Occupational Ergonomics - Volume 10, issue 4

Authors: Landau, Kurt | Brauchler, Regina | Diaz-Meyer, Marianela | Kiesel, Johannes | Lenz, Andreas | Meschke, Herwig | Presl, Angelika

Article Type: Research Article

Abstract: Disorders of the musculo-skeletal system are one of the main occupational diseases occurring in industrial countries and the number of reported cases is rapidly increasing, especially among the older age groups. Musculo-skeletal diseases can be influenced by a number of stress factors arising during physical work. The aim of this study is to identify the physical work stress factors, to which persons already suffering from musculo-skeletal diseases (patients at a rehabilitation center) have been exposed in their work, and, firstly, to examine whether these data can be used to predict the probability of future musculo-skeletal disorders in workers occupying this …type of job, secondly, to determine how these factors interact with each other in the development of these disorders. Trained specialists in occupational medicine using a program called Medical Job-oriented Rehabilitation (MJOR), collected data on 6668 patients by means of a standardized checklist called Bavaria Rehabilitation Assessment Method (BRA). Analysis of the recursive binary partitioning trees revealed that 19 predictor variables corresponding to age and gender, plus repetitive operations, rotation in sedentary position, degree of hand force used and forced head/neck postures were good predictors for the disorders of the hand-/arm system, the cervico-brachial syndrome and the impingement syndrome of shoulder. Show more

Keywords: Musculo-skeletal disease, physical stress, medical job-oriented rehabilitation (MJOR), ergonomic assessment

DOI: 10.3233/OER-2012-0198

Citation: Occupational Ergonomics, vol. 10, no. 4, pp. 139-153, 2012

Authors: Sun, Yun | Nimbarte, Ashish D.

Article Type: Research Article

Abstract: In this study the effect of horizontal pushing and pulling exertions on the activity of major neck muscles, sternocleidomastoid and cervical trapezius, was studied biomechanically by using electromyography (EMG). Twenty-two (11 males and 11 females) healthy individuals participated in this study. Each participant performed constrained horizontal pushing and pulling exertions, in a seated posture, exerting 25%, 50%, and 75% of their respective maximum strengths. The activity of the neck muscles increased with the increase in the pushing and pulling force. The direction of force application had a minimal effect on the activation of neck muscles. The effect of gender on …the activity of the neck muscles was significant. Female participants used sternocleidomastoid muscle to a significantly greater extent than male participants. A significantly higher activation of cervical trapezius muscle was observed for male participants than female participants. Show more

Keywords: Horizontal pushing, horizontal pulling, neck muscles, gender, electromyography, musculoskeletal disorders

DOI: 10.3233/OER-2012-0199

Citation: Occupational Ergonomics, vol. 10, no. 4, pp. 155-164, 2012

Authors: Aghazadeh, Fereydoun | Mokrani, Mohamed | Al-Qaisi, Saif | Ikuma, Laura | Hassan, Marwa

Article Type: Research Article

Abstract: The purpose of this study was to determine the effects of varying amount of lifted weight on upper extremity joint angles and muscle activity of the neck and shoulder. Two-dimensional elbow and shoulder kinematics of overhead lifting were determined, and simultaneously surface electromyographic (EMG) data from the upper trapezius and sternocleidomastoid muscles were collected. Results show that as lifted weight increased, the EMG activity of both muscles increased accordingly. Increasing the weight also resulted in increased maximum elbow joint angle and decreased maximum shoulder joint angle, but the effects were not significant. Shoulder angle and muscle activity were highly correlated. …The correlation coefficients ranged from 0.39 to 0.75 for the trapezius muscle and from 0.38 to 0.42 for the sternocleidomastoid muscle. The elbow joint angle had low to no influence on shoulder and neck muscle activity. Show more

Keywords: Musculoskeletal disorders, maximal voluntary contraction, overhead lifting, muscle electromyography activity, joint angles

DOI: 10.3233/OER-2012-0200

Citation: Occupational Ergonomics, vol. 10, no. 4, pp. 165-174, 2012

Authors: Oliver, Michele Lea | Northey, Greg Warren | Murphy, Taylor Andrew | MacLean, Alexander | Sexsmith, James Richard

Article Type: Research Article

Abstract: The manipulation of joysticks to control heavy machinery requires repetitive wrist and upper limb movements which can increase operator susceptibility to repetitive strain injuries. The purpose of this study was to analyse muscle activation using surface electromyography (EMG) on eight muscles of the upper limb during joystick manipulation. Experiments (n=8 subjects) involved a series of 4 motion types (forward, backwards, inwards, outwards) at 2 speeds (fast, slow) using 3 identical joysticks with different stiffnesses (light, regular, heavy). Results showed that all experimental conditions required at least a constant low level (between 2–5% Task Maximal Voluntary Contraction) activation for all muscles. …The joystick utilized in this study maintains the wrist in a more neutral posture, however, Integrated EMG (iEMG) and peakEMG results suggest that the muscle strain is transferred from the wrist to the shoulder. EMG results also suggest that shoulder strain is further exacerbated by the armrest as it forces the operator to elevate the shoulder while pulling the controller backwards and inadequately supporting the forearm while moving it in the forward direction. Muscles involved as prime movers had higher activation levels when joystick stiffness was increased, however, muscles that provided directional, positional or postural support to the prime movers were relatively unaffected by joystick stiffness. Muscle activation was increased for all muscles when the joystick was moved quickly. This finding may be important for work environments using joysticks which require increased precision and fine movements coupled with short, highly repetitious cycle times. Show more

Keywords: Joysticks, electromyograph (EMG), integrated EMG, peak EMG

DOI: 10.3233/OER-2012-0201

Citation: Occupational Ergonomics, vol. 10, no. 4, pp. 175-187, 2012

Authors: Taber, Michael John | Sayle, Stephen | Carrol, Joel

Article Type: Research Article

Abstract: A primary objective of this study was to determine if the 15 minutes of air contained in an emergency breathing apparatus afforded sufficient time to carry out an evacuation from an offshore installation in the event of an uncontrolled hydrogen sulfide (H2 S) release. Twenty-four male and 12 female volunteers performed relevant evacuation skills during a simulated evacuation into a 36-person lifeboat. An observational analysis and subjective ratings of difficulty were used to determine potential ergonomic and safety issues. Results indicate that even under the worst-case scenario, all personnel would be able to safely evacuate to the lifeboat and abandon …the installation given similar conditions used during this study. It was noted however, that ergonomic improvements to the design of the personal protective and safety equipment could improve usability, thus decrease abandonment times. Show more

Keywords: Observational task analysis, abandonment procedures, human performance, installation evacuation, escape breathing air, lifeboat

DOI: 10.3233/OER-2012-0202

Citation: Occupational Ergonomics, vol. 10, no. 4, pp. 189-206, 2012

Article Type: Other

DOI: 10.3233/OER-2012-10406

Citation: Occupational Ergonomics, vol. 10, no. 4, pp. 207-209, 2012

Article Type: Other

DOI: 10.3233/OER-2012-10407

Citation: Occupational Ergonomics, vol. 10, no. 4, pp. 211-212, 2012