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Showing 13 results for Electromyography

Mr Ehsan Tasoujian, Mr Homman Minoonejad, Mr Mohammad Hossein Alizadeh, Mrs Shahrzad Zandi,
Volume 0, Issue 0 (11-2019)

Purpose: Volleyball has a high potential for shoulder dyskinesia due to the repetitive nature of spike, serve and block, so the aim was to investigate electromyography analysis of shoulder girdle muscle in male volleyball players with different types of scapular dyskinesia while performing a floater serve.
Methods: The current research method is the causal-comparative type. 41 volleyball players aged 18-25 were selected non-randomly and purposefully and were divided into three groups (n=13 inferior angle of scapula prominence, n=13 medial border of scapula prominence, n=13 without scapulae dyskinesia). Electromyography of 4 muscles including serratus anterior, upper, middle, and lower trapezius in the dominant shoulder was evaluated while performing a floater serve using MyoMuscle. Data were analyzed using analysis of variance test at the significance level of 0.05.
Results:  The results showed that during the acceleration phase of the serving, there was a significant difference in EMG of the upper trapezius (p=0.009) and middle trapezius (p=0.01) between the medial border of scapula prominence group and without dyskinesia group, and there was a significant difference in EMG of serratus anterior (p=0.007) and middle trapezius (p=0.01) between the inferior angle of scapula prominence group and without dyskinesia group.
Conclusion: It seems that during the acceleration phase of the floater serve, volleyball players with medial border of scapula prominence experienced an abnormal increase in upper trapezius activity and inhibition of the middle trapezius activity, while probably volleyball players with inferior angle of scapula prominence experience inhibition the activity of the middle trapezius and serratus anterior.
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Volume 10, Issue 3 (6-2012)

Background: In sports such as handball, tennis and volleyball the player need to involve the great loads over his shoulders. In these sports, players are predisposed to overuse injuries. Infraspinatus syndrome’s meaning is the painless weakness and atrophy of this muscle that observe following Suprascapularis nerve neuropathy. In this investigation we want to survey the effects of a short term of progressive endurance-strengthening training and electrical stimulation on strength and electromyography in infraspinatus muscle. Method: 12 volleyball players with Infraspinatus syndrome were randomly divided to two groups: progressive endurance-strengthening training (6 persons, age 24/8±3/8, height 189/3±2/6, weight 83/8±7/9, sport background 9/4±2/5 and national team’s background 3/24±1/7) and electrical stimulation (6 persons, age 24/2±4/5, height 192/5±1/5, weight 86/2±6/4, sport background 8/5±4 and national team’s background 4/3±2/8). 20 persons of healthy players were considered to be as a control group (age 25/1±4/2, height 187/7±3/9, weight 75/6±7/1, sport history 9±3/8 and national team history 3/9±2/3), too. Therapeutic interventions performed for 8 weeks. Surface electromyography of infraspinatus and tress minor muscles and maximal isometric strength of external rotator muscles were measured before and after interventions. Data analyzing performed by SPSS.12 and we used of Paired sample T test and one-way ANOVA. Confidence level considered to be 95% (P<0.05). Results: After eight weeks, maximal isometric strength of external rotators in both experimental groups was increased significantly, but there were observed no significant changes in IEMG and RMSEMG. Conclusion: Progressive endurance-strengthening training and electrical stimulation can result in increase of maximal isometric strength of shoulder external rotator muscles. But both therapeutic methods have no effect onelectromyograghic parameters in infraspinatus and tress minor muscles. It seems that we can't use of surface electromyography for detecting the effect of these protocols on above muscles (P<0/05).

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Volume 12, Issue 7 (4-2014)

The main purpose of the present study was to investigate the kinematics and kinetics of successful versus
unsuccessful basketball free throw shots. Six professional basketball players (age= 23±2.09 years members
of Iranian premier basketball league participat in test. Kinematics of arm motion during basketball free throws
were recorded by two Casio zr200 camera in frequency of 240 Hz. Wilcoxon test was used for significant
differences between successful versus unsuccessful free throws (p ≤ 0/05). Angular velocity of the wrist was
found to be significantly higher in successful versus unsuccessful shots at the time of ball release (p ≤ 0/028).
Wrist (p ≤ 0/008) and shoulder (p ≤ 0/023) joints were found to have significantly more flexion in successful
versus unsuccessful shots while elbow (p ≤ 0/002) remained significantly less flexed in successful shots.
Angular displacement of wrist (p ≤ 0/034) and elbow (p ≤ 0/004) was shown to be significantly greater in
successful versus unsuccessful shots. Integrated EMG of Anterior Deltoid (AD), Triceps Brachii (TB) and
Flexor Carpi Radialis (FCR) muscles was more in successful free throw versus unsuccessful free throw, but
the only significant difference was observed in the Integrated EMG of the Triceps Brachii muscle (p ≤ 0/034).
In summery, increasing the wrist angular velocity and activity of triceps brachii muscle affected successful
free throws.

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Volume 12, Issue 8 (10-2014)

As one of the most famous martial arts karate kata and kumite are two main ]1[. Different techniques when doing sports, including quadriceps muscles and joints (knee extensor muscles) and joint use. In this study, called the internal and external obliques broad kata and kumite athletes dominant leg when the two techniques were compared Znkutsudachi and Movashi Gray. Therefore, local and wide flat external obliques muscle activity during the two techniques in the dominant leg Karate Twenty healthy female elite athletes, (mean age 21/8) were recorded. After the onset of muscle activity was determined and the results of data processing using statistical techniques to design a mixed ANOVA between groups and within groups were examined. The results showed that flattened the internal oblique muscle Znkutsudachi techniques in kumite athletes Katakaran to be done first.

Masomeh Abdi, Hamed Esmaeili, Dr Farzad Nazem, Dr Mehrdad Anbariyan,
Volume 13, Issue 9 (4-2015)

The aim of this study was to compare the effects of two pedaling methods on lower limb muscles fatigue
index and muscular activity in road cyclists. For this purpose eight road cyclists participated in two separately
session in laboratory. They were pedaling with pushing technique in first session and circling (pullingpushing)
technique in the other session. Surface electromyography activity of the Rectus Femoris, Vastus
Medialis, Vastus Lateralis, Biceps Femoris, Semitendinosous, Gastrocnemius Medialis, Gastrocnemius
Lateralis and Tibialis Anterior muscles of the subjects were recorded. Each session was performed
according to predetermined protocol until exhaustion. There was a significant difference between pushing
and rest phases during two pedaling techniques with higher muscle activity in pushing technique. Subjects
during circling technique exhausted later. According to the results of this study, the circling technique caused
lower muscle activity consequently, increases gross efficiency. It is recommended that road cyclists utilize
the circling technique.

Mrs Fatemeh Malek Hoseini, Dr Mehdi Rafei Boroojeni, Dr Shahram Lenjan Nezhadian,
Volume 13, Issue 10 (10-2015)

The aim of the study was to compare the electrical activity pattern of major muscles involved in handball
triple shooting in two groups of adolescents and adults. Ten adolescent elite handball players playing in
national club league (16.4 ± 0.69) and 10 adult handball players (23.55± 2.69) participated in this research.
They performed triple shooting و assuming in a match situation and electrical activity of the Biceps brachii,
Triceps brachii, pectorialis major muscles and three anterior, middle and posterior parts of deltoid was
recorded using surface electromyography. Parameters related to the muscular activity pattern, including
time, peak, action amplitude and contraction sequences were obtained. The results of t-student statistical
test for two independent groups (p≤ 0.05) shown that there were no significant difference between time,
peak and electrical activity amplitude variables between groups. It seems the factors such as experience in
adolescent athletes, better utilization of muscle and being close to the end of puberty makes no difference
between adolescents and adults.

Mehdi Soltani Ichi, Pezhman Motamedi, Hamid Rajabi,
Volume 17, Issue 17 (4-2019)

The purpose of this research was to determine the acute effects of plyometric training with changing of height landing on the electromyographic activity during preparatory phase land-jump in male students. The population of this research were 10 physical education male students of Kharazmi University, which selected as sample. (21/10±1/286yrs, 173±6/467 height, 68/2±7/42 weight). In four different days subjects Performed as single leg one of four protocols plyometric training and land - jump from a height of 40 and 60 cm. EMG activity of the quadriceps and hamstring muscle group 150 milliseconds before foot contact with the ground was recorded. Analysis of variance with repeated measures and Bonferroni post hoc test was used. The results of this study showed that muscle activity after changing of height landing in preparatory phase (from 40 to 60 cm) has increased significantly (P=0/002, P=0/001, P=0/001) respectively. Activity of muscles (rectus femoris, vastus lateralis, biceps femoris) during landing after performing plyometric and changing of height landing in preparatory phase has increased significantly (P=0/039, P=0/001) (P=0/006, P=0/000) (P=0/001, P=0/014) respectively. Jump height has increased significantly (P=0/007, P=0/002) respectively. The results showed that acute perform plyometric training with changing of height landing result in significant changes in the electrical activity of muscles and also the height of the jump in the preparatory phase.

S Ilbeigi, M.r Poorbahram, M Saghebjoo,
Volume 17, Issue 17 (4-2019)

Purpose:The aim of this study was to investigate the effect of muscle soreness due to the plyometric exercises on leg muscle EMG activity after concentric and eccentric contractions in untrained people. 20 students from untrained male students (at least 6 months out of practice), were randomly assigned to experimental (n=10) and control (n=10) groups. At  pre-test, surface electromyographic activity of gastrocnemius muscle were recorded using by the Biovision 18 channel device during the both concentric (squat / plantar flexion of the ankle) and eccentric (wirepuller / ankle dorsiflexion) contractions. Then, in order to build muscle soreness, experimental group exerted 10 minutes selected plyometric exercises, while the control group did not have any training. Finally, immediately after protocol training and also after 48 hours the same record was done. Data were analyzed by Dasylab and Matlab software, and the ANOVA Repeated Measure and Bonferroni post hoc also were used for statistical analysis at a significance level of P≤0/05. The results showed that fatigue resulting from plyometric exercises, could have significant reduction in activity of gastrocnemius muscle immediately and 48 hours after exercise during eccentric contraction (P=0/001), while it was not true for concentric. According to the results, the risk of eccentric contraction could be considered for untrained people during training.

S.f Qeysari, Sh Tahmasebi Broujeni, M Shahbazi,
Volume 18, Issue 19 (7-2020)

Various studies have shown that the external focus of attention is better than the internal focus of attention. But, so far no study has been investigated the level of electrical activity of the rectus abdominus muscle as a trunk stabilizer muscle. Therefore, the purpose of this study was to investigate the effect of focus of attention on electromyography activity of the rectus abdominus muscle during Different phases of vertical jump.Twelve male elite volleyball players from university of Tehran Participated in this research voluntary. They performed a vertical jump on the force plate in both internal and external focus of attention condition. Rectus abdominus Surface electromyography (SEMG) signals recorded by electromyography apparatus during vertical jump and The electrical activity of this muscle was calculated in the different phases of vertical jump motion.  Paired t-test results showed that height of jump under the external focus was higher than the internal focus. In addition, this  results showed that internal focus caused significant increasing in Rectus abdominus EMG in comparison to external focus during concentric phase. But, there was no significant difference in the eccentric phase between the external and internal focus of attention conditions. These results suggest that the external focus of attention effectively increases the efficiency of vertical jump. Therefor; we recommend using the external focus of attention instructions when executing vertical jump movement.


Mr Amir Reza Sedighi, Dr Mehrdad Anbarian,
Volume 18, Issue 20 (11-2020)

 The purpose of this study was to determine the immediate effect of three types of shoe insoles, on electromyography activity of selected lower extremity muscles during running on treadmill. The electromyography activity of the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, tibialis anterior and gastrocnemius lateralis muscles of 14 male athletes were recorded in non-insole, wearing soft, semi-rigid and rigid insoles conditions during running on treadmill. Electromyography activity of the rectus femoris muscle in the loading phase was lower in soft insole condition than other conditions. In the pre-swing/early swing phase, there was difference of the rectus femoris muscle activity in the soft/non-insole and soft/semi-rigid conditions. In this phase, the biceps femoris muscle had different activity in the semi-stiff/non-insole and semi-rigid/rigid conditions. In the mid-swing phase, there was a difference in the activity of the rectus femoris and the tibialis anterior muscles in the non-insole/semi-rigid condition, and the gastrocnemius lateralis muscle in the non-insole condition with other conditions. There was difference also for biceps femoris muscle activity in the semi-rigid/non-insole condition in the pre-activation phase. The vastus lateralis and gastrocnemius lateralis muscles activity in the soft insole condition was lower than that of the semi-rigid condition. It seems that the intensity and contraction pattern of the muscles change while using different shoe insoles with different variety of stiffness during running. It could be useful in choosing a shoe insole with a suitable stiffness material level for clinical and training purposes.

Dr. Leila Ghazaleh, Mis Fahimeh Bakhshizadeh, Dr. Rana Fayazmilani,
Volume 19, Issue 21 (9-2021)

It is necessary to examine the changes of muscle co-contraction in different percent of fatigue-induced force reduction. The present study aims to investigate the effect of fatigue-induced force reduction of knee extension on muscle co-contraction. Ten healthy and active women aged 26.10±2.99 years performed fatigue protocol including 5 seconds of maximal voluntary isometric contraction (MVIC) of the knee extension and a 5-second rest. Muscle co-contraction was calculated for each subject in the repetitions in which the MVIC force was reduced by 10, 20, 30, 40 and 50% as compared to the pre-fatigue MVIC force. Knee extension force and muscle activity measured by Isokinetic and electromyography apparatus, respectively. The difference between co-contraction of vastus lateralis and medialis in different percentages of force reduction was not statistically significant. The co-contraction of rectus femoris and biceps femoris increased by 40 and 50% of force reduction compared to pre-fatigue co-contraction (P<0.01). Co-contraction of biceps femoris and vastus lateralis increased by 20, 30, and 40%, as well as co-contraction of biceps femoris  and vastus medialis increased 40% of the force reduction, compared to pre-fatigue co-contraction (P <0.05). The results, overall, showed that the change of co-contraction during fatigue is influenced by the selected muscle and the rate of force reduction. This finding can help researchers decide how neuromuscular fatigue effects on muscle co-contraction

Mr Mohamadreza Hatefi, Dr Ramin Balochi, Dr Farideh Babakhani,
Volume 19, Issue 21 (9-2021)

The purpose of this study was to investigate the effect of different hip joint postures on electromyographic activity of selected lower limb muscles during squat's movement. Electromyographic activity of selected lower limb muscles of 15 healthy male students was recorded while performing a squat with neutral, 15°, 30°, 45° external and internal rotation of the hip. Friedman's nonparametric test was used to compare muscle activation at different angles of the hip rotation and the Wilcoxon test was used to determine within-group differences. The results of this study showed no significant difference in the activity of Vastus medialis (p = 0.052), Vastus lateralis (p = 0.102) and tensor fasciae lata (p = 0.193) in squat between different hip joint angles, but Significant differences were observed in gluteus medius muscle activation (p = 0.001) and biceps femoris (p = 0.015) in squat between different hip joint angles. Also, the results of this study showed that gluteus medius to tensor fascia lata activation ratio was significant in squat between different hip joint angles. squat with the external hip angles can be considered as an effective method to increase gluteus medius activation and gluteus medius to the tensor fasciae latae activation ratio. On the other hand, 45 ° external and 30 ° internal hip angles can be considered as an effective method to increase the biceps femoris activation.
Dr Mostafa Haj Lotfalian, Dr Heydar Sadeghi, Mr Soroosh Bagheri,
Volume 21, Issue 25 (9-2023)

The purpose of this study was to examine and compare the difference between inside kick, outside kick, toe foot kick and cheap kick with maximum effort, in some parameters associated with the electromyographic activity of the quadriceps muscle. Eight skilled collegiate soccer players volunteered as subjects in the study. These variables were included the average and maximum activation, activation time (AT), the time which the muscles reached to zenith activity (ZAT) and work (W). In order to calculate electromyography of selected muscles contain, RectusFemuris, VastusMedialis and VastusLateralis, ME6000 apparatus with 1080 Hz sample rate was used. Paired sample t-test was used to analyze data. The results indicate similarity between outside and toe foot kicks in average and maximum activity, activation time and work. thus there was no significant difference in electromyographic activity of the quadriceps muscles between these two kicks. But in many parameters, these two kicks were different with inside and cheap kicks. In a nutshell, according to the results, it can be said, quadriceps muscles during various kicks, adapting different trend of contraction which are dependent on the position of the muscles and limbs interaction during soccer kick. And outside kick could be created maximum stimulation in quadriceps.

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