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Incline Dumbbell Curl (IDC) and Dumbbell Preacher Curl (DPC) are two variations of the standard Dumbbell Biceps Curl (DBC), generally applied to optimize biceps brachii contribution for elbow flexion by fixing shoulder at a specific angle. The aim of this study is to identify changes in the neuromuscular activity of biceps brachii long head for IDC, DPC and DBC exercises, by taking into account the changes in load moment arm and muscle length elicited by each dumbbell curl protocol. A single cycle (concentric-eccentric) of DBC, IDC and DPC, was applied to 22 subjects using a submaximal load of 40% estimated from an isometric MVC test. The neuromuscular activity of biceps brachii long head was compared by further partitioning each contraction into three phases, according to individual elbow joint range of motion. Although all protocols elicited a considerable level of activation of the biceps brachii muscle (at least 50% of maximum RMS), the contribution of this muscle for elbow flexion/extension varied among exercises. The submaximal elbow flexion (concentric) elicited neuro muscular activity up to 95% of the maximum RMS value during the final phase of IDC and DBC and 80% for DPC at the beginning of the movement. All exercises showed significant less muscle activity for the elbow extension (eccentric). The Incline Dumbbell Curl and the classical Dumbbell Biceps Curl resulted in similar patterns of biceps brachii activation for the whole range of motion, whereas Dumbbell Preacher Curl elicited high muscle activation only for a short range of elbow joint angle. Key pointsThe Incline Dumbbell Curl and the Dumbbell Biceps Curl resulted in a considerable neuromuscular effort throughout the whole elbow range of motion.The Incline Dumbbell Curl and the Dumbbell Biceps Curl may be preferable for the improvement of biceps brachii force in training programs.
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©Journal of Sports Science and Medicine (2009) 8, 24-29
http://www.jssm.org
Received: 14 April 2008 / Accepted: 30 October 2008 / Published (online): 01 March 2009
Effect of the shoulder position on the biceps brachii EMG in different dumbbell
curls
Liliam F. Oliveira 1, Thiago T. Matta 1, Daniel S. Alves 1, Marco A.C. Garcia 1 and Taian M.M.
Vieira 1,2
1 Biomechanics Laboratory, Bioscience Department, Physical Education and Sports School, Federal University of Rio
de Janeiro, Rio de Janeiro, Brazil. 2 Laboratory for Engineering of the Neuromuscular System, Polytechnic of Turin,
Turin, Italy.
Abstract
Incline Dumbbell Curl (IDC) and Dumbbell Preacher Curl
(DPC) are two variations of the standard Dumbbell Biceps Curl
(DBC), generally applied to optimize biceps brachii contribution
for elbow flexion by fixing shoulder at a specific angle. The aim
of this study is to identify changes in the neuromuscular activity
of biceps brachii long head for IDC, DPC and DBC exercises,
by taking into account the changes in load moment arm and
muscle length elicited by each dumbbell curl protocol. A single
cycle (concentric-eccentric) of DBC, IDC and DPC, was ap-
plied to 22 subjects using a submaximal load of 40% estimated
from an isometric MVC test. The neuromuscular activity of
biceps brachii long head was compared by further partitioning
each contraction into three phases, according to individual
elbow joint range of motion. Although all protocols elicited a
considerable level of activation of the biceps brachii muscle (at
least 50% of maximum RMS), the contribution of this muscle
for elbow flexion/extension varied among exercises. The sub-
maximal elbow flexion (concentric) elicited neuro muscular
activity up to 95% of the maximum RMS value during the final
phase of IDC and DBC and 80% for DPC at the beginning of the
movement. All exercises showed significant less muscle activity
for the elbow extension (eccentric). The Incline Dumbbell Curl
and the classical Dumbbell Biceps Curl resulted in similar pat-
terns of biceps brachii activation for the whole range of motion,
whereas Dumbbell Preacher Curl elicited high muscle activation
only for a short range of elbow joint angle.
Key words: Biceps curl, EMG, biceps brachii.
Introduction
Resistance training exercises are mostly applied to over-
load the musculoskeletal system, leading to the acceler-
ated enhancement of muscle strength (Fleck and Kraemer,
1997). Equipments like dumbbells, barbells and cable
machines are often used in conditioning and strengthening
programs (Biscarini et al., 2005). However, the use of free
loads may be preferred in some occasions, since it does
not constrain the movement and different exercises can be
performed, eliciting the contribution of specific muscles
(Cotterman et al., 2005). Furthermore, free load-based
exercises mimics body movements in natural situations
and elicits joint and segments stabilization (Cotterman et
al., 2005). Many people are addicted to the benefits pro-
vided by training programs based on the use of free loads,
from experienced athletes to children and elderly
(Faigenbaum et al., 2003; Falk and Tenenbaum, 1996;
Fleck and Kraemer, 1997).
The weight of dumbbells or barbells is constantly
oriented in a vertical direction, so that the load torque
changes with joint angle and the peak of the load torque
changes for different body positions (i.e. horizontal or
inclined benches). According to a biomechanical model
for simulating Dumbbell Biceps Curl (DBC) exercise
(Biscarini et al., 2005), the force produced by elbow flex-
ors in quasi-static exercises increases with the load mo-
ment arm, which highly affects the direction and magni-
tude of joint internal forces. Moreover, the classic length-
tension relationship is critical for muscle force produc-
tion, especially during low velocity/high intensity exer-
cises (Lieber, 2002). Although such relationship holds for
isometric contractions, it can still be used to predict mus-
cle force from joint angle during low velocity contrac-
tions.
Incline Dumbbell Curl (IDC) and Dumbbell
Preacher Curl (DPC) are two variations of the standard
DBC, generally applied to optimize biceps brachii contri-
bution for elbow flexion by fixing shoulder angle at a
specific value. These different protocols for dumbbell curl
may impose different demands to the neuromuscular
system, resulting in different solutions for the load shar-
ing between elbow flexors.
The aim of this study is to identify changes in the
neuromuscular activity of biceps brachii long head for
IDC, DPC and DBC exercises, by taking into account the
changes in load moment arm and muscle length elicited
by each dumbbell curl protocol. In the IDC protocol the
biceps brachii long head is initially lengthened, whereas
in DPC the shoulder is flexed and, thus, the biceps long
head is initially shortened. Therefore, we expect to ob-
serve greater neuromuscular activity for the beginning of
IDC and DPC exercises than for DBC, mainly due to
different postural demands.
Methods
Subject
A group of 22 male subjects (23.0 ± 3.5 years, 79.6 ± 11.6
kg and 1.8 ± 0.1 m) participated of the study after provid-
ing written consent. All participants were right handed,
did not relate any history of osteomyoarticular injuries
and were engaged in strength programs for at least one
year. This experiment was approved by the University
Ethical Committee.
Research article
Oliveira et al.
25
Figure 1. Schematics of the experimental setup. a) Body orientation for each dumbbell curl protocol and for the MVC trial
including electrodes placement; b) Time sequence of each test trial (randomized) and rest periods; c) Partition of the dumb-
bell curls cycle into concentric and eccentric contractions and further division into three phases according to elbow joint
angle.
Experimental setup
A single cycle (concentric-eccentric) of DBC and its
variations, IDC and DPC, was applied to each subject
using a submaximal load of 40%, estimated from a single
6s isometric MVC test (Kamen, 2004). Although in
practical situations most lifters may choose a different
load for each exercise, the use of a fixed load was
compulsory to compare the neuromuscular demand
elicited between DPC, IDC and DBC protocols. The 40%
MVC load was chosen on empirical basis, since with this
load all subjects could perform one or two cycles of
dumbbell curl with slow speed. Dumbbell curls were
randomly applied with two minutes (2 min) interval, after
the three minutes (3 min) rest period following the MVC
trial. A complete schematic of trials sequence is shown in
Figure 1b, whereas body orientation for each trial is out-
lined in Figure 1a and is defined as: MVC – seated posi-
tion with right elbow at 90° and forearm supinated; IDC –
seated with trunk in vertical position and right shoulder
flexed at 50°; IDC – seated with 50° of trunk hyperexten-
sion and the right arm hanging freely; DBC – standing
with a comfortable support base and the arms alongside
the body.
The display of force output was provided during
MVC trials and all subjects were allowed to track it be-
fore starting the test. Each subject performed the whole
cycle of dumbbell curls at his preferred speed, thus repro-
ducing the movement observed in practical situations.
EMG signal of biceps brachii.
26
Although the use of a metronome is important for control-
ling movement speed, it likely provides biased compari-
sons between subjects, since individual strategies may
emerge to compensate the fixed pace imposed by an
external stimulus.
Single differential surface EMG (gain = 1k, CMRR
= 106 dB, and bandwidth of 10-500 Hz) and elbow joint
angle were synchronously sampled at 1 kHz by a 16 bits
A/D converter (±10V dynamic range). Elbow joint angle
was estimated from changes in the direction of the uniax-
ial accelerometer (0-200 Hz bandwidth and 315
mVg-1 sensitivity) with respect to gravity acceleration
vector, assuming that all subjects flexed and extended the
elbow with constant velocity. The accelerometer was
fixed to the subject’s wrist with a tape and with its normal
axis orientated vertically. Two circular (20 mm diameter,
20 mm interelectrodes distance) Ag-AgCl pre-gelled
electrodes were positioned on biceps brachii long head
according to SENIAM recommendations, after skin
preparation (Freriks et al., 1999). A load cell (200 Kgf
fullscale) was used to measure the peak force during the
MVC trial.
Data analysis
The neuromuscular activity of biceps brachii long head
was compared by dividing a curl cycle into concentric and
eccentric contractions, and by further partitioning each
contraction into three phases, according to individual
elbow joint range of motion (Figure 1c; i.e. phase 1 = 0 –
33%; phase 2 = 34 – 67% and phase 3 = 68 – 100% of
ROM). The sEMG root mean square (RMS) was esti-
mated for each phase and contraction according to the
following equation:
=
+
=
pe
psn
pc nx
pspe
RMS ][
1
12
, (1)
where x[n] is the raw sEMG, c and p stands for contraction type
(concentric or eccentric) and contraction phase (1, 2 or 3), re-
spectively, and n is the sample number ranging from phase start
(ps) to phase end (pe), for each one within each contraction
type. To avoid the effect of geometrical and physiological factor
on sEMG data, the RMS amplitude was normalized for the
maximum RMS value estimated from the MVC trial, by using
equation 1 with n ranging from 1000 (1s) to 5000 (5s).
Statistical analysis
A multifactorial ANOVA design 3x2x3 (exercises x con-
traction types x contraction phases) was applied to com-
pare changes in RMS amplitude according to different
contraction types and phases, within and between the
dumbbell curl protocols. Significant changes in the size or
duration of the elbow flexion/extension cycles between
exercises were assessed by applying the one-way
ANOVA design. The Tukey Post Hoc test was applied to
identify significant difference between means with p
value set to 0.05 (Statistica 6.0 - StatSoft, Inc.).
Results
The maximal force achieved during the MVC trial was
34.4 ± 5.0 Kg. The load corresponding to 40% of the
MVC score, which was applied in this study for the
dumbbell curl exercises, represented about 43.6 % of
individual body mass.
Figure 2. Mean and SD of RMS values for all phases of
concentric contractions, divided according to each exercise
(DBC, IDC and DPC). * p < 0.05 between exercises, † p < 0.05
between phases.
When comparing RMS values for the concentric
contractions between IDC and DBC exercises, no statisti-
cal differences were observed, even when considering
each phase independently (Figure 2). On the other hand,
the sEMG amplitude increased for both IDC and DBC
protocols from the beginning to the end of concentric
contraction, reaching statistical significance (p <0.05) at
phase 3. Interestingly, for DPC protocol the RMS mean
values showed an opposite trend throughout the three
phases, decreasing from phase 1 to phase 3 (p < 0.05). In
addition, statistical difference was observed between DPC
and the other two exercises. RMS amplitude was higher
and lower for DPC at phase 1 and 3, respectively, when
compared to RMS values for IDC and DBC, suggesting
that shoulder flexion angle affects biceps brachii activa-
tion.
Figure 3. Mean and SD (whiskers) of RMS values for all
phases of eccentric contractions, divided according to each
exercise (DBC, IDC and DPC). * p < 0.05 between exercises, † p <
0.05 between phases.
Oliveira et al.
27
Figure 3 shows the RMS values for all phases of
the eccentric contraction. Even for the eccentric contrac-
tion, IDC and DBC presented no differences for the
muscle activation between the three phases. The RMS
value for the initial phase of DPC was significantly lower
when compared to that measured for DBC and IDC.
Table 1 shows the amplitude and time duration
(mean values and standard deviation) of both concentric
and eccentric contractions. A significant increase of curl
duration was observed for the eccentric contraction, inde-
pendent of the exercise. IDC protocol was performed
within a statistical smaller ROM of the elbow joint, with
respect to the other two dumbbell curl exercises.
Table 1. Mean (SD) of duration and range of motion (ROM)
of the concentric end eccentric phases of each exercise.
Exercise Duration (sec) ROM (degrees)
Concentric Eccentric
DBC 3.59 (.91) * 4.05 (.93) 131.9 (18.3)
IDC 3.81 (1.13)* 4.67 (1.57) 134.3 (19.5)
DPC 4.47 (1.60)† 4.65 (1.68) 115.5 (11.2) *
* p < 0.05 between phases, † p < 0.05 between exercises.
Discussion
By dividing elbow flexion and extension in three different
phases, according to joint ROM, we expected to observe
changes in modulation of neuromuscular activity for the
three dumbbell curl protocols. Dumbbell Biceps Curl and
Inclined Dumbbell Curl elicited similar pattern of increas-
ing and decreasing muscle activation along the three
phases, for the concentric and eccentric contractions re-
spectively, whereas an opposite trend of sEMG RMS
amplitude was observed for the Dumbbell Preacher Curl.
Concerning the choice of an appropriate load rep-
resenting 40% of individual maximum, the mean MVC
score observed in this study (43.6 ± 7.7% of individual
body mass) was far higher than that reported by Kasprisin
and Grabiner (2000) (30.6 ± 4.7% for 10 healthy adults).
This difference likely results from the elbow joint angle
considered for the MVC trial, since at 90° of elbow flex-
ion the biceps brachii fibers may be closer to optimal
length for isometric force production (Hay, 1991; Inman
et al., 1982; Langenderfer et al., 2005; Oliveira, 2004),
with respect to the 75° elbow flexion considered by
Kasprisin and Grabiner (2000).
The submaximal elbow flexion elicited neuromus-
cular activity up to 95% of the maximum RMS value
during the phase 3 of the concentric contraction for the
IDC and DBC protocols. This relatively high neuromus-
cular activity suggests that the 40% MVC load was suffi-
cient to elicit high modulation of sEMG amplitude.
The mean duration and size of either concentric or
eccentric contractions ranged from 3.59 ± 0.91 to 4.65 ±
1.68 s and from 115.50 ± 11.20 to 131.91 ± 18.25°, re-
spectively, therefore characterizing a quasi-isometric
movement (Siff, 2004). Since force production is criti-
cally affected by muscle tension-length relationship, only
for movements performed at low velocities (Lieber,
2002), the neuromuscular activity for all protocols was
expected to be highly dependent on muscle length.
Furthermore, Prilutsky (2004) observed a similar level of
neuromuscular activity of biceps brachii muscle for
eccentric contractions with constant speed, corroborating
the almost constant RMS values (Figure 3) observed for
the eccentric contractions performed in this study. This
evidence supports the effect of muscle length on the
muscle force production, since dumbbell curls may have
been performed with minimal changes at movement
velocity.
Although subjects were instructed to start from
full elbow extension, their movements started from a
slightly flexed position (around 20°), suggesting a com-
pensation mechanism to optimize the contribution of
elbow flexors and passive tension. Some studies reported
similar strategy for starting the movement, with elbow
joint angle ranging from 15° to 48° (Hansen et al., 2003;
Keeler et al., 2001; Uchiyama et al., 1998).
During isometric contractions, the increase of
muscle force heavily relies on both motor unit firing rate
and recruitment, according to the size principle (Henne-
man, 1985). However, the use of these strategies seems to
be reweighted in a different way during dynamic contrac-
tion, with the recruitment of additional motor units play-
ing a critical role in muscle force production (Sbriccoli et
al. 2003; Søgaard et al., 1998). Such changes in motor
unit recruitment pattern, in addition to different load shar-
ing strategies, may have contributed to the high variability
of RMS values between subjects (coefficient of variation
ranged from 31 to 69 %, for all phases and contractions).
Regarding the changes in sEMG amplitude for dif-
ferent dumbbell curl protocols, it was expected an in-
crease of neuromuscular activity during IDC, especially
when elbow joint was close to full extension. The shoul-
der hyperextension, elicited by the IDC protocol, stretches
the long head of biceps brachii muscle beyond its optimal
length, leading to an inefficient actin-myosin coupling.
On the other hand, the similar RMS values between IDC
and DBC (Figure 2) indicates an increased contribution of
other elbow flexors, besides the contribution of passive
tension from muscle and soft tissues, at the beginning of
concentric and at the end of eccentric contraction. The
low values of sEMG amplitude observed for the begin-
ning of concentric contractions, independent of the dumb-
bell curl protocol, may be explained by the reduced load
moment arm and/or the right shift of muscle length value
with respect to the muscle tension-length relationship
(Falk and Tenenbaum, 1996). Although at about 90o of
elbow flexion the moment arm of biceps brachii is close
to its highest value (Murray et al., 1995; 2002), such posi-
tion was not sufficient to compensate the increment of the
resistance torque, which is maximal for this joint angle,
and thus resulting in high RMS values.
The shoulder flexed position in the DPC exercise
elicited a particular pattern of muscle activation, which
significantly decreased and increased from the initial to
the final phases of the concentric and eccentric contrac-
tions, respectively. Although the early phase of the con-
centric contraction elicited high muscle activity to over-
come the load torque, the neuromuscular demand de-
creased rapidly for the biceps brachii throughout the mid-
dle and late phases. The main reason for this pattern of
activation is likely linked to the initial moment arm of the
load, resulting from the shoulder flexion at the starting
EMG signal of biceps brachii.
28
position (phase 1), and the inefficient length of elbow
flexors. As the elbow flexes the load torque reduces, until
the hand crosses elbow line, thus shifting the force pro-
duction from elbow flexors to extensors (phase 3). There-
fore, DPC exercise seems to have elicited high myoelec-
tric activity only within a short range of elbow joint angle
(i.e. the beginning of concentric and ending of eccentric
contractions), which may be disadvantageous for training
programs focused on the improvement biceps brachii
ability to produce force.
The use of a couple of electrodes could have been
a limiting factor in this study. The shift of the innervation
zone (IZ), inherent to dynamic contractions, attenuates or
enlarges sEMG amplitude as the IZ gets closer or farer
from the electrodes (Farina et al., 2001). However, the IZ
effect on the RMS values estimated in this study was
minimized by positioning the electrodes on the location
recommended by SENIAM, since this location is close to
half way between the biceps brachii IZ and the distal
tendon (Merletti and Parker, 2004).
Conclusion
Although all protocols elicited a considerable level of
activation of the biceps brachii muscle (at least 50% of
maximum RMS), the contribution of this muscle for el-
bow flexion depended of the dumbbell curl protocol. For
the Dumbbell Preacher Curl cycle, the activation of bi-
ceps brachii long head was maximal, only for elbow joint
angles close to full extension, and the elbow joint range of
motion was shorter. The Incline Dumbbell Curl and the
Dumbbell Biceps Curl resulted in a considerable neuro-
muscular effort throughout the whole elbow range of
motion and, thus, may be preferable for the improvement
of biceps brachii force in training programs.
References
Biscarini, A., Borio, R., Coscia, F., Mazzolai, G., Simonetti, S. and Rosi,
G. (2005) Biomechanics of dumbbell/barbell and cable biceps
curl exercises. Italian Journal of Sports Science 12, 83-93.
Cotterman, M.L., Darby, L.A. and Skelly, W.A. (2005) Comparison of
muscle force production using the smith machine and free
weights for bench press and squat exercises. Journal of
Strength and Conditioning Research 19(1), 169-176.
De Luca, C.J. (1997) The use of surface electromyography in biome-
chanics. Journal of Applied Biomechanics 13, 135-163.
Faigenbaum, A.D., Milikenm, L.A. and Westcott, W.L. (2003) Maximal
strength testing in health children. Journal of Strength and
Conditioning Research 17(1), 162-166.
Falk, B. and Tenenbaum, G. (1996) The effectiveness of resistence
training children. Sports Medicine 22(3), 176-186.
Farina, D., Merletti, R., Nazzaro, M. and Caruso, I. (2001) Effect of
joint angle on EMG variables in leg and thigh muscles. IEEE
Engineering in Medicine and Biology 20(6), 62-71.
Fleck, W.J. and Kraemer, S.J. (1997) Designing resistance training
programs. Human Kinetics, Champaign.
Freriks, B., Hermens, H.J., Disselhorst-Klug, C. and Rau, G. (1999) The
recommendations for signal processing methods for surface
electromyography, In: European recommendations for surface
electromyography – SENIAM Project. Eds: Hermens, H.J., Fre-
riks, B., Merletti, R., Stegeman, D., Blok, J., Rau, G., Dissel-
horst-Klug, C. and Hâag, G. Enschede: Roessingh Research
and Development b.v. 13-25.
Hansen, E.A., Lee, H., Barrett, K. and Herzog, W. (2003) The shape of
the force-elbow angle relationship for maximal voluntary con-
tractions and sub-maximal electrically induced contractions in
human elbow flexors. Journal of Biomechanics 36, 1713-1718.
Hay, J.G. (1991) Mechanical basis of strength expression, In: Strength
and power in sport. Ed: Komi, P.V. Oxford: Blackwell Sci-
ence. 197-207.
Henneman, E. (1985) The size-principle: a deterministic output emerges
from a set of probabilistic connections. Journal of Experimen-
tal Biology 115, 105-112.
Inman, V.T., Ralston, H.J. and Todd, F. (1982) Human walking. Wil-
liams & Wilkins, Baltimore.
Kamen, G. (2004) Reliability of motor-evoked potentials during resting
and active contraction conditions. Medicine Science Sports Ex-
ercise 36(9), 1574-1579.
Kasprisin J. E. and Grabiner M. D. (2000) Joint angle-dependence of
elbow flexor activation levels during isometric and isokinetic
maximum voluntary contractions. Clinical Biomechanics 15,
743-749.
Keeler, L.K., Finkelstein, L.H., Miller, W. and Fernhall, B. (2001)
Early-phase adaptations to traditional-speed vs. superslow re-
sistance training on strength and aerobic capacity in sedentary
individuals. Journal of Strength Conditioning Research 15,
309-314.
Langenderfer, J., LaScalza, S., Mell, A., Carpenter, J.E., Kuhn, J.E. and
Hughes, R.E. (2005) An EMG-driven model of the upper ex-
tremity and estimation of long head biceps force. Journal of
Computers in Biology and Medicine 35, 25-39.
Lieber, R.L. (2002) Skeletal muscle structure and function. Williams &
Wilkins, Baltimore.
Merletti, R. and Parker, P.A. (2004) Electromyography: physiology,
engineering and noninvasive applications. Wiley Interscience,
Italy.
Murray, W.M., Buchanan, T.S. and Delp, S.L. (2002) Scaling of peak
moment arms of elbow muscles with upper extremity bone di-
mensions. Journal of Biomechanics 35, 19-26.
Murray, W.M., Delp, S.L. and Buchanan, T.S. (1995) Variation of
muscle moment arms with elbow and forearm positions.
Journal of Biomechanics 28(5), 513-525.
Oliveira, L.F. (2004) Biomecânica, In: Aspectos diversos da medicina do
exercício. Ed: Rocha, M.L. Rio de Janeiro, Ed. Revinter. 224-
233.
Prilutsky, B.I. (2004) Ação muscular excêntrica no esporte e no
exercício, In: Biomecânica do esporte. Ed: Zatsiorsky, V.M.
Rio de Janeiro, Guanabara Koogan. 49.
Sbriccoli, P., Bazzucchi, I., Rosponi, A., Bernardi, M., De Vito, G. and
Felici, F. (2003) Amplitude and spectral characteristics of bi-
ceps Brachii sEMG depend upon speed of isometric force gen-
eration. Journal of Electromyography Kinesiology 13(2), 139-
147.
Siff, M.C. (2004) Fundamentos biomecânicos do treinamento de força e
de potência, In: Biomecânica do esporte. Ed: Zatsiorsky, V.M.
Rio de Janeiro, Guanabara Koogan. 96.
Søgaard, K., Christensen, H., Fallentin, N., Mizuno, M., Quistorff, B.
and Sjøgaard, G. (1998) Motor unit activation patterns during
concentric wrist flexion in humans with different muscle fiber
composition. European Journal of Applied Physiology and Oc-
cupational Physiology 78(5), 411-416.
Uchiyama, T., Bessho, T. and Akazawa, K. (1998) Static torque-angle
relation of human elbow joint estimated with artificial network
technique. Journal of Biomechanics 31, 545-554.
Key points
The Incline Dumbbell Curl and the Dumbbell Bi-
ceps Curl resulted in a considerable neuromuscular
effort throughout the whole elbow range of motion.
The Incline Dumbbell Curl and the Dumbbell Bi-
ceps Curl may be preferable for the improvement of
biceps brachii force in training programs.
Oliveira et al.
29
AUTHORS BIOGRAPHY
Liliam F. DE OLIVEIRA
Employment
Biomechanics Laboratory, Bioscience De-
partment, Physical Education and Sports
School, Federal University of Rio de Janeiro,
Rio de Janeiro, Brazil.
Degree
D.Sc. in Bioengineering
Research interests
Biomechanics, muscle modelling, EMG
E-mail: liliam@eefd.ufrj.br
Thiago T. DA MATTA
Employment
Biomechanics Laboratory, Bioscience Department, Physical
Education and Sports School, Federal University of Rio de
Janeiro, Rio de Janeiro, Brazil.
Degree
Ms.C. student in Biomechanics
Research interests
Biomechanics.
E-mail: ttmatta@yahoo.com.br
Daniel DE SOUZA ALVES
Employment
Biomechanics Laboratory, Bioscience Department, Physical
Education and Sports School, Federal University of Rio de
Janeiro, Rio de Janeiro, Brazil.
Degree
M.Sc. student in Biomedical Engineering
Research interests
Biomechanics.
E-mail: danielves@ig.com.br
Marco A.C. GARCIA
Employment
Biomechanics Laboratory, Bioscience De-
partment, Physical Education and Sports
School, Federal University of Rio de Janeiro,
Rio de Janeiro, Brazil.
Degree
D.Sc. student in Biomedical Engineering
Research interests
EMG, mechanomyography, spasticity.
E-mail: marcoacg@unisys.com.br
Taian M.M. VIEIRA
Employment
Laboratory for Engineering of the Neuro-
muscular System, Polytechnic of Turin,
Turin, Italy
Degree
Ph.D. candidate in Biomedical Engineering
Research interests
Electromyography, postural balance
E-mail: taian.vierira@polito.it
Liliam Fernandes De Oliveira
Rua Lauro Muller 96 apt 105, RJ, Brasil. CEP 22290-160
... Among the exercises performed with intent to stimulate the upper limb muscles, the biceps curl is definitely one of the most common. Basically, a biceps curl consists of an elbow flexion against an external resistance that, when constant, can be a dumbbell, a barbell, a cable or a selectorized load on a gym device [10][11][12][13][14][15]. The biceps curl has its main target in the elbow flexors, i.e., brachialis, brachioradialis and biceps brachii. ...
... However, while the first two are single-joint muscles, the biceps brachii can act as a wrist supinator and arm flexor [11,16]. Consequently, performing wrist supination and/or arm flexion, as well as placing the wrist and/or the arm in a given position isometrically, can impact the biceps brachii excitation [11,15,17]. Moreover, the biceps curl can be performed unilaterally, e.g., using a dumbbell or cable alternating the limbs or performing a set with a given limb first, or bilaterally, e.g., using two dumbbells simultaneously or a barbell. ...
... The literature has previously investigated the excitation of the biceps curl prime movers in a series of direct comparisons. For example, elbow flexion performed at different arm flexion angles showed a greater biceps brachii excitation at the longer muscle, i.e., at increased arm extension [15], as also reported in another study [17]. However, in these studies the arm flexion was isometric but not dynamic, and in the practice the latter is often performed, so the information about is scarce. ...
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The present study investigated the excitation of the biceps brachii and anterior deltoid during bilateral biceps curl performed using the straight vs. EZ barbell and with or without flexing the arms. Ten competitive bodybuilders performed bilateral biceps curl in non-exhaustive 6-rep sets using 8-RM in four variations: using the straight barbell flexing (STflex) or not flexing the arms (STno-flex) or the EZ barbell flexing (EZflex) or not flexing the arms (EZno-flex). The ascending and descending phases were separately analyzed using the normalized root mean square (nRMS) collected using surface electro-myography. For the biceps brachii, during the ascending phase, a greater nRMS was observed in STno-flex vs. EZno-flex (+1.8%, effect size [ES]: 0.74), in STflex vs. STno-flex (+17.7%, ES: 3.93) and in EZflex vs. EZno-flex (+20.3%, ES: 5.87). During the descending phase, a greater nRMS was observed in STflex vs. EZflex (+3.8%, ES: 1.15), in STno-flex vs. STflex (+2.8%, ES: 0.86) and in EZno-flex vs. EZflex (+8.1%, ES: 1.81). The anterior deltoid showed distinct excitation based on the arm flexion/no-flexion. A slight advantage in biceps brachii excitation appears when using the straight vs. EZ barbell. Flexing or not flexing the arms seems to uniquely excite the biceps brachii and anterior deltoid. Practitioners should consider including different bilateral biceps barbell curls in their routine to vary the neural and mechanical stimuli.
... where ∆y is the vertical distance, y f is the y-axis value coordinate at the final position, and y i is the y-axis coordinate at the starting position. The barbell ∆y might be an additional information indicating the undesirable adjustments in limb position (i.e., shoulder flexion, elbow rising and lumbar extension) with load increment [36,37]. ...
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This paper presents a comparison of mathematical and cinematic motion analysis regarding the accuracy of the detection of alterations in the patterns of positional sequence during biceps-curl lifting exercise. Two different methods, one with and one without metric data from the environment, were used to identify the changes. Ten volunteers performed a standing biceps-curl exercise with additional loads. A smartphone recorded their movements in the sagittal plane, providing information on joints and barbell sequential position changes during each lift attempt. An analysis of variance revealed significant differences in joint position (p < 0.05) among executions with three different loads. Hidden Markov models were trained with data from the bi-dimensional coordinates of the joint positional sequence to identify meaningful alteration with load increment. Tests of agreement tests between the results provided by the models with the environmental measurements, as well as those from image coordinates, were performed. The results demonstrated that it is possible to efficiently detect changes in the patterns of positional sequence with and without the necessity of measurement and/or environmental control, reaching an agreement of 86% between each other, and 100% and 86% for each respective method to the results of ANOVA. The method developed in this study illustrates the viability of smartphone camera use for identifying positional adjustments due to the inability to control limbs in an adequate range of motion with increasing load during a lifting task.
... Therefore, this itself comes into play between the shoulder joint and the elbow joint. This locomotion in the forearm make the bicep between joints perform flexion and supination action that brings tensile and compressive action in the mechanical sense [36][37][38]. Therefore, this compressive action and tensile action in the forearm makes the biceps develop piezoaction on the surface of the Lycra denim smart textile sensor. ...
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The main purpose of this article is to monitor the natural frequency of stainless steel (SS304) with and without defect by spray-coated smart graphene nanoplatelet (GNPs)-doped poly (methyl methacrylate) (PMMA) nanocomposite strain sensor and human health by smart Lycra denim textile sensor. Methods such as impact hammer test and NI-daq, finite element method (FEM) simulation by abacus 6.12, and fast Fourier transform (FFT) study were applied for frequency monitoring of SS304. For human health monitoring, edema disease inspection, cough, and biceps locomotion were studied by graphene sol–gel textile sensor. We report eight sensors fabricated by scotch tape exfoliation method and their sensitivity was checked in terms of gauge factor (GF). The highest and lowest GF-based sensors were checked for sensitivity in the defect (hole) specimen. These sensors were used to sense the natural frequency of SS304 at three different positions in the cantilever beam. The same quantity of GNPs was used for making Lycra denim textile sensors for human health monitoring. The Lycra denim textile sensor showed a 216% change in resistance in the left calf muscle, which is less than right leg flexibility, indicating good sensitivity. In addition, the textile sensor helped in sensing coughing and biceps monitoring. The ease in fabrication and high sensitivity demonstrate the potential ability of GNPs for futuristic smart material for structural and human health monitoring.
... The verbal command was given to gradually produce force until reach the maximum elbow flexion strength. Then, the participants sustain the maximal strength for 5 seconds until hearing the command to stop the contraction [22]. Between each MVC at least a 30-s rest time was given. ...
Article
Objectives Cumulative fatigue is the unwanted belated result of consecutive days of exercise. We hypothesize that a natural antioxidant such as green tea extract from C amellia sinensis could reduce the effects of cumulative fatigue. Here we determine whether green tea extract could prevent muscle damage and preserve neuromuscular activity in a condition of cumulative fatigue. Equipment and methods Sixteen untrained men were divided into intervention (500 g green tea extract) and placebo (500 g celulomax E) groups and tested for biceps brachii strength and neuromuscular activity, muscle damage, and oxidative status before and after cumulative fatigue induced by two consecutive days of biceps curl exercise. In fatigue induction, work volume was assessed. The significance level adopted was 0.05. Results Cumulative fatigue caused muscle damage in both groups (P<0.01) without affecting strength. Green tea extract group was able to sustain the exercise volume (P=0.43), while it was reduced for the placebo group (P=0.04). Green tea extract group showed preserved neuromuscular activity (entropy and frequency slope) compared to placebo. Green tea extract group showed stable oxidative status (P=0.09), which increased in placebo (P=0.03). Conclusion Green tea extract supplementation did not affect the magnitude of muscle damage after cumulative fatigue but helps preserve neuromuscular performance and maintain exercise volume by minimizing oxidative stress resulting from cumulative fatigue.
... Participants were asked to sit on a rigid armless chair with the right elbow flexed at 90º and the forearm supine, while keeping the trunk at 90º regarding the chair seat, and the shoulder at 0º of flexion, as described by Oliveira et al. (2009) and Linz, Gourmelon and Langereis (2007). All joint angles were measured with a goniometer. ...
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Textile electrodes are an alternative to conventional silver-chloride electrodes in wearable systems. Their easy integration in garments and comfort provided to the user make them an interesting development of textile engineering. The potential of such electrodes to allow more unobtrusive data collection in health and sports context may enable the development of biosensing garments to be used in biomechanics. However, proper validation of the recorded signals is paramount, and few studies have yet presented consistent methodologies for textile-based electromyographic recordings. This study presents the validation of the electrical and morphological properties of electromyographic signals recorded with textile electrode, in comparison to conventional silver-chloride electrodes. Results indicate that both sets of electrodes have identical signal-to-noise ratios, but with distinct impedance frequency responses. Electromyographic envelope morphologies are also identical, although textile electrodes usually have lower amplitudes.
... 38 The long head of biceps is known to show increased electromyographic activation in a position of shoulder flexion employed in arm wrestling. 39 Ulnar collateral ligament rupture or "skier's thumb" or "gamekeeper's thumb" has been reported secondary to arm-wrestling. 40 Isolated rupture of the subscapularis tendon has also been reported likely due to the massive internal rotation moment at the shoulder joint. ...
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Objective Arm wrestling is common sport amongst amateur enthusiasts. Multiple injuries are described as a result of the sport. The authors present a narrative review of the common injuries associated with the sport. Design Systematic review with a critical appraisal of the literature and a narrative review of the injuries associated with arm wrestling. Data sources Seven electronic databases were systematically searched using medical subject headings (MeSH) terms as follows. Arm wrestling, Indian Wrestling, Fractures, Injury, Ligament Injury with Boolean search terms “AND”. An extensive review of orthopaedic textbooks was also performed. Eligibility criteria for selecting studies Inclusion criteria were publications which included patients who suffered bony or soft tissue injuries as a result of arm wrestling published in English language. Results A total of 152 patients was seen across all studies. Spiral fractures of the distal third of the humerus are by far the most common injury reported in the setting of arm wrestling. The humerus fails due torsional and bending stresses. 23% were complicated by medial butterfly fragment and the incidence of radial nerve palsy was 23%. Fracture patterns differ in the skeletally immature arm wrestler, who show an increased incidence of medial humeral epicondyle fractures. We also report on the atypical fracture and soft tissue injury patterns that present.
... Probably, this causes the sarcomeres to have to produce force in a length above the optimum, taking into account the length-tension relationship [24]. This tension along the entire muscle may have favored the increase in muscle thickness at all measured sites [23,25,26]. ...
Article
The study aimed to compare the effect of performing the same or different exercises for a muscle group on resistance training (RT) sessions on muscle hypertrophy at different sites along muscle length. Twenty-two detrained men (23.3 ± 4.1 years) were randomly allocated to the following groups: a group that performed the same exercises in all training sessions (N-VAR = 11) or one that varied the exercises for the same muscle groups (VAR = 11). All were submitted to 3 weekly sessions for nine weeks. Muscle thickness was assessed at the proximal, middle, and distal sites of the lateral and anterior thigh, elbow flexors, and extensors by B-mode ultrasound. The VAR group significantly increased all the sites analyzed (P < 0.05). Furthermore, the proximal site of the lateral thigh showed a larger relative increase when compared to the middle site (P < 0.05). In contrast, the N-VAR group were not revealed significant improvements only for the middle site of the lateral thigh and the proximal site of the elbow flexors (P > 0.05). Our results suggest that to perform different resistance exercises can induce hypertrophy of all sites assessed in detrained young men.
... Biomechanical analyses of human motion as a function of the angle have demonstrated that the muscles at the joints develop their maximum torque only within a specific range of motion. The range of changes in muscle strength potential is different for different groups of muscles and joints, and the differences between the maximum and minimum values can reach 90% [12][13][14][15][16][17]. It may be assumed that the most effective workout will occur using a machine where the load value, as a function of the angle, is best tailored to human strength abilities. ...
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The study aimed to analyse the effectiveness of two variants of 8-week strength training (hypertrophy, strength) with different modes of resistance. Healthy male subjects (n=75) were allocated to five groups of equal size: hypertrophy training with a variable cam (Hyp-Cam), hypertrophy training with disc plates (Hyp-Disc), maximal strength training with a variable cam (Str-Cam), maximal strength training with disc plates (Str-Disc), and a control group (CG). The Hyp-Cam and Str-Cam groups trained with a machine where the load was adjusted to the strength capabilities of the elbow flexors. The Hyp-Disc and Str-Disc groups trained on a separate machine in which a load was applied with disc plates. The CG did not train. All groups were assessed for changes and differences in one-repetition (1RM) lifts, isokinetic muscle torque, arm circumference and arm skinfold thickness, and plasma creatine kinase (CK) activity. Within the 8-week training period the 1RM increased (p<.001) in all groups by over 20%, without significant between-group differences. Muscle torque increased significantly (p<.001) only in the Hyp-Cam group (by 13.7%). Arm circumference at rest increased by 1.7 cm (p<.001) and 1.1 cm (p<.001) in the Hyp-Cam and Hyp-Disc groups, respectively, but not in the Str-Cam (0.3 cm; p>.05) or Str-Disc (0.2 cm; p>.05) group. Skinfold thickness of the biceps and triceps decreased more within the 8-week period in Str-Cam (by 1.1 and 2.1 cm; p<.001 and p<.001 respectively) and Str-Disc (0.7 and 1.5 cm; p<.001 and p<.01 respectively) than in Hyp-Cam (by 0.4 and 1.8 cm; p>.05 and p<.01 respectively) and Hyp-Disc groups (by 0.2 and 1.4 cm; p>.05 and p<.05 respectively). CK activity was significantly (p<.05) elevated in each training group except Hyp-Cam (p>.05). The 8-week hypertrophy training with a variable cam results in greater peak muscle torque improvement than in the other examined protocols, with an insignificant increase in training-induced muscle damage indices.
Article
BACKGROUND: Few studies have reported the contribution of isometric-specific exercise of the biceps brachii muscle to increased strength under manual fixation of the scapula. OBJECTIVE: To investigate the activation amplitude of the biceps brachii (BB), serratus anterior (SA), and upper trapezius (UT) in a supine lying posture based on various exercise conditions. METHODS: The EMG activity of BB, SA, and UT was measured in 25 healthy adults while performing maximal elbow flexion exercise with or without manual stabilization of the scapula in two different loading conditions. RESULTS: Muscle activation of the BB was significantly greater when performed with manual fixation of the scapula under the wrist-loading exercise condition (p< 0.05) but manual fixation of the scapula or absence thereof did not have an effect. Elbow flexion force was significantly increased when applying manual fixation to the scapula in both the hand and wrist-loading exercise conditions (p< 0.05). There were no interaction effects between exercise conditions and manual fixation (with or without) in any of the EMG activation values (p> 0.05). CONCLUSION: Manual stabilization of the scapula is a useful therapeutic technique to increase BB strength. Such an intervention may also be indicated for accurate strength measurement of this muscle.
Article
Orderly, size-related recruitment of motoneurones (MNs) illustrates how hundreds of cells operate as a functional entity to produce a highly deterministic output. The coherent action of the pool depends largely on the distribution of input to its members through the connections of afferent fibres. Three types of spike-triggered averaging have been utilized to study these connections. Impulses in individual Ia afferents elicit excitatory postsynaptic potentials ('single-fibre' EPSPs) in about 80% of homonymous MNs. After spinal transection 100% may respond, suggesting that Ia fibres project anatomically to all homonymous MNs. Functionally absent Ia connections are due to transmission failure. The sum of all the EPSPs elicited in a large population of MNs was recorded electrotonically from ventral roots. The mean amplitudes of these 'postsynaptic population potentials' (PSPPs) were correlated with the conduction velocities (CVs) of the Ia or spindle group II fibres. The greater the distance between the spinal entry point of a Ia fibre and the ventral root, the smaller was the PSPP. Tape recording of multiple afferents and the responses of up to 24 MNs permitted study of as many as 264 possible connections in a single, acute experiment. Construction of wiring diagrams and connectivity matrices from the data showed that functional connectivity is influenced by afferent fibre size, the effect of branching on fibre size, MN size and probably transmission failure, but that on a cell-to-cell level, connectivity does not follow strict, deterministic rules. The results raise the question of how probabilistic connections between afferent fibres and MNs give rise to deterministic outputs from the whole pool.
Article
We hypothesized that the moment arms of muscles crossing the elbow vary substantially with forearm and elbow position and that these variations could be represented using a three-dimensional computer model. Flexion/extension and pronation/supination moment arms of the brachioradialis, biceps, brachialis, pronator teres, and triceps were calculated from measurements of tendon displacement and joint angle in two anatomic specimens and were estimated using a computer model of the elbow joint. The anatomical measurements revealed that the flexion/extension moment arms varied by at least 30% over a 95 degrees range of motion. The changes in flexion/extension moment arm magnitudes with elbow flexion angle were represented well by the computer model. The anatomical studies and the computer model demonstrate that the biceps flexion moment arm peaks in a more extended elbow position and has a larger peak when the forearm is supinated. Also, the peak biceps supination moment arm decreases as the elbow is extended. These results emphasize the need to account for the variation of muscle moment arms with elbow flexion and forearm position.
Article
Many recent studies have reported that resistance training can be effective in producing strength gains among prepubescents. These studies appear to refute the early claims of ineffectiveness of resistance training in children. A meta-analysis procedure combines the results of individual empirical studies and estimates a standardised effect, termed effect size. This effect size is based on the scores of the control and experimental groups before and after training. It defines the difference between the gain of the experimental and control groups, divided by the standard deviation of the pooled variances of both groups. A literature search revealed 28 studies which described a resistance training programme for girls and boys under the age of 12 and 13 years, respectively. Presumably, these children were pre- or early-pubescents. However, only 9 of these studies provided the necessary data to calculate the effect size and could be included in the analysis. The majority of the studies showed a gain in strength between 13 and 30%. The overall mean effect size was found to be 0.57. This signifies that following training, the average child in the resistance training group was above 71.6% of the children in the control group. The effectiveness of resistance training can be influenced by factors such as age and maturation, gender, as well as the frequency, duration and intensity of the training programme. The studies included in the analysis examined participants of varying ages and did not demonstrate a clear influence of age. Most studies examined only boys or a mixed group of boys and girls. Therefore, the influence of gender on the effectiveness of resistance training in prepubescents cannot yet be determined. Nevertheless, in the few studies where boys and girls were examined separately, no difference was found in the effect of resistance training between genders. It appears that a training frequency of twice per week is sufficient to induce strength gains in children. However, the minimal, or for that matter optimal, duration and intensity are not clear. Some of the weaknesses observed in the reviewed studies include: (i) the lack of control for a possible learning effect; (ii) non-randomisation into the training and control groups; (iii) no report of adherence rate; (iv) a reliance on boys as study participants; and (v) too little information on the type, volume and intensity of training. Future studies should take these weaknesses into consideration.
Article
Static relations between elbow joint angle and torque at constant muscle activity in normal volunteers were investigated with the aid of an artificial neural network technique. A subject sat on a chair and moved his upper- and forearm in a horizontal plane at the height of his shoulder. The subject was instructed to maintain the elbow joint at a pre-determined angle. The wrist was then pulled to extend the elbow joint by the gravitational force of a weight hanging from a pulley. Integrated electromyograms (IEMGs), elbow and shoulder joint angles and elbow joint torque were measured. Then the relation among IEMGs, joint angles and torque was modeled with the aid of the artificial neural network, where IEMGs and joint angles were the inputs and torque was the output. After back propagation learning, we presented various combinations of IEMGs, shoulder and elbow joint angles to the model and estimated the elbow joint torque to obtain the torque-angle relation for constant muscle activation. The elbow joint torque increased and then decreased with extension of the elbow joint. This suggests that if the forearm is displaced from an equilibrium point, the torque angle relation would not act like a simple spring. In a view of the musculoskeletal structure of the elbow joint, the relation between the elbow joint angle and the moment arm of the elbow flexor muscles seems to have a dominant effect on the torque-angle relation.
Muscle activity was recorded from the flexor carpi radialis muscle during static and dynamic-concentric wrist flexion in six subjects, who had exhibited large differences in histochemically identified muscle fibre composition. Motor unit recruitment patterns were identified by sampling 310 motor units and counting firing rates in pulses per second (pps). During concentric wrist flexion at 30% of maximal exercise intensity the mean firing rate was 27 (SD 13) pps. This was around twice the value of 12 (SD 5) pps recorded during sustained static contraction at 30% of maximal voluntary contraction, despite a larger absolute force level during the static contraction. A similar pattern of higher firing rates during dynamic exercise was seen when concentric wrist flexion at 60% of maximal exercise intensity [30 (SD 14) pps] was compared with sustained static contraction at 60% of maximal voluntary contraction [19 (SD 8) pps]. The increase in dynamic exercise intensity was accomplished by recruitment of additional motor units rather than by increasing the firing rate as during static contractions. No difference in mean firing rates was found among subjects with different muscle fibre composition, who had previously exhibited marked differences in metabolic response during corresponding dynamic contractions. It was concluded that during submaximal dynamic contractions motor unit firing rate cannot be deduced from observations during static contractions and that muscle fibre composition may play a minor role.
Article
Recent experimental advances in structural biology, biophysics, and molecular biology have dramatically increased our understanding of the molecular mechanism of muscle contraction, as well as the assembly of myosin filaments. Future studies are required to detail, for example, the molecular cause of the conformational change during the power stroke and ATP hydrolysis, as well as the nature of the communication between nucleotide and actin binding sites. Based on the structural and functional homology between myosin and other molecular motors, these findings have implications not only for understanding muscle contraction, but for understanding numerous aspects of motility in all cellular systems as well.
Article
The influences of elbow joint angle and the type of contraction on the activation levels of biceps brachii and brachioradialis during maximum voluntary isometric and isokinetic contractions were investigated. A within-session repeated measures design. Activation of synergistic elbow flexor muscles has been reported to be affected disparately by elbow joint angle and contraction type. Ten subjects performed concentric isokinetic, eccentric isokinetic, and isometric maximum voluntary contractions of the elbow flexor muscles. For the isokinetic contractions the activation levels of two ranges of motion were compared. For the isometric contractions the activation levels at two joint angles were compared. The activation levels of the biceps brachii and brachioradialis acquired simultaneously using bipolar surface electrodes and a surface electrode array were compared. Results from the electrode array were similar to those acquired using conventional bipolar electrodes. The activation of biceps brachii was significantly affected by joint angle during concentric isokinetic and isometric maximum voluntary contractions. The activation of brachioradialis was significantly affected by joint angle only during eccentric isokinetic maximum voluntary contractions. The results confirm that joint angle and contraction type contribute to the distinction between the activation of synergistic elbow flexor muscles during isometric and isokinetic contractions. Relevance The results point to the complexity of control of elbow joint synergists and raise questions about the plasticity of this dependency of elbow flexor activation on joint angle. Solutions to these questions are of importance in the areas of upper extremity rehabilitation and modeling the upper extremity neuromechanics.
Article
We performed a randomized exercise training study to assess the effects of traditional Nautilus-style (TR) or superslow (SS) strength training on muscular strength, body composition, aerobic capacity, and cardiovascular endurance. Subjects were 14 healthy, sedentary women, 19-45 years of age (mean +/- SD age, 32.7 +/- 8.9 years), randomized to either the SS or TR training protocols and trained 3 times per week for 10 weeks. Measurements were taken both before and after training, which included a maximal incremental exercise test on a cycle ergometer, body composition, and 1 repetition maximum (1RM) tests on 8 Nautilus machines. Both groups increased their strength significantly on all 8 exercises, whereas the TR group increased significantly more than the SS group on bench press (34% vs. 11%), torso arm (anterior lateral pull-down) (27% vs. 12%), leg press (33% vs. 7%), leg extension (56% vs. 24%), and leg curl (40% vs. 15%). Thus, the TR group's improvement in total exercise weight lifted was significantly greater than that of the SS group after testing (39% vs. 15%). Exercise duration on the cycle ergometer and work rate significantly improved for both groups, but there was no group-by-training interaction. No significant differences were found for body composition or additional aerobic variables measured. Both strength training protocols produced a significant improvement in strength during a 10-week training period, but the TR protocol produced better gains in the absence of changes in percentage of body fat, body mass index, lean body mass, and body weight. In addition, strength training alone did not improve Vo2max, yet short-term endurance increased.