Biomedical subjects

O Ro

Publications and source records attributed to O Ro.

4 recordsLinked to original sources

PubMed2001

Musculoskeletal, visual and psychosocial stress in VDU operators before and after multidisciplinary ergonomic interventions. A 6 years prospective study--Part II.

A prospective epidemiological field study covering a 2 years period has earlier been published. The study has a parallel group design with two intervention groups (T and S) and one control group (C) of Visual Display Unit (VDU) operators. The present paper covers the period from 2 to 6 years of the study. After 3.5 years, the C group got the same intervention in terms of new lighting system, new workplaces and at last an optometric examination and corrections if needed. The C group reported a significant reduction in visual discomfort after interventions while the two groups (T and S) continued to report significant reduction of visual discomfort after 6 years. By supporting the forearm on the table top, the C group reported significant reduction of shoulder and neck pain while the T group reported significant reduction in shoulder and back pain after 6 years. Organizational and psychosocial factors at work and outside work did not show any significant changes during the study period.

Computer Terminals↗

PubMed1998

Musculoskeletal, visual and psychosocial stress in VDU operators before and after multidisciplinary ergonomic interventions.

The study has a parallel group design with two intervention groups (T and S) and one control group (C) of VDU operators. Three serial interventions were carried out in the T and S groups, first a new lighting system, then new workplaces and last an optometric examination and corrections if needed. The new lighting gave significantly increased illuminance levels, increased luminances of the room surfaces and better luminance distribution. The two intervention groups reported significant improvement of the lighting conditions, as well as of the visual conditions and significantly reduced visual discomfort and glare. Significant reduction of headache was found in one of the intervention groups. Optometric corrections reduced the visual discomfort in both the intervention groups. When looking at those given new corrections, a significant reduction was found in the T group and a clear tendency was also found in the S group. The C group reported no improvements for any of these health outcomes. The workplace intervention gave the operator the possibility to support the whole forearm and hand on the table top. Before the intervention there were no significant differences between the three groups regarding shoulder pain and static trapezius electromyographic (EMG) load. Two years after the intervention, a significant reduction of shoulder pain was reported in the T and S groups in parallel with a significant reduction in static trapezius load, while no such reduction was found in the C group. At the same time, both static trapezius load and shoulder pain were significantly lower in the T and S groups compared with the C group. Pain in the forearm and hand showed no significant changes in any of the groups during the study period. However, there seem to be a relationship between pain in the forearm and hand and the time the operator used the mouse. The C group reported significantly higher intensity of pain and used the mouse significantly more than the S group.

Back Pain↗

PubMed1997

Postural load during VDU work: a comparison between various work postures.

The aim of this study was to compare the postural load during VDU work in the following work postures: (1) Supporting and not supporting the forearms on the table top, (2) Sitting and standing positions, and (3) Sightline to the centre of the screen at an angle of 15 degrees and 30 degrees below the horizontal. The muscle load from the upper part of musculus trapezius and from the lumbar part of musculus erector spinae (L3 level) was measured by electromyography (EMG). Postural angles of head, upper arm and back were measured by inclinometers. The load on m. trapezius when using the keyboard was significantly less in sitting with supported forearms compared to sitting and standing without forearm support. Further, the time and number of periods when the trapezius load was below 1% MVC was significantly greater with support versus no support. The load on the right erector spinae lumbalis was also significantly less and the time when the load was below 1% MVC was significantly longer in a sitting work position with support versus standing without support. In addition, when using a mouse supporting the forearms reduced the static trapezius load in sitting. The results from this study document clearly the importance of giving the operator the possibility of supporting the forearms on the table top.

Adult↗

PubMed1996

Reproducibility and stability of normalized EMG measurements on musculus trapezius.

The reliability of normalized EMGrms (root mean square value of the electromyographic signal) measurements from musculus trapezius were evaluated in a field study. The reproducibility and stability of the method as well as the reproducibility of the results for nine variables were examined. The variables were: static, median and peak values of the ADF (amplitude distribution function) and the total time and number of periods when the muscle's load was below 1, 2 and 5% of MVC (maximum voluntary contraction). Twelve data operators, performing entry work, were measured twice with an interval of a week. Coefficients of repeatability were calculated. The coefficient of repeatability for 5 of the variables showed that 95% of the differences between measurements 1 and 2 for each subject were less than two standard deviations from the group mean. The same was true for the other four variables if the result of one of the twelve measurements was removed. The agreement index, twice the standard deviation of the difference between the two measurements divided by the mean of the two measurements was low only for the static value of the ADF and the number of periods below 5% MVC. Six data operators performing entry work were examined six times at weekly intervals. The stability ratio SDmm/SDv was less than 1 for all variables except for time and number of periods when the muscle's load was below 5% MVC. SDmm is the standard deviation of the difference between minimum and maximum value for each of the subjects for the six measurements. SDv is the average of the standard deviations of the six measurements at each visit. Two groups, each consisting of 24 VDU operators doing similar work were compared using the results from one EMG measurement on the trapezius. No significant differences were found between the groups for any of the nine variables (0.07 < p < 0.87).

Adult↗