Occupational Ergonomics - Volume 4, issue 3

Authors: Gielo-Perczak, Krystyna

Article Type: Research Article

Abstract: The current study proposes a method of geometrical description of the shoulder articulating surfaces in order to deduce an unrecognized relationship between shoulder geometry and strength during a one-handed pulling task. The paper reports the results of a study of the strength of 12 participants during one-handed pulling correlated with the geometries of their shoulder joints derived from magnetic resonance imaging (MRI) scans. The measurements of a mean force during pulling were recorded when an upper arm was adducted in the frontal plane from 5 to 30 degrees during maximum voluntary contraction (MVC). It was observed in the study that …an area determined by the height and width of the glenoid fossa closely relates to the mean force during pulling. Show more

Keywords: one-handed pulling in frontal plane, shoulder joint, maximum acceptable load, geometry of joint articulating surfaces

DOI: 10.3233/OER-2004-4301

Citation: Occupational Ergonomics, vol. 4, no. 3, pp. 143-155, 2004

Authors: Button, Duane C. | Behm, David G. | Holmes, Michael | Mackinnon, Scott N.

Article Type: Research Article

Abstract: The objective of this study was to determine the effects of muscle contraction intensity, neuromuscular fatigue, and noise on vigilance performance. Dependent variables included simple (reaction time and movement time) and complex (video game: Tetris) vigilance tasks (SVT and CVT respectively) and maximum voluntary contraction (MVC) force and activation. Vigilance tasks and MVC were randomly allocated to 5 minute blocks during a pre-test. Following the pre-test, the tests were again randomly allocated within three, 15 minute testing sessions over 65 minutes, while 1) being exposed to high (95 dB (A)) or low (53 dB (A)) levels of noise, and 2) …performing muscle contractions at 20% and 5% of MVC, or no contractions. Ninety-five (95) dB (A) noise increased (p ≤ 0.01) SVT (reaction time and movement time combined) by 11.2% and decreased (p ≤ 0.01) CVT by 20%. Both 20% and 5% MVC impaired SVT and CVT to a similar extent, while no changes were seen with no contractions. Furthermore, neuromuscular fatigue had no apparent effect on vigilance task performance. These findings suggest that the distraction of noise and divided attention between muscle contraction and a vigilance task decreases performance. Show more

Keywords: noise, muscle contraction, vigilance task, reaction time, movement time, electromyography

DOI: 10.3233/OER-2004-4302

Citation: Occupational Ergonomics, vol. 4, no. 3, pp. 157-171, 2004

Authors: Jorgensen, Michael J. | Handa, Amit | Veluswamy, Prabaharan

Article Type: Research Article

Abstract: The objective of this study was to assess the affect of pallet location on torso kinematics during lifting. Participants transferred 11.3 kg boxes to pallets at two orientations and two distances from a constant lift origin. When reorienting the pallet from 180° to 90°, torso twist, lateral and sagittal torso kinematics increased when palletizing to various locations on the pallet when keeping the pallet distance far. Torso flexion increased slightly at the lowest level on the pallet independent of the pallet distance. When keeping the pallet distance close, torso twist kinematics decreased only when palletizing to the highest and closest …position of the pallet. When reorienting the pallet from 180° to 90° adjacent to the lift origin, the best strategy to reduce torso kinematics appears to be to eliminate the transferring of loads to the lowest level of the pallet, and keeping the pallet close to the lift origin. Show more

Keywords: manual material handling, torso kinematics, low back disorders, ergonomic interventions

DOI: 10.3233/OER-2004-4303

Citation: Occupational Ergonomics, vol. 4, no. 3, pp. 173-183, 2004

Authors: Kothiyal, Kamal | Yuen, Tai Wai

Article Type: Research Article

Abstract: This study presents the results of an evaluation of a patient handling aid commonly used for transferring patients from bed to toilet or other type of chairs. The results of the study showed that use of the patient handling aid (sling) increased the rate of perceived exertion at the lower back and the shoulder. Investigation of the muscular activity using electromyography in the shoulder and the lower back regions revealed that there was significant increase in the erector spinae activity in the lower back region. The increase in the back strain in the sling transfer was related to the increase …in lumbar flexion resulting from the relatively smaller size of the sling. Trapezius muscle on the other hand did not indicate any difference in activity. The results of this study indicate that for positive outcomes there is a need for ergonomic evaluation of the sling and the postures adopted by the patient handler while transferring the patient with the sling. Show more

Keywords: manual handling, patient handling aids, nursing staff, perceived exertion, electromyography, musculoskeletal disorders, back pain, patient transfer

DOI: 10.3233/OER-2004-4304

Citation: Occupational Ergonomics, vol. 4, no. 3, pp. 185-197, 2004

Authors: Yeung, Simon S. | Genaidy, Ash | Levin, Linda

Article Type: Research Article

Abstract: This study aims to investigate how different prevalence selection criteria affect the prevalence rates of musculoskeletal symptoms in single and multiple body regions among female nurses working in a hospital setting in the Hong Kong area. Results showed that the 12-month prevalence rate for each body region was consistently higher than the 1-month prevalence rate. The 1-month prevalence rate for lower back was 59%, and 30–39% for lower extremity, upper back and neck, and the corresponding values for 12-month prevalence rates were 98% for lower back, and 89–91% for lower extremity, upper back, and neck. A similar trend was recorded …for the 12-month prevalence of musculoskeletal disorder cases (MSD) (a case was defined as a reported symptom by the study participant, which is characterized by high frequency and/or intensity symptom) in the lower back (42%), knees/lower legs (30%), upper back (23%), hips – thigh (21%), and shoulders (21%). The 12-month MSD prevalence rates for lower back and one other body region ranged from 6% to 17%. The prevalence of MSD in the lower back – knees – and hips or ankles ranged from 11% to 12%. In addition, MSD cases in the lower back regions were significantly associated with those in the upper back, hip, knee, and hand regions. It is concluded that musculoskeletal symptoms are prevalent in single and multiple body regions, and symptoms originating from one body region may be associated with those in other body regions. A holistic approach in the evaluation and prevention of musculoskeletal problems for high-risk occupations is needed. Show more

Keywords: musculoskeletal symptoms, low back symptoms, prevalence, nursing

DOI: 10.3233/OER-2004-4305

Citation: Occupational Ergonomics, vol. 4, no. 3, pp. 199-208, 2004