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Electrostimulation Training Effects on the Physical Performance of Ice Hockey Players

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  • Schulthess Clinic, Zürich

Abstract and Figures

The aim of this study was to examine the influence of a short-term electromyostimulation (EMS) training program on the strength of knee extensors, skating, and vertical jump performance of a group of ice hockey players. Seventeen ice hockey players participated in this study, with nine in the electrostimulated group (ES) and the remaining height as controls (C). EMS sessions consisted of 30 contractions (4-s duration, 85 Hz) and were carried out 3x wk for 3 wk. Isokinetic strength of the knee extensor muscles was determined with a Biodex dynamometer at different eccentric and concentric angular velocities (angular velocities ranging from -120 to 300 degrees .s). Jumping ability was evaluated during squat jump (SJ), countermovement jump (CMJ), drop jump (DJ), and 15 consecutive CMJ (15J). Sprint times for 10- and 30-m skates in specific conditions were measured using an infrared photoelectric system. After 3 wk of EMS training, isokinetic torque increased significantly (P<0.05) for ES group in eccentric (-120 and -60 degrees .s) and concentric conditions (60 and 300 degrees .s), whereas vertical jump height decreased significantly (P<0.05) for SJ (-2.9+/-2.4 cm), CMJ (-2.1+/-2.0 cm), and DJ (-1.3+/-1.1 cm). The 10-m skating performance was significantly improved (from 2.18+/-0.20 to 2.07+/-0.09 s, before and after the 3-wk EMS period, respectively; P<0.05). It was demonstrated that an EMS program of the knee extensors significantly enhanced isokinetic strength (eccentric and for two concentric velocities) and short skating performance of a group of ice hockey players.
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Electrostimulation Training Effects on the
Physical Performance of Ice Hockey Players
FRANCK BROCHERIE
1
, NICOLAS BABAULT
2
, GILLES COMETTI
1
, NICOLA MAFFIULETTI
3
, and
JEAN-CLAUDE CHATARD
4
1
Performance Expertise Center, UFR STAPS, University of Burgundy, Dijon, FRANCE;
2
Sport Sciences, UFR STAPS,
Marc Bloch University, Strasbourg, FRANCE;
3
Motricity-Plasticity, UFR STAPS, University of Burgundy, Dijon,
FRANCE; and
4
Laboratory of Physiology, PPEH, St-Etienne, FRANCE
ABSTRACT
BROCHERIE, F., N. BABAULT, G. COMETTI, N. MAFFIULETTI, and J.-C. CHATARD. Electrostimulation Training Effects on
the Physical Performance of Ice Hockey Players. Med. Sci. Sports Exerc., Vol. 37, No. 3, pp. 455– 460, 2005. Purpose: The aim of
this study was to examine the influence of a short-term electromyostimulation (EMS) training program on the strength of knee
extensors, skating, and vertical jump performance of a group of ice hockey players. Methods: Seventeen ice hockey players participated
in this study, with nine in the electrostimulated group (ES) and the remaining height as controls (C). EMS sessions consisted of 30
contractions (4-s duration, 85 Hz) and were carried out 3wk
1
for 3 wk. Isokinetic strength of the knee extensor muscles was
determined with a Biodex dynamometer at different eccentric and concentric angular velocities (angular velocities ranging from 120
to 300°·s
1
). Jumping ability was evaluated during squat jump (SJ), countermovement jump (CMJ), drop jump (DJ), and 15 consecutive
CMJ (15J). Sprint times for 10- and 30-m skates in specific conditions were measured using an infrared photoelectric system. Results:
After 3 wk of EMS training, isokinetic torque increased significantly (P0.05) for ES group in eccentric (120 and 60°·s
1
) and
concentric conditions (60 and 300°·s
1
), whereas vertical jump height decreased significantly (P0.05) for SJ (2.9 2.4 cm), CMJ
(2.1 2.0 cm), and DJ (1.3 1.1 cm). The 10-m skating performance was significantly improved (from 2.18 0.20 to 2.07
0.09 s, before and after the 3-wk EMS period, respectively; P0.05). Conclusion: It was demonstrated that an EMS program of the
knee extensors significantly enhanced isokinetic strength (eccentric and for two concentric velocities) and short skating performance
of a group of ice hockey players. Key Words: KNEE EXTENSORS, STRENGTH TRAINING, SPRINT, VERTICAL JUMP
Research on the use of electromyostimulation (EMS)
as a method of training of healthy skeletal muscle
has increased over the past decade (10,13,15,23).
Several studies have indicated that this training modality
enables the development of maximal force, albeit with a
great diversity in reported strength gains, ranging from 0 to
44% (11,12,23). Differing stimulation modes (frequency,
pulse duration), testing procedures, training protocols (num-
ber and duration of the sessions), pretraining status, and
interindividual differences may account, at least partly, for
the observed discrepancies (5,10).
Recently, some studies have attempted to investigate the
effect of EMS training on the specific performance of ath-
letes from various team sports. For instance, Maffiuletti et
al. (13) and Malatesta et al. (15) demonstrated the positive
effects of short-term EMS training on the vertical jump
performance of basketball and volleyball players. These
changes were also associated with isokinetic and isometric
strength gains (13). However, to the best of our knowledge,
no study has been published regarding EMS training effects
on the specific performance of ice hockey players.
Analysis of physiological profile of elite ice hockey
teams reveals the importance of aerobic endurance, an-
aerobic power and endurance, muscular strength, and
skating speed (9,18). It was also pointed out that the
strength decrement observed during the hockey season
can be attributed to the lack of specific strength programs
(18). Our study used EMS training as a complement to
standard training practices with the goal of improving
both the muscular strength and physical performance of
ice hockey athletes. Therefore, the purpose of the present
study was to determine the influence of a 3-wk EMS
training program on the quadriceps femoris muscle
strength and on specific physical abilities of ice hockey
players, such as vertical jump and speed skating perfor-
mance. The quadriceps muscle group was firstly chosen
because it develops the largest contractile strength during
the push-off of the skating thrust, whereas the hamstrings
and gastrocnemius muscles primarily act to stabilize the
knee joint (18). This muscle group was secondly chosen
because three of its four component muscles are super-
ficial and can be easily stimulated.
Address for correspondence: Nicolas Babault, EA 1342 Sciences du sport,
UFR STAPS, Universite´ Marc Bloch, 14 rue Rene´ Descartes, 67084
Strasbourg Cedex, France; E-mail: nbabault@umb.u-strasbg.fr.
Submitted for publication July 2004.
Accepted for publication October 2004.
0195-9131/05/3703-0455
MEDICINE & SCIENCE IN SPORTS & EXERCISE
®
Copyright © 2005 by the American College of Sports Medicine
DOI: 10.1249/01.MSS.0000155396.51293.9F
455
MATERIALS AND METHODS
Subjects
A group of 17 ice hockey players competing in the French
Ice Hockey Federation League, division II (age 22.6 4.5
yr; height 178.3 4.8 cm; mass 73.8 7.6 kg) partic-
ipated in the study. They were randomly divided into two
groups with nine assigned to the electrostimulated (ES) and
eight to the control players (C). None of them had previously
engaged in systematic EMS experience. All the subjects agreed
to participate in the study on a voluntary basis and signed an
informed consent form. The study was conducted according to
the declaration of Helsinki and approval for the project was
obtained from the University of Burgundy committee on hu-
man research. During the experiment, the ice hockey training
was the same for all players and was performed with the same
coach with all athletes practicing three times a week in 1.5-h
sessions and playing one game per week. No subjects had to
stop the experiment due to injuries resulting from EMS training
and/or ice hockey practicing.
Training
EMS training. A total of nine EMS sessions were
spread over a 3-wk period, with 12 min per session and three
sessions per week, as recommended by Sale and MacDou-
gall (22). EMS sessions, separated from the specific ice
hockey training, were always performed at the same time of
day and the same days of a week. During EMS, athletes
were seated in a leg extension machine with the knee flexed
at a 60° angle (0° corresponding to complete leg extension).
EMS was delivered to both quadriceps simultaneously with
a Compex-2 stimulator (MediCompex SA, Ecublens, Swit-
zerland). Two pairs of self-adhesive positive electrodes
(each measuring 25 cm
2
;55 cm), which have the prop-
erty of depolarizing the membrane, were placed on the
vastus medialis and vastus lateralis muscle bellies. Two
rectangular negative electrodes, each measuring 50 cm
2
(10
5 cm) were placed over the femoral triangle of each leg,
1–3 cm below the inguinal ligament. Pulse currents of
85-Hz frequency lasting 250
s were used. The contraction
time was 4 s, and the rest time was 20 s. During each
training session, 30 EMS contractions were completed. To
ensure identical contraction intensity throughout the training
session, electrically evoked (isometric) force was consis-
tently measured with a myostatic type dynamometer (Alle-
gro, Sallanches, France). At the beginning of each training
session, the subject’s maximal voluntary isometric force
was measured at 60° (i.e., the angle of stimulation). Then
stimulation intensity was individually increased to the max-
imal tolerated intensity, and to attain at least 60% of each
individual pretest maximal voluntary contraction score. This
contraction level was reached at the beginning of the stim-
ulation and maintained for 4 s.
Testing
Isokinetic test. Maximal voluntary torque of the right
knee extensor muscles (N·m) was measured before and after
the 3-wk period, using a Biodex isokinetic dynamometer
(Biodex Corporation, Shirley, NY) validated by Taylor et al.
(26). A 7-min period of standardized warm-up and famil-
iarization with the measurement apparatus was conducted
with submaximal repetitions at each experimental angular
velocity. Then subjects performed three maximal voluntary
knee extensions at five concentric angular velocities (60,
120, 180, 240, and 300°·s
1
) and at two eccentric velocities
(60 and 120°·s
1
) with a 90° range of motion (starting
position 10° knee flexion). In each case, only the best
performance was retained. A 4-min rest period was allowed
between each trial. To minimize hip and thigh motion dur-
ing all contractions, a series of straps were applied across
the chest, pelvis, mid-thigh, and lower leg. The latter strap
secured the leg to the dynamometer lever arm. The align-
ment between the center of rotation of the dynamometer
shaft and the axis of the knee joint (lateral femoral condyle)
was checked at the beginning of each trial. The subject’s
arms were positioned across the chest with each hand clasp-
ing the opposite shoulder. Torques were gravity corrected at
each joint angle, using the torque produced by the weight of
the limb at a joint angle corresponding to the maximal
gravity effect (26). For each angular velocity, the 60° knee
flexion maximal voluntary torque (constant angular torque
technique) was directly computed by the Biodex software
and included in the analyses.
Vertical jump test. Jumping ability was evaluated with
a contact mat (Globus, Codogne, Italy). The squat jump
(SJ), countermovement jump (CMJ), and drop jump (DJ)
from a height of 30 cm were randomly performed according
to Asmussen and Bonde-Petersen’s recommendations (1).
Three tests were carried out for each type of jump, and the
best result was retained. Fifteen consecutive CMJ (15J)
were also performed to evaluate the resistive capacities of
the knee extensors. During this 15J test, jump height and power
were measured for each jump and then averaged together.
Sprint test. Times, determined at the hip level for 10-
and 30-m sprints on ice, were measured with infrared pho-
toelectric cells (TEL.SI s.r.l., Vignola, Italy) positioned 10
and 30 m from the start line and controlled by commercially
available software. The players set off upon a visual signal
and skated as fast as possible the 30-m distance. This sprint
allowed us to directly measure both times with the 10-m
time as intermediate. Only the best performance of three
trials was retained.
Statistical Analysis
Mean values and standard deviations (SD) were calcu-
lated for all variables. A repeated measures analysis of
variances (ANOVA) followed by a Newman–Keuls post
hoc procedure was used to test differences between both
groups and the effects of the EMS program on dependent
variables (strength, jump, and sprint performances) in each
group before and after the 3-wk period. Relationships be-
tween isokinetic strength, vertical jump, and skating perfor-
mance were also examined using Pearson product correla-
456
Official Journal of the American College of Sports Medicine http://www.acsm-msse.org
tions. In all statistical procedures, a 0.05 level of
significance was adopted.
RESULTS
Before training, no significant difference was observed
between ES and C groups in physical characteristics, knee
extensor strength, and skating performance. C group had,
however, significantly higher values for 15J height (P
0.01) and power (P0.05) compared with ES group (Table
1). When considering both groups (N17) before the 3-wk
period, a significant negative relationship was observed
between the 10- and 30-m skating performance and the
240°·s
1
concentric torque (r ⫽⫺0.61, P0.01 and r
0.76, P0.01, respectively, for 10 and 30 m; Fig. 1).
Muscular strength. After 3 wk of EMS training, the
isokinetic torque increased significantly (Fig. 2) for ES in
eccentric (37.1 21.9% at 120°·s
1
and 24.2 17.9% at
60°·s
1
;P0.01), and concentric conditions (41.3
37.6% at 60°·s
1
and 49.2 48.9% at 300°·s
1
;P0.05).
Except for the 60°·s
1
eccentric condition, the C group
did not exhibit any significant torque increase. When com-
paring torque changes after the 3-wk period, it appears that
the ES group had significantly higher torque increases than
the C group. The 60°·s
1
eccentric torque increase was,
however, not significantly different between the ES and C
groups.
Vertical jump performance. Vertical jump results,
obtained before and after the 3-wk period, are shown on
Table 1 for both ES and C groups. After EMS training, the
ES group vertical jump height decreased significantly (P
0.05) for the SJ (8.4 6.9%), CMJ (6.1 6.0%), and
DJ (5.2 4.6%). No significant difference was found
before and after the 3-wk period for members of the C
group. For the ES group, the 15J power increased after
training (14.3 17.2%; P0.05), whereas gain in 15J
height was not significant. No significant difference was
obtained for the C group.
Skating performances. For the ES group, the 10-m
skating time significantly declined (4.8 5.8%, P
0.05), whereas no change was observed for 30-m sprints
(Fig. 3). C-group skating performances were comparable
before and after the 3-wk period.
DISCUSSION
The present study demonstrated that a 3-wk EMS training
program enhanced isokinetic eccentric and concentric
strength of the knee extensor muscles as well as skating
performance of a group of competitive ice hockey players
compared with a control group. This suggests that EMS may
be a useful mean for developing muscular strength and
skating speed in ice hockey players. These findings are
consistent with previous reports confirming that brief peri-
ods of EMS have beneficial effects on muscle strength
(13,16,21) and specific abilities of highly skilled athletes
(14,15,20).
It is generally accepted that neural adaptations predomi-
nate in short-term voluntary strength training and EMS
training (5,16). For instance, Maffiuletti et al. (14) recently
suggested that EMS training would increase the neural drive
from supraspinal centers, resulting in a greater number of
recruited motor units. Therefore, strength gains observed
after the present EMS training during concentric (60 and
300°·s
1
) but more likely during eccentric (120 and
60°·s
1
) maximal voluntary isokinetic contractions could
be partly attributed to neural adaptations. Surprisingly, the
60°·s
1
eccentric strength was also improved for the C
group, the improvement being similar to the ES group. This
result suggests that strength gains, observed in the present
study, could be partly explained by the fact that after the
3-wk period subjects were more accustomed to perform
isokinetic contractions. Nevertheless, such a conclusion is
only valid for a given angular velocity, and strength gains
obtained for our ES group would be primarily attributed to
FIGURE 1—Relationship between the 240°·s
1
concentric torque and
the 30-m skating time obtained before the 3-wk period. ES (filled
square) and C groups (open circle) have been grouped together to fit
the linear relation.
TABLE 1. Vertical jump performances on electrostimulated (ES) and control (C) groups before and after a 3-wk period. Values are means (SD).
ES Group C Group
Before After Before After
SJ (cm) 34.9 6.0 32.0 3.1†* 35.8 4.3 35.5 4.3
CMJ (cm) 38.1 5.0 36.0 4.5†* 40.8 3.5 40.6 3.6
DJ (cm) 31.6 1.9 30.3 2.4* 32.2 0.3 29.9 7.1
15J height (cm) 26.3 2.7† 26.9 3.1† 29.5 1.1 29.3 2.9
15J power (W) 24.1 4.0† 26.4 5.4* 27.7 2.3 26.9 5.5
SJ, squat jump; CMJ, countermovement jump; DJ, drop jump; 15J, 15 repetitive CMJ.
* Significantly different than before the 3-wk period (P0.05); † Significantly different than the C group for a similar period (P0.05).
ELECTROMYOSTIMULATION IN ICE HOCKEY Medicine & Science in Sports & Exercise
457
neural adaptations preferentially affecting fast-twitch fibers.
Indeed, fast-twitch fibers have been suggested to be prefer-
entially recruited during eccentric contractions ((7,19); for a
contrary view, see (25)) and increasingly recruited at high
concentric velocities (2,4,8). Moreover, the effectiveness of
supplementing training with electrical stimulation is based
on the concept that fast-twitch fibers are activated first and
to a greater extent than that predicted by Henneman’s size
principle (3,5,6,24). Whatever the underlying mechanisms
related to strength gains, the present study supports Kots and
Chwilon’s previous hypothesis (11). Indeed, as originally
obtained (11), EMS-induced contraction increases strength
and would correct the maximal voluntary contraction force
deficit by achieving maximal motor unit recruitment,
thereby allowing greater force production. The fact that
EMS corrected the force deficit by possibly resulting in a
greater proportion of fast motor units being recruited be-
yond those of voluntary contraction could be the basis for
greater strength gains.
Research concerning the effect of EMS training on ver-
tical jump performance is very limited. In the present study,
SJ, CMJ, and DJ height significantly decreased after 3 wk of
EMS. Such findings are somewhat surprising but are in
general accordance with previous experiments. Indeed, sev-
eral studies dealing with the effects of EMS on vertical jump
found no significant change in single jump height (27,29).
Other authors observed improvements of the jumping ability
only 10 d (15) or 4 wk (13) after the end of the EMS training
period, whereas no or few gains were registered immedi-
ately after the training program. Compared with these two
last-cited studies (13,15), which use quite similar stimula-
tion procedures to our experiment, our observed impairment
in vertical jump ability could be attributed to the population
tested. Indeed, these two studies (13,15) considered subjects
that were specifically trained for vertical jumps, also in
addition to their EMS program, because they were volley-
ball (15) or basketball (13) players. Contrarily, in our study,
subjects were not specifically trained for vertical jumps but
for speed skating. Therefore, training alone does not appear
efficient enough to improve the neuromuscular performance
during complex and specific abilities such as vertical jumps
but seems sufficient to improve the monoarticular perfor-
mance by a neural drive enhancement. Thus, specific and
longer training sessions are required to observe beneficial
effects in vertical jump performances by allowing a more
complete control of the neuromuscular properties and/or to
develop the elastic behavior of skeletal muscle. In the
present study, such more complete control of the neuromus-
cular properties during complex tasks has been demon-
strated when considering the skating performance (see
below).
FIGURE 2—Torque–angular velocity relationship of the knee exten-
sors using a constant angular torque (60°) for electrostimulated (ES
group; upper graph) and control group (C group; lower graph). Val-
ues are means (SD); * and ** indicate values significantly higher
than before the 3-wk period at P<0.05 and P<0.01, respectively.
FIGURE 3—Skating times for electrostimulated (ES) and control
groups (C) over 10 m (upper graph) and 30 m (lower graph). Values
are means (SD); * indicates values significantly lower than before
the 3-wk period at P<0.05.
458
Official Journal of the American College of Sports Medicine http://www.acsm-msse.org
Nevertheless, EMS training also has positive effects on
vertical jump ability and, more particularly, on the 15J mean
power. This significant power increase in the 15J procedure,
already registered (15), would reveal better resistive capac-
ities of the knee extensor muscles. Translated in practical
terms, this finding suggests higher performances toward the
end of specific ice hockey sequences. Moreover, it may be
speculated that this 3-wk EMS training program may have
a specific effect during match situations. Indeed, these im-
proved resistive and neuromuscular capacities of the knee
extensors could be beneficial, since skating requires repet-
itive and rapid movement direction changes.
Skating performance was significantly correlated to the
240°·s
1
concentric muscular strength (r ⫽⫺0.61 and r
0.76, respectively, for 10 and 30 m). Thus, the practical
applications of EMS training cannot solely amount to
strength gains and better resistive capacities, but also to an
improvement of the skating performance, with a significant
decrease in 10-m (but not in 30-m) skating time. The 30-m
results are much more representative of the maximum
sprinting speed but are less important in ice hockey situa-
tions. Indeed, during match-winning situations, players are
able to exceed an 8-m·s
1
velocity just after four strides
(18). The quick dash at the beginning of the sprint, con-
comitant with the increased knee extensor strength, could be
a result of the EMS training and could suggest a possible
translation effect on short-sprinting performance. However,
no correlation was found between gains in muscular
strength and in 10-m skating performances. Therefore, as
suggested by others (15), this specific EMS training-induced
adaptation could result from the concomitant ice-hockey
workouts during the EMS training program that would en-
able the central nervous system to optimize the neuromuscular
properties control. Thus, sport-specific trainings should be per-
formed during EMS to obtain specific adaptations.
The EMS training used in the present study was basically
a form of isometric strength training. Like in the present
study, strength increases are often observed after EMS
(12,17,21,23), but, interestingly, these are not superior to
those obtained during voluntary training performed with
similar intensities and durations (12,17,23). Thus, when
used in conjunction with periodized exercise programs,
EMS appears more effective to increase the knee extensor
strength (11,13,28) through its translation effect on dynamic
performance like the 10-m speed skating. Another advan-
tage with EMS would be that training sessions have more
often than not shorter duration (12 min) compared with
voluntary strength trainings. However, the effects of EMS
training on the physical performance of healthy individuals
is still unclear, and more research is needed to investigate
the use of EMS in conjunction with isometric contraction
(either voluntary or EMS-induced) and in conjunction with
other types of training, thereby increasing the specificity of
training (e.g., plyometrics).
To summarize, the present study demonstrated that an
increase in the eccentric and concentric strength of the knee
extensors and skating performance can be achieved in a
relatively short period (3 wk) by using EMS training. As a
practical recommendation for ice hockey players, it is sug-
gested that EMS training could be used over the season to
enhance strength and skating performance without interfer-
ing with ice hockey training. Nevertheless, further experi-
ments are needed to determine long-term benefits of the
EMS training during ice hockey.
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Official Journal of the American College of Sports Medicine http://www.acsm-msse.org
... The total sample size was 445 respondents, of which 158 females and 287 males. Nine studies were based on examining only the male gender (Maffiuletti et al., 2000;Brocherie et al., 2004;Herrero et al., 2005;Babault et al., 2007;Billot et al., 2010;Amaro-Gahete et al., 2016;Filipović et al., 2016;Wirtz et al., 2016), four studies included female respondents (Willoughby et al., 1998;Marqueste et al., 2010;Deley et al., 2011;Dörmann et al., 2019), while two studies included respondents of both genders (Benito-Martinez et al., 2011;Martinez-Lopez et al., 2012). The age of the respondents ranged on average from 16.16±1.72 ...
... to 27.0±7.5 years of age. One study examined the impact of EMS on physical performance of basketball players (Maffiuletti et al., 2000), hockey players (Brocherie et al. 2004), rugby players (Babault et al., 2007) and female gymnasts (Deley et al., 2011), while two studies examined this impact on football players (Billot et al., 2010;Filipović et al., 2013) and volleyball players Marqueste et al., 2010). Four studies used athletes of different orientations as a sample of respondents (Herrero et al., 2005;Amaro-Gahete et al., 2016;Wirtz et al., 2016;Dörmann et al., 2019). ...
... Four studies used athletes of different orientations as a sample of respondents (Herrero et al., 2005;Amaro-Gahete et al., 2016;Wirtz et al., 2016;Dörmann et al., 2019). The duration of the experimental program was from three weeks and three trainings, (Brocherie et al., 2004) up to 14 weeks and 28 training sessions (Filipović et al., 2016). In three studies (Filipović et al., 2016;Amaro-Gahete et al., 2016;Dörmann et al., 2019) the impact of global EMS was examined, while all the other studies examined the impact of EMS on the lower extremities. ...
Conference Paper
Full-text available
Electromyostimulation (EMS) represents an artificial muscle stimulation with a well-defined protocol that is precisely designed to reduce discomfort during unnatural muscle activation. The main goal was to find new information on the basis of systematic review of many studies which examined the impact of EMS on athletes vertical jumping performance, as well as to expand the already known conclusions. Electronic databases (Google Scholar, Pub Med, Web of Science and ResearchGate) were searched for the original scientific research projects on the topic of the impact of EMS on athletes' vertical jumping performance. The last search was conducted in June 2020 with a limitation to study published in English. As many as 415 scientific studies were indentified and only 15 of them were selected and then systematically reviewed and analyzed. The results of the research projects with the total sample size of 445 athletes showed that the treatment of global and local EMS, in combination with another types of training, is an effective method for the development of explosive strength, such as vertical jumping. It has been proven that the EMS represents an effective strategy for improving vertical jumping performance, as well as for improving physical performance of athletes in general.
... Some studies have reported the effects of NMES using PC along with resistance training on vertical jump height. [4,6,[25][26][27] For example, 12 weeks of NMES training using PC (100 Hz) in rugby players resulted in a significant improvement in squat jump (SJ) (11.8%) and drop jump (DJ) (7.6%) performance. [28] However, no study has investigated the effect of NMES training alone on jump performance. ...
... Numerous studies have reported the effects of NMES such as PC in combination with resistance training on vertical jump performance. [4,6,[25][26][27]47] Babault et al. [28] have examined the effect of electromyostimulation (EMS) training (PC, 100 Hz) along with resistance training on the knee extensor, plantar flexor, and gluteus muscles in rugby players. Their methods of EMS training lasted for 12 weeks (three times per week in the first 6 weeks and once a week in the last 6 weeks). ...
... Although there are studies showing that target-muscle-oriented EMS applications have positive effects on neuromuscular parameters in athletes and healthy individuals (Bax et al., 2005;Brocherie et al., 2005;Strojnik, 1998) there are few studies on the effects of EMS training with multi-joint on muscular performance Filipovic, et al., 2016;Kemmler et al., 2016;Porcari et al., 2002). There is no study on the effects of LB-EMS, which is applied to the lower body and includes multi-joint or the effects of EMS synchronous with isometric voluntary maximal contractions including lower body bilateral multi-joints on muscular performance. ...
... Its difference from the current study might derive from the fact that the EMS training in elite athletes have more effective results compared to untrained subjects, as Filipovic et al. (2012) stated. Brocherie et al. (2005) investigated the effects of isometric EMS training applied on Quadriceps 3 times a week for 3-week on elite ice hockey players and observed improvement (4.8%) in 10m skate sprint time. According to these results, it can be concluded that the EMS applied to the main muscles involved in the movement may be effective in sports-specific performances of elite athletes. ...
Article
Full-text available
Objective: the aim of this study was to investigate the effects of 6-week lower-body EMS (LB-EMS) training and detraining on anthropometric parameters and muscular performance. Method: physically active 38 volunteers (21.5±2.5 years, 175±6.5 cm, 67.7±7.7 kg, BMI: 21.7±1.9 kg/m 2 , body fat percentage: 14.4±5.3 %) were randomly divided into LB-EMS group (n: 16) and voluntary group (n: 22). In pre-training, post-training and post-detraining, anthropometric measurements and tests including squat jump (SJ) and countermovement jump (CMJ), 40m sprint, knee isokinetic strength at 60, 180 and 300 o .s-1 angular velocities, anaerobic power (AP) and anaerobic capacity (AC) were conducted. EG with LB-EMS and VG without LB-EMS participated in the training applied with maximal voluntary isometric contractions (MVIC) between the knee joint angles of 110-120 o on a seated leg press machine for a 6-week. Following this period all participants didn't perform any lower-body exercises during 4-week detraining period. Results: in SJ, significant differences between the groups (p: 0.043) and within the groups (p: 0.034) were reported after training and detraining. No statistically significant intergroup difference was reported in terms of parameters of anthropometry, CMJ, 40m sprint, isokinetic strength, AP-AC. The results showed that 6-week LB-EMS training and the following 4-week detraining didn't have effect on muscular performance parameters except for SJ. As a result, the 6-week LB-EMS training and the following 4-week detraining didn't cause any change in anthropometric and muscular performance parameters except for SJ height. Conclusion: It has concluded that LB-EMS training applied to MVICs isn't more effective than conventional voluntary training in physically active individuals.
... 23 trials used a two-armed design (Amaro-Gahete et al., 2018;Avila et al., 2008;Babault et al., 2007;Billot et al., 2010;Brocherie et al., 2005;da Cunha et al., 2020;Dörmann et al., 2019;Filipovic et al., 2015Filipovic et al., , 2016Kale & Gurol, 2019;Ludwig et al., 2020;Maffiuletti et al., 2000Maffiuletti et al., , 2002Martin et al., 1994;Mathes et al., 2017;Micke et al., 2018;Miller & Thépaut-Mathieu, 1993;Oliveira et al., 2018;Pantović et al., 2015;Pichon et al., 1995;Schuhbeck et al., 2019;Wirtz et al., 2016;Zory et al., 2010), 9 studies a three-armed design (Benito-Martínez et al., 2013;Dervisevic et al., 2002;Filipovic et al., 2019;Girold et al., 2012;Gulick et al., 2011;A. J. Herrero et al., 2010aA. ...
Article
This systematic review and network meta-analysis aimed to evaluate the effectiveness of different electromyostimulation (EMS) interventions on performance parameters in athletes. The research was conducted until May 2021 using the online databases PubMed, Web of Science, Cochrane and SPORTDiscus for studies with the following inclusion criteria: (a) controlled trials, (b) EMS trials with at least one exercise and/or control group, (c) strength and/or jump and/or sprint and/or aerobic capacity parameter as outcome (d) sportive/trained subjects. Standardized mean differences (SMD) with 95% confidence interval (CI) and random effects models were calculated. Thirty-six studies with 1.092 participants were selected and 4 different networks (strength, jump, sprint, aerobic capacity) were built. A ranking of different exercise methods was achieved. The highest effects for pairwise comparisons against the reference control “active control” were found for a combination of resistance training with superimposed EMS and additional jump training (outcome strength: 4.43 SMD [2.15; 6.70 CI]; outcome jump: 3.14 SMD [1.80; 4.49 CI]), jump training with superimposed whole-body electromyostimulation (WB-EMS) (outcome sprint: 1.65 SMD [0.67; 2.63 CI]) and high intensity bodyweight resistance training with superimposed WB-EMS (outcome aerobic capacity: 0.83 SMD [−0.49; 2.16 CI]). These findings indicate that the choice of EMS-specific factors such as the application mode, the combination with voluntary activation, and the selection of stimulation protocols has an impact on the magnitude of the effects and should therefore be carefully considered, especially in athletes. Superimposed EMS with relatively low volume, high intensity and outcome-specific movement patterns appeared to positively influence adaptations in athletes. • HIGHLIGHTS • Key performance parameters such as maximal strength, jump height and sprint time can be increased by adequate EMS intervention programs in already well-trained athletes. • The effectiveness of EMS training in athletes is highly dependent on the selected EMS method. Volume, intensity, exercise and movement specificity play a crucial role for the efficiency of the training. • The most effective option for athletes appears to be a combination of superimposed EMS with relatively low EMS volume, high intensity, and movement-specific exercise pattern.
... Electrostimulation consists of electrical currents applied in muscles or peripheral nerves in order to provoke involuntary muscle contractions [12]. Its main advantage for athletes is an increase in the maximum strength and power during voluntary contractions [13,14]. ...
Article
Full-text available
Introduction. The aim of the present study was to investigate the effects of a 6-week low intensity plyometric training (PT) + whole-body electrostimulation (WBES) combined program, compared with traditional PT, on vertical jump performance, 20 m sprint-time and handgrip strength. Material and methods. 10 male and 10 female Physical Education students were randomly allocated to a control (CON) or an experimental (EXP) group. Both groups performed a 6-week low intensity PT 3 days per week, and during the third day, PT was simultaneously combined with WBES in the EXP group. Countermovement jump (CMJ) height, CMJ peak power, 20 m sprint-time and handgrip strength were measured before (pre-test) and after (post-test) the training period. Repeated measures ANOVA was performed to identify differences after the training program. Effect sizes (ES) were assessed using Hedge’s g. Results. No significant differences between groups were observed at post-test. CMJ height and CMJ peak power significantly increased in both groups, with greater ES in the EXP group (p < 0.001, g = 0.68; p < 0.001, g = 0.70, respectively). 20 m sprint-time significantly improved in both groups, with greater ES in the CON group (p < 0.001, g = -1.68). Handgrip strength also increased in both groups, but ES were minimal. Conclusions. Both training methods demonstrated to be a good strategy to improve CMJ performance and 20 m sprint-time. The most effective training method for improving CMJ performance was PT + WBES combined program, and traditional PT obtained better results in 20 m sprint-time.
... The benefits of electrical stimulation are most noticeable in orthopaedics and sports medicine. in sports, electrical stimulation as a procedure supporting regular training to increase muscle strength and endurance is nothing innovative nowadays [1][2][3]. Current fitness facilities also offer training with the use of stimulation with low and medium frequency currents. in this kind of training, one can observe a comprehensive simultaneous effect on multiple muscles due to the application of several or over a dozen electrodes to the body at the same time. ...
Article
Electrical stimulation is a branch of physical therapy that applies low and medium frequency currents to stimulate the human body. The effects of electrical impulses on human beings have been observed since antiquity. The development of research in that scope commenced in the 18th century, the most important turning point, and is now continuing. The purpose of this narrative study is to present electrical stimulation in terms of its progressing development and to draw attention to its significant role in the therapeutic processes utilized in numerous medical specializations and comprehensive strength and endurance training of healthy people. The notions ‘electrical stimulation’ and ‘electrotherapy,’ as well as differences between electric current applications are explained. The most critical moments in the history of electrical stimulation development are highlighted. Recent research is presented, exhibiting the important role of electrical stimulation both in the therapeutic process and in strength and endurance training. This paper contains the most significant aspects of contemporary application of electrical stimulation, as well as recommendations and limitations for current usage in such areas as whole-body electrostimulation, urinary incontinence, pelvic floor muscle rehabilitation, rehabilitation after anterior cruciate ligament surgery, endurance training, and improvement of physical strength and appearance.
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Resistance training has been known to have a positive effect on muscle performance in exercisers. Whole-body electromyostimulation (WB-EMS) is advertised as a smooth, time-efficient, and highly individualized resistance training technology. The purpose of this study is to evaluate the effects of WB-EMS training on maximum isometric elbow muscle strength and body composition in moderately trained males in comparison to traditional resistance training. The study was a randomized controlled single-blind trial. Twenty, moderately trained, male participants (25.15 ± 3.84, years) were randomly assigned to the following groups: a WB-EMS training group ( n = 11) and a traditional resistance training group (the control group [CG]: n = 9). Both training intervention programs consisted of 18 training sessions for six consecutive weeks. All subjects performed dynamic movements with the WB-EMS or external weights (CG). The primary outcome variables included maximum isometric elbow flexor strength (MIEFS), maximum isometric elbow extensor strength (MIEES) and surface electromyography amplitude (sEMG RMS ). Secondary outcomes involved lean body mass, body fat content, arm fat mass, and arm lean mass. ANOVAs, Friedman test and post hoc t -tests were used ( P = 0.05) to analyze the variables development after the 6-week intervention between the groups. Significant time × group interactions for MIEFS (η ² = 0.296, P Bonferroni = 0.013) were observed, the increase in the WB-EMS group were significantly superior to the CG [23.49 ± 6.48% vs. 17.01 ± 4.36%; MD (95% CI) = 6.48 (1.16, 11.80); d = 1.173, P = 0.020]. There were no significant differences were observed between interventions regarding MIEES, sEMG RMS and body composition. These findings indicate that in moderately trained males the effects of WB-EMS were similar to a traditional resistance training, with the only exception of a significantly greater increase in elbow flexor strength. WB-EMS can be considered as an effective exercise addition for moderately trained males.
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This review aims to 1) be the first systematic review and meta-analysis of the literature examining the physiology and assessment of goaltenders, and 2) present a physiological profile of ice-hockey goaltenders. It will 1) highlight physiological differences between goaltenders and players at other positions, 2) determine strengths and weaknesses of ice hockey goaltenders, and 3) offer possible guidelines for strength and conditioning coaches. Six electronic databases were systematically searched in October 2019 using the PRISMA model. A total of twelve scientific articles published in peer-reviewed journals were included. Professional male (PM) goaltenders had the following profile for age (A) 26.8 ± 2.5 years, body weight (BW) 85.64 ± 3.79 kg, height (H) 184.38 ± 2.79 cm, body fat % (BF%) 11.9 ± 2.22, VO2max 49.9 ± 4.45 ml/kg/min, anaerobic power (AP) 12.78 ± 1.63 W/kg, and combined hand grip strength (GS) 120.7 ± 15 kg. Amateur male (AM) goaltenders presented the following: A: 18.2 ± 0.75, BW: 83.85 ± 4.51, H: 184.96 ± 2.06, BF%: 10.51 ± 1.61, VO2max: 55.73 ± 4.57, AP: 10.9 ± 1.2 and GS: 109.08 ± 14.06. Amateur female (AF) goaltenders presented the following: A: 21.04 ± 1.84, BW: 63.4 ± 5.14, H: 164.86 ± 5.73, BF%: 22.12 ± 2.27 and VO2max: 42.84 ± 3.59. Overall, PM goaltenders are heavier, have a higher BF%, and exhibit greater GS and abdominal muscular endurance than AM, while AM goaltenders are heavier, taller, leaner, and can generate greater lower-body muscular power than AF goaltenders. In the current literature, there were a small number of studies on women players and a lack of distinction between player position in reported results. Specific physiological assessments during NHL Combines should be developed for goaltenders in accordance with their specific positional demands.
Article
Introduction Neuromuscular electrical stimulation (NMES) is used by athletes to improve muscle performance. However, evidence on the use of NMES in long distance runners is scarce. As such, this study aimed to evaluate the effects of NMES on the muscle torque and sports performance of long-distance recreational runners. Methods This was a blinded randomized controlled trial. Data from 30 volunteers were analyzed. Participants were randomly allocated to an experimental (n = 15) or control group (n = 15). The experimental group was submitted to running training (RT) and a strengthening protocol with NMES (1 kHz, modulated in 2ms bursts, 50Hz modulated burst frequency and 10% duty cycle, 15 minutes totaling 18 contractions per sessions) for 6 weeks, with 3 sessions per week, while controls were submitted to RT alone. The following variables were analyzed: peak isometric (ISO), concentric (CON), and eccentric (ECC) torque of the quadriceps muscle in voluntary contractions, ventilatory anaerobic thresholds (VATs), maximal oxygen uptake (VO2max), and oxygen cost of transport (OCT). Results The NMES group obtained higher values of ISO, 21.04% (p = 0.001), CON, 21.97% (p = 0.001) and ECC, 18.74% (p = 0.001) peak torque and VAT1, 9.56% (p = 0.001), as well as a statistically significant improvement in oxygen cost of transport at VAT1 when compared to controls (p = 0.001). Conclusion NMES was effective in improving peak isometric, concentric and eccentric quadriceps muscle torque, in addition to being an interesting resource for enhancing sports performance in long-distance recreational runners and future clinical trials should be performed to compare the use of NMES to different forms of training over longer training periods.
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Skeletal muscle undergoes substantial adaptation when it is subjected to a strength training regimen. At one extreme, these effects are manifested as profound morphological changes, such as those exemplified by bodybuilders. However, it is possible to increase strength without any change in muscle size. This dissociation underscores the notion that strength is not solely a property of muscle but rather it is a property of the motor system. The nervous system seems to be of paramount importance for the expression and development of strength. Indeed, it is probable that increases in strength can be achieved without morphological changes in muscle but not without neural adaptations. This review focuses on the role of the nervous system in the development of strength. In the strength literature, 3 topics exemplify the importance of the nervous system in strength development. These 3 topics are considered in detail in the review: electromyostimulation, cross-training effects, and EMG-force relationships. Evidence is presented from several different paradigms emphasising the significant contribution of neural mechanisms to the gains in strength with short term training. Although little is known about the specific neural mechanisms associated with strength training adaptations, the literature emphasises that the measure of human performance known as strength can be influenced by a variety of neurophysiological processes.
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Training programs for ice hockey players have two fundamental objectives: namely, to optimize performance and to minimize the risk of injury. The design of efficient and successful programs to meet these purposes depends on a careful analysis of the physiological demands of the game and the environment in which it is played. Moreover, if the program is to meet individual needs, the physical and physiological status of the player must be considered. Ice hockey is a demanding sport that involves the recruitment of essentially all of the skeletal muscles of the body in order to perform the diverse skills of the game.
Article
The purpose of this study was to determine whether short-term weight training supplemented with electrical stimulation (ES) increases muscular strength, vertical jump performance and power more than weight training alone. Thirty-three subjects were divided into three groups: WT supplemented with ES (Group 1), n = 13; weight training only (Group 2), n = 12; and control (Group 3), n = 8. Weight training consisted of performing 10 exercises including the parallel squat using free weights, three days per week for five weeks. In addition, Group 1 was stimulated with ES of both quadriceps three times per week. ES consisted of 10 maximal tolerated l0-second isometric contractions with 60 seconds of rest between contractions. A symmetrical biphasic square wave with a phase duration of 200 microseconds and a pulse rate of 50 pulses per second was used. Muscular strength was assessed using a one-repetition maximum parallel squat. Power was assessed using vertical jump scores that were converted using the Lewis formula. After training MS was not significantly different (p > 0.05) between the two experimental groups (20.6 percent increase for Group 1 und 20.7 percent increase for Group 2). Vertical jump performance was not significantly (p > 0.05) different between the two experimental groups (3.0 percent increase for Group 1 and 7.5 percent increase for Group 2). However, Group 2 (5.7% increase) had a significantly (p < 0.05) greater power than Group 1 (3.1 percent increase). In conclusion, short-term weight training supplemented with ES does not appear to enhance muscular strength, vertical jump performance or power more than weight training alone. (C) 1991 National Strength and Conditioning Association
Article
The purpose of this 6-wk study was to determine the effects of dynamic contractions supplemented with electromyostimulation (EMS) employed during a weight lifting exercise on knee extensor strength and vertical jump performance. Twenty female college track & field athletes were randomly assigned to 1 of 4 groups: non-weight-training/non-EMS (Control); weight-training-only (Wgt); EMS-only (Stim); and weight training + EMS (Wgt + Stim). All groups were pre-and posttested for knee extensor strength (1-RM) and vertical jump height (cm) using the bilateral knee extension exercise and countermovement vertical jump (VJ). The Wgt and Wgt + Stim groups trained 3 times a week at 85% of their 1-RM employing 3 sets of 8-10 reps; the Stim received EMS 3 times a week. Strength and VJ increased for all 4 groups. The 3 experimental groups differed significantly (p < 0.05) from Controls for both strength and VJ. Also, Wgt + Stim differed significantly from Wgt and Stim, while Wgt differed significantly only from Stim. These results suggest that supplementing dynamic contractions with EMS appears more effective than EMS only, or weight training only, for increasing knee extensor strength and VJ in female track & field athletes.
Article
The question, if muscles can absorb and temporarily store mechanical energy in the form of elastic energy for later re-use, was studied by having subjects perform maximal vertical jumps on a registering force-platform. The jumps were performed 1) from a semi-squatting position, 2) after a natural counter-movement from a standing position, or 3) in continuation of jumps down from heights of 0.23, 0.40, or 0.69 m. The heights of the jumps were calculated from the registered flight times. The maximum energy level, Eneg, of the jumpers prior to the upward movement in the jump, was considered to be zero in condition 1. In condition 2 it was calculated from the force-time record of the force-platform; and in condition 3 it was calculated from the height of the downward jump and the weight of the subject. The maximum energy level after take-off, Ep0s, was calculated from the height of the jump and the jumper's weight. It was found that the height of the jump and Epos increased with increasing amounts of Eneg, up to a certain level (jumping down from 0.40 m). The gains in Epos over that in condition 1, were expressed as a percentage of Eneg and found to be 22.9 % in condition 2, and 13.2, 10.5, and 3.3 % in the three situations of condition 3. It is suggested that the elastic energy is stored in the active muscles, and it is demonstrated that the muscles of the legs are activated in the downward jumps before contact with the platform is established.
Article
Neuromuscular electrical stimulation (NMES) has been in practice since the eighteenth century for the treatment of paralysed patients and the prevention and/or restoration of muscle function after injuries, before patients are capable of voluntary exercise training. More recently NMES has been used as a modality of strengthening in healthy subjects and highly trained athletes, but it is not clear whether NMES is a substitute for, or a complement to, voluntary exercise training. Moreover the discussion of the mechanisms which underly the specific effects of NMES appears rather complex at least in part because of the disparity in training protocols, electrical stimulation regimens and testing procedures that are used in the various studies. It appears from this review of the literature that in physical therapy, NMES effectively retards muscle wasting during denervation or immobilisation and optimises recovery of muscle strength during rehabilitation. It is also effective in athletes with injured, painful limbs, since NMES contributes to a shortened rehabilitation time and aids a safe return to competition. In healthy muscles, NMES appears to be a complement to voluntary training because it specifically induces the activity of large motor units which are more difficult to activate during voluntary contraction. However, there is a consensus that the force increases induced by NMES are similar to, but not greater than, those induced by voluntary training. The rationale for the complementarity between NMES and voluntary exercise is that in voluntary contractions motor units are recruited in order, from smaller fatigue resistant (type I) units to larger quickly fatiguable (type II) units, whereas in NMES the sequence appears to be reversed. As a training modality NMES is, in nonextreme situations such as muscle denervation, not a substitute for, but a complement of, voluntary exercise of disused and healthy muscles.
The validity and accuracy of the Biodex dynamometer was investigated under static and dynamic conditions. Static torque and angular position output correlated well with externally derived data (r = 0.998 and r greater than 0.999, respectively). Three subjects performed maximal voluntary knee extensions and flexions at angular velocities from 60 to 450 degrees.s-1. Using linear accelerometry, high speed filming and Biodex software, data were collected for lever arm angular velocity and linear accelerations, and subject generated torque. Analysis of synchronized angular position and velocity changes revealed the dynamometer controlled angular velocity of the lever arm to within 3.5% of the preset value. Small transient velocity overshoots were apparent on reaching the set velocity. High frequency torque artefacts were observed at all test velocities, but most noticeably at the faster speeds, and were associated with lever arm accelerations accompanying directional changes, application of resistive torques by the dynamometer, and limb instability. Isokinematic torques collected from ten subjects (240, 300 and 400 degrees.s-1) identified possible errors associated with reporting knee extension torques at 30 degrees of flexion. As a result of tissue and padding compliance, leg extension angular velocity exceeded lever arm angular velocity over most of the range of motion, while during flexion this compliance meant that knee and lever arm angles were not always identical, particularly at the start of motion. Nevertheless, the Biodex dynamometer was found to be both a valid and an accurate research tool; however, caution must be exercised when interpreting and ascribing torques and angular velocities to the limb producing motion.
Article
Electrical stimulation to augment or maintain muscle performance has been well documented. The purpose of this preliminary report is to present the results of a single-case study conducted to determine the order of activation of skeletal muscle fibers as a result of electrical stimulation. The subject's quadriceps femoris muscles were electrically stimulated at 80% of maximal isometric torque. Pre-stimulation and immediate post-stimulation muscle biopsy samples were obtained, and a modification of the glucogen-depletion method was used to determine activation of muscle fibers. The pre-stimulation muscle biopsy sample demonstrated uniform periodic acid-Schiff (PAS)-positive staining in all fiber types, whereas the post-stimulation muscle biopsy sample showed glycogen depletion of type II muscle fibers. The most PAS-negative muscle fibers were type IIa skeletal muscle fibers. The results of this single-case study provide evidence that electrical stimulation, as described, selectively activates type II skeletal muscle fibers. The implication of this finding is that, in many chronic diseases, type II fibers are selectively and preferentially affected. Electrical stimulation may be a clinically viable technique to use in patients with type II fiber involvement.
Article
Electrical stimulation of muscle is a commonly used, well-substantiated strategy that physical therapists use to augment strength in patients with muscle weakness. Two distinctly different theories of strength augmentation using percutaneous muscle stimulation are presented. The first theory proposes that augmentation of muscle strength with electrically elicited muscle contractions occurs in a similar manner to augmentation of muscle strength with voluntary exercise. Electrically elicited muscle contractions of relatively high intensity with low numbers of repetitions strengthen muscle proportionally to the external load on the muscle in a manner that is equivalent to voluntary contraction. The second theory proposes that augmentation of muscle strength using percutaneous stimulation is fundamentally different from augmentation of strength with voluntary exercise. This theory uses the physiological differences between electrically elicited and voluntary contractions, such as the reversal of motor unit recruitment order, as a basis for argument. Both theories are partially substantiated using published literature. Strategies for testing both theories are also presented.