جستجوی مقالات مرتبط با کلیدواژه « الکترومیوگرافی » در نشریات گروه « پزشکی »

Electromyographic activity of lower limb muscles decreases in knee osteoarthritis. Whole body vibration is a suitable intervention in strengthening muscles, whose effect on the electromyographic activity of lower limb muscles during functional activity has not been properly investigated. The purpose of this study is to investigate the effects of whole-body vibration on the electromyography of the lower limb muscles of people with knee osteoarthritis during functional activity.

This clinical trial study was conducted on 30 people with knee osteoarthritis who were included in the study based on the inclusion and exclusion criteria. The participants were randomly divided into intervention and control groups (15 people in each group). Both groups were subjected to routine physiotherapy treatment, and the intervention group was subjected to whole-body vibration with a frequency of 30 Hz and an amplitude of 2 mm for 4 weeks and 3 times a week. Before and after the intervention, the EMG of the vastus medialis, vastus lateralis, biceps femoris, and semitendinosus muscles were recorded using surface electromyography while walking.

The results of this study showed that the RMS activity of the lower limb muscles increased significantly in both the intervention and control groups, and no statistically significant difference was observed between the two groups.

Whole body vibration has no significant effect on electromyography of lower limb muscles of people with knee osteoarthritis. Another study with a larger sample size is recommended.

 Muscle weakness and low muscle tone may cause chewing and swallowing disorders in people with Down syndrome. This study investigated the electromyography of the masseter and temporal muscles in children with Down syndrome, aged 2 to 12, during maximal voluntary isometric contraction and rest.

 The current descriptive-analytical and case-control study investigated the electromyography frequency indicators of the masseter and temporal muscles at maximum voluntary contraction and resting states in 15 children aged 2 to 12 with Down syndrome and 15 normal children of the same age.

 The average frequency of the mean and median in the electrical signal of the masseter and temporal muscles on the left and right sides and in two different positions in children with Down syndrome is lower than in normal children. In comparing the average frequency of the mean, except for the left and right temporal muscles in the maximum voluntary isometric contraction and the left master muscle during rest, there is a significant difference in the rest. Also, in comparing the average frequency of the median, except for the left and right temporal muscles in the resting state, there are non-significant differences in the rest of the cases.

 The average frequency of the electrical signal of the masseter and temporal muscles in children with Down syndrome is lower than that of normal children. Unlike typically developing children, those with Down syndrome struggle with chewing and swallowing.  

Anterior cruciate ligament reconstruction (ACLR) reestablishes electromyography activity during moderate activities such as walking but it is unclear whether this is also the case in sports activities such as running. Therefore, the present study aimed to evaluate the acute effect of using anti- pronation insoles on muscle frequency content in an individual with anterior cruciate ligament reconstruction with pronated feet during running.

The sample of this study consisted of 13 individuals with both ACLR and pronated feet aged 23.2±4.5 years and 13 healthy ones aged 22.9±4.1 years. During both Pre and Post-tests, participants ran barefoot on an 18-m runway at a constant speed of 3.3±5 m/s. The electromyography activity of the lower limb muscles was recorded during running with and without anti-Pronation insoles. Two-way ANOVA with repeated-measures test was used for statistical analysis.

The results indicated greater vastus medial frequency content in ACLR with the pronated feet group than that the healthy group during the loading phase (p=0.024). Also, results demonstrated that the rectus femoris frequency content was greater at the insole condition compared with and without it during the loading phase (p=0.014).

The results of this research showed a significant change in the activity of the quadriceps, hamstrings, gluteus medius, and gastrocnemius when using anti-pronation insoles in people with anterior cruciate ligament reconstruction and pronate feet. Therefore, it could be useful clinically.

People experiencefrom neck pain, headaches, kyphosis and back pain while working with computers, and these issues seem to be increasing with the advancement of technology. The aim of the present study was to investigate the effect of 10 sessions using simple and sensory thoracolumbosacral brace on lower limb muscle activities in kyphosis patients during typing.

This study was a semi-experimental and laboratory investigation. The statistical population of the   study was people with kyphosis in Ardabil city. The sample consisted of 30 male employees with kyphosis who were randomly divided into users of the sensor brace and users of the simple brace groups. The electrical activity of the upper limb muscles was recorded by the electromyography system during typing in both pre and post-test. Both groups used brace during ten weeks in their training sessions. All statistical analyses were done using SPSS software, and a two-way ANOVA analysis was conducted with a significance level of 0.05.

 The results demonstrated significant main effects of "time" for extensor digitorum muscle (P=0.016; d=0.180), anterior deltoid (P=0.014; d=0.196), middle deltoid (P=0.001; d=0.447) and trapezius (P=0.046; d=0.116) activity during typing. Findings showed significant main effect of group for the anterior deltoid (P=0.008; d=0.223) and posterior deltoid (P=0.013; d=0.201). Furthermore, significant group-by-time interactions  were found for superficial extensor digitorum muscle (P=0.019; d=0.189), triceps (P=0.001; d=0.310), middle deltoid (P=0.044; d=0.133) and posterior deltoid (P=0.001; d= 0.554) activity during typing phase.

The decreased electromyographic activity of the muscles when using thoracolumbosacral braces in employees with kyphosis confirms the effectiveness of this intervention. However, further study is needed to better establish this issue.

 hamstring injury is the most common injury in football. Nordic hamstring exercise (NHE) is one of the best hamstring injury prevention strategies. This study was aims to compare the effect of six weeks of standard NHE and modified NHE on electromyography of hamstring, hip and trunk muscles and sprint performance in young male football players

Methods:

 In this study, participants were 26 male football players in Kerman, Iran who were selected using purposeful and convenience sampling methods and randomly divided into two groups of NHE (Age: 16.31±0.51 years, Height: 173.08±5.15 cm, weight: 59.85±5.71 kg) and modified NHE (Age: 16.41±0.54 years, Height: 173±6.84 cm, weigh: 64.20±8.76 kg). Sprint performance was measured by the 20-meter sprint test, and muscles activity was measured by electromyography. Repeated-measure analysis of variance was used for data analysis.

 In the modified NHE group, there was a significant difference between the pretest and posttest phases in the electrical activity of biceps femoris (P=0.001), semitendinosus (P=0.001), gluteus maximus (P=0.016) and erector spinae muscles (P=0.001). In the NHE group, although the activity of muscles increased by 13% in the biceps femoris, 11% in the Semitendinosus, 9% in the gluteus maximus and 4% in erector spinae muscles, the difference was significant only in the biceps femoris (P=0.001) and Semitendinosus (P=0.024). The results also showed a significant difference between the two groups in electrical activity of biceps femoris (P=0.021), semitendinosus (P=0.046) and erector spinae muscles (P=0.039). 

 Both standard and modified NHE are effective in preventing hamstring injury by increasing the electrical activity of the Biceps femoris and Semitendinosus, but the modified NHE is more effective in prevention of injury by changing the parameters of NHE and increasing the training load.

Athletic groin pain (AGP) is one of the most common injuries among athletes. It causes the use of compensatory mechanisms to adjust pain and affects lumbar-pelvic and hip movements, which leads to prolonging the pain healing process. This study aims to compare the timing of electromyographic activity in selected lumbar-pelvic muscles during a cross-cutting maneuver in football players with AGP and healthy peers.

In this quasi-experimental study, 28 football players in the second division league of Iran participated in two groups of control (n=14) and AGP (n=14). The timing of electromyography activity in the gluteus medius, adductor longus, rectus abdominis, multifidus, and transverse abdominis/internal oblique during a cross-cutting maneuver was recorded bilaterally with a one-minute interval since the time of foot-ground contact in two groups.

Results:

 The time for the onset of activity in the gluteus medius muscle in the dominant foot (P=0.033) and in the multifidus muscle in the opposite foot (P= 0.023) for the AGP group was significantly delayed in compared to the control group; however, the rectus abdominis muscle in the dominant foot was activated significantly earlier and before the heel contact with the ground (P=0.001).

 It seems that AGP changes the timing of electromyographic muscle activity in football players. These changes and compensatory mechanisms may put the athletes at the potential risk of lower limb injuries. It is recommended to find solutions to reduce the effects of AGP and the resulting changes.

Attention deficit/hyperactivity disorder is a common neurocognitive disorder that has been one of the most extensive research fields and also one of the largest sources of referrals to mental health centers in recent decades. The aim of the present study was to compare muscular frequency content in healthy children and children with overactive/attention deficient during walking.

The present study was a case-control type. The statistical sample included 20 boys with attention deficit/hyperactivity disorder and 20 healthy boys with an age range of 7-9 years, who were selected by convenient sampling method. A bipolar EMG system with 8 paires of electrodes was used to record EMG data of tibialis anterior, medial gastrocnemius, vastus medialis, vastus lateralis, rectus femoris, biceps femoris, and gluteus medius while walking. Independent sample t-test was used for statistical analysis.

The results indicated that the frequency of the medial gastrocnemius muscle during the loading phase is higher in the hyperactive group than the healthy group (p<0.001). Also, results demonstrated that frequency continent of vastus medialis during loading phase and frequency continent of gluteus medius during mid-stance phase were lower in overactive group than healthy group (p<0.001).

Lower vastus medialis and gluteus medius activities in overactive group may be due to weal postural control in sagittal and frontal planes.

Background and Aims :

Urinary incontinence (UI) has been known as one of the clinical manifestations of pelvic floor muscle (PFM) instability; however, limited research has been published on PFM function in patients with different types of UI. This study aimed to compare the PFM function of the continent women and women with Stress urinary incontinence (SUI) and overactive bladder (OAB).

Methods :

This cross-sectional comparative study was performed on 30 women, 10 continents, 10 SUI, and 10 OAB, with a mean age of 42.67±4.77 years. PFM function was assessed using manual muscle testing, a perimeter, and surface electromyography. Data analysis was performed using SPSS software and the level of significance was considered as P≥0. 05.

Results :

There was no significant difference in the PFM function, strength, and electromyographic activity between SUI and OAB patients.  However, it decreased in both groups compared to the healthy group (P=0.001). Also, a strong correlation was found between clinical examination, a perimeter, and electromyography (r=0.82, P=0.0001).

Conclusion:

 This study revealed that the PFM function was impaired in both groups of women with SUI and OAB. Also, both manual examination and the perimeter can be used as clinical methods in evaluating PFM function.

The manufacturing, service professions, and other occupations commonly require their employees to spend more than 2 hours of their workday in an upright position which can potentially cause temporary or permanent health effects. The objective of this study is to determine the effect of anti-fatigue mats on leg muscle discomfort and muscle activity due to prolonged standing.

A total of 100 workers were involved in the study. The control and experimental group stood for 2 hours in a controlled room with or without the anti-fatigue mat while sorting an assortment of mixed items.  Borg’s scale questionnaire and EMG signals were used to monitor the muscle discomfort and activity of the respondents.

The discomfort ratings and muscle activity in the experimental group were always at lower levels compared to the control group, which meant there was a reduction in mean perceived exertion rating for the knees, calves, and feet, i.e., 1.8, 2.5 and 2.6, respectively. The results showed that there was a statistically significant (P < 0.001) difference in the Borg’s scale of discomfort ratings and leg muscle activity between both groups.

The anti-fatigue mat can have a positive effect in preventing muscle discomfort and reduce muscle activity among the respondents during prolonged standing.

The aim of this study was to investigate the effect of two types of eccentric and concentric training programs on neuromuscular adaptations of quadriceps muscle.

For this purpose, 24 subjects including non-athlete boys in the age range of 19 to 27 years in Bojnourd were randomly divided into two groups: eccentric (12 people) and concentric (12). The eccentric exercise group performed knee flexion with one leg at 150% 1RM to the limit of fatigue and the concentric exercise group performed knee extension with one leg at 75% 1RM to the limit of fatigue for 8 weeks. Surface electromyographic signals were measured and recorded before and after eight weeks of training for both groups. Multivariate analysis of variance (M-ANOVA) was used to examine changes in EMG variables before and after training sessions, muscle and training group as dependent variables.

Multivariate analysis of variance showed an increase in conduction velocity of action potential in both eccentric and concentric training groups after eight weeks of training. However, the rate of acceleration of the action potential in the quadriceps muscle of the eccentric group is significantly higher than the concentric group.

In general, the eccentric exercise group showed a greater increase in electromyographic indices compared to the concentric exercise group, which is probably related to the application of central nervous system mechanisms to eccentric contractions.

Swallowing disorder is a common and constant problem in people with Down Syndrome. In experimental method electromyography can be used to evaluate Mastication . The aim of this study was to evaluate the electromyography of the masseter and temporal muscles during Mastication in 2 to 12 years old children with Down syndrome in Arak.

This is a descriptive-analytical and case-control study, that conducted with the purpose of electromyographic study of masseter and temporal muscles during Mastication  on 15 children from available 2 to 12 years old Down Syndrome and 15 children that were matched according the method of person-to-person matching in terms of age and gender with samples with Down syndrome.

 In this study, conscious consent was obtained from all parents and no physical harm was inflicted on individuals.

About the comparison of the mean of amplitude (intensity) of electrical signal of muscle between two groups except right temporal muscle during Mastication  and about the mean of the mean frequency when Mastication  except for left temporal muscle, in other cases the difference was significant. In the case of comparing the median frequency of the electrical signal of the muscle in most muscles the difference was not significant.

 Mean amplitude (intensity) and frequency of the mean electrical signal of the muscle when chewing in most muscles was different between the two groups with Down syndrome and normal, but the differences in mean median frequency in most muscles were insignificant.

The movement pattern and coordination of patients with unilateral cerebral palsy when walking is different from that of healthy individuals. The aim of the present study was to compare the symmetry of trunk extensor muscle and hip and knee flexors in women with left unilateral cerebral palsy and healthy women when walking normally.

The research method was descriptive-comparative. The statistical population of the study included women with left unilateral cerebral palsy. By convenience by purposive sampling method, 12 patients aged 17 to 26 years as the left unilateral cerebral palsy group and 12 homogeneous healthy women as the control group. were chosen. Women with left unilateral cerebral palsy were referred by a physician at the Mehr Rehabilitation Center in Tabriz. Data collection instruments included demographic questionnaire, electromyograph and bipolar surface electrodes. The validity and reliability of the instruments have been confirmed in previous studies and in the present study it has been sufficientt. The method was that the intensity of electrical activity of the muscles that straighten the spine at the level of the third lumbar vertebra, right hip and biceps when walking at normal speed was recorded in women with unilateral left cerebral palsy and healthy homogeneous women. The signals were processed using OT Bio lab software. Data were analyzed in SPSS .22.

Women with left unilateral cerebral palsy had more electromyographic activity than healthy women on the affected side (P <0.05). Also, the normalized electromyographic activity of erector spine muscle in the intact side of cerebral palsy was higher than that of healthy individuals at the same side (P=0.001). In women with unilateral left cerebral palsy, asymmetric muscle activity was observed and a significant interaction was observed between the body side factor and the disease factor (P=0.040).

When walking, the intensity of electrical activity of the involved side muscles as well as the rectus muscle of the healthy lumbar spine was higher in women with unilateral left cerebral palsy than in healthy women, and women with unilateral left cerebral palsy showed asymmetric muscle activity. Therefore, in designing training programs for cerebral palsy patients, it is recommended to pay attention to the muscles of both involved and healthy sides.

The use of exoskeletons as a new ergonomics intervention to reduce musculoskeletal disorders risk factors and increase human performance has emerged in the fourth-generation industrial revolution. The aim of this study was to assess the cervical exoskeleton effect on the neck and shoulder muscles electrical activity.

In this experimental study, 14 male participants were asked to perform the simulated overhead work with and without using the cervical exoskeleton at two neck postural angles randomly. During the task, electromyography of the target muscles in the neck and shoulders was recorded. In addition, at the end of each task, participants completed a perceived discomfort questionnaire. Electromyographic signals were processed with Matlab 2017b software and the level of the electrical activity of the target muscles was normalized to the maximum muscle activity. Data analysis was performed using Random intercept mix model in STATA 14 software.

Mean perceived discomfort in the neck and shoulders regions significantly reduced by the exoskeleton device, but there was no statistically significant difference in other areas. Also, the mean activity level of sternocleidomastoid and splenius capitis muscles on the right and left was significantly decreased during the use of the cervical exoskeleton. However, this difference showed a significant increase in trapezius muscles.

The use of the neck exoskeleton was associated with a reduction of muscle electrical activity and the perceived discomfort in the neck area. These results may be related to transferring neck and head weight by the exoskeleton retaining jack during the neck extension to other areas of the body. The exoskeleton design did not provide support for the shoulder and arm area, which explains the reason for the non-significant results in the shoulder area. Using the exoskeleton with the additional support in shoulder area could be considered as an ergonomic intervention in such overhead works.

Harmful factors in the workplace such as noise and heat stress can have adverse effects on muscle activity. This study was performed to investigate the effect of simultaneous exposure to noise and heat stress on the activity level of biceps and flexor muscles.

This experimental study was performed on 24 male students in laboratory conditions. Participants in three groups exposure to SPL of 75, 85 and 95 dBA and WBGT =22, 30 and 35°C randomly. During light manual activity, the activity level of biceps and flexor muscles was measured in a sitting manner using surface electromyography. Normalized RMS (Root Mean Square) of muscles was used to compare the level of muscle activity in different conditions. ANOVA test was used to examine the relationship between variables.

The mean (SD) age of the study participants was 21±1.6 years. Based on the muscle activity WBGT=30°C and SPL=85 dB were defined as border points in changes of biceps activity. The highest and lowest levels of flexor muscle activity were observed at SPL of 75 and 95 dB, respectively. The interaction between noise and heat stress exposure show that exposure to both factors causes significant changes in muscle activity levels (P.value<0.05).

Exposure to noise and heat stress in the workplace affects the function of the biceps and flexors muscles. To more accurately determine the effects of noise exposure and heat stress on muscle activity, further studies are recommended.

Benches play a basic role in students sitting in the correct posture for a long period. The purpose of this study was to investigate the effect of ergonomics of common school benches on the electrical activity of selected muscles of healthy female students or with lumbar lordosis.

For this purpose, 24 students with an average age of 10.26±1.78 years were selected and divided into two groups of 12 healthy subjects or with lordosis by convenience sampling. The students were sat down on two types of common benches in the school. At the beginning of sitting, a 30-second signal was taken from their selected muscles (rectus abdominis, spinal extensors, rectus femoris and biceps femoris), then a half-hour educational video was shown to them, and at the end, a 30-second signal was taken from their muscles. Statistical analysis of covariance was used to analyze the data.

There was a significant difference in the electrical activity of the muscles of healthy and lordosis students in attached benches in rectus femoris, biceps femoris and spinal extensors (p<0.001). There was no significant difference in rectus abdominis muscle (p<0.19). There was a significant difference in the electrical activity in the detached benches of the rectus femoris muscles (p<0.001). However, there was no significant difference in rectus abdominis (p<0.24), biceps (p<0.37) and spinal extensors (p<0.09).

The results showed that sitting on attached benches was more inappropriate for students with lordosis. Therefore, it is recommended to design ergonomics standard table and benches based to the students' static anthropometric measurements.

Low back pain is one of the most common musculoskeletal disorders leading to disability around the world. Several studies have suggested that prolonged computer/ laptop work contributes to the development of low back pain and discomfort. The results of the studies conducted on the association of back discomfort and muscle activity are contradictory. Thus, the present study aims to evaluate the relationship between the activity level and relative rest time of the trunk muscles with back discomfort while working with a laptop in a sitting position.

First, 20 young healthy males performed laptop work including mouse work and typing in conventional and ergonomic setups. In the ergonomic setup, the screen height and keyboard placement were specifically adjusted for each individual. In addition, the electromyographic activity of the lumbar erector spinae, right and left multifidus and transversus abdominis, rectus abdominis, external oblique muscles, and the posture of the lumbar spine were recorded in the first and last two minutes of an 8-min task. After the end of each task, the participants scored their back discomfort.

The results showed a positive correlation (r=0.57 and p=0.009) between back discomfort and the EMG amplitude of the lumbar erector spinae muscle. In addition, back discomfort was negatively correlated to the relative rest time of the multifidus muscle (r=0.50 and p=0.023), and a positive correlation was reported with the relative rest time of the transversus and rectus abdominis (r=0.47, p=0.039, and r=0.45, p=0.049, respectively).

The relative rest time of the trunk muscles may be a better index than that of the EMG amplitude to highlight the risk factors for back discomfort. However, a causative link between muscle activity and discomfort cannot be implied from this study. The current results do not undermine the role of other factors associated with the increased level of discomfort during sitting.

Lumbar disc herniation is one of the most common types of low back pain and researchers are interested in novel exercises in treatment of this condition. The aim of this study was to investigate the effect of suspension exercises on electromyography in men with disc herniation.

Twenty two men with disc herniation in Rasht participated in this clinical trial in 2020 and were randomly divided into two groups of suspension exercises (n=12, age: 34.25±8.81, BMI: 24.02±01.7) and control (n=10, age: 34.4±6.67, BMI: 23.1±76.45). Before and after an intervention period, the electrical activity of rectus abdominis, internal and external oblique and erector spinae muscles were measured by electromyography and abdominal muscle strength was investigated using straight leg raising test. The intervention period consisted of 8 weeks of suspension exercises, while the control group was only followed up. Paired sample t-test and analysis of covariance were used for intragroup and intergroup comparisons, respectively.

Electromyography of four muscles and strength test showed significant improvements in post-test compared to pre-test in intervention group (P<0.05) while no significant change was observed in control group (P˃0.05). Patients who did suspension exercises were found with significant improvements in muscle electromyography compared to the control group (P<0.05), but no significant difference was observed in abdominal muscle strength test (P˃0.05).

In current study, suspension exercise improved core muscle activation and abdominal muscle strength, so, it could be considered in rehabilitation of low back pain caused by disc herniation.

The present study was designed to evaluate the pattern of lower limb muscle activity during the gait initiation in patients with multiple sclerosis (MS) compared with healthy individuals.

16 female MS patients and 16 age, weight, high and sex-matched healthy subjects were selected by simple non-random sampling participants. Subjects also underwent a thorough neurological examination to assess their disability using the Expanded Disability Status Scale (EDSS≤4.5). Surface electromyography of tibialis anterior, soleus, biceps femoris, gluteus medius, rectus femoris were recorded during gait initiation. The activity of muscles including recruitment order, reaction time, and root mean square (RMS) were processed and compared in two groups.

In the patients group muscles had a significant delay (P<0.02) compared to healthy group. Examination of the RMS ratio of each muscle to the total muscles in the two groups showed that the soleus and gluteus medius muscles were significantly different between the two groups (P<0.05).

Surface electromyography activity showed that the recruitment order was the same in the healthy and multiple sclerosis patients. However, decreasing the share of soleus and gluteus medius muscle co-contraction relative to other selected lower limb muscles in the patients may be useful in examining muscle synergies at the gait initiation in future studies.

Since fatigue is known as a common phenomenon during exercise and it is hypothesized that it often impairs motor function and causes various injuries, the purpose of the present study was to determine the effects of local and global fatigue on the myoelectric variables of selected lower limb muscles in healthy young men active in single leg jump-landing task.

A total of 20 able-bodied healthy young males participated in the current quasi-experimental study. Wingate and Bruce tests were used to create local and global fatigue, respectively. Electrical activities of selected lower limb muscles (Gluteus Medius, Vastus lateralis, Tibialis Anterior, Peroneus Longus, Gastrocnemius and soleus muscles) were recorded using electromyography device, and Analysis of Variance (ANOVA) with repeated measures tests were used for data analysis. The significance level was set at P≥0.05.

The results showed a significant difference between the effects of local and global fatigue on the mean normalized middle serine muscle activity (P=0.046) and medial Gastrocnemius muscle midline frequency (P=0.019). However, there was no significant difference between mean and maximum normalized activity and frequency of middle serine, Vastus lateralis, anterior tibia, fibular longus, and soleus (P<0.05).

According to the findings of the present study, it seems that the effects of the types of local and global fatigue on lower limb muscle performance during single jump-landing exercise are similar.

Sewing is one of the occupations where the prevalence of musculoskeletal disorders is high. Sewing conditions at the workstation have made tailors face musculoskeletal injuries in various areas of their body, particularly pain in the neck, shoulder, and upper back and even waist. The purpose of this study was to evaluate the effect of a workstation designed for tailoring considering the results of previous studies on the neck and shoulder muscles of users by electromyography.

In this interventional analytical study, the activity levels of four superficial neck and shoulder muscles (meridian, anterior deltoid, middle deltoid, posterior deltoid) were Electromyographed on 33 participants (male and female) at two new and custom designed workstations.

There was a significant difference in the amount of muscle activity in the new and existing workstations (P<0.05). But there was no significant difference between the different modes of the new workstation.

All four muscles were less active at the new workstation than the conventional workstation, meaning that the designed workstation was able to reduce neck and shoulder muscle activity during work.