Understanding the Effects of Physical & Psychosocial Stress, and Personality Type on Neck Muscle Load among Healthcare Workers

In spite of strong prevalence of neck and shoulder musculoskeletal disorders among health care workers, the effect of their routine work activities, which demands physical exertion and high cognitive load, on the loading of neck-shoulder musculatures is not clearly understood. Additionally, it is currently unknown as to how the internal loading of the neck-shoulder musculature caused by the external work-related factors is affected by the individual personality. The purpose of this study was to evaluate the musculoskeletal loading of neck-shoulder musculature when human participants performed physically and cognitively demanding exertions. The loading of neck-shoulder musculature was evaluated using objective and subjective assessment methods. Electromyography (EMG) of the neck-shoulder musculature was used as the objective assessment method, whereas NASA-TLX scores were used as the subjective assessment method. Individual personality types were determined using MBIT personality test. Twenty (18 males and 2 females) participants were recruited for data collection. Each participant performed two experimental sessions: Session 1 - physical exertion, participant performed 10 maximum static pulling exertions in semi standing posture simulating a bed-to-stretcher patient transfer task. Session 2 - physical and cognitive exertion, during this session, in addition to 10 static pulling exertions (same as session 1), the participant performed mentally demanding tasks such as memorizing and recalling a list of words. The activities of three major neck-shoulder muscles: upper trapezius, sternocleidomastoid, and cervical trapezius, were studied. Muscle activity data showed that the neck-shoulder muscles worked harder while performing a combination of physical and cognitive exertions than purely physical exertions. The effect of the loading of neck-shoulder muscles was found sensitive to the individual personality. In general for all the muscles, among the participants with feeling personalities, a higher increase in the activation level of muscles was observed. The knowledge gained from this study imply that investigations viewing the entire work system (the interaction of physical and psychosocial workplace issues, as well as individual factors) will most likely to derive the root causes of neck-shoulder MSDs among healthcare occupations

Neck Muscle Function and Adolescent Headache

Muscular function of the neck region may be of importance for the etiology of headache, especially of tension-type headache. However, very few data exist on the association of neck muscle function with different types of headache in adolescents. The main aim of the study was to examine the association of neck muscle function with adolescent headache. The associations between leisure time activities, endurance strength of the upper extremities (UE endurance) and mobility of the neck-shoulder region and adolescent headache were studied. In addition, the associations of force production, EMG/force ratio, co-activation and fatigue characteristics, and cross-sectional area (CSA) of neck muscles with adolescent headache were studied. The study is part of a population-based cohort study of 12-year-old children with and without headache. The study had five phases (years 1998-2003). At the age of 13 years, a sample of 183 adolescents (183/311) participated in endurance strength and mobility measurements of the neck-shoulder region. In addition, the type and level of physical and other leisure activity were elicited with open and structured questions. At the age of 17 years, a random sample of 89 adolescents (89/202) participated in force and EMG measurements of the neck-shoulder muscles. In addition, at the age of 17 years, a sample of 65 adolescents (65/89) participated in CSA measurements of the neck muscles. At the age of 13 years, intensive participation in overall sports activity was associated with migraine. Frequent computer use was associated both with migraine and tension-type headache. The type of sports or other leisure activity classified them on the basis of body loading was not associated with headache type. In girls, low UE endurance of both sides, and low cervical rotation of the dominant side, were associated with tension-type headache, and low UE endurance of non-dominant side with migraine. In boys, no associations occurred between UE endurance and mobility variables and headache types. At the age of 17 years, in girls, high EMG/force ratios between the EMG of the left agonist sternocleidomastoid muscle (SCM) and maximal neck flexion and neck rotation force to the right side as well as high co-activation of right antagonist cervical erector spinae (CES) muscles during maximal neck flexion force were associated with migraine-type headache. In girls, neck force production was not associated with headache types but low left shoulder flexion force was associated with tension-type headache. In boys, no associations were found between EMG and force variables and headache. Increased SCM muscles fatigue of both sides was associated with tension-type headache. In boys, the small CSA of the right SCM muscle and, in girls, of combined right SCM and scalenus muscles was associated with tension-type headache. Similarly, in boys, the large CSA of the right SCM muscle, of the combined right SCM and scalenus muscles, of the left semispinalis capitis muscle, of the combined left semispinalis and splenius muscles was associated with migraine. No other differences in the CSA of neck flexion or extension muscles were found. Differences in the neuromucular function of the neck-shoulder muscles were associated with adolescent headache, especially in girls. Differences in the cross-sectional area of unilateral neck muscles were associated with headache, especially in boys. Differences in the neuromuscular function and in the cross-sectional area of the neck muscles also occurred between different types of headache. It remains to be established whether the findings are primary or secondary to adolescent migraine and tension headache. Keywords: adolescent, cross-sectional area, electromyography, endurance strength, fatigue, force, headache, leisure time activity, migraine, mobility, neck muscles, tension-type headacheNiskalihasten toiminta nuorten päänsäryssä Niskalihasten toimintahäiriöillä voi olla merkitystä päänsäryn aiheuttajana, erityisesti tensiotyyppisessä päänsäryssä. Tutkittua tietoa niskalihasten toiminnan ja päänsäryn yhteydestä lapsilla ja nuorilla on olemassa erittäin vähän. Tutkimuksen päätarkoituksena oli selvittää niskalihasten toimintahäiriöiden yhteyttä nuoren päänsärkyyn. Tutkimuksessa tutkittiin vapaa-ajan harrastusten, niskahartiaseudun kestävyysvoiman ja liikkuvuuden sekä niskalihasten voiman, EMG/voimasuhteen, yhtäaikaisen aktivoitumisen, väsyvyyden ja poikkipinta-alan yhteyttä nuoren päänsärkyyn. Tämä tutkimus on osa väestöpohjaista 12-vuotiaiden päänsärkyisten ja päänsäryttömien lasten kohortti-tutkimusta. Tutkimus koostuu viidestä eri vaiheesta (vuodet 1998-2003). 13-vuotiaina 183 nuorta (183/311) osallistui niskahartiasedun kestävyyden ja liikkuvuuden mittauksiin. Lisäksi selvitettiin liikunnan ja muun vapaa-ajan harrastuksen sisältöä ja määrä avoimilla ja suljetuilla kysymyksillä. 17-vuotiaina 89 nuorta (89/202) osallistui niskalihasten voima- ja EMG-mittauksiin. Lisäksi 17-vuotiaina 65 nuorta (65/89) osallistui niskalihasten poikkipinta-alamittauksiin. Nuorten ollessa 13-vuotiaita, liikunnan harrastamisen intensiivisyys oli yhteydessä migreeniin ja tietokoneen runsas käyttö sekä migreeniin että tensiotyyppiseen päänsärkyyn. Liikunnan tai muulla vapaa-ajan harrastuksella, luokiteltaessa harrastukset kehon eri osien kuormittavuden suhteen, ei ollut yhteyttä päänsärkyyn. Tytöillä alhainen sekä hallitsevan että ei-hallitsevan puolen hartiaseudun lihaskestävyys ja alentunut niskan kiertoliike hallitsevalle puolelle olivat yhteydessä tensiotyyppiseen päänsärkyyn ja ei-hallitsevan puolen alhainen hartiaseudun lihaskestävyys migreeniin. Pojilla ei esiintynyt eroja lihaskestävyyden ja liikkuvuuden suhteen eri päänsärkyryhmissä. Nuorten ollessa 17-vuotiaita, tytöillä korkea EMG/voimasuhde vasemman puolen sternocleidomastoideus lihaksen (SCM, agonisti) EMG aktiivisuuden ja vastaavan niskalihasten maksimaalisen fleksiovoiman ja oikealle suunnatun maksimaalisen kiertovoiman välillä oli yhteydessä migreeniin. Lisäksi korkea oikeanpuolen niskan ojentajalihasten (CES, antagonisti) yhtäaikainen aktivoituminen maksimaalisen fleksio-voimantuoton aikana olivat yhteydessä migreeniin. Tytöillä niskalihasten voima ei ollut yhteydessä päänsärkytyyppiin, mutta alhainen olkanivelen fleksiovoima oli yhteydessä tensiotyyppiseen päänsärkyyn. Pojilla ei esiintynyt eroja niskalihasten voiman ja EMG-aktiivisuuden suhteen eri päänsärkyryhmissä. Sekä oikean että vasemman puolen SCM lihasten lisääntynyt väsyvyys oli yhteydessä tensiotyyppiseen päänsärkyyn. Pojilla oikean SCM lihaksen pieni poikkipinta-ala ja tytöillä oikean puolen yhdistetyn SCM ja scalenus lihaksen pieni poikkipinta-ala olivat yhteydessä tensiotyyppiseen päänsärkyyn. Vastaavasti pojilla suuret oikean puolen SCM lihaksen, oikean puolen yhdistetyn SCM ja scalenus lihaksen, vasemman puolen semispinalis capitis lihaksen, yhdistetyn semispinalis capitis ja splenius lihaksen poikkipinta-alat olivat yhteydessä migreeniin. Muissa niskalihasten poikkipinta-aloissa ei esiintynyt eroja ryhmien välillä tytöillä ja pojilla. Niska- ja hartialihasten toiminnan poikkeavuudet olivat yhteydessä päänsärkyyn, erityisesti tytöillä. Toispuoliset poikkeavuudet niskalihasten poikkipinta-alassa olivat yhteydessä päänsärkyyn, erityisesti pojilla. Niskalihasten toiminnassa ja poikkipinta-alassa esiintyi myös eroja päänsärkyryhmien välillä. Se, ovatko löydökset nuorilla päänsärkyä aiheuttavia tekijöitä vai seurausta päänsärystä jää selvitettäväksi.Siirretty Doriast

Smart system for aircraft passenger neck support

Air travel is becoming increasingly more accessible to people due to the availability of low cost air travel. However, long distance air travel is not a normal activity for human. During air travel, people experience different levels of physiological and psychological discomfort. The discomfort may affect the passenger’s health and feeling. With the rapid development of technology, the comfort of service has become an important issue. Nowadays, comfort is an attribute which is highly demanded by aircraft passengers. The comfort of aircraft passengers depends on different features and the cabin environment during air travel. Seat is one of the important features for the passengers and in which a passenger spends almost all their time during air travel. Different seat aspects have to be seen and taken into account in the comfort model. The research has five goals. First goal, literature research starts with the study on the state of the art and recent development of vehicle seat design which is available in current literature and products. The literature review gives a general idea about the research and the measurement method related to seating comfort and discomfort. Second goal, four surveys were conducted to identify the comfort factor of economy class aircraft passenger, body discomfort for truck driver, body discomfort for economy class aircraft passenger and relationship between seat location and sitting posture. The first survey is to identify and investigate the comfort factors for economy class aircraft passenger seat. Subsequently, survey on the body back sitting discomfort over travel time was conducted for truck driver and economy class aircraft passenger. The third survey is to investigate the relationship of the seat location and sitting posture of passengers in the economy class aircraft cabin. The postures of subjects were observed and recorded based on seven predefined sitting postures. Third goal, we contributed to develop a smart neck support system for economy class aircraft passenger. Our system aims to support and reduce neck muscle stress. A functional and working prototype was built to demonstrate the design concept and to perform experimental validation. Forth goal, we developed a low cost aircraft cabin simulator and we utilized it to validate our developed smart neck support system. The aircraft cabin simulator was built with motion platform and it is able to simulate a broad range of flight procedures. Next, a calibration experiment was conducted to investigate SCM muscle stress in relation to different support conditions, time interval and head rotation angle. Fifth goal, a validation experiment was conducted in the aircraft cabin simulator to evaluate the smart neck support system. The objective and subjective results show that the smart neck support system is able to reduce SCM muscle stress adaptively in a fully automate manner

Chronic Cold Exposure Increases Skeletal Muscle Oxidative Structure and Function in Monodelphis domestica, a Marsupial Lacking Brown Adipose Tissue

Monodelphis domestica (Marsupialia: Didelphidae) was used as a model animal to investigate and compare muscle adaptation to exercise training and cold exposure. The experimental treatment consisted of four groups of animals: either warm or cold acclimation temperature and with or without endurance exercisetraining. Maximal aerobic capacity during a running Vo2max test in the warm-exercised or cold-exposed (with or without without exercise) groups was about 130 mL O2/kg/min, significantlyhigher than the warm-acclimated controls at 113.5mL O2/kg/min. Similarly, during an acute cold challenge (Vo2summit ), maximal aerobic capacity was higher in these three experimental groups at ∼95 mL O2/kg/min compared with 80.4mL O2/kg/min in warm-acclimated controls. Respiratory exchange ratio was significantly lower (0.89-0.68), whereas relative heart mass 0.52%-0.73%) and whole-body muscle mitochondrialvolume density (2.59 to 3.04 cm[sup3]) were significantly higher following cold exposure. Chronic cold exposure was a stronger stimulus than endurance exercise training for tissue specific adaptations. Although chronic cold exposure and enduranceexercise are distinct challenges, physiological adaptations to each overlap such that the capacities for aerobic performance in response to both cold exposure and running are increased by either or both treatments

Modeling of heart rate variability and respiratory muscle activity in organophosphate poisoned patients

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksWe propose an extended model of cardiovascular regulation to assess heart rate variability in patients poisoned with organophosphate during their treatment with mechanical ventilation. The model was modified to fit a population of 21 patients poisoned with organophosphorus compounds and undergoing mechanical ventilation. The extended model incorporated the respiratory muscle activity measured by surface electromyography for quantifying the vagal-sympathetic engagement during spontaneous breathing test. The order and structure of the parasympathetic and the sympathetic transfer function with respect to the original model were modified to a second-order system. In this extended model, the parameters related to the vagal-sympathetic response (corner frequency and constant gain) were correlated with respiratory muscle activity. When the diaphragm's contractions were stronger, the sympathetic corner frequency increased while the parasympathetic corner frequency and gain decreased. Thus, the proposed model could be useful to improve the ventilatory support and pharmacological treatment for patients poisoned with organophosphorus compounds considering the vagal-sympathetic response inferred from the respiratory muscle activityPeer ReviewedPostprint (author's final draft

Physical Risk Factors Associated with the Work-Related Neck/Cervical Musculoskeletal Disorders: A Review

Work-related musculoskeletal disorders (MSD) of the neck or cervical spine result in longer sick leaves, substantial levels of human suffering, and high costs for society. Epidemiological studies clearly indicate strong associations between MSD of the neck and the work activities requiring forceful arm exertions and heavy lifting. However, most of the existing studies that evaluate the neck or cervical spine disorders focus mainly on exertions demanding sustained neck postures of repetitive arm exertions. The purpose of this study is to conduct a systematic review of existing epidemiological and experimental studies that evaluates neck or cervical spine disorders and identify the gaps in the literature for future research

Shoulder muscle activity in sport climbing in naturally chosen and corrected shoulder positions

Objective: The aim of the study was to determine electromyographic activity of the scapula stabilizing muscles in naturally chosen and corrected shoulder positions in typical static climbing postures. Methods: Six male participants undertook surface electromyography measurement in four climbing postures for two different shoulder positions. The activity of the lower, middle and upper trapezius, serratus anterior, pectoralis major, and sternocleidomastoid was recorded. Electromyographic activity was expressed as the percentage of maximal voluntary contraction (MVC) for each muscle. Results: Climbing postures induced higher activation of middle and lower trapezius in corrected shoulder positions (35.3 ± 11.8 and 61.7 ± 15.4% MVC respectively) than in naturally chosen shoulder positions (18.4 ± 8.9 and 30.1 ± 13.8% MVC respectively). The highest activity of the middle and lower trapezius was found in postures with the arm in external rotation and 90° abduction and in an overhanging posture. Low activation was stated for the other muscles in both shoulder conditions. Conclusion: Results showed that climbers naturally elevate the shoulder during typical static postures. Corrected shoulder positions induce higher activation of the scapula stabilizing muscles than naturally chosen shoulder positions.N/

Short-Term Morphological Changes in Asymptomatic Perimandibular Muscles after Dry Needling Assessed with Rehabilitative Ultrasound Imaging: A Proof-of-Concept Study

Facial anatomical structures are not easily accessible to manual palpation. The aim of our study is to objectively assess temporomandibular joint and perimandibular muscles dimensions by means of sonographic measurements before and after dry needling (DN) in asymptomatic subjects. Seventeen subjects participated in this before-after study with a within-subject control. After random allocation, one side of the face was used for the intervention and the contralateral as control. DN was performed on the temporal, masseter, and sternocleidomastoid muscles. Each subject was examined bilaterally before, immediately after, and one month after the intervention through Rehabilitative Ultrasound Imaging (RUSI) of the temporomandibular articular disc and the three target muscles. Maximum mouth opening was measured at baseline and at one month. After a single DN session, articular disc thickness significantly decreased; muscles' thicknesses (except for temporal thickness) significantly decreased immediately and at follow-up on the treated side; no significant changes resulted for the control side. The maximum mouth opening increased from 4.77 mm to 4.86 mm. RUSI may be useful to assess the dimensions and thickness of the temporomandibular disc and muscles before and after an intervention. DN influences muscle morphology, and it has a positive influence on mouth opening in the short term

Neck muscles activity and upper body extremity angles in dynamic overhead lifting

Injuries of the neck and shoulders are common among workers who perform overhead tasks. In order to develop an injury-free working environment with regards to occupational musculoskeletal stress, it is pivotal to understand the pathophysiology of mechanical stress on the musculoskeletal system. The objective of this research was to study the effect of overhead lifting on the sternocleidomastoid and upper Trapezius muscles. Upper body joint angles were also analyzed using APAS during the overhead lifting. This study was conducted using two devices. The set of equipment incorporates an electromyography device, and the APAS. Two electrodes were placed at the muscle belly of the sternocleidomastoid and the upper Trapezius muscles to record the muscle activity. Each participant was asked to lift 15%, 30% and 45% of his/her MVC, The MVC was determined by a non dynamic lifting task. ANOVA was performed to test the effect of different loads on the muscle activity. Correlation analysis was performed to observe the effect of increasing the lifted weight on the joint angles of the upper body extremities. Results of this research show a strong relationship between neck muscle activities and overhead lifting. The level of sternocleidomastoid activity increased 11.8% from a 15% MVC load to a 30% MVC load and increased 16.53% from a 30%MVC to a 45% MVC. All these values were statistically significant. At the trapezius: a 10.64% increase from 15% MVC to 30% MVC, and a 7.76 % increase from 30% MVC to 45% MVC. The significance level of alpha = 0.05 reveals that weight increase has a significant effect on the MAV EMG of the neck muscles. A slight increase in the elbow joint angle of 0.1% was recorded from 15% MVC to 30% MVC. A 2.88% increase in elbow joint angle was recorded from 30% MVC to 45% MVC, with an overall 2.98% increase from 15% MVC to 45% MVC. There was no effect of changing elbow angles on the sternocleidomastoid muscle. On the other hand, flexion of the shoulder angle in the sagital plane had a significant effect on both the Trapezius and the sternocleidomastoid muscles

Relationship between self-reported pain, pain threshold, pain catastrophization and quality of life in patients with TMD

The aim of this study was to verify if there is a relationship between self-reported pain, PPT (pressure pain threshold) of the masseter, temporal and sternocleidomastoid muscles, pain catastrophizing and quality of life in patients with TMD (temporomand