CONTENTS:

Articles:

Strategies of International Cooperation in an International Project: Advantages and Pitfalls Marvin J. Dainoff, Arne Aarås, Ola Ro & Barbara G.F. Cohen, 3-8       The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Entry Work: Organization and Methodology of the International Study Marvin J. Dainoff, Arne Aarås, Gunnar Horgen, Maria Konarska, Stig Larsen, Magne Thoresen, Barbara G.F. Cohen & the MEPS Study Group, 9-23       The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The Norwegian Part of the International Study Arne Aarås, Gunnar Horgen, Ola Ro, Ellen Løken, Geir Mathiasen, Hans-Henrik Bjørset, Stig Larsen & Magne Thoresen, 25-47       The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The United States Part of the International Study Marvin J. Dainoff, Barbara G.F. Cohen & Marilyn Hecht Dainoff, 49-63       The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The Polish Part of the International Study Maria Konarska, Agnieszka Wolska, Maria Widerszal-Bazyl, Joanna Bugajska, Danuta Roman-Liu & Arne Aarås, 65-76       A Cross-Country Comparison of Shortand Long-Term Effects of an Ergonomic Intervention on Musculoskeletal Discomfort, Eyestrain and Psychosocial Stress in VDT Operators: Selected Aspects of the International Project Gunnar Horgen, Arne Aarås, Marvin J. Dainoff, Maria Konarska, Magne Thoresen, Barbara G.F. Cohen & the MEPS Study Group, 77-92       Upper Limb Load as a Function of Repetitive Task Parameters: Part 1—A Model of Upper Limb Load Danuta Roman-Liu, 93-102       Upper Limb Load as a Function of Repetitive Task Parameters: Part 2—An Experimental Study Danuta Roman-Liu & Tomasz Tokarski, 103-112

Strategies of International Cooperation in an International Project: Advantages and Pitfalls
Marvin J. Dainoff, Arne Aarås, Ola Ro & Barbara G.F. Cohen

The MEPS (musculoskeletal—eyestrain—psychosocial—stress) study involved an extensive degree of multidisciplinary and multicultural cooperation. The objective was to examine the effects of multiple ergonomic interventions on visual, musculoskeletal, postural, and psychosocial outcomes amongst operators of visual display terminals (VDTs). The inherent complexity of a comprehensive ergonomic investigation requires participation of researchers from a variety of disciplines, as well as comparisons among populations with different geographical and cultural backgrounds. The design and execution of the resulting research protocol presents a number of challenges. This paper discusses the advantages and pitfalls associated with multidisciplinary multinational cooperation. Advantages include the necessity for development of a common language and perspective providing a basis for future collaboration. Pitfalls include logistic and coordination difficulties associated with conducting standardized procedures in different
locations, as well as the inherent potential for professional conflict. It is argued that such pitfalls ought to be understood and integrated into the project planning process.

The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Entry Work: Organization and Methodology of the International Study
Marvin J. Dainoff, Arne Aarås, Gunnar Horgen, Maria Konarska, Stig Larsen, Magne Thoresen, Barbara G.F. Cohen & the MEPS Study Group

This special issue of the International Journal of Occupational Safety and Ergonomics (JOSE) reports the results from an extensive multinational and multidisciplinary collaborative investigation of the impacts on visual display terminal (VDT) work of musculoskeletal, visual, ergonomic, and psychosocial factors. For brevity, this effort has been referred to as the MEPS project (musculoskeletal—eyestrain—psychosocial—stress). This paper lays out the basic methodological structure of the study. The study was conducted in 4 countries utilizing VDT data entry workers as the primary subject population. A battery of objective and subject assessment measures, including muscle load, visual function, physical and visual strain, postural, ergonomic and psychosocial factors, were assessed at 3 different points in time. A pre-test was given prior to an ergonomic intervention. Two posttests were given 1 month and 1 year after the ergonomic intervention.

The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The Norwegian Part of the International Study
Arne Aarås, Gunnar Horgen, Ola Ro, Ellen Løken, Geir Mathiasen, Hans-Henrik Bjørset, Stig Larsen & Magne Thoresen

The Norwegian MEPS (musculoskeletal—eyestrain—psychosocial—stress) study included 3 groups: data entry, data dialogue (female) and data dialogue (male). Before intervention, the data entry group reported significantly more symptoms and signs of musculoskeletal illness and had longer periods in front of the video display terminal (VDT) without a break. The ergonomic intervention consisted mainly of ergonomic information and training. After intervention, the data dialogue female group reported a significant reduction in shoulder pain in parallel with a reduction in trapezius load. Increasing the understanding in how to adjust the work stand and chair may have been contributing factors to reducing the pain level. There was a significant reduction in eye problems in all groups; the greatest reduction in eye symptoms was seen in the groups who had new optometric corrections.

The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The United States Part of the International Study
Marvin J. Dainoff, Barbara G.F. Cohen & Marilyn Hecht Dainoff

The United States MEPS (musculoskeletal—eyestrain—psychosocial—stress) study consisted of 1 group of 28 female data entry operators. The intervention was in 3 parts: workstation redesign (including advanced ergonomic chairs, motorized adjustable workstations, advanced adjustable keyboards, adjustable copyholders, adjustable footrests, monitor support surfaces) and ergonomic training/coaching and corrective lenses. After the intervention, statistically significant reductions in physical signs (trigger points, neck and shoulder mobility), subjective reports of intensity and frequency of musculoskeletal pain, and subjective reports of visual problems were observed. Static load during the work sample, as assessed by experts, improved after the intervention as did measured postural angles of head and trunk and subjective assessment of users of ergonomic characteristics of the workplaces. For all of these measures, improvements observed 1 month after intervention were also
observed in the 1-year follow-up. Trapezius load, as assessed by electromyography (EMG), decreased after intervention, but then increased in the follow-up. The increase was interpreted as a calibration problem.

The Effect of an Ergonomic Intervention on Musculoskeletal, Psychosocial and Visual Strain of VDT Data Entry Work: The Polish Part of the International Study
Maria Konarska, Agnieszka Wolska, Maria Widerszal-Bazyl, Joanna Bugajska, Danuta Roman-Liu & Arne Aarås

A group of routine data entry operators (female) was included in the Polish MEPS (musculoskeletal—eyestrain— psychosocial—stress) study. Before the intervention, ergonomic assessment revealed improper working conditions such as inadequate lighting, uncomfortable chairs, and lack of forearm and wrist support while medical examination revealed that trapezius muscle load along with upper arm, head and back angles were higher than advisable. Subjects complained about neck and shoulder pain, visual problems, and psychosocial conditions. The ergonomic intervention included installation of new luminaires and Venetian blinds, new chairs, repair of ventilators, and optometric corrections. The results after the intervention showed mainly improvement in chair comfort, lighting conditions, visual strain, and sitting posture. However, financial limitations did not allow satisfactory completion of the intervention leading to a mixed interpretation of the results.

A Cross-Country Comparison of Shortand Long-Term Effects of an Ergonomic Intervention on Musculoskeletal Discomfort, Eyestrain and Psychosocial Stress in VDT Operators: Selected Aspects of the International Project
Gunnar Horgen, Arne Aarås, Marvin J. Dainoff, Maria Konarska, Magne Thoresen, Barbara G.F. Cohen & the MEPS Study Group

Three groups of data entry female visual display terminal (VDT) workers from Norway (n = 30), Poland (n = 33) and the USA (n = 29) were compared. Before intervention, the Norwegian group reported more neck pain compared with the Polish group. The Polish group reported less shoulder pain than both the U.S. and the Norwegian groups. The clinical examination documented fewer symptoms and signs of musculoskeletal illness among the Polish participants compared with the Norwegian and the U.S. groups. After intervention, the Norwegian group reported a reduction in neck pain while the U.S. group reported a reduction in shoulder pain. The Polish group reported an increase in neck, shoulder and forearm pain at follow-up compared to after intervention. The Polish group recorded higher flexion of the upper arm at follow-up parallel with an increase of pain in the upper part of the body. Visual discomfort showed variable results in the 3 countries.

Upper Limb Load as a Function of Repetitive Task Parameters: Part 1—A Model of Upper Limb Load
Danuta Roman-Liu

The aim of the study was to develop a theoretical indicator of upper limb musculoskeletal load based on repetitive task parameters. As such the dimensionless parameter, Integrated Cycle Load (ICL) was accepted. It expresses upper limb load which occurs during 1 cycle. The indicator is based on a model of a repetitive task, which consists of a model of the upper limb, a model of basic types of upper limb forces and a model of parameters of a repetitive task such as length of the cycle, length of periods of the cycle and external force exerted during each of the periods of the cycle. Calculations of the ICL parameter were performed for 12 different variants of external load characterized by different values of repetitive task parameters. A comparison of ICL, which expresses external load with a physiological indicator of upper limb load, is presented in Part 2 of the paper.

Upper Limb Load as a Function of Repetitive Task Parameters: Part 2—An Experimental Study
Danuta Roman-Liu & Tomasz Tokarski

The aim of the study was to compare the theoretical indicator of upper limb load with the physiological indicator of musculoskeletal load, which is present while performing a repetitive task (a normalized electromyography [EMG] amplitude recorded from the muscles of the upper limb involved in the performed task). In an experimental study of a repetitive task, the EMG signal from 5 main muscles of the shoulder girdle, arm and forearm was registered: extensor carpi radialis longus, flexor carpi ulnaris, deltoideus anterior, biceps brachii caput breve and trapezius descendent. The results of the study showed a strong correlation between the theoretical indicator (Integrated Cycle Load) and the physiological indicator (root mean square of a normalized EMG amplitude from the 5 muscles). This proves that the developed theoretical indicator can be accepted as an indicator of upper limb musculoskeletal load during a work task.