Occupational Ergonomics - Volume 6, issue 1

Authors: Albert, Wayne J. | Duncan, Carolyn | Currie-Jackson, Nadine | Gaudet, Véronique | Callaghan, Jack P.

Article Type: Research Article

Abstract: This study was undertaken to investigate the biomechanical demands on the low back of Massage Therapists performing typical massage therapy techniques and the nature of the associated cumulative exposure. Ten Massage Therapists performed a standardized relaxation back massage that incorporated a series of basic massage therapy techniques used in standard treatments. The 44-minute massage treatment was videotaped and a posture-matching approach was used to determine 3D peak and cumulative loads on the low back. Although the resultant peak low back loads would be considered safe in relation to current published compression and shear guidelines, the cumulative loading values were well …within the ranges considered disconcerting in other health care and industrial workers. The therapists were found to assume non-neutral trunk, neck and arm postures for a significant portion of the massage, which could place these professionals at risk of cumulative musculoskeletal disorders. Show more

Keywords: Massage therapy, cumulative loading, peak loading, posture analysis

DOI: 10.3233/OER-2006-6101

Citation: Occupational Ergonomics, vol. 6, no. 1, pp. 1-11, 2006

Authors: Yeung, Simon S. | Deddens, James | Genaidy, Ash M. | Karwowski, Waldemar | Leung, P.C.

Article Type: Research Article

Abstract: The Revised NIOSH Lifting Equation [13] integrated the findings of different approaches reported in the scientific literature into a single mathematical formulation based on the empirical model proposed by Drury and Pfeil [5]. This simple model was tested on a limited basis and the model generalizations have not been examined. The primary objectives of this study were to investigate the performance of the NIOSH lifting equation with general formulations reported by Karwowski [7], and to examine the structure of the lifting index and the relative importance of physical factors (as defined by the lifting index) and non-physical factors (as defined …by perceived risk of injury and work dissatisfaction) with respect to workers' perceived effort associated with the lifting conditions. A cross-sectional study was conducted on 217 experienced manual handling workers in the Hong Kong area to validate the study objectives. In this investigation, information was collected on lifting task parameters, perceived effort, perceived risk of injury, and work dissatisfaction. The results suggest that a multiplicative model is better than an additive model in evaluating the effort associated with lifting task performance. In this regard, the exponents of the parameters in the lifting index should be different from 1.0. The best model for evaluating effort emerged from perceived risk of injury and the general lifting index (GLI). Given the limitations of our observational study, the main findings from this research suggest that the multiplicative structure of the NIOSH lifting equation is better than an additive model. In addition, the weighing of lifting task multipliers may need further investigation, and the study of manual lifting tasks should include both physical and non-physical factors when examining the etiologic factors leading to musculoskeletal symptoms and disorders. Show more

Keywords: Manual lifting, general lifting index, field study, task evaluations, worker-based assessment

DOI: 10.3233/OER-2006-6102

Citation: Occupational Ergonomics, vol. 6, no. 1, pp. 13-24, 2006

Authors: Smith, Derek R. | Zhang, Xing | Zheng, Yuxin | Zhang, Bing | Wang, Rui-Sheng

Article Type: Research Article

Abstract: Although musculoskeletal disorders (MSD) represent an important occupational issue worldwide, surprisingly few investigations have been conducted among white-collar workers in Mainland China. The current study examined MSD and their after-effects among 334 health professionals in Beijing, by means of an anonymous questionnaire (response rate: 99.4%). Of the respondents, 92.2% reported an MSD occurring in the previous 12 months, with the neck (72.2%), shoulder and lower back (59.9% each) being the most commonly affected body sites. Fifty-six percent of all MSD had persisted > 24 hours, 23.0% had interfered with their work ability and 15.9% required medical treatment. MSD of the …hand/wrist and MSD of the shoulders were the most likely to last > 24 hours. MSD of the lower back, upper legs or hand/wrist were all associated with a reduction of work ability. Medical treatment was more likely to have been sought for MSD of the lower back or knees, when compared to other body sites. Females were five times more likely to report an MSD at any body site, while tobacco smokers were three times more likely to have sought medical treatment for an MSD. Overall, this study suggests that MSD are becoming an increasingly important cause of functional disability among white-collar workers in China. As some significant correlations were found during statistical analysis, further research should now investigate the complicity of various factors on MSD development within this emerging Chinese demographic. Show more

Keywords: Musculoskeletal disorders, after-effects, China, low back pain, functional disability

DOI: 10.3233/OER-2006-6103

Citation: Occupational Ergonomics, vol. 6, no. 1, pp. 25-34, 2006

Authors: Stave, Christina | Pousette, Anders | Törner, Marianne

Article Type: Research Article

Abstract: A hypothetical model based on theories on stress, coping and motivation, describing the associations between risk perception and self reported safety activity, was tested. Structural Equation Modeling (SEM) was used for the analysis of data from a cross-sectional questionnaire survey of 315 randomly selected Swedish farmers and farm workers. The results lent support for a model where the effects of risk perception on safety activity were mediated by two parallel paths, job stress and risk manageability. These two mediating mechanisms balanced each other out so that no direct influence of risk perception on safety activity was found. The results therefore …suggest that, to increase and prioritize safety activity, efforts should be made to increase perceived risk manageability, supporting safety solutions simultaneously with efforts to reduce felt stress. Interventions focusing solely on risk perception, such as giving information about the negative consequences of risks, may result in little positive effect on safety activity. Show more

Keywords: Occupational accidents, risk perception, safety activity, agriculture

DOI: 10.3233/OER-2006-6104

Citation: Occupational Ergonomics, vol. 6, no. 1, pp. 35-45, 2006

Authors: Griefahn, Barbara | Künemund, Christa | Blaszkewicz, Meinolf

Article Type: Research Article

Abstract: Infrared radiation presented in the early night was expected to delay the circadian rhythm via suppression of melatonin synthesis. Seven healthy men (16–22 yrs) had completed a constant routine (24-h bedrest, <30 lux, 18°C) and 2 experimental sessions where bright light (BL, 1 500 lux) or infrared radiation (IR, 65°C) was applied from 1700 to 0100 h. Salivary melatonin levels were determined hourly, rectal temperature and heart rate continuously. Melatonin synthesis was suppressed by BL; the onset and the maximum of the melatonin profile and the minima of rectal temperature and heart rate were then delayed thus indicating a circadian …effect. IR did not affect melatonin concentration whereas the minima of rectal temperature and heart rate were delayed indicating a dissociation due to the heat-induced elevation of both the latter variables rather than a chronobiologic effect. This study does not indicate that infrared radiation affects the circadian rhythm in night shift workers. Show more

Keywords: Bright light, infrared radiation, melatonin, rectal temperature, heart rate, circadian rhythm

DOI: 10.3233/OER-2006-6105

Citation: Occupational Ergonomics, vol. 6, no. 1, pp. 47-53, 2006

Article Type: Calendar

DOI: 10.3233/OER-2006-6106

Citation: Occupational Ergonomics, vol. 6, no. 1, pp. 55-55, 2006