Left Trapezius Research Articles

Electromyographic analysis of bilateral upper trapezius muscles at different levels of work-pace among sewing machine operators

Workers are driven to work faster in the industrial work environment to meet high productivity targets. An increased work pace leads to increased muscle activation. However, the effect of work pace on bilateral upper trapezius muscles during sewing machine operation in an industrial work environment has not been thoroughly investigated in experimental studies. Therefore, this research aims to conduct an experimental study to analyze the bilateral upper trapezius muscle activity of industrial sewing machine operators at different levels of work pace. Thirty subjects (15 males, and 15 females) continuously performed the sewing operation for two hours in an industrial work environment. Experiments were conducted for two levels of work pace i.e. low pace (100% of standard cycle time) and high pace (120% of standard cycle time). Electromyographic signals were recorded from the bilateral upper trapezius muscles. The EMG amplitude (RMS) among the muscles was computed. A statistically significant (p < 0.05) increase in muscle activity was observed with an increased work pace. In this study, right upper trapezius muscle activity increased by 30.4% during high work pace tasks compared to low pace, while the left upper trapezius showed a 24.12% increase. The right upper trapezius showed a mean difference of 0.696 (%MVC), and the left upper trapezius showed 0.399 (%MVC), both indicating greater activity during high-pace tasks. The increase in muscle activity with time indicated the presence of muscle fatigue among sewing machine operators. Furthermore, higher muscular activity was observed among females than males. This research highlights the critical need to balance productivity goals with the health and safety of workers, reducing the risk of muscle fatigue and associated work-related musculoskeletal disorders.

Inferior Trapezius Muscle Agenesis and Scapular Dyskinesis in a 58 Year-Old Black Male Donor: A Cadaveric Case Report

A functionally significant abnormality was observed in a 58 year-old Black male donor with a cause of death of thyroid cancer. He exhibited left inferior trapezius muscle agenesis as well as scapular dyskinesis. The left scapula is shown pressing into the adjacent vertebral bodies of C7 and T1, which resulted in deviations in the location of the left semispinalis capitis, semispinalis cervicis, and splenius cervicis muscles. This resulted in compromise of the left levator scapulae muscle. It is suspected that these abnormalities would have resulted in functional limitations in arm movement, particularly in adduction. A literature review was completed to understand the significance of these abnormalities.

Effect of scapular posterior tilting exercise on scapular muscle activities in men and women with a rounded shoulder posture

Round-shoulder posture (RSP) is a common postural condition, characterized by protraction, downward rotation, anterior tilting and internal rotation of the scapula. RSP can lead to shoulder dysfunction. Different methods have been proposed for rehabilitating and correcting the altered posture in RSP including stretching, strengthening exercises, and shoulder brace or taping. However, the findings are controversial and studies are ongoing to develop more effective method. The present study is aimed at investigating the effects of scapular posterior tilting (SPT) exercise in different support positions on scapular muscle activities in men and women with RSP. In a prospective observational clinical study, we assessed demographic, basic clinical parameters and study variables of the subjects with RSP (n = 20) (men/women = 9/11) attending Daegu University in Gyeongsan, South Korea. To do so, we compared electromyographic (EMG) activities of lower trapezius and serratus anterior muscles between men and women with RSP during SPT exercise on four different support surfaces to determine any difference in the EMG activities. The results revealed that women showed significant differences in EMG activities in the lower and left upper trapezius and serratus anterior muscles, while men showed significant differences in EMG activity only in the lower trapezius muscle during SPT exercise on four different surfaces (P < 0.05). The post-hoc analysis revealed significantly greater EMG activity values in the lower trapezius and serratus anterior muscles during SPT exercise on the upper body unstable surface and whole-body unstable surface (p < 0.05). Independent t-tests after the Bonferroni correction showed no significant differences in muscle activities between men and women on the four different surfaces (p > 0.0125).

Exploring the link between occupationally relevant whole body vibration and headache and neck pain: is elevated muscle tension an intermediary factor?

Whole body vibration (WBV) is linked to short- and longer-term adverse health outcomes, including cognitive impairment, stress and memory loss, loss of balance, reduced proprioception, visual and vestibular disturbances, gastrointestinal problems, and musculoskeletal disorders. Epidemiological evidence supports the link between WBV and headache and head discomfort, but few experimental studies have examined this relationship, particularly with increased muscle tension, as an intermediary. This study aimed to investigate the relationship between muscle tension and vibration intensity, between perceived neck pain and headache/head discomfort and vibration intensity, and between muscle tension and reported neck pain and headache symptoms from simulated WBV based on field measurements of all-terrain vehicle operation on farm terrain. We observed significantly higher electromyography amplitude in the High condition (equivalent to EU Directive's Exposure Limit Value) compared to both Low (equivalent to EU Directive's Exposure Action Value) and Control (quiet sitting) conditions at the left upper trapezius muscle but there were no significant time effects. Neck pain and headache/head discomfort significantly increased after both Low (91% increase from baseline) and High (154% increase from baseline) vibration conditions but there were no significant differences between conditions. Based on simple regression modeling, the relationship between muscle activity and neck pain or headache was very weak (R2 = 0-0.093). Given the possibility of multiple factors contributing to headache symptoms, future research should not only consider the role of muscle tension but also sensory conflict, excessive noise, biodynamic responses, and a combination of these factors.

Prevention of Musculoskeletal Injuries in Gastrointestinal Endoscopists

Gastroenterologists are exposed daily to musculoskeletal (MSK) stress during upper and lower gastrointestinal endoscopy, both during routine endoscopies and during long, demanding therapeutic procedures. There is evidence that endoscopy-related MSK injuries are becoming more common, particularly in the back, neck, shoulders, elbows, and hands. The aims of this study were to identify the most stressed muscle groups during endoscopy; to measure their activity using surface electromyographical (EMG) sensors; to detect areas of muscle overload; and to identify the number of microbreaks taken in specific muscles. Furthermore, we measured differences in the loading of these muscle groups with and without the use of special support systems such as a belt-like holder. Measurements were performed on 15 subjects (7 experienced endoscopists and 8 non-endoscopists). Due to this small sample size, inside each group, we achieved inconclusive results regarding statistically significant differences in different muscle groups. We increased the sample size by comparing all participants with and without the belt support system, disregarding their endoscopic background. There was a statistically significant difference (p &lt; 0.05) in muscle tension and in levels of microbreaks in the muscles of the left forearm, biceps, and trapezius muscles. No statistically significant difference was observed in the muscle tension and level of microbreaks in the left deltoid muscle (p &gt; 0.05). We hypothesize that the increased level of muscle loading and decreased level of microbreaks in the deltoid muscle are due to different muscle activity and different shoulder movements. Additionally, the deltoid muscle is not connected to the kinetic chain of body posture and stabilization. It is our belief that MSK injuries in gastrointestinal (GI) endoscopy can be prevented with the use of a belt-like support system.

A Comprehensive Analysis of Trapezius Muscle EMG Activity in Relation to Stress and Meditation

Introduction: This study analyzes the efficacy of trapezius muscle electromyography (EMG) in discerning mental states, namely stress and meditation. Methods: Fifteen healthy participants were monitored to assess their physiological responses to mental stressors and meditation. Sensors were affixed to both the right and left trapezius muscles to capture EMG signals, while simultaneous electroencephalography (EEG) was conducted to validate cognitive states. Results: Our analysis of various EMG features, considering frequency ranges and sensor positioning, revealed significant changes in trapezius muscle activity during stress and meditation. Notably, low-frequency EMG features facilitated enhanced stress detection. For accurate stress identification, sensor configurations can be limited to the right trapezius muscle. Furthermore, the introduction of a novel method for determining asymmetry in EMG features suggests that applying sensors on bilateral trapezius muscles can improve the detection of mental states. Conclusion: This research presents a promising avenue for efficient cognitive state monitoring through compact and convenient sensing.

Dynamic Reconstruction Using Accessory-innervated Pedicled Latissimus Dorsi Flap for Upper Trapezius Muscle Defect.

The upper part of the trapezius muscle attaches to the acromion and elevates the shoulder, so a defect in the trapezius muscle greatly impairs shoulder-brachial movement. We encountered a case in which the upper trapezius muscle was completely resected due to myxofibrosarcoma that occurred in the upper part of the left trapezius muscle, and reconstruction was performed using a pedicled latissimus dorsi flap with the accessory nerve transferred, resulting in favorable motor function. A 74-year-old woman developed myxofibrosarcoma in her left neck 1 year and 4 months ago, and underwent two surgical excisions at a nearby hospital. However, two months prior, she relapsed again, and was referred to our hospital, where she underwent submandibular lymph node dissection, wide tumor resection, and reconstruction using a latissimus dorsi flap. For latissimus dorsi myocutaneous flap transfer, the stump of the thoracodorsal nerve and accessory nerve were anastomosed to facilitate nerve transfer. Four months after surgery, she was able to raise her shoulder, and surface electromyography showed potentials comparable to her unaffected side. The innervated latissimus dorsi myocutaneous flap is frequently used for dynamic reconstruction of facial, brachialis, rectus abdominis, and deltoid muscles, but this is the first case report describing its use for dynamic reconstruction of the trapezius muscle.

The effect of myofascial techniques on the electrical activity of the neck muscles

Introduction. Research by foreign scientists often present the results of studies of the effects of specific osteopathic techniques on the body. Myofascial techniques are dynamic low-amplitude techniques in which the myofascial complex of tissues is rhythmically stretched in areas where their mobility is limited. In one study of paravertebral muscles using surface electromyography (sEMG) before and after myofascial techniques, a statistically significant (p&lt;0,05) decrease in their electrical activity was obtained. No publications devoted to the study of the effect of myofascial techniques on the electrical activity of the neck muscles were found.The aim is to study the effect of myofascial techniques on the electrical activity of the neck muscles in individuals with increased tone of these muscles.Materials and methods. A prospective study was conducted in the Department of Osteopathy of Mechnikov North-West State Medical University in which 30 apparently healthy volunteers who did not present active complaints, aged from 23 to 35 years, took part, with a median of 25 years. Inclusion criteria were palpation-determined increased tone of the sternocleidomastoid and upper trapezius muscles. Non-inclusion criteria were the presence of diseases and/or conditions that are an absolute contraindication to osteopathic correction, a history of neck injuries; taking medications that affect muscle tone at the time of the study; neuromuscular diseases. At the beginning of the study, all volunteers underwent palpation of the upper trapezius and sternocleidomastoid muscles on both sides. The degree of increase in muscle tone was assessed in points: 1 — weak; 2 — medium; 3 — strong; 0 — normal tone. Next, they underwent myofascial mobilization techniques: longitudinal and unilateral lateral mobilization of the soft tissues of the neck, separate mobilization of the sternocleidomastoid muscles. Before, immediately after, and three days after the session, muscle tone was recorded using surface electromyography (sEMG), which was performed on a wireless monitoring complex for electrophysiological signals «Kolibri» (OOO NMF «Neurotech», Russia). At rest, the average and maximum amplitude of electrical activity of the sternocleidomastoid and upper trapezius muscles was measured. The recording was made synchronously from the right and left sides of the body.Results. The sEMG indices of muscles with different tone based on the results of subjective assessment were statistically highly significant (p=0,0001). Moreover, according to the A(avg) indicator, the range diagrams either did not intersect or intersected only slightly. The electrical activity of the sternocleidomastoid muscles after myofascial mobilization techniques decreased statistically significantly and remained at the same level for 3 days (p=0,01). Such dynamics were observed in both the average and maximum amplitude of electrical activity. The amplitude of electrical activity of the right sternocleidomastoid muscle was slightly greater than that of the left (all subjects were right-handed), but these differences did not reach statistical significance (p&gt;0,05). After treatment, there was a trend towards a decrease in the asymmetry of electrical activity between the left and right sternocleidomastoid muscles, both middle and maximum, but these changes were not statistically significant (p&gt;0,05). The electrical activity of the upper part of the right trapezius muscle decreased statistically significantly after treatment and remained at this level for 3 days (p=0,01). The left trapezius muscle was excluded from the study due to technical reasons.Conclusion. The study showed that osteopaths (who are completing residency training in osteopathy) palpably distinguish between normal muscle tone and its increase in weak and moderate degrees. One session of myofascial mobilization techniques leads to a decrease in the tone of the sternocleidomastoid muscles and the upper part of the right trapezius muscle according to sEMG. Such changes occur immediately after the session and then persist for at least three days in young people with increased tone of these muscles. Surface electromyography can be used to objectively record and measure the results of specific osteopathic techniques. This is important for increasing the evidence of clinical research in osteopathy.

Assessment of the stiffness of the upper trapezius muscle in a group of asymptomatic people with cervical spine rotation asymmetry.

This study investigated the relationship between the stiffness of the upper trapezius muscle and the range of rotational movement of the cervical spine. A total of 60 right-handed asymptomatic students participated in the study. Participants (N = 22) characterised by asymmetry in rotational movements were selected for the experimental group. A difference of ≥10° between right and left rotation of the cervical spine was considered asymmetrical. The control group (N = 38) included participants whose rotation difference was < 10°. Belonging to the experimental or control group did not significantly differentiate trapezius muscle stiffness. The rotation side differentiated the stiffness of the right and left trapezius muscles only in the group of people with rotational movement asymmetry. There were high correlation coefficients between right cervical rotation and the stiffness of the muscle on the right side, and between rotation to the left and the stiffness of the muscle on the left side. There is a relationship between the stiffness of the right and left upper trapezius muscles and the range of right and left rotational motion of the cervical spine. Stiffness of the upper trapezius correlates more strongly with rotation to the side on which the muscle lies than to the opposite side. Increased stiffness of the upper trapezius muscle on the side of limited cervical spine rotation is likely to be determined by the muscle fibre stretching mechanism.

Evaluation of a passive arm-support exoskeleton for surgical team members: Results from live surgeries

Background: Musculoskeletal symptoms and injuries adversely impact the health of surgical team members and their performance in the operating room (OR). Though ergonomic risks in surgery are well-recognized, mitigating these risks is especially difficult. In this study, we aimed to assess the impacts of an exoskeleton when used by OR team members during live surgeries. Methods: A commercial passive arm-support exoskeleton was used. One surgical nurse, one attending surgeon, and five surgical trainees participated. Twenty-seven surgeries were completed, 12 with and 15 without the exoskeleton. Upper-body postures and muscle activation levels were measured during the surgeries using inertial measurement units and electromyography sensors, respectively. Postures, muscle activation levels, and self-report metrics were compared between the baseline and exoskeleton conditions using non-parametric tests. Results: Using the exoskeleton significantly decreased the percentage of time in demanding postures (>45° shoulder elevation) for the right shoulder by 7% and decreased peak muscle activation of the left trapezius, right deltoid, and right lumbar erector spinae muscles, by 7%, 8%, and 12%, respectively. No differences were found in perceived effort, and overall scores on usability ranged from “OK” to “excellent.” Conclusions: Arm-support exoskeletons have the potential to assist OR team members in reducing musculoskeletal pain and fatigue indicators. To further increase usability in the OR, however, better methods are needed to identify the surgical tasks for which an exoskeleton is effective.

Myotonometric Assessment of the Short-Term Effects of Manual Therapy on Upper Trapezius Myofascial Trigger Points

(1) Background: The aim of this study was to assess the short-term effects of one manual therapeutic intervention by quantifying the biomechanical and viscoelastic properties of upper trapezius myofascial trigger points. (2) Materials and Methods: Fourteen volunteer subjects (six males and eight females) aged 22 to 47 years, with myofascial trigger points in the upper trapezius muscle on both sides participated in this study. The biomechanical and viscoelastic properties were assessed with the Myoton Pro (Estonia) before the application of manual therapy (T0), then immediately after the end of the treatment session (T1) and finally one hour after the end of the treatment session (T2) in order to evaluate the effectiveness of the applied treatment. (3) Results: The oscillation frequency in the right upper trapezius muscle was significantly lower than in the left upper trapezius muscle both immediately, after the end of the manual therapy session (p = 0.03) and one hour after the session (p = 0.03). Regarding the state of tension in the right upper trapezius, a significant decrease was observed one hour after treatment compared to baseline (p = 0.04). In the left upper trapezius muscle, one hour after treatment, the dynamic stiffness value was significantly higher than in the right upper trapezius (p = 0.01). (4) Conclusions: Myotonometry could become a useful method to assess the biomechanical and viscoelastic properties of muscles, identifying trigger points and monitoring the results of therapy.

Редкая причина одностороннего паралича гортани

A clinical case of unilateral paralysis of the larynx due to the Collet — Sicard Syndrome is described. A patient with hoarseness due to paresis of the left half of the larynx of unknown origin underwent a comprehensive examination: CT scan of the neck, chest, MRI of the brain, ultrasound examination of the brachiocephalic arteries, consultation with a neurologist. Paresis of the left half of the larynx, left deviation of the tongue and uvula to the right, paresis of the left trapezius and sternocleidomastoid muscle, a decrease in the volume of the left half of the tongue with single fasciculations were diagnosed. Symptoms of damage to the IX, X, XI, and XII cranial nerves on the left were revealed, which corresponds to the syndrome of damage to the nerves of the caudal group in the jugular foramen. The disease arose against the background of acute bronchopneumonia. Treatment and phonopedic rehabilitation were carried out. During therapy, a complete restoration of the vocal cord palsy and the disappearance of neurological symptoms were noted. Timely diagnosis and proper treatment of a patient with Collet — Sicard Syndrome demonstrates good functional results.

The Effect of Shoulder Muscle Succinylcholine Injection on Foreleg Raising Power (Sion`s Local Paralysis): A second experiment

Background\n Sion\'s local paralysis (SLP) is the local application of neuromuscular blocking agents (NMBAs) to achieve local paralytic effects while avoiding the side effects of systemic paralysis.\n\nObjective:\nWe examined the changes in foreleg raising power after Sion\'s local paralysis (SLP) in an advanced porcine model.\n\nMethods:\nThis was a randomized, double blind, placebo-controlled, porcine study. Ten male Korean native Jeju black pigs were randomized into an intervention group (n = 5) and a control group (n = 5). The injection points were in the middle of the left trapezius muscle and middle of the left deltoid muscle, as described in a previous study. The control group received 2 ml normal saline (NS), with 1 ml injected at each point. The intervention group received 0.5 mg/kg succinylcholine diluted to 2 ml in NS, and 1 ml was injected at each point. The height of the left foreleg from the baseline (experimental table) was measured. We measured foreleg height and oxygen saturation at −4, −2, 0, +2, +4, +6, +8, +10, +20, +30, and +60 min. Unlike previous experiments, the study animals received pain stimuli before each measurement using the Kelly forcep that were clamped on their dew claws.\n\nResults:\nAfter SLP, foreleg height values immediately declined in the intervention group by approximately 20%. This effect was sustained for a few minutes. After satisfying the sphericity assumption (P-value = 0.015), repeated-measures analysis of variance (ANOVA) identified a significant main effect of group (P-value = 0.039) and time (P-value = 0.001) at 0, 2, 4, and 6 min. Hypoxic events were not observed.\n\nConclusions\nCompared with the control group, the foreleg raising power in the intervention group decreased significantly after SLP, without hypoxia, in an advanced pig model.

Akıllı Telefon Bağımlılığına Bağlı Boyun Ağrısında Kı̇nesyolojik Bandın Ağrı ve Trapez Kasının Mekanı̇k Özellı̇klerı̇ Üzerı̇ne Akut Etkı̇sı̇

This study aimed to assess the short-term effects of inhibitory kinesiologic tape (KT) and sham tape on neck pain and muscle tone in individuals with smartphone addiction. Forty-two healthy participants were randomized to receive either KT or sham tape application to their upper trapezius muscle (UTM). Smartphone addiction was assessed using the Smartphone Addiction Scale (SAS), and pain severity was measured using the Visual Analogue Scale (VAS). Muscle tone and stiffness were evaluated using a myotonometer. No significant differences were found in pain or muscle mechanical properties between the groups after treatment. However, KT recipients had significantly higher tone and stiffness in their left trapezius muscle compared to their right trapezius muscle (p &lt; 0.05). Additionally, right trapezius stiffness was significantly higher in participants with SAS scores of 100 points or more compared to those with SAS scores below 100 points (p &lt; 0.05). Finally, left trapezius elasticity increased significantly in participants with SAS scores of 100 points or more (p &lt; 0.05). Overall, the study findings suggest that short-term application of KT to the UTM may reduce neck pain in individuals with smartphone addiction.

Global Postural Exercise Program Versus Muscle Energy Technique on Management of Temporomandibular Joint Disorders

Objective: To compare between the effects of global postural exercise program against muscle energy technique on maximum pressure pain threshold, maximal mouth opening range of motion as well as quality of life on patients with temporomandibular joint disorders. Methods: 63 patients having temporomandibular disorders were randomized into three groups; Group (A) were given global postural exercise program in addition to conventional therapy (in the form of LASER and hot packs), Group (B) were given muscle energy technique as well as traditional therapy and the Group (C) control were given traditional therapy only. All patients were examined by the pressure algometer, paquimeter and Arabic version of Oral health impact profile 14 questionnaire as well as the duration of treatment were 6 weeks. Results: there were no significant statistical differences revealed pretreatment for all variables, Mmaximal mouth opening range of motion, quality of life scale, as well as pain) as in mouth opening (P=0.130), OHIP-14 (P=0.642), right temporalis muscles (P=0.384), left temporalis muscles (P=0.930), right masseter muscles (P=0.790), left masseter muscles (P=0.064), right trapezius muscle (P=0.403), and left trapezius muscle (P=0.058) among groups where (P&gt;0.05). While after-treatment and follow up , there were significant statistical differences were P value was (P&lt;0.05), in mouth opening (P=0.0001 and P=0.0001, respectively), OHIP-14 (P=0.0001 and P=0.0001, respectively), right temporalis muscles (P=0.035 and P=0.020, respectively), left temporalis muscles (P=0.0001 and P=0.0001, respectively), right masseter muscles (P=0.001 and P=0.0001, respectively), left masseter muscles (P=0.004 and P=0.035, respectively), right trapezius muscle (P=0.0001 and P=0.0001, respectively), and left trapezius muscle (P=0.031 and P=0.001, respectively) between groups. Conclusion: Both Muscle energy technique and global postural exercise program improved mouth opening, pressure pain threshold, as well as quality of life in temporomandibular joint disorders patients, with the superiority of muscle energy technique over global postural exercise program.

Changes in Neck and Shoulder Muscles Fatigue Threshold When Using a Passive Head/Neck Supporting Exoskeleton During Repetitive Overhead Tasks.

This study aimed to investigate the effects of a head/neck supporting exoskeleton (HNSE) on the electromyographic fatigue threshold (EMGFT) of the neck and shoulder muscles during a simulated overhead work task. Overhead work is a well-known risk factor for neck and shoulder musculoskeletal disorders due to the excessive strain imposed on the muscles and joints in these regions. Fourteen healthy males performed a repetitive overhead nut fastening/unfastening task to exhaustion while wearing and not wearing the HNSE at two neck extension angles (40% and 80% of neck maximum range of motion). Electromyographic signals were continuously recorded from the right and left sternocleidomastoid (SCMR, SCML), splenius capitis (SCR, SCL), upper trapezius (UTR, UTL), and anterior deltoid (ADR, ADL) muscles. The normalized electromyographic amplitude (nEMG) data was time normalized, and a bisegmental linear regression was applied to determine the muscle fatigue break point. The results showed a significant increase in fatigue threshold time in the SCMR (p < .001), SCML (p = .002), and UTR (p = .037) muscles when the HNSE was used. However, the EMGFT times for the right and left deltoid and left trapezius muscles showed a nonsignificant reduction due to the head/neck support exoskeleton use. In addition, the neck extension angle did not reveal a significant effect on muscles' EMGFT time. Overall, the findings confirmed a significant delay in fatigue onset in sternocleidomastoid muscles, as measured by the electromyographic fatigue threshold. This finding suggests that the HNSE can be an effective ergonomic intervention for reducing the risk of musculoskeletal disorders in overhead workers. However, further studies are needed to investigate the effect of the HNSE at other neck extension angles and more realistic tasks to ensure the generalizability of our results. The present findings emphasize the application of the fatigue onset time to evaluate the effectiveness of ergonomic interventions, including exoskeletons, which can subsequently be utilized to alleviate postural demands and reduce the risk of musculoskeletal disorders.

Cervical Impairments in Subjects with Chronic Migraine: An Observational Study.

The aim of this investigation was to compare the thickness of the deep local muscles in the neck region, as well as local and widespread sensitivity and functionality, between individuals with migraine and healthy control subjects. An observational study was carried out in accordance with the STROBE statements. The flexor longus colli and multifidus, two neck-stabilizing muscles, were measured using B-mode ultrasound imaging. The upper trapezius, masseter, temporalis, anterior tibialis, and median nerve all underwent bilateral pressure-pain threshold (PPT) assessments. The statistical program SPSS 29.0 was used to implement the Mann-Whitney U test and Chi-squared test. Spearman Rho was utilized to establish the correlations between the variables. Sixty participants were enrolled in the study. The subjects, who were matched in terms of age, gender, and body mass index (BMI), were equally divided into migraine and control groups. No significant differences between the groups were found in the multifidus CSA regarding both sides at rest (right: p = 0.625; left: p = 0.203). However, in contraction, the multifidus CSA showed a significant decrease on the left side in the patients with migraine compared to the controls (p = 0.032), but no significant differences were found in the right multifidus CSA in contraction between the two groups (p = 0.270). In comparison to the healthy volunteers, the migraine sufferers showed a substantial reduction in CSA in the longus colli muscle on both the left side (p = 0.001) and the right side at rest (p = 0.003), as well as in the CSA of the left longus colli in contraction (p < 0.001). Furthermore, the migraine patients showed significantly lower PPT compared to the healthy subjects in local and widespread areas bilaterally. All the parameters revealed higher sensitization in the migraine group in the following areas: the right and left temporal regions (p < 0.001), the right and left upper trapezius (p < 0.001 and p < 0.01, respectively), the right and left masseter muscles (p < 0.01), the right and left median nerves (p < 0.001 and p < 0.01, respectively), and the right and left anterior tibialis muscles (p < 0.001). In terms of the craniocervical flexion test (CCFT), the migraine patients demonstrated significantly lower values than the healthy subjects (p < 0.001). A moderate positive correlation was noted between the PPT in the right temporalis muscle and that in the left longus colli and the right multifidus in contraction. The PPT in the right temporalis muscle also exhibited a positive correlation with the CCFT, although this correlation was low. Between the PPT values, the upper trapezius on both sides showed a moderate positive correlation with the median nerve bilaterally. This research suggests that individuals with migraine may experience local and widespread pain sensitization. A decrease in functionality due to the low muscle endurance of the deep cervical muscles is also accompanied by low values of muscle thickness in contraction. These findings may help to select more accurate treatment approaches for patients with migraine.

Immediate effect of virtual reality intervention on task related neck pain and muscle fatigue in dentists

Background: Dentistry requires long hours of static body postures while executing activities in which permanently forced loads influence the musculoskeletal system. Methods: 25 dentists were recruited where neck pain or fatigue was assessed subjectively using NRS and Borg CR10 scale respectively and the pain pressure threshold of the upper trapezius muscle was assessed objectively using a handheld algometer pre- and post- intervention. Mobile VR game- Froggy VR was administered as a virtual reality. Results: A Wilcoxon signed rank test showed a statistically significant reduction in the intensity of task related neck pain and fatigue post VR intervention with Z-score=-4.549, n=38, p&lt;0.001 and Z-score=-4.588, n=38, p&lt;0.001 respectively. Also, there was a statistically significant increase in the pain pressure threshold of the right and left upper trapezius muscle post VR intervention with Z-score=-4.937, n=38, p&lt;0.001 and Z-score=-4.512, n=38, p&lt;0.001 respectively. Conclusions: Virtual reality intervention led to an immediate reduction in task-related neck pain and muscle fatigue among dentists with an immediate reduction in pain sensitivity of the upper trapezius muscle in dentists.

Muscle fatigue during assisted violin performance

Muscle fatigue is a primary risk factor in developing musculoskeletal disorders, which affect up to 93% musicians, especially violinists. Devices providing dynamic assistive support (DAS) to the violin-holding arm can lessen fatigue. The objective was to assess DAS effects on electromyography median frequency and joint kinematics during a fatiguing violin-playing task. Fifteen university-level and professional violinists were equipped with electromyography sensors and reflective markers to record upper-body muscle activity and kinematics. They played G scales with and without DAS until exhaustion. Paired t-tests assessed DAS effects on delta (final–initial) electromyography median frequencies and joint kinematics. DAS prevented the median frequency decrease of left supraspinatus, superior trapezius, and right medial deltoid, and increases in trunk rotation, left-wrist abduction, and right arm-elevation plane. DAS effects on kinematics were marginal due to retention of musical performance despite fatigue. However, DAS reduced fatigue of several muscles, which is promising for injury prevention. Practitioner summary: Violinists are greatly affected by musculoskeletal disorders. Effects of a mobility assistive device on muscle fatigue during violin playing was investigated. The assistive technology slowed down the development of fatigue for three neck/shoulder muscles, making assisted musical performance a promising avenue to prevent violinists’ injuries.

The effect of shoulder muscle succinylcholine injection on the foreleg raising power: Sion's local paralysis

ObjectiveWe examined the change in foreleg raising power after Sion's local paralysis (SLP) with succinylcholine in the shoulder muscle. MethodsA randomized, double blind, placebo-controlled, porcine study was designed and performed at a research institution. Ten male Korean native pigs were randomized into an intervention group (n = 5) and a control group (n = 5). The injection points were in the middle of the left trapezius muscle and the middle of the left deltoid muscle. The control group received 2 ml normal saline (NS), 1 ml injected in each point. The intervention group received 0.4 mg/kg succinylcholine diluted to 2 ml in NS, and 1 ml was injected in each point. To represent the foreleg raising power, the height of the left forelegs from baseline (experiment table) was measured. We measured the foreleg height and oxygen saturation at −4, −2, 0, +2, +4, +6, +8, +10, +20, +30, and +60 min. ResultsAfter SLP, foreleg height immediately declined in the intervention group. It recovered slightly for a few minutes and declined from 4 to 8 min. In the control group, foreleg height was relatively similar throughout the study period. A repeated-measure analysis of variance revealed a significant group × time interaction (F10,80 = 2.37, P = 0.017), a significant main effect for group (F1,8 = 6.25, P = 0.037), and a significant main effect for time (F10,80 = 4.41, P < 0.001). Post hoc analysis demonstrated that the intervention group showed significantly less foreleg raising power than the control group at 0, 4, 6, 8, 20, and 30 min (P < 0.05). ConclusionsCompared with the control group, the foreleg raising power in the intervention group immediately decreased significantly and persisted for a period after SLP, without hypoxia, in a pig model.