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Biomedical subjects

A Aarås

Publications and source records attributed to A Aarås.

10 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↗
PubMed2001

Company strategies and program for implementing ergonomics.

Three periods of work environmental activity in the company will be presented: (a) A period without a work environmental organization and an environmental budget, covered approximately 1 year; (b) A period when an environmental organization with a separate work environmental budget was established. This period covered 15 years; (c) A period when the company was divided in 3 companies without a separate work environmental budget, but still an environmental organization, covering the last 12 years.

Budgets↗
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↗
PubMed1994

The impact of ergonomic intervention on individual health and corporate prosperity in a telecommunications environment.

This paper is a summary of several papers published in different journals and conference proceedings. The contents deal with the incidence of load related musculoskeletal illness of female workers exposed to various workloads. Furthermore, the changes in workload due to improved workplace design and the effect on the incidence of musculoskeletal illness was evaluated. The sick-leave due to musculoskeletal illness was reduced from 5.3% to 3.1% and the reduction in turn-over from 30.1% to 7.6%. The cost and the benefits of this ergonomic intervention were analysed, and showed that an investment of NOK. 350,000 produced total savings of NOK. 3,200,000. Postural load was assessed by recording electromyography (EMG) on the upper part of musculus trapezius, postural angles of the upper arm and flexion/extension of the head and back. A quantitative relationship was found between the static trapezius load and the development of musculoskeletal sick-leave, related to the length of employment. Indications were found that certain factors were associated with reduced incidence of musculoskeletal illness. These were: increasing the number and total duration of trapezius load below 1% to 2% MVC (Maximum Voluntary Contraction); reducing the magnitude of flexion angle of the upper arm in the sagittal plane and distributing the work between flexors and extensors; and a more dynamic work pattern of the upper arm. The relationship between postural load and musculoskeletal injury was studied in comparable groups of female workers with respect to age, working hours per day and time of employment. Psychosocial problems, spare time activities and living habits of the workers did not show any significant differences across the groups. The results from this study indicate that: the static trapezius load must be kept at a minimum; a median arm flexion should be less than 15 degrees and a median arm abduction less than 10 degrees. These values seem roughly to approach an acceptable arm position; and a forward median flexion of the back of less than 20 degrees seems not to lead to a higher rate of low back pain for workers with long periods of employment.

Biomechanical Phenomena↗
PubMed1987

Postural load and the development of musculo-skeletal illness.

Early in the 1970s, high rates of sick-leave due to musculo-skeletal complaints were frequently recorded among workers at Standard Telefon and Kabelfabrik's (STK's) factory in Norway. Workstations were redesigned according to ergonomics principles that allowed workers a wider choice of working postures and following their introduction in 1975, there was a marked reduction in sickness absence. Postural load was studied in groups of female workers in well defined assembly tasks. Trapezius load was recorded by electromyography (EMG). Simultaneously, postural angles of the upper arm in the shoulder joint and flexion/extension of head/neck and back were measured by using pendulum potentiometers. A quantitative relationship was found for the group between its median value of static trapezius load and the development of musculo-skeletal sick-leave, as a function of length of employment. Further support for a relationship between musculo-skeletal injury and trapezius load was found for the same subjects who suffered less musculo-skeletal sick-leave, consistent with the reduced trapezius load when working at the redesigned work stands. The relationship between postural load and musculo-skeletal injury was studied in comparable groups of the female workers with respect to age, working hours per day and time of employment. Psychosocial problems, spare time activities and living habits of workers did not show any significant difference across the groups. Postural load, both in terms of the magnitude of the flexion angle of the upper arm in the shoulder joint and the distribution of the work load between flexors and extensors, appeared to influence the incidence of load-related musculo-skeletal illness in the upper part of the body. The incidence of musculo-skeletal sick-leave in a group of workers with a median static trapezius load of about 1 to 2% MVC (Maximum Voluntary Contraction) for most of the work day, was approximately the same as for a group of comparable female workers without continuous work load. This suggests that a static trapezius load level of about 1% MVC is acceptable for the major part of the work day if adequate breaks in the load pattern are allowed when needed. At the same time, a median arm flexion of 15 degrees and a median arm abduction less than 10 degrees indicate the amplitude of these angles for 50% of the recording time. No details about the work-pause pattern was obtained, therefore these limits are only a rough indication of an acceptable arm position.

Absenteeism↗
PubMed1985

Trunk posture and trapezius muscle load while working in standing, supported-standing, and sitting positions.

A study of standing, supported-standing ("riding" on a rounded seat), and sitting postures was carried out on persons simulating assembly work in places with poor leg space. These postures and the upper trapezius muscle load were examined using statometric and electromyographic methods, respectively. While supported-standing or sitting, the lumbar spine moved toward kyphosis, even where there was no backward rotation of the pelvis. In adopting the position for anteriorly placed work, the upper arms were raised 30 degrees forward or more; then, if a greater reach was necessary, the trunk was flexed as well. It is concluded that if leg space is poor, variation between supported-standing and standing should be encouraged, and an ordinary office chair avoided. Working level should be arranged so that it is lower than 5 cm above elbow level if no arm/wrist support is possible.

Adult↗