Musculoskeletal Load Assessment of the Upper Limb Positions Subjectively Chosen as the Most Convenient Danuta Roman-Liu, Adam Wittek, Krzysztof Kędzior, 273-283 A Comparison of VDT Workstation Adjustment Methods by Evaluating and Optimizing VDT Operator's Seated Posture Suebsak Nanthavanij, 284-293 Footedness and Mounting-Short Review and Two Case Studies Seppo Väyrynen, Nina Nevala-Puranen, Heli Kirvesoja, 294-304 Work-Related Accidents Among Young Workers in Finland Simo Salminen, 305-314 Defending the Wrist Deviation Test for Carpal Tunnel Syndrome Screening: A Comparison of Vibration Thresholds and Distal Motor Latency Keith M. White, Jerome J. Congleton, Olga J. Pendleton, R. Dale Huchingson, Rodger J. Koppa, 315-335 Morphology-Related Isometric Trunk Strength of South African Manual Workers: Implications for Prevention of Occupational Low-Back Stress Jack Charteris, Pat A. Scott, 336-346

Musculoskeletal Load Assessment of the Upper Limb Positions Subjectively Chosen as the Most Convenient
Danuta Roman-Liu, Adam Wittek, Krzysztof Kędzior, 273-283

Work posture is determined by interdependence between work stand design, the necessity to perform given activities, and the anthropometric dimensions of the worker, but it also depends on individual preferences. The aim of the study was to compare the musculoskeletal load of the right upper extremity undr conditions of imposed (standard) upper limb position and subjectively chosen ones, and to assess the influence of the changes in magnitude of the external force on the musculoskeletal load in the examined limb positions.
Ten healthy male participants took part in a study. Muscular load associated with different upper extremity positions with and withoutexternal load were assessed.
   Musculoskeletal load for standard and subjectively chosen limb positions and two different values of external load were compared by means of theoretical and experimental methods.
Results indicate that differences in musculoskeletal load between imposed and subjectively chosen limb positions were not high enough to show statistically significant differences and the upper limb position chosen by the participant does not always causes the lowest musculoskeletal load.

A Comparison of VDT Workstation Adjustment Methods by Evaluating and Optimizing VDT Operator's Seated Posture
Suebsak Nanthavanij, 284-293

Three methods of visual display terminal (VDT) workstation adjustment were compared in this study in order to investigate their effects on the operator's seated posture. The first two methods were adjustments made both with and without any suggestion on the correct seated posture. The third method was an adjustment after which the workstation settings were initially set according to the results recommended by the IntelAd computer program. Ten male and five female participants were asked to readjust a VDT workstation until their most comfortable seated posture was obtained. When comparing the final seated postures to the ones ergonomically recommended, it was found that the workstation adjustment assisted by the computer program yielded the best result, followed by the adjustment without any suggestion on the seated posture, and then the adjustment with a suggestion on the seated posture. Furthermore, factors such as sex and typing skill level were not found to have any significant influence on the results.

Footedness and Mounting-Short Review and Two Case Studies
Seppo Väyrynen, Nina Nevala-Puranen, Heli Kirvesoja, 294-304

Footedness is a personal quality like handedness. Footedness may be associated with moving ability during mounting, dismounting, and jumping movements. Occupational accidents have occurred during movement to different working levels, during the use of access and exit systems, and during the mounting of vehicles. Aging can also affect accident risk and body laterality. For example, falling accidents on stairs are common among the elderly. One reason for accidents may be that the structure of the access system or stair system is unsuitable for individual moving patterns depending partly on body laterality. Footedness and the way the feet are used may be contradictory to the demands of the moving situation, especially during uncommon or rapid situations. This contradiction may trigger disturbance during moving. The aims of this pilot study were (a) to review the literature briefly and (b) to describe the use of the dominant and non-dominant foot by farmers and the elderly when mounting a tractor and stairs, respectively. The study also gives ideas for future studies based on both (a) and (b).

Work-Related Accidents Among Young Workers in Finland
Simo Salminen, 305-314

The aim of this study was to discover accident factors specific to young workers, using two accident data sets gathered at the same time but with different methods. The flrst data set consisted of 99 serious occupational accidents in which occured in Southern Finland in 1988 and 1989. The second data set was based on the interview study of over 13, 000 people of whom 792 were involved in an accident at work. Both data sets showed consistently that the accident frequency of young workers was higher than that of older workers. The accidents of young workers, however, were less severe. Young accident victims hurted themselves more often when feeding or cleaning machines. Incautiousness contributed more often to accidents of young workers. In order to prevent occupational accidents of young workers, companies should introduce training programmes for new employees.

Defending the Wrist Deviation Test for Carpal Tunnel Syndrome Screening: A Comparison of Vibration Thresholds and Distal Motor Latency
Keith M. White, Jerome J. Congleton, Olga J. Pendleton, R. Dale Huchingson, Rodger J. Koppa, 315-335

This research used distal motor latency (DML) and vibration thresholds (VT) to evaluate 84 hand activity and wrist deviation combinations to determine the best association with carpal tunnel syndrome (CTS). Female volunteers, two healthy and two CTS diagnosed, were age matched and operated a keyboard for 4 hrs a day. Room temperature was 28 C (± 2). Beginning DML and VT were taken with a relaxed neutral posture hand. The wrist was deviated in a randomly selected combination and determinations were taken at 5-min intervals. The trial ended at 20 min or when discomfort was felt. CTS conditions were discriminated by pain four times, DML once and VT 14 times. Vibrometry was the most consistent CTS discriminator. The best VT results for wrist positions were obtained with wrist extension and extended extension whereas the unclenched, clenched, and loaded power grip activities proved to be the most consistent hand activities.

Morphology-Related Isometric Trunk Strength of South African Manual Workers: Implications for Prevention of Occupational Low-Back Stress
Jack Charteris, Pat A. Scott, 336-346

Occupational back-stress among manual workers in South Africa is now a cause of governmental concern. Yet no data on the back-strength of the South African workforce have been published. This study represents a first step in reporting the trunk strength of Xhosa workers in South Africa, in absolute and size-relative terms. Thirty five male manual workers were tested isometrically while making maximal extension and flexion efforts at 0° , 23° , 46° , 69° , and 92° of stoop. The results show non-linearity of the extensor-to-flexor (E/F) ratio of the trunk musculature. The E/F ratio increases in deep stoop because of a drop in flexor torques. The data suggest that predictions of flexor from extensor torques or vice versa can confidently be made so long as testing is done away from the fully flexed position. Significant differences between morphologically gracile and robust workers in this sample are discussed. The study has implications for occupational rehabilitation and for prophylaxis, for whereas muscular strength alone may not protect the spine from occupational injury, muscular weakness certainly predisposes it.