Miotec - Eq-
uipamentos Biomédicos, Porto Alegre, RS, Brazil)
was employed using bipolar conguration, sampling
signals at 2KHz and 14 bits of resolution. Electrodes
with 15mm radius (Kendall Mini Medi-Trace 100 -
Tyco Healthcare, São Paulo, SP, Brazil) and 20 mm
of centre-to-centre distance were attached to the
skin on the muscle belly after careful shaving and
cleaning of the area with an abrasive cleaner and
alcohol swabs to reduce the skin impedance (lower
than 3KW) 20 measured using a digital multimeter.
Location for electrodes placement followed recom-
mendation from SENIAM.21 A reference electrode
placed over the skin at the clavicle to act as a neutral
site for the EMG signals. A transparent sheet was
used to mark the position of the electrodes in rela-
tion to anatomical locations to reduce between-days
variation in position of the electrodes.20, 22
EMG signals were exported from the data acqui-
sition software (Miograph - Equipamentos Biomé-
dicos, Porto Alegre, RS, Brazil) for ofine analysis
(SAD 32 - developed by the Engineering School of
the local university). After gain compensation and
off-set correction, a band-pass digital lter (5th order
Butterworth with cut-off frequencies of 20-500Hz)
was applied to the signals. A section of one second
of the signal from each muscle was selected from the
MVIC force measurement assessed by the load cell
to compute the root mean square value (RMS) where
force signal was steady and maximum. This value
was then used for normalization of signals from the
ten repetitions of each exercise.
The RMS of each muscle during the three exer-
MINERVA MEDICA
COPYRIGHT®
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies
(either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other
means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is
not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo,
or other proprietary information of the Publisher.
DE AZEVEDO FRANKE ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DURING SINGLE
718 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS July-August 2015
line with our ndings. The anterior deltoid activation
can be justied as shoulder stabilization strategy via
coactivation 26 and low activation levels (under 20%
of MVIC) are in agreement with values reported in
the literature.27 Moreover, the level of co-activation
of the anterior deltoid was not modied during single
and multijoint exercises, which suggests the same
level of joint instability during the performance of
both types of exercises.
Differences comparing the inclined lateral pull-
down to the reverse peck deck and the seated row
may be due the single joint characteristic in the re-
verse peck deck and a double action required (shoul-
der isometric abduction and horizontal abduction) in
the seated row. The greater activation for the pos-
terior deltoid in the reverse peck deck could be ex-
plained by a restricted motion for the shoulder joint
compared to the inclined lateral pull-down and seat-
ed row. Greater activation is required in single joint
motion (compared to multi-joint) due the reduced
number of muscles involved.8 During multijoint ex-
ercises (i.e. inclined lateral pull-down and seated
row) the larger external force observed in our study
was potentially shared among elbow and shoulder
joint muscles. Possibly, similar activation for mid-
dle portion of deltoid compared to the reverse peck
deck was found at the seated row due the upper limb
position. In this exercise, there is need for sustaining
the upper arm at 90° of shoulder regular abduction in
For the posterior portion of deltoid, there was
greater activation during the reverse peck deck com-
pared to the seated row and to the inclined lateral
pull-down (P<0.01), without differences between
these last two exercises (P=0.22).
Discussion
The main ndings of this study were that: 1) the
posterior portion of deltoid was largely recruited
during the reverse peck deck (single joint exercise)
compared to the seated row and inclined lateral pull-
down (multijoint exercises); 2) the middle portion of
deltoid was mostly recruited during the reverse peck
deck and the seated row than during the inclined lat-
eral pull-down; 3) the anterior portion of deltoid had
minimal activation during the three exercises.
Various primary and secondary actions have been
suggested for each portion of the deltoid muscle.1,
2 Therefore, it is possible that the three portions of
deltoid may be activated in opposite actions. For the
anterior portion, it is intuitive to relate the low ac-
tivations recorded in the three exercises to the role
of this portion in shoulder exion and horizontal ad-
duction (opposite to the required actions). Ferreira et
al.25 observed that any exercise with focus on shoul-
der horizontal abduction elicited low levels from the
anterior portion of the deltoid muscle, which is in
Figure 4.—Load (kg) from participants (mean±SEM) during the
ten maximum repetitions test during the seated row, the inclined
lateral pull-down and the reverse peck deck. aSignicant differ-
ences to inclined lateral pull-down; bsignicant differences to the
reverse peck deck (P≤0.05).
Figure 5.—Activation of the three portions of the deltoid (mean
± SEM) during the three assessed exercises. aDifference to the
inclined lateral pull-down; bDifference to the seated row (P≤0.05).
MINERVA MEDICA
COPYRIGHT®
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies
(either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other
means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is
not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo,
or other proprietary information of the Publisher.
ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DURING SINGLE DE AZEVEDO FRANKE
Vol. 55 - No. 7-8 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS 719
joint exercise (all performed in machines) resulting
in greater activation for the posterior deltoid in the
single joint exercise.
Likewise, Welsch et al.11 did not nd differences
in activation of pectoralis major and anterior por-
tion of deltoid during barbell bench press, dumbbell
bench press or dumbbell y exercises. However, the
authors indicated that differences in elbow exion
angle during the dumbbell y execution may have
led to discrepancies. An alteration in elbow exion
angle may have changed the resistant torque during
the exercise and limited their results.
Apart from using machines with resistive weight
guided by cables, the reverse peck deck machine
employs a cam system. This system changes the mo-
ment arm of the resistive load throughout the range
of motion and consequently the torque required to
perform a single joint exercise, according to the mus-
cle moment arms.8, 31 To our knowledge, none of the
previous studies referred to the use of cam system in
single joint exercises machines, except for Enocson
et al.,8 who linked the greater muscle contribution to
the existence of an eccentric pulley in the exercise
machine, which enforces our results, since the condi-
tions and results were similar.
To a certain level, our results could not be fully
related to most studies because they had focus on
lower limb exercises.6-8, 10 Others assessed shoulder
horizontal adductors during upper body exercises 9, 11
which is limited compared to our approach where as-
sessments of the muscle group that acts in the shoul-
der horizontal abduction were conducted. Therefore,
our study expands the existing knowledge in muscle
function during strength training exercises.
Our option for using the maximum repetitions
testing is because it is the most common choice in
previous studies.8-11 Another reason is the greater ap-
plication for strength training prescription. However,
an increased number of repetitions could lead to
greater muscle activation due to fatigue effects in the
EMG signals.10, 17, 32 Previous studies with similar
methods 6, 7 opted for using only two maximum rep-
etitions to minimize fatigue effects. In these studies,
leg press exercise and knee extensions performed
in a machine did not differ in terms of quadriceps
muscle activation, which may be explained by the
reduced number of repetitions and consequently,
minor fatigue inuence, resulting in a different ac-
tivation pattern. This is a possible reason to explain
order to perform horizontal abduction by primary ac-
tion of the middle and posterior portions of deltoid1,2
and minimize the action of other muscles. That re-
quires a double action from middle portion of deltoid
(isometric abduction and dynamic horizontal ab-
duction) which leads to comparable activation than
single joint exercises (e.g. reverse peck deck), since
whenever a muscle is required to perform two simul-
taneous actions, greater activation is required.19 Dif-
ferently, in the reverse peck deck and in the inclined
lateral pull-down, gravitational force may not lead to
an isometric action, due to the handles and position
of the trunk and upper limbs, respectively.
A previous study showed similar activation levels
comparing the machine chest y (single joint exer-
cise) to the bench press (multijoint exercise) 9 whilst
another study observed greater activation for vastus
medialis and lateralis during squats compared to
knee extensions.10 These studies compared exercises
using free-weights (bench press and squat) to oth-
ers performed in exercise machines with a lead for
the resistive weight (machine chest y and knee ex-
tensor machine). Free-weight exercises may require
additional muscle activation to sustain body balance
compared to exercise machines.28-30 Thus, the in-
creased activation for the free weight exercises may
have similar activation level to the observed during
exercises performed in machines, even for single
joint exercises. Differently, in our study all exercises
were performed in exercise machines and did not re-
quire additional muscle recruitment to sustain body
balance, which may have elicited the larger muscle
requirement to perform single joint than multijoint
exercises.
Load can also be an intervenient factor in the re-
sults. Signorile et al.10 justied the greater activation
during squats to the greater load used in this exercise
compared to the load used during knee extensions.
In this case, the load and the exercise characteristic
(free weight) contributed to greater activation. Al-
though multijoint exercises are normally performed
with greater loads, Junior et al.9 showed greater
load for the machine chest y than the barbell bench
press. In this study, the activation may have been
favored by the load in the single joint exercise and
by the free weight in the multijoint exercise, pro-
viding no signicant difference between exercises.
In the present study, the absolute load was greater
in both multijoint exercises compared to the single
MINERVA MEDICA
COPYRIGHT®
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies
(either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other
means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is
not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo,
or other proprietary information of the Publisher.
DE AZEVEDO FRANKE ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DURING SINGLE
720 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS July-August 2015
bulk tissues and deltoid to static inferior glenohumeral stability. J
Shoulder Elb Surg 1994;3:313-9.
6. Alkner B, Tesch P, Berg H. Quadriceps EMG/force relationship in knee
extension and leg press. Med Sci Sport Exer 2000;32:459-63.
7. Damirchi A, Jalali M, Rahmaninia F, Mohebi H. Comparison of
EMG Activity of Knee Extensor Muscles in Knee Extension and
Leg Press. J Mov Sci Sport 2008;1:7-12.
8. Enocson AG, Berg HE, Vargas R, Jenner G, Tesch PA. Signal in-
tensity of MR-images of thigh muscles following acute open- and
closed chain kinetic knee extensor exercise - index of muscle use.
Eur J Appl Physiol 2005;94:357-63.
9. Júnior VAR, Gentil P, Oliveira E, do Carmo J. Comparação entre a
atividade EMG do peitoral maior, deltóide anterior e tríceps braqui-
al durante os exercícios supino reto e crucixo. Rev Bras Med Es-
porte 2007;13:51-4.
10. Signorile JF, Weber B, Roll B, Caruso J, Lowesteyn I, Perry A. An
eletromyographical comparison of the squat and knee extension ex-
ercises. J Strength Cond Res 19948:178-83.
11. Welsch EA, Bird M, Mayhew JL. Electromyographic activity of the
pectoralis major and anterior deltoid muscles during three upper-
body lifts. J Strength Cond Res 2005;19:449-52.
12. Fleck SJ, Kraemer WJ. Designing Resistance Training Programs.
Champaign: Human Kinects; 2004.
13. Kraemer WJ, Ratamess NA. Fundamentals of resistance train-
ing: progression and exercise prescription. Med Sci Sport Exer
2004;36:674-88.
14. Baechle T, Earle R. Essentials of strength training and conditioning.
Champaign: Human Kinetics; 2008.
15. Kraemer WJ, Adams K, Cafarelli E, Dudley GA, Dooly C, Fei-
genbaum MS et al. American College of Sports Medicine position
stand. Progression models in resistance training for healthy adults.
Med Sci Sport Exer 2002;34:364-80.
16. McNair PJ, Depledge J, Brettkelly M, Stanley SN. Verbal encour-
agement: effects on maximum effort voluntary muscle: action. Brit
J Sports Med 1996;30:243-45.
17. Basmajian JV, Luca CJD. Muscles alive: their functions revealed by
electromyography. Baltimore: Williams & Wilkins; 1985.
18. De Luca CJ. Myoelectrical manifestations of localized muscular fa-
tigue in humans. Crit Rev Biomedl Eng 1984;11:251-79.
19. Signorile JF, Zink AJ, Szwed SP. A comparative electromyo-
graphical investigation of muscle utilization patterns using vari-
ous hand positions during the lat pull-down. J Strength Cond Res
2002;16:539-46.
20. Narici MV, Roi GS, Landoni L, Minetti AE, Cerretelli P. Changes
in force, cross-sectional area and neural activation during strength
training and detraining of the human quadriceps. Eur J Appl Physiol
Occup Physiol 1989;59:310-9.
21. Hermens HJ, Freriks B, Merletti R, Stegeman D, Blok J, Rau G
et al. European recommendations for surface electromyography.
Roessingh Research and Development: The Netherlands; 1999.
22. Hakkinen K, Komi PV. Electromyographic changes during strength
training and detraining. Med Sci Sport Exer 1983;15:455-60.
23. Escamilla RF, Babb E, DeWitt R, Jew P, Kelleher P, Burnham T et
al. Electromyographic analysis of traditional and nontraditional ab-
dominal exercises: implications for rehabilitation and training. Phys
Ther 2006;86:656-71.
24. Kalmar JM, Cafarelli E. Central excitability does not limit post-
fatigue voluntary activation of quadriceps femoris. J Appl Physiol
2006;100:1757-64.
25. Ferreira MI, Bull ML, Vitti M. Electromyographic validation of ba-
sic exercises for physical conditioning programmes. I. Analysis of
the deltoid muscle (anterior portion) and pectoralis major muscle
(clavicular portion) in rowing exercises with middle grip. Electro-
myogr Clin Neurophysiol 1995;35:239-45.
26. Suzuki M, Shiller DM, Gribble PL, Ostry DJ. Relationship between
cocontraction, movement kinematics and phasic muscle activity in
single-joint arm movement. Exp Brain Res 2001;140:171-81.
the fact that these studies did not found signicant
differences between single and multijoint exercises,
unlike the present study.
However, it is speculated that muscle activation
levels does not depend exclusively of single or multi-
joint exercise characteristics. The number of actions
performed by the same muscle in an exercise, the
active muscle group and their mechanical proper-
ties, the characteristics of the exercise machine or
equipment used, among other aspects may inuence
muscle recruitment. Thus, it is necessary to consider
these aspects when comparing single and multijoint
exercises.
Conclusions
Our ndings indicated that the seated row, the in-
clined lateral pull-down and the reverse peck deck
leads to similar low levels of activation for the anterior
portion of deltoid muscle due the fact that this portion
has antagonist action in the assessed movements. On
the other hand, seated row was effective in recruiting
the middle portion of the deltoid muscle because they
combine two primary actions of this muscle. The re-
verse peck deck was effective in recruiting the middle
and the posterior portions of the deltoid muscle. This
result provides evidence, for these exercises, that sin-
gle joint exercises should optimize the contribution of
less muscle mass and improve the contribution of each
muscle, rather than a multijoint exercise when force is
shared among more muscles.
For an advanced stage of training programs look-
ing for improvements in strength for the middle and
posterior portions of the deltoid, it is recommended
the option for single joint exercises, rather than mul-
tijoint exercises. That should enhance gains in mus-
cle strength compared to multijoint exercises.
References
1. Rasch PJ, Burke RK. Kinesiology and applied anatomy: The science
of human movement. London: Henry Kimpton Publishers; 1978.
2. Smith LK, Weiss EL, Lehmkuhl LD. Brunnstrom’s clinical kinesi-
ology. Philadelphia: FA Davies; 1996.
3. Ackland DC, Pandy MG. Lines of action and stabilizing potential of
the shoulder musculature. J Anat 2009;215:184-97.
4. Halder AM, Zhao KD, Odriscoll SW, Morrey BF, An KN. Dy-
namic contributions to superior shoulder stability. J Orthopaed Res
2001;19:206-12.
5. Motzkin NE, Itoi E, Morrey BF, An KN. Contribution of passive
MINERVA MEDICA
COPYRIGHT®
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies
(either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other
means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is
not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo,
or other proprietary information of the Publisher.
ANALYSIS OF ANTERIOR, MIDDLE AND POSTERIOR DELTOID ACTIVATION DURING SINGLE DE AZEVEDO FRANKE
Vol. 55 - No. 7-8 THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS 721
32. Vollestad NK. Measurement of human muscle fatigue. J Neurosci
Meth 1997;74:219-27.
Funding.—The authors would like to thank Coordenação de Aper-
feiçoamento de Pessoal de Nível Superior (CAPES-Brazil) and Con-
selho Nacional de Pesquisa (CNPq-Brazil) for nancial support and all
volunteers for their participation in this project.
Conicts of interest.—The authors certify that there is no conict of in-
terest with any nancial organization regarding the material discussed
in the manuscript.
Received on September 11, 2013.
Accepted for publication on June 18, 2014.
Epub ahead of print on June 20, 2014.
27. Kellis E. Quantication of quadriceps and hamstring antagonist ac-
tivity. Sports Med 1998;25:37-62.
28. McCaw ST, Friday JJ. A comparison of muscle activity between
a free weight and machine bench press. J Strength Cond Res
1994;8:259-64.
29. Schick EE, Coburn JW, Brown LE, Judelson DA, Khamoui AV,
Tran TT et al. A comparison of muscle activation between a
Smith machine and free weight bench press. J Strength Cond Res
2010;24:779-84.
30. Schwanbeck S, Chilibeck PD, Binsted G. A comparison of free
weight squat to Smith machine squat using electromyography. J
Strength Cond Res 2009;23:2588-91.
31. Folland J, Morris B. Variable-cam resistance training machines: do
they match the angle - torque relationship in humans? J Sports Sci
2008;26:163-69.
MINERVA MEDICA
COPYRIGHT®
This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies
(either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other
means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is
not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo,
or other proprietary information of the Publisher.
... The deltoid is considered a primary motor muscle in many upper body strength training (ST) exercises (Andersen et al., 2014;Botton et al., 2013;Franke et al., 2015;Welsch et al., 2005;Wilk et al., 2019). Due to its triangular shape, the deltoid muscle is commonly subdivided into anterior, medial and posterior portions (Botton et al., 2013) being responsible for several movements of the glenohumeral joint such as shoulder abduction (medial deltoid, anterior and posterior) (Hall, 2006;Houglum and Bertoti, 2011), shoulder flexion and horizontal adduction (anterior deltoid) (Hall, 2006;Houglum and Bertoti, 2011), as well as shoulder extension and horizontal abduction (posterior deltoid) (Hall, 2006;Houglum and Bertoti, 2011). ...
... The use of different exercises with different mechanical strains has been highly recommended for the complete development of different deltoid portions. In this sense, priority exercises such as the bench press (McCaw and Friday, 1994;Schick et al., 2010;Welsch et al., 2005;Wilk et al., 2019), lat pulldown (Andersen et al., 2014;Vilaça-Alves et al., 2014), seated row (Botton et al., 2013;Franke et al., 2015), and complementary exercises such as the lateral raise (Botton et al., 2013), shoulder press (Saeterbakken and Fimland, 2013), and reverse pec deck fly (Botton et al., 2013;Franke et al., 2015) can be used. However, the importance of including complementary exercises in ST routines, as well as how these different exercises affect the muscle recruitment of the deltoid portions remain still unclear. ...
... The use of different exercises with different mechanical strains has been highly recommended for the complete development of different deltoid portions. In this sense, priority exercises such as the bench press (McCaw and Friday, 1994;Schick et al., 2010;Welsch et al., 2005;Wilk et al., 2019), lat pulldown (Andersen et al., 2014;Vilaça-Alves et al., 2014), seated row (Botton et al., 2013;Franke et al., 2015), and complementary exercises such as the lateral raise (Botton et al., 2013), shoulder press (Saeterbakken and Fimland, 2013), and reverse pec deck fly (Botton et al., 2013;Franke et al., 2015) can be used. However, the importance of including complementary exercises in ST routines, as well as how these different exercises affect the muscle recruitment of the deltoid portions remain still unclear. ...
Preprint
Full-text available
The aims of this study were to compare muscle activity of the anterior deltoid, medial deltoid, and posterior deltoid in the bench press, dumbbell fly, shoulder press, and lateral raise exercises. Thirteen men experienced in strength training volunteered for the study. Muscle activation was recorded during maximum isometric voluntary contraction (MVIC) for data normalization, and during one set of 12 repetitions with the load of 60% 1RM in all exercises proposed. One-way repeated-measures ANOVA with Bonferroni's posthoc was applied using a 5% significance level. For anterior deltoid, the shoulder press (33.3% MVIC) presented a significantly higher level of activation when compared to other exercises. Also, no significant difference was found between the bench press (21.4% MVIC), lateral raise (21.2% MVIC), and dumbbell fly (18.8% MVIC). For the medial deltoid, the lateral raise (30.3% MVIC) and shoulder press (27.9% MVIC) presented a significantly higher level of activity than the bench press (5% MVIC) and dumbbell fly (3.4% MVIC). Besides, no significant difference was found between the bench press and the dumbbell fly. For the posterior deltoid, the lateral raise (24% MVIC) presented a significantly higher level of activation when compared to other exercises. For the posterior deltoid portion, the shoulder press (11.4% MVIC) was significantly more active than the bench press (3.5% MVIC) and dumbbell fly (2.5% MVIC). Moreover, no significant difference was found between the bench press and the dumbbell fly. In conclusion, the shoulder press and lateral raise exercises showed a higher level of muscle activation in the anterior deltoid and medial deltoid when compared to the bench press and dumbbell fly exercises.
... This variability makes it difficult to choose the exercise in rehabilitation or resistance training programs, since muscle activation above 40% of isometric maximum voluntary contraction (iMVC) are indicated for strength gains 17,18 . A possible reason for this great variability may be the type of load applied in different studies, ranging from body mass 11 to elastic resistance 19 since the intensity of exercise changes the pattern of muscle activation 20 . Although the use of maximal repetitions is the most common method for determining intensity in resistance training and broadly used in previous studies to determine muscular activation 20,21 , the literature lacks studies regarding the muscle activation that involves maximal repetitions in the most common multi-joint exercises focusing strengthening of GMed 16 . ...
... However, our values were higher than those found by Selkowitz, Beneck, Powers 11 (15%). One possible hypothesis is related to the load employed in our study, which leads to higher levels of muscle activation 20 . ...
... Even so, the researches gave the participants the orientation to perform the eccentric phase at the maximum of the range of motion. Additionally, we used the RMS value during entire repetition (concentric and eccentric phases), similar to previous studies 11,20 . We believe that another method of analysis (such as the use of peak value) during each exercise could change the results. ...
Article
Full-text available
Aim: To compare the activation of GMed and TFL in four multi-joint exercises in strength training protocols and to verify if the level of muscle activation is indicated for strength gains in resistance training protocols. Methods: Eleven recreational lifters had normalized muscle activation of GMed and TFL assessed during ten maximal repetitions of four multi-joint exercises: (1) bilateral supine bridge (BiBRG); (2) bilateral supine bridge with hip abducted (BiBRG-AB); (3) unilateral supine bridge (UniBRG) and (4) single-leg squat (SLS). Results: A load of exercises was significantly greater for the BiBRG and BiBRG-AB compared to the UniBRG and SLS (p<0.001). We observed that GMed activation was significant greater compared to TFL among the four exercises (p=0.004) [BiBRG: Δ=26.2%; BiBRG-AB: Δ=27.3%; UniBRG: Δ=24.5% and SLS: Δ=18.8%]. Additionally, GMed activation was classified as moderate (<40%iMVC) and TFL activation was classified as low (<20%iMVC) in all exercises. Conclusion: Our results demonstrated that GMed is more active than TFL in all analyzed exercises. However, the level of activation observed for GMed was below that recommended to strength gain in resistance training programs.
... The greater activation of the UT, MT, and PD occurred in the techniques with greater shoulder abduction angles (60° and 90°); on the contrary, the greater activation of the UL and LL occurred in the techniques with smaller shoulder abduction angles (PRO, SUP, and NEU). Previous studies investigating variations of the rowing exercise found results similar to the present one [2,[12][13][14]. García-Jáen et al. [2] while studying the dumbbell chest-supported row, observed an increase in UT, MT, and PD activation when subjects were oriented to perform the exercise with 90° of shoulder abduction in comparison to shoulder adduction. ...
... Kara et al. [12] investigating the scapular-retraction exercise at 0°, 45°, and 90° of shoulder abduction also reported an increase in MT and UT activity from 0° to 45°, 0° to 90°, and 45° to 90° of shoulder abduction. Botton et al. [14] and Franke et al. [13] also reported high activation of the posterior deltoid (>40% of MVIC) during the machine seated row with 90° of shoulder abduction. In both studies, DP activity during the machine seated row was comparable to the incline lat pull-down but lower than the reverse fly machine. ...
Article
Full-text available
The purpose of this study was to compare the peak force and electromyographic activation in different techniques of the seated row. Eleven recreationally trained male (28±5 years, 176±5 cm, 94±16 kg) and ten female (27±5 years, 168±8 cm, 65±11 kg ) performed an isometric and a dynamic assessment of the seated cable row and the preacher curl: pronated grip (PRO), supinated grip (SUP), neutral grip (NEU), 30° (30°), 60° (60°), 90° (90°) of shoulder abduction, and cable preacher curl (PC). Peak force and muscle activation of upper trapezius, middle trapezius, upper latissimus, lower latissimus, posterior deltoid, and biceps bracii were recorded during the isometric and dynamic assessment of the exercises. p values<0.05 were considered statistically significant. The peak force was greater when shoulder abduction angle was closer to 0° (PRO, SUP, and NEU) and decreased as abduction angle increased (60° and 90°). Muscle activation of the upper back (upper trapezius, middle trapezius) and posterior deltoid increased as abduction angle increased (60° and 90°) on both isometric and dynamic analysis. Muscle activation of the upper and lower latissimus increased as abduction angle was closer to 0° (PRO, SUP, and NEU) on both isometric and dynamic analysis. Biceps brachii activation on both isometric and dynamic analysis during the PC was greater than all other rowing conditions; among the rowing techniques, BB activation was greater during SUP, NEU, and 90° techniques. In conclusion, the closer to 90° shoulder abduction the greater UT, MT, and PD activity, on the other hand, the closer to 0° shoulder abduction the greater peak force, UL, and LL activity during the variations of the rowing exercise.
... Shoulder muscles, one of the upper body muscle groups, is a penne muscle that surrounds the shoulder joint with three muscle parts assigned to move the humerus relative to the scapula and is considered the primary motor muscle in many upper body strength training exercises (Botton et al., 2013;Franke et al., 2015;Smith, 1996). In most sports and daily life activities, the muscles surrounding the shoulders are involved in a series of multi-plane movements and various exercises are performed to strengthen these muscles (Escamilla et al., 2009). ...
... This study showed that combining 2 unbalanced strategies in shoulder presses (standing + dumbbells) increased shoulder muscle activation. Franke et al. (2015) examined the activity level of the seated row, incline lat pulldown, and reverse peck deck fly exercises in the shoulder muscles and found that seated row was effective in working the medial part of the shoulder and reverse peck deck fly was effective in working the medial and back parts of the shoulder. Dickie et al. (2017) compared the muscle activity level of different variations in the pull-up exercise and found that the pronation grip variation activates the medial trapezius muscle more than the neutral grip. ...
Article
Full-text available
This study aimed to compare the effects of handgrip and range of motion (ROM) variations on muscle activity in different deltoid exercises. 14 resistance-trained men volunteered for 1RM and EMG testing with a load corresponding to 80% of 1RM. The subjects performed three different handgrips during Dumbell Front Raise (DFR), two different ROM variations for Dumbell Lateral Raise (DLR), and two different handgrips during Dumbell Rear Delt Raise (DRDR). Electromyogram (EMG) activity was measured in the anterior, medial, and posterior heads of deltoids. For the DFR exercise, the highest mean EMG activity was greater for the anterior deltoid, and the highest activity was observed in pronate grip (PG) con (51.57%). For the anterior deltoid EMG activity was significantly greater in PG con (51.57%) compared with hammer grip (HG) con (43.36%) (p˂0.05). HG ecc activity (40.36%) was significantly greater than PG ecc (36.4%) in posterior deltoid (p˂0.05). For the DLR exercise, the highest activity was observed in medial deltoid, and for limited ROM (LTR) (20.74%). LTR con activity (19.37%) was significantly greater than full ROM con (FLR) (16.88%) in the anterior head (p˂0.05). For the DRDR exercise, the mean activity was greater in medial deltoid, and HG con showed the highest activity (24.47%). The mean electromyography activity for the posterior deltoid was significantly greater in standard grip (STD) ecc compared with HG ecc (17.3%) (p˂0.05). In conclusion, for the heads of the deltoid muscle, the use of the different handgrip and ROM variations may increase neuromuscular activity.
... Exercises were specifically designed for anterior, middle and posterior deltoid, avoiding the imbalance between the anterior and middle-posterior portion. In fact, the selective predominance of anterior deltoid may increase glenohumeral instability, while strengthening of each part of deltoid may enhance shoulder stabilization15 . ...
Article
Background The three portions of the deltoid muscle (anterior, middle, and posterior) are primary movers of several strengthening exercises and their contribution to different exercises can be measured using surface electromyography. Purpose To systematically review studies that evaluated the activation of commonly used exercises and their variations. Methods A search was conducted in PubMed (MEDLINE), Web of Science, Scopus and SciELO. Thirty-three studies met the inclusion criteria, evaluating at least one deltoid portion during conventional isotonic exercises (minimum load: 60% of one-repetition maximum or body weight) and reporting normalized values. Similar exercises were grouped, averaged, and ranked according to the resulting activation. Individual exercise variations were also ranked. Results For anterior deltoid, horizontal adductions (inclined) and horizontal adductions (horizontal) generated the greatest activation, while the inclined dumbbell fly was the individual exercise with greatest activation; for middle deltoid, abductions and horizontal abductions presented the greatest activation, with lateral raises associated with internal rotation being the exercises producing greatest activation. For posterior deltoid, pull-ups generated greatest activation, with the standard pull-up and the inverted row with a suspension device requiring the greatest individual exercise activation. Conclusions These findings can be useful for coaches and practitioners when choosing the most appropriate exercise for strengthening programs.
Article
The primary purpose of this study was to measure the acute effects on muscle thickness, arm circumference, and peak force between unilateral seated row and unilateral biceps curl exercises for elbow flexors after a RT session in recreationally-trained subjects. MeThodS: fourteen resistance-trained men (25.3±2.5years, 76.5±6.4kg, 174.6±7cm) performed 6 sets of 10rM and 2-min rest for one of two exercises (unilateral seated row exercise, uSr or unilateral biceps curl, uBc). Muscle thickness (MT), arm circumference (ac), and peak force (pf) were measured before 10-min (control), pre-rT session and post-rT (immediately after, 15-min and 30-min). all acute rT variables were measured during both exercises: maximal number of repetitions (MNr), total number of repetitions (TNr), time under tension (TuT), rating of perceived exertion (rpe). Two-way aNoVas were used to test differences between exercises and moments with an alpha of 5%. RESULTS: For PF, there was a significant difference between pre-and post-0 for UBC and USR (P<0.001). For AC, there were significant differences between pretest × post-0-min for both exercises (P<0.001). For MT, there were significant differences between pretest × post 0-min (P<0.001), pretest × post 15-min (P<0.001) for both exercises and pretest × post 30-min only for UBC (P=0.006). CONCLUSIONS: Both exercises induced similar increases in AC and MT for elbow flexors and reduction in peak force.
Article
Background: The primary purpose of this study was to measure the acute effects on muscle thickness, arm circumference, and peak force between unilateral seated row and unilateral biceps curl exercises for elbow flexors after a RT session in recreationally-trained subjects. Methods: Fourteen resistance-trained men (25.3 ± 2.5years, 76.5± 6.4kg, 174.6 ± 7cm) performed 6 sets of 10RM and 2-min rest for one of two exercises (unilateral seated row exercise, USR or unilateral biceps curl, UBC). Muscle thickness (MT), arm circumference (AC), and peak force (PF) were measured before 10-min (control), pre-RT session and post- RT (immediately after, 15-min and 30-min). All acute RT variables were measured during both exercises: maximal number of repetitions (MNR), total number of repetitions (TNR), time under tension (TUT), rating of perceived exertion (RPE). Two-way ANOVAs were used to test differences between exercises and moments with an alpha of 5%. Results: For PF, there was a significant difference between pre- and post-0 for UBC and USR (p<0.001). For AC, there were significant differences between pre-test x post-0-min for both exercises (p<0.001). For MT, there were significant differences between pre-test x post 0-min (p<0.001), pre-test x post 15-min (p<0.001) for both exercises and pre-test x post 30- min only for UBC (p=0.006). Conclusions: Both exercises induced similar increases in AC and MT for elbow flexors and reduction in peak force.
Article
Full-text available
The bench press exercise exists in multiple forms including the machine and free weight bench press. It is not clear though how each mode differs in its effect on muscle activation. The purpose of this study was to compare muscle activation of the anterior deltoid, medial deltoid, and pectoralis major during a Smith machine and free weight bench press at lower (70% 1 repetition maximum [1RM]) and higher (90% 1RM) intensities. Normalized electromyography amplitude values were used during the concentric phase of the bench press to compare muscle activity between a free weight and Smith machine bench press. Participants were classified as either experienced or inexperienced bench pressers. Two testing sessions were used, each of which entailed either all free weight or all Smith machine testing. In each testing session, each participant's 1RM was established followed by 2 repetitions at 70% of 1RM and 2 repetitions at 90% of 1RM. Results indicated greater activation of the medial deltoid on the free weight bench press than on the Smith machine bench press. Also, there was greater muscle activation at the 90% 1RM load than at the 70% 1RM load. The results of this study suggest that strength coaches should consider choosing the free weight bench press over the Smith machine bench press because of its potential for greater upper-body muscular development.
Article
Full-text available
The objective of the present study was to measure the lines of action of 18 major muscles and muscle sub-regions crossing the glenohumeral joint of the human shoulder, and to compute the potential contribution of these muscles to joint shear and compression during scapular-plane abduction and sagittal-plane flexion. The stabilizing potential of a muscle was found by assessing its contribution to superior/inferior and anterior/posterior joint shear in the scapular and transverse planes, respectively. A muscle with stabilizing potential was oriented to apply more compression than shear at the glenohumeral joint, whereas a muscle with destabilizing potential was oriented to apply more shear. Significant differences in lines of action and stabilizing capacities were measured across sub-regions of the deltoid and rotator cuff in both planes of elevation (P < 0.05), and substantial differences were observed in the pectoralis major and latissimus dorsi. The results showed that, during abduction and flexion, the rotator cuff muscle sub-regions were more favourably aligned to stabilize the glenohumeral joint in the transverse plane than in the scapular plane and that, overall, the anterior supraspinatus was most favourably oriented to apply glenohumeral joint compression. The superior pectoralis major and inferior latissimus dorsi were the chief potential scapular-plane destabilizers, demonstrating the most significant capacity to impart superior and inferior shear to the glenohumeral joint, respectively. The middle and anterior deltoid were also significant potential contributors to superior shear, opposing the combined destabilizing inferior shear potential of the latissimus dorsi and inferior subscapularis. As potential stabilizers, the posterior deltoid and subscapularis had posteriorly-directed muscle lines of action, whereas the teres minor and infraspinatus had anteriorly-directed lines of action. Knowledge of the lines of action and stabilizing potential of individual sub-regions of the shoulder musculature may assist clinicians in identifying muscle-related joint instabilities, assist surgeons in planning tendon reconstructive surgery, aid in the development of rehabilitation procedures designed to improve joint stability, and facilitate development and validation of biomechanical computer models of the shoulder complex.
Article
Background and Purpose. Performing nontraditional abdominal exercises with devices such as abdominal straps, the Power Wheel, and the Ab Revolutionizer has been suggested as a way to activate abdominal and extraneous (nonabdominal) musculature as effectively as more traditional abdominal exercises, such as the crunch and bent-knee sit-up. The purpose of this study was to test the effectiveness of traditional and nontraditional abdominal exercises in activating abdominal and extraneous musculature. Subjects. Twenty-one men and women who were healthy and between 23 and 43 years of age were recruited for this study. Methods. Surface electromyography (EMG) was used to assess muscle activity from the upper and lower rectus abdominis, external and internal oblique, rectus femoris, latissimus dorsi, and lumbar paraspinal muscles while each exercise was performed. The EMG data were normalized to maximum voluntary muscle contractions. Differences in muscle activity were assessed by a 1-way, repeated-measures analysis of variance. Results. Upper and lower rectus abdominis, internal oblique, and latissimus dorsi muscle EMG activity were highest for the Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees. External oblique muscle EMG activity was highest for the Power Wheel (pike, knee-up, and roll-out) and hanging knee-up with straps. Rectus femoris muscle EMG activity was highest for the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up. Lumbar paraspinal muscle EMG activity was low and similar among exercises. Discussion and Conclusion. The Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees not only were the most effective exercises in activating abdominal musculature but also were the most effective in activating extraneous musculature. The relatively high rectus femoris muscle activity obtained with the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up may be problematic for some people with low back problems.
Article
The seated knee extension is commonly used with the parallel squat to promote balance between the vastus medialis (VM) and vastus lateralis (VL). No controlled studies have examined the relative contributions of each muscle during these exercises, so this study employed EMG analysis to determine their contributions. Ten experienced lifters performed squats and knee extensions at their 10-RM. Sets were separated by 15 min rest and the order of performance was reversed between sessions, which were 1 week apart. EMG was collected on the VL and VM of the dominant leg during the first and last repetition of each exercise. Since EMG activity differed significantly between the two testing days, each was analyzed separately. No significant differences were found between the root mean square of the amplitude of the EMG for the VL and VM during either exercise. The parallel squat elicited more electrical activity than the knee extension in both muscles, and the downward shift in frequency of the EMG signal was greater for both the VM and VL during the parallel squat. The results question the value of the knee extension as a supplemental exercise in this case. (C) 1994 National Strength and Conditioning Association
Article
The relative stabilizing effect of the passive bulk tissues and deltoid to inferior humeral displacement was studied. The humeral head center relative to the glenoid center was determined by a magnetic tracking device in 10 shoulder specimens for the bulk tissue study and in 13 for the deltoid study. Twelve static recordings were obtained per specimen: (1) with and without a 1.5 kg load, (2) with the humerus adducted hanging freely and abducted 90° in neutral rotation, and (3) in three stages of dissection: with all tissues intact, after removal of the tissues superficial to the deltoid, and after removal of the deltoid. In both humeral adduction and abduction, the passive bulk tissues and deltoid did not provide significant stability to the shoulder joint.
Article
The purpose of this experiment was to determine whether free weight or Smith machine squats were optimal for activating the prime movers of the legs and the stabilizers of the legs and the trunk. Six healthy participants performed 1 set of 8 repetitions (using a weight they could lift 8 times, i.e., 8RM, or 8 repetition maximum) for each of the free weight squat and Smith machine squat in a randomized order with a minimum of 3 days between sessions, while electromyographic (EMG) activity of the tibialis anterior, gastrocnemius, vastus medialis, vastus lateralis, biceps femoris, lumbar erector spinae, and rectus abdominus were simultaneously measured. Electromyographic activity was significantly higher by 34, 26, and 49 in the gastrocnemius, biceps femoris, and vastus medialis, respectively, during the free weight squat compared to the Smith machine squat (p < 0.05). There were no significant differences between free weight and Smith machine squat for any of the other muscles; however, the EMG averaged over all muscles during the free weight squat was 43% higher when compared to the Smith machine squat (p < 0.05). The free weight squat may be more beneficial than the Smith machine squat for individuals who are looking to strengthen plantar flexors, knee flexors, and knee extensors.
Article
This study calculated IEMG values during the ascent and descent phases of the bench press and compared the values between lifts performed with free weights versus a guided weight machine. In Phase 1 of the study the 1-RM on each mode was determined for each subject. In Phase 2, EMG data were collected from five muscles of the upper extremity while each subject completed five trials at 80% of 1-RM and five trials at 60% of 1-RM for each mode. Linear envelopes were created from the EMG data of each trial, and IEMG values were calculated during the descent and ascent phases of each trial. Planned comparisons were used to compare mean IEMG values between the two loads within the same mode, and between the two modes at both the 60% and 80% loads. Results suggested greater muscle activity during the free-weight bench press, especially at the 60% 1-RM load, although there were notable differences among the patterns of individual subjects.