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Isokinetic and isometric strength after electrical stimulation on Judo players

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This study investigated the effects of electrical stimulation (ES) on isometric and isokinetic strength of Judo athletes. Four subjects from the judo national team performed strength tests in three different occasions are: pretraining (Pre), Post after 28 days of training (Post1) and 45 days after the termination of the training (Post2). After signing the informed consent and finishing the Pre strength test, the subjects underwent 20 sessions of titanic and tonic ES contraction for the lower extremity over 28 days. The stimulation protocol was conducted to both agonist and antagonist muscles were contracted bilaterally. Strength was measured by a (CYBEX P{cyrillic}) dynamometer at 0°, 60°, 90°, and 120°/s velocities. Two protocols of surface electrical stimulation SES was studied in the 28 days of the experimental period. Strength post-tests were performed 45 days after the termination of the exercise protocol. The comparisons were between pretest vs. posttest 1, pretest vs. posttest2, posttest 1 vs. posttest 2 for all the events of the strength test. The results indicate that ES conducted over (28) days have significantly affected strength in national team judo players.
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Journal of Physical Education and Sport
®
(JPES), 13(3), Art 64, pp. 400 - 408, 2013
online ISSN: 2247 - 806X; p-ISSN: 2247 – 8051; ISSN - L = 2247 - 8051 © JPES
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Corresponding Author: AMAN S. KHASAWNEH, E-mail: amana752001@yahoo.com
Original Article
Isokinetic and isometric strength after electrical stimulation on Judo players
AKEF M. TAIFOUR¹; ALI AL NAWAISEH²; AMAN S. KHASAWNEH³
1, 2
Department of Sport Rehabilitation/ Hashemite University,
ZARQA, JORDAN
3
Department of Coaching and Sport Management, ,
ZARQA, JORDAN
Published online: September 30, 2013
(Accepted for publication September 15, 2013)
DOI:10.7752/jpes.2013.03064;
Abstract:
This study investigated the effects of electrical stimulation (ES) on isometric and isokinetic strength of Judo
athletes. Four subjects from the judo national team performed strength tests in three different occasions are: pre-
training (Pre), Post after 28 days of training (Post1) and 45 days after the termination of the training (Post2).
After signing the informed consent and finishing the Pre strength test, the subjects underwent 20 sessions of
titanic and tonic ES contraction for the lower extremity over 28 days. The stimulation protocol was conducted to
both agonist and antagonist muscles were contracted bilaterally. Strength was measured by a (CYBEX П)
dynamometer at 0˚, 60˚, 90˚, and 120˚/s velocities. Two protocols of surface electrical stimulation SES was
studied in the 28 days of the experimental period. Strength post-tests were performed 45 days after the
termination of the exercise protocol. The comparisons were between pretest vs. posttest 1, pretest vs. posttest2,
posttest 1 vs. posttest 2 for all the events of the strength test. The results indicate that ES conducted over (28)
days have significantly affected strength in national team judo players.
Key words: electrical stimulation, isokinetic strength, isometric strength, Judo players.
Introduction
In recent years there is an increasing interest in electrical stimulation of skeletal muscles in athletes.
Achievement of a top level in sports and the increasing intensity of the struggle for the high rank and gold
medals needs more than super performances for athlete aiming at international champion, evidence were
provided that former Soviet Union have been used the method of electrical stimulation in preparing national
teams for the 1972 Munchen Olympics game and other important competition (Ward & Shakuratova, 2002).
In the sphere of sports the method of electrical stimulation as a training protocol is studied most
intensively by Soviet authors such as (Kotz & Chullon, 1975., Adrianova , Koz, Martjanova & Chwilon,1974)
this work is concerned above all with the problem of selection of suitable parameters for electrical stimulation of
muscle, their aim being to obtain artificial maximum muscular contraction as a response to electrical stimulation
involve stimulating the muscle with a complex protocol that is designed to minimize the pain and discomfort
associated with this procedure. The Soviets reportedly use electrical stimulation with their best athletes in sports
where strength is a limiting factor for example weight lifting, wrestling, sprinting, and throwing events. Steib,
Schoene, Pfeifer (2010) demonstrated that the greatest effect as regards an increase in muscular strength and
perseverance of strength is obtained by intensive electrical stimulation applied daily, in sedentary subjects not
engaged in sports they achieved an increase of muscular strength by a mean of 16%, of dynamic strength, by
25% and perseverance of achieved strength by 94%, contrary to electrical stimulation applied only twice a week,
when the corresponding increments were only 9%, 6% and perseverance of achieved strength by 32%.
Interestingly, some authors have observed that an electro stimulation training program carried out in
isometric conditions can increase both isometric and dynamic strength (Martin, Cometti, Pousson & Morton,
1993; Pichon, Chatard, Martin & Comtti, 1995; Colson, Martin & Hoeck, 2000). This non specificity of the
isometric contraction mode in training sessions might be ascribable to the nonselective recruitment of motor
units (i.e., a partial reversal order as compared with voluntary contractions )Solomonow, 1984; Knaflitz ,
Merletti & Deluca,1990; Feiereisen, Duchateau & Hainaut,1997; Gregory & Bickel, 2005).
Halbach & Straus (1980) demonstrated in a sedentary group of young healthy subjects that electrical
stimulation is a suitable method not only for developing muscle strength and tonus but that it may become also a
suitable method for reduction of subcutaneous fat. Anzil, Modotto & Zanon (1974) achieved considerable
improvement of the explosive strength during the start in 100 m sprinters after electrical stimulation of the
muscles of the sole of the foot.
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This method is particularly is very important and valuable, although not yet fully appreciated in the
sphere of rehabilitation, e. g. the case of the top jumper Enzo del Forno who after surgical operation of the right
knee meniscus used one third of the time given by his doctors for convalescence for electrical stimulation to
preserve the standard of his static and dynamic strength.
Also among the therapeutic modalities, neuromuscular electrical stimulation (NMES) is presented as a
non-invasive technique used by physical therapists to promote muscle strengthening, to minimize muscle
hypotrophy, to reduce muscle spasm and spasticity and to increase range of motion in the joint. Particularly,
with respect to knee osteoarthritis (OA) treatment, neuromuscular electrical stimulation (NMES) has been
suggested as an alternative therapy for quadriceps muscle strengthening, mainly when elderly present chronic
pain and joint stiffness, which prevent them from engaging in voluntary exercises. Also using (NMES) early
after total knee arthroplasty (TKA) surgery may enhance recovery of physical function such as walking.
(Oliveira , Fernando & Marco, 2013; Burch, Tarro, Greenberg & Carroll, 2007 )
Electrical stimulation method was used under isotonic condition during a certain close dynamic
movement as (Anzil & et.al,1974)) used this method in javelin throwers and elite athletes from deferent sports.
Kots & Chullon (1975) recommends the ES training to promote and hasten in this way the rebound strength, the
aim of this method is not so much the development of static muscular strength but rather to hasten the training of
a certain correct position or hastening of a certain component of a movement in a complex of movements or to
enhance the explosive strength. Brocherie, Babault, Cometti, Maffiuletti & Chatard (2005) quoted by Lagasse &
Boucher (1979) in their study on the training effects of the functional electrical stimulation on the performance
of novice weightlifters, demonstrated that functional electrical stimulation is an efficient technique for the
learning of physical skills requiring muscular coordination in weight lifting events. Paillard (2008) developing
muscle power by electrical stimulation and mention that the response to strengthening by electrical stimulation is
not the same in all sport subjects and individuals, even muscle groups respond in a different manner for example
in extensors of the elbow (triceps brachia muscles) immediately after stimulation a decline of muscle strength
occurred, only 8 days after completed stimulation of muscle strength increased on the left side by a maximum of
20%, and on the right side by 13%. In the extensors of the knee joint (quadriceps femora's muscle) after
electrical stimulation in three subjects a marked increase of the muscle strength was recorded on both
extremities, and in two subjects a decline of muscle strength was observed; a certain improvement occurred after
8 days. Maximum increments of muscle strength of the knee extensors were on the left extremity 24% and on the
right by a mean of 49%. In a group of subjects not engaged in sports, immediately after electrical stimulation in
all pro bands a marked improvement of the strength of the stimulated muscles occurred from 6% to 51% and the
greatest improvement of muscle strength was achieved in a subject not engaged in any sports activity. Maffiutetti
(2010) studying the effect of the training using a technique of imitational electric stimulation on high level
swimmier, the result showed that the thickness of the sub skin layer cells decreased after the first 5 training unit,
and after 25 training unit, there was an intense increase in muscle mass by a mean of 1.5 to 3 cm in
circumference, and in cross sectional area which was accompanied by an increase in strength by 16% to 23%.
Also Colson,Martin & Hoecke (2009) were find that the isometric torque gains of EMS
(electromyostimulated group )were greater than those of VOL (voluntary isometric group ) and that the eccentric
and concentric torque gains were equivalent. They can be concluded that electromyostimulation training would
be more efficient than voluntary isometric training to improve both isometric and dynamic strength
Thus, a difference in strength gains could also be expected between electro stimulation and voluntary
isometric training (i.e., identical isometric muscle contraction but different motor unit recruitment). In addition,
recent reports about hybrid muscle activation (i.e., electromyostimulation superimposed onto voluntary
contraction) have demonstrated that the muscle strength produced during a muscle contraction induced by
electromyostimulation is also dependent of the central nervous system (Langzam, Nemirovsky, Isakov &
Mizrahi, 2007).
Kotz & chullon (1975) documented the use of electrical stimulation for the treatment of muscle disuse
atrophy, pain, and posttraumatic edema. Throughout the history of the search for enhanced muscle performance,
electrical stimulation was considered an option in the development of enhanced muscle strength. (Currier,
Lehman & Lightfoot, 1979; Eriksson, 1976; Eriksson & Haggmark,1979) found no significant difference in
isometric strength training regimens using maximum intensity electrical stimulation. Similarly, (Halback &
Straus,1980) found no difference in isokinetic strength development with electrical stimulation. Strength
improved with electrical stimulation, but no advantage was found over training, and isometric strength gains
from electrical stimulation did not carry over to dynamic tasks.
Delitto, Rose, Mckowen, Lehunan, Thomas & Shively (1998)., Dawn, John , Francis, & David (2000)
showed a significant improvement in strength and Isokinetic Torque During High Speed Movement for Elite
Judo Athletes.
Taifour et al, (1988) used the electrical stimulation method in preparing Tsukuba University soccer
team in preparation period, pre-competition period and competition period, the results achieved a significant
improvement in sprinting power, dynamic strength, isometric strength, and vertical jump abilities improvement.
According to that the current study discuss the possibilities of promoting muscular strength by means of
electrical stimulation to healthy and well trained subjects engaged for judo players and its importance to
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increased muscular strength without a concomitant increase in muscular bulk . And also the importance of the
study was used electrical stimulation in the same time for the agonist and antagonists muscles.
Statement of Problem
Several studies have emphasize the important of electrical stimulation in strength training in many
different field such as training, treatment and rehabilitain with many different way like (Ward & Shkuratova,
2002; Hortobagyi & Malliuletti 2009; Martin & et al; 1993; Pichon & et al; 1995; Colson & et al; 2000).
Thorstensson, Karlsson, Viittusalo & Komi (1976); Kitai & Sale (19890; Weir & Weir (1995); Behm & Sale
(1993); Rich & Cafarelli (2000); Maffiuletti & Martin (2001) which provides evidence that electrostimulation
strength training (EST) increases the force of a maximal voluntary contraction (MVC) through neural
adaptations in healthy skeletal muscle, Although electrical stimulation and voluntary effort activate muscle
differently, there is substantial evidence to suggest that EST modifies the excitability of specific neural paths and
such adaptations contribute to the increases in MVC force. Similar to strength training with voluntary
contractions, EST increases MVC force after only a few sessions with some changes in muscle biochemistry but
without overt muscle hypertrophy, and the interest for the electrical stimulation increasing achievement, and also
its increasing both isometric and dynamic strength.
However bax , staes, & verhagen (2005); Oliveira & et.al (2013); Burch & et.al (2007); Kotz &
Chullon (1975) focused on the important of electrical stimulation in rehabilitation which there studies show that
Electrical stimulation for rehabilitation purposes is usually conducted in isometric conditions and specific
isometric strength improvements have been observed. Using neuromuscular electrical stimulation (NMES) early
after total knee arthroplasty TKA surgery may enhance recovery of physical function such as walking. NMES
has been suggested as an alternative therapy for quadriceps muscle strengthening, and finally the use of electrical
stimulation for the treatment of muscle disuse atrophy, pain, and posttraumatic edema.
From the survey of these studies it is well observed that increased muscular strength is associated with
the enlargement of muscle fibers (hypertrophy) as well as an increase in the number of motor units activated
(recruitment), this kind of strength lead for increase in body weight, and this is undesired for weight category
sport. The data generated by this study seems to evaluate the possibility of gain an isometric and isokinetic
strength without a concomitant increase in muscular bulk, using electrical stimulation with short contraction time
less than 5 second, the electrical stimulation was applied in the same time for the agonist and antagonists
muscles very similar to the super set technique in the weight training protocols.
Study Aims
1. The main aim of the present study was to demonstrate the possibilities of promoting muscular
strength by means of electrical stimulation for national team judo players.
2. The secondary aim was derived to evaluate the possibility of gain isometric and isokinetic strength
without a concomitant increase in muscular bulk.
Method
The design
A quasi-experimental, pretest-posttest experimental group design using a sample of intact groups was
used in this study.
The Sample
Four male Judoka athletes from the Jordanian national Judo team were recruited to participate in the
study. Table (1) shows the descriptive statistic of the sample.
Table 1. Descriptive statistics of the subjects
Men SD
1 Age (years) 20 1
2 Height (cm) 176 7
3 Weight (kg) 81 13
4 BMI (kg/m
2
) 26.1 2.2
5 Body fat (%)* 14 2
6 Experience years of competition 5 2
Note: n = 4
* Sub of 4 skin fold treated with BH formal
Training program
The electrical stimulation program consisted of isometric electrical stimulation contraction both titanic
and tonic contraction of the muscles. The electrodes were placed at the proximal and distal margins of the belly
of the agonists muscles, using a bipolar technique, another electrodes were placed on the antagonists muscles,
using the same bipolar technique, i. e. the electrical stimulation was applied in the same time for the agonist and
antagonists muscles very similar to the super set technique in the weight training protocols in all cases of the
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treatment expect the (Gluteus maximums muscles), surface stainless steel sheet metal electrodes cover with
water-soaked foam rubber were used for stimulation, the skin was cleaned with alcohol and abraded with redux
electrode paste applied with a gauze pad to reduce the skin's electrical impedance. Occasionally, the electrodes
pads were adjusted slightly to achieve a more forceful contraction.
Prior to their participation, each subject signed on informed consent that was approved by the
instigators, and the strength of the knee flexors and extensors of both leg was measured using (CYBEX II)
isokinetic dynamometer.
Subjects were fitted into the CYBEX protocol according to the manufactures instructions, all the
subjects complete a warm up, each subject completed (four) to (six) sub-maximal knee flexion and extension to
be familiarize to the (CYBEX) at 180ْ deg/sec with 60 sec intervals between each trials and a static stretching for
five minutes before testing processes.
However encouragement was given to the subjects during the testing protocol. The testing velocities
were 60ْ deg/sec, 90ْ deg/sec, 120 deg/sec, and 0 deg/sec this same testing protocols was applied in the pre-test,
post 1 and post 2 test, the post-test 2 result were served as the control period, the post-test 2 were conducted after
45 days from E.S termination. Variables examined in this study and the test of the 4 velocity (0ْ, 60ْ, 90ْ, 120ْ).
At the beginning of each electrical stimulation treatment, subjects were placed in a seated position, for
stimulating the lower limps muscles, both legs were positioned in 110 degree of knee flexion and stabilized at
this angle with straps. This procedure prevented movement of the legs during the treatment so that the muscles
contracted isometricaly in the same time the Stimulation intensity was slowly increased until the muscles of
agonist and antagonists exhibited equally strong visible contractions with minimal discomfort. The 2Hz
frequency was applied at the beginning for three minutes as muscles warming up, flowed by the 70Hz frequency
with a sex minutes total stimulation time, flowed by the 2Hz frequency for three minutes stimulation as a cool
down. Intense titanic contractions were experienced with the 70Hz stimulation, while gentle pulsating
contraction were produced by 2Hz stimulation e. i. the subjects received 360 tonics contraction as a warming up,
72 titanic contraction as a training treatment, and 360 tonic contraction as cool down, the training treatment
stimulation was 4 seconds stimulation and 4 seconds interval. Each subject determined the intensity of the
stimulation, but was encouraged to make this as high as was tolerable. The electrical stimulation training was
daily; all subjects accomplished a total of 20 titanic and tonic ES contraction for the lower extremity over 28
days in the experimental period.
Pre-post training measures
The pre tests were formed from the four velocities (60ْ, 90ْ, 120ْ , and 0 deg/sec) of the strength of the
knee flexors and extensors of both leg by using (CYBEX II) is kinetic dynamometer.
The same testing protocols was applied in post test 1 after 20 titanic and tonic ES contraction for the
lower extremity over 28 days in the experimental period and the post test 2 after 45 days from the termination of
the training, the post-test 2 result were served as the control period. The comparisons were between pretest vs.
posttest 1, pre-test vs. post-test 2 and post-test 1 vs. post-test 2 for all the events of the strength test.
Data analysis
Analysis of variance for repeated measure (ANOVA) was used to achieve the main and the secondary
aims of the study as following:
1. To detect statistically differences in muscular strength by means of electrical stimulation for national
team judo players in the pre-test vs. post-test1, pre-test vs. post-test 2 and post-test 1 vs. post-test 2.
2. To evaluate the possibility of gain isometric and isokinetic strength without a concomitant increase
in muscular bulk for national team judo players.
Results
The main aim of the present study was to demonstrate the possibilities of promoting muscular strength
by means of electrical stimulation for judo national team players, analysis of variance for repeated measures
(ANOVA) was used to achieve this aim and assess the differences in strength variables. Tables 2 and 3 show
that.
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Table 2. Descriptive statics of mean peak torque variables after the experiment in the pre-test, post-test 1, and
post-test 2 (N = 4)
Pretest Post 1 Post 2
Mean SD Mean SD Mean SD
Velocity
Degree/Seconds Nm Nm Nm
RL EXT 60ْ 130.750 2.217 156.250 1.500 131.500 2.380
RL EXT 90ْ 109.750 1.893 121.000 2.160 112.250 3.403
RL EXT 120ْ 88.250 1.708 101.000 1.155 90.750 1.500
RL EXT Isometric 0/S 218.500 6.245 237.250 2.062 219.750 6.186
RL FLX 60ْ 108.250 21.793 127.500 35.341 110.500 23.216
RL FLX 90ْ 90.000 24.000 100.750 23.557 90.750 22.765
RL FLX 120ْ 73.250 19.379 88.750 24.568 75.000 21.463
RL FLX Isometric 0/S 209.750 14.385 223.500 15.351 211.000 15.384
LL EXT 60ْ 119.500 2.082 151.500 8.104 123.000 4.967
LL EXT 90ْ 103.750 6.238 120.250 2.679 107.000 6.481
LL EXT 120ْ 85.750 4.349 100.750 2.754 87.000 6.055
LL EXT Isometric 0/S 225.500 3.873 245.000 6.377 227.500 2.082
LL FLX 60ْ 95.000 30.210 120.000 33.506 96.500 31.332
LL FLX 90ْ 90.750 17.289 99.250 18.626 91.750 16.998
LL FLX 120ْ 70.000 20.944 84.000 27.289 72.000 21.463
LL FLX Isometric 0/S 227.250 6.500 245.750 8.694 229.250 6.292
From the table it appeared that there were differences between means for the tests, (ANOVA) test for
repeated measures used to make sure that the differences statistically significant as table 3 show that.
Table 3. Effects of E.S training on strength peak torque variables after the experiment in the pre-test, post-test 1,
and post-test 2 (N = 4)
Source
Between subjects Pre-test vs. Post-test 1 Pre-test vs. Post-test 2 Post-test 1 vs. Post-
test 2
RLEXT p = 0.001
F = 28022.76, df = 3 -25.500* Ns 24.75*
RLFIX p = 0.003
F = 74.866, df = 3 Ns Ns Ns
LLEXT p = 0.001
F = 40496.348, df = 3 -32.000* Ns 28.500*
Peak Torque at
60ْ/second
LLFIX p = 0.007
F = 43.022, df = 3 -25.000* Ns 23.500*
RLEXT p = 0.001
F = 14406.00, df = 3 -11.250* Ns 8.750*
RLFIX p = 0.004
F = 64.031, df = 3 -10.250* Ns 9.500*
LLEXT p = 0.001
F = 2073.710, df = 3 -16.500* 3.250* 13.250*
Peak Torque at
90ْ/second
LLFIX p = 0.002
F = 114.265, df = 3 -8.500* Ns 7.500*
RLEXT p = 0.001
F = 36184.615, df = 3 -12.750* -2.500* 10.250*
RLFIX p = 0.005
F = 52.535, df = 3 -15.500* Ns 13.750*
LLEXT p = 0.001
F = 1767.486, df = 3 -14.500* Ns 13.250*
Peak Torque at
120ْ/second
LLFIX p = 0.007
F = 42.084, df = 3 -14.000* -2.000* 12.000*
RLEXT p = 0.001
F = 9202.644, df = 3 -18.750* Ns 17.500*
RLFIX p = 0.001
F = 840.659, df = 3 -13.750* Ns 12.500*
LLEXT p = 0.001
F = 35219.566, df = 3 -19.500* Ns 17.500*
Peak Torque at
/second
LLFIX p = 0.001
F = 5151.565, df = 3 18.500* -2.000* 16.500*
Note: RLEXT = Right Leg Extension.
RLFLX = Right Leg Flexion.
LLEXT = Left Leg Extension.
LLFLX = Left Leg Flexion.
Experimental Period between the Pre-test and Post-test 1 = (28 days).
Control period between the Post-test 1 and Post-test 2 = (45 days).
Fisher's Protected Least Significant Difference (PLSD) was fixed at < 0.005 level.
(n = 4)
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The preceding presentation of data has shown that in some areas tested in this study there were decisive
differences, while in others there were no significant differences between the treatments groups tested.
An examination of the CYBEX variables indicated that both isometric strength and isokinetic strength
were significantly developed, during the electrical stimulation training in the experimental period. Isometric
strength peak torque at 0 degree/second and isokinetic strength peak torque tested at 60˚, 90˚, 120 degree/second,
were development for right / lift knee extension and flexion.
The differences between tests show that the significant differences noted by post test1 vs. pre test, and
between post test 1 vs. post test 2 for favor to the post test 1 which refereed to the period which the subjects used
electrical stimulation.
After testing these variables 45 days after termination of the electrical stimulation, in the control
period the results show a significant decrease in the strength gains in both isometric and isokinetic strength as
shown in tables 2 and 3. However, as it was discussed previously in regard to the girth variables, this kind of
strength increase could be the results of the neural adaptation that has occurred. An alternative explanation is that
muscle quality increased; that is, the intrinsic strength of muscle per unit cross-sectional area (specific tension)
increased after electrical stimulation training i.e. a process takes place that is term by athletes and couch
awakened of awakening muscle. This implies that sportsmen are more aware of a muscle which was subjected to
electrical stimulation. During training they are more capable of using this muscle under voluntary control.
From the literature and physical training practice it is known that massive muscular contraction in
particular under conditions of an isometric regime, leads to an increase of the muscle mass and improvement of
muscle strength (Hainaut & Duechateau, 1992). Therefore, it is necessary to select such parameters of electrical
stimulation of muscle which lead to maximum muscle contraction which does not cause pain. In the present
experiment, there was a wide modification of the method described by (Kotz & Chullon 1975), and the method
described by (Enoka, 1988) i.e.the overload principle states that the mechanism for strength augmentation is the
load exereted at the tendon measured as an external force, it must be stressed to the maximal contraction than in
normal training, the placement of the electrodes in the agonist and antagonists muscle in the present study leads
for a maximum artificial contraction with more tolerance to the electrical stimulation current. The duration of the
contraction time in this study was modified to prevent hypertrophy in muscles mass.
And to make sure of that the secondary aim was derived to evaluate the possibility of gain isometric and
isokinetic strength without a concomitant increase in muscular bulk. A repeated measure (ANOVA) was used to
achieve this aim and assess the differences in body compositions variables. Tables 4 and 5 show that.
Table 4. Descriptive statics of body composition parameters during the experiment and control period
PRE-TEST POST-TEST 1 POST-TEST 2
Variables Mean SD Mean SD Mean SD
BODY WEIGHT 81 13.441 81.925 13.442 81.85 12.499
BODY FAT (%) 14 2.00 14.00 3.00 14.00 3.00
RIGHT ARM GIRTH 34 1.786 35.525 1.097 35.225 1.763
LEFT ARM GIRTH 35.15 1.561 35.75 1.708 35.325 1.7
RIGHT FORARM GIRTH 29.875 1.548 29.95 1.196 30.25 1.323
LEFT FORARM GIRTH 29.65 2.336 30.05 1.891 29.625 1.109
RIGHT THIGH GIRTH 58.275 4.626 58.75 3.8 58.625 4.328
LEFT THIGH GIRTH 57.65 4.396 58.425 4.014 58.625 4.385
RIGHY CALF GIRTH 39.7 4.202 39.925 3.664 39.925 3.776
LEFT CALF GIRTH 39.5 4.183 40.45 3.368 40.000 4.378
Note: experiment period (between the pre-test and post-test 1) = 28 days.
Control period (between the post-test 1 and post-test 2) = 45 days.
Note: n = 4
From the table it seems that the differences between means for the tests were little and simple,
(ANOVA) test for repeated measures used to make sure that the differences statistically not significant as table 5
show that.
Table 5. Repeated Measurement Test of the E.S training effect on body composition
Source F Sig Pre-test VS
Post- test1
Pre-test VS
Post- test2
post-test 1 VS
Post- test2
BODY WEIGHT 1.99 0.216 NS NS NS
BODY FAT (%) 0.49 0.643 NS NS NS
RIGHT ARM GIRTH 1.503 0.296 NS NS NS
LEFT ARM GIRTH 2.488 0.163 NS NS NS
RIGHT FOR ARM GIRTH 1.45 0.306 NS NS NS
LEFT FOR ARM GIRTH 0.46 0.652 NS NS NS
RIGHT THIGH GIRTH 0.905 0.454 NS NS NS
LEFT THIGH GIRTH 2.654 0.149 NS NS NS
RIGHT CALF GIRTH 0.544 0.607 NS NS NS
LEFT CALF GIRTH 2.823 0.137 NS NS NS
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As indicated in the tables 4 and 5 the body composition variables have no significant deference's in the
three tests conducted at the pre, post 1, and post 2 tests.
The data generated by this study seems to support that it could be gain an isometric and isotonic
strength without a concomitant increase in muscular bulk. This result conflict with previous studies which
referred that increased muscular strength is associated with the enlargement of muscle fibers (hypertrophy) as
well as an increase in the number of motor units activated (recruitment).
Short-term training studies have demonstrated increases in voluntary strength without increases in
muscle size (Stevens, Mizner, Snyder-Mackler, 2003; Kyung-Min, Ted & Susan, 2010; Kotz, 1976; Bickel,
Gregory & Dean, 2011). And thus data shows to be very important finding in certain athletic events in sports
such as Judo, Taekwondo, Wrestling, Boxing, Weightlifting and all weight category sports. Previous research in
the field shown that strength gains by the method of electrical stimulation often was a companied by an increase
of the girth (hypertrophy). In summary the present investigators found that the muscle hypertrophy occurred
when the duration of the contraction time is within 5-12 second and more. However, a duration contraction time
of less than 4 second may cause an increase in strength level without hypertrophy. For this reason, the present
investigators used the 70Hz frequency with a duration time contraction of 4 seconds to prevent hypertrophy in
muscle size bulk, but in the same time the strength gain was developed progressively in both dynamic and static
strength.
Discussion
The results of this study indicated that 20 sessions of electrical stimulation conducted over a 28 days
had a marked effect on isometric and isokinetic strength in a well trained judo player. The results agree in part
with (Zhan, Mantilla & Sieck, 2003) that an electrical stimulation with 4 second contraction duration time, have
no significant influence at girth, and disagree with the same investigator, that, the electrical stimulation
procedure had no effects as the speed of movement increased. However, the present investigators tested the
subjects at 60˚, 90˚, 120 degree/second using the same CYBEX, and found a significant development greater
than the strength gains that occurred in isometric strength tested at (0 degree/second). An inspection of the
(Zhan, Mantilla & Sieck, 2003) study shows that the test order effected their results, and the electrical
stimulation was conducted 10 sessions over 5 weeks, which is considerably long, and the effects of the training
is doubtful. This study disagrees with ( Eriksson & Haggmark, 1979) that electrical stimulation had no benefit
when electrical stimulation was added to the training program of well trained athletes. Similar studies in the
former Soviet Union support the results of this study using a well developed strength subject’s e. g (Kotz &
chullon, 1970., Pandyan, Granat & Stott, 1997). The present study agrees with (Cabric & Aplle ,1987), that a
contraction time of 5 second had no effects on girth thickness. At the same time it had significant effects on
strength level.
A relatively large increase of maximum isometric strength after electrical stimulation was demonstrated
by a number of investigators (Cabric & Aplle,1987, Hainaut & Duchateau, 1992., Durmus, Alayli & Cantürk,
2007., Paillard , 2008., Pandyan, Granat & Stott, 1997., Adrianova & et.al, 1974., Currier & et al. 1979.,
Eriksson & Haggmark, 1979., Selkowitz 1985). The values reported for increase of strength in the above
mentioned studies were mainly within limits of 10% - 40%. Some studies shows increase of about 200%
(Duclay, Martin, Robbe & Pousson, 2008). It is difficult, to compare the results of this experiment with those
mentioned before, because of methodological differences, the duration of experiment, the variables tested, if the
results are compared with the results of those authors (Cabric & Appell, 1985., Kotz & Chullon, 1975.,
Andrianova & et.al, 1974., Gabriel, Kamen & Frost, 2006., Paillard , 2008) whose experimental protocols
closely resembled that of the present study, one can observe that increase of maximum isokinetic force (at 60˚,
90˚, 120 degree/second) was higher in the present study, and researchers reported much higher isometric strength
(at 0 degree/second) increase, than in this study.
This difference can probably be explained by the E.S superset of the agonist and antagonist stimulation
initiated number of contraction given to the subjects, in the present study (72 titanic contraction + 720 tonic
contraction) in other studies 10-25 contraction with 5-10 second duration, and by the duration of the pause
between each contraction (in this study 4 second) in other studies was 20-50 second.
Conclusions
It recommended that the ES method of the type described here can be applied when the demands for
high level performances by elite athletes are limited by traditional training methods and when the demands of the
training are beyond the individual possibilities of the athletes.
We recommended the ES method similar to that used in this study electrode placement, intensity, and
volume to well trained athletic training program specially in the pre competition period.
References
Adrianova, G., Koz, M., Martjanova, W., & Chwilon, A. (1974). : Die Anwendung der Elektrostimulation for
das Training der Muskelkraft, Leistongssport: 4 (2): 138-142
AKEF M. TAIFOUR; ALI AL NAWAISEH; AMAN S. KHASAWNEH
---------------------------------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------------------
JPES ®
www.efsupit.ro
407
Anzil, F., Modotto, P., & Zanon, S.( 1974). Erfahungsbericht uber die Vermehrung der isometrischen masimalen
Muscelkraft durch zusatzliche Flektrostimulation and die kriterien inrer Anwendung in Sport.
Leistungssport: 4 (2): 143-146.
Bax, L., Staes, F & Verhagen, A .(2005). Does neuromuscular electrical stimulation strengthen the quadriceps
femoris? A systematic review of randomized controlled trials. Sports Med: 35(3):191–212.
Behm, DG & Sale, DG. (1993). Intended rather than actual movement velocity determines velocity-specific
training response. Euro Journal of Applied Physiology: 74(1):359–68.
Bergstrom. M. & Hultman E. (1988). Energy cost and fatigue during intermittent electrical stimulation of human
skeletal muscle. Journal of Applied Physiology: 65: 1500-1505.
Bickel, CS., Gregory, CM & Dean, JC. (2011). Motor unit recruitment during neuromuscular electrical
stimulation: a critical appraisal. European Journal of Applied Physiology; 111:2399–2407.
Brocherie, F., Babault, N., Cometti, G., Maffiuletti, N & Chatard, JC.(2005). Electrostimulation training effects
on the physical performance of ice hockey players. Medicine & Science in Sports & Exercise; 37:455–
460.
Bruce, Brandell. (1982). Development of a universal control unit for functional electrical stimulation. American
Journal of Physical Medicine: 61: 279-301.
Burch, FX., Tarro, JN., Greenberg, JJ & Carroll WJ.(2007). Evaluating the benefits of patterned stimulation in
the treatment of osteoarthritis of the knee. Osteoarthrartil;16(8):865-72.
Cabric. M., & Appell, H. (1987). Effect of electrical stimulation of high and low frequency on maximum
isometric force and some morphological characteristics in men. International Journal of Sports Med:
(8) 4): 256-260.
Colson, S., Martin, A & Jacques, Hoecke .(2009). Effects of electromyostimulation versus voluntary isometric
training on elbow flexor muscle strength, Journal of Electromyography and Kinesiology, Elsevier Ltd:
(19), 311–319.
Colson, S., Martin, A & Van, Hoecke. (2000). Re-examination of training effects by electrostimulation in human
elbow musculoskeletal system. International Journal Sports Med:21(4):281–8.
Currier, DP., Lehman, J & Lightfoot, P.(1979). Electrical stimulation in exercise of the quadriceps femoris
muscle. Physical Therapy ;59(12):1508-1512.
Dawn, T., John, C., Francis, X., & David, O.(2000). Effect of Patterned Electrical Neuromuscular Stimulation on
Vertical Jump in Collegiate Athletes, Journal of the American Physical Therapy Association, Sport
health, sage.
Delitto, Anthony., Rose, Steven J., McKowen, Joseph., Lehunan, Kichard M., Thomas, James A., & Shively,
Robert .( 1988). Electrical stimulation versus voluntary surgery. Physical Therapy Journal: 68(5): 660-
663.
Duclay, J., Martin, A., Robbe, A & Pousson, M.(2008). Spinal reflex plasticity during maximal dynamic
contractions after eccentric training. Medicine & Science in Sports & Exercise; 40:722–734.
Durmus D, Alayli G, Cantürk F. (2007).Effects of quadriceps electrical stimulation program on clinical
parameters in the patients with knee osteoarthritis. Clin Rheumatol; 26(5):674e8.
Enoka, R .(1988). Muscle Strength and its Development: new perspectives, Sports Medicine: 6: 146.
Eriksson, E & Haggmark, T. (1979).Comparison of isometric muscle training and electrical stimulation
supplementing isometric muscle training in the recovery after major knee ligament surgery. The
American journal of sport medicine.;7:169-171.
Eriksson E et al: Effect of electric stimulation on human skeletal muscle, Int Journal of Sports Medicine :2:
1981.
Feiereisen, P., Duchateau, J & Hainaut, K. (1997). Motor unit recruitment order during voluntary and electrically
induced contractions in the tibialis anterior. Exp Brain Res;114(1):114–23.
Gabriel, DA., Kamen, G & Frost, G. (2006). Neural adaptations to resistive exercise: mechanisms and
recommendations for training practices. Sports Med; 36:133–149.
Gregory, CM & Bickel, CS. (2005). Recruitment patterns in human skeletal muscle during electrical stimulation.
Physical Therapy Journal: 85(4):358–64.
Hainaut, K & Duchateau, J. (1992).Neuromuscular electrical stimulation and voluntary exercise. Sports
Med;14(2):100–11.
Halbach, JW & Straus, D. (1980). Comparison of electro-myostimulation to isokinetic training in increasing
power knee extensor mechanism. Journal of Orthopaedic & Sports Physical Therapy; 2:20-24.
Hortobágyi, Tibor., & Maffiuletti, Nicola.(2009). Neural adaptations to electrical stimulation strength training,
European Journal of Applied Physiology, Springer.
Kitai, TA & Sale, DG. (1989).Specificity of joint angle in isometric training. European Journal of Applied
Physiology ;58(7):744–8.
Knaflitz, M., Merletti, R & De Luca, C. (1990). Inference of motor unit recruitment order in voluntary and
electrically elicited contractions. Journal of Applied Physiology; 68:1657–67.
Kotz, YM. (1976).Methods of Investigation of Muscular Apparatus. Moscow, Russia: State Central Institute of
Physical Culture.
AKEF M. TAIFOUR; ALI AL NAWAISEH; AMAN S. KHASAWNEH
---------------------------------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------------------
JPES ®
www.efsupit.ro
408
Kotz, YM & Chullon, VA. (1975). The Training of Muscular Power by Method of Electrical Stimulation.
Moscow, Russia: State Central Institute of Physical Culture
Kyung-Min, Kim., Ted, Croy & Susan, Saliba. (2010). Effects of Neuromuscular Electrical Stimulation After
Anterior Cruciate Ligament Reconstruction on Quadriceps Strength, Function, and Patient-Oriented
Outcomes: A Systematic Review, Journal of Orthopedic and Sports Physical therapy: 40: 383-391.
Lagasse, Pierre & Boucher, Jean .(1979). Training effects of Functional electrical stimulation in Weightlifting.
Journal of Human Movement Studies: 5: 61-67.
Langzam, E., Nemirovsky, Y., Isakov, E & Mizrahi J. (2007). Muscle enhancement using closed-loop electrical
stimulation: volitional versus induced torque. Journal of Electromyogric Kinesiology;17(3):275–84.
Maffiuletti, NA. (2010). Physiological and methodological considerations for the use of neuromuscular electrical
stimulation. European Journal of Applied Physiology;110:223–234.
Maffiuletti, NA & Martin, A.(2001). Progressive versus rapid rate of contraction during 7 wk of isometric
resistance training. Med Sci Sports Exerc ;33(7):1220–7.
Martin, L., Cometti, G., Pousson, M & Morlon B.(1993). Effect of electrical stimulation training on the
contractile characteristics of the triceps surae muscle. European Journal of Applied Physiology and
Occupational Physiology;67(5):457–61.
Oliveira, Mônica., Fernando, Aragão., & Marco, Vaz .(2013). Neuromuscular electrical stimulation for muscle
strengthening in elderly with knee osteoarthritis: A systematic review. Complementary Therapies in
Clinical Practice, Elsevier Ltd: 19: 27- 31.
Paillard T. (2008). Combined application of neuromuscular electrical stimulation and voluntary muscular
contractions. Sports Med; 38(2):161-71.
Pandyan, AD., Granat, MH & Stott, DJ. (1997). Effects of electrical stimulation on flexion contractures in the
hemiplegic wrist. Clinical Rehabilitation; 11(2):123-130.
Pichon, F., Chatard, JC., Martin, A & Cometti G. (1995).Electrical stimulation and swimming performance. Med
Sci Sports Exerc;27(12):1671–6.
Pichon, F., Chatard, JC., Martin, A & Cometti, G. (1995).Electrical stimulation and swimming performance.
Med Sci Sports Exerc;27(12):1671–6.
Rich C & Cafarelli E. (2000).Submaximal motor unit firing rates after 8 wk of isometric resistance training.
Med Sci Sports Exerc;32(1):190–6.
Selkowitz, DM.(1985). Improvements in isometric strength of the quadriceps femoris. Physical Therapy
Journal;65:186–96
Solomonow, M. (1984). External control of the neuromuscular system. IEEE Trans Biomed Eng; 31:752–63.
Steib, S., Schoene, D & Pfeifer, K. (2010). Dose-response relationship of resistance training in older adults: a
meta-analysis. Medicine & Science in Sports & Exercise; 42:902–914.
Stevens, JE., Mizner, RL & Snyder-Mackler, L. (2003).Quadriceps strength and volitional activation before and
after total knee arthroplasty for osteoarthritis. Journal of Orthopaedic Research; 21:775–779.
Thorstensson, A., Karlsson, J., Viitasalo, J., Luhtanen, P & Komi, P. (1976). Effect of strength training on EMG
of human skeletal muscle. Acta Physiol Scand;98(2):232.
Ward, Alex., & Shakuratova, Nataliya.(2002). Russian electrical stimulation: The Early experiments. Physical
Therapy Journal: 82: 1019-1030.
Weir, Housh & Weir, Johnson. (1995). Effects of unilateral isometric strength training on joint angle specificity
and cross-training. European Journal of Applied Physiology;70(4):337–43.
Zhan, WZ., Mantilla, CB & Sieck, GC. (2003). Regulation of neuromuscular transmission by neurotrophins.
Sheng Li Xue Bao; 55(6):617-624.
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