Ergonomic study of dynamic office workstations

Status:

completed 01/2014

Aims:

Resulting from numerous factors, both lifestyle and work-related, physical inactivity is becoming a problem that affects an increasing number of people. Numerous evidence was found for the association of health risk factors, such as increased risk of developing type 2 Diabetes mellitus, musculoskeletal and cardiovascular disorders with prevalent occupation-based physical inactivity. In recent years, various commercial dynamic office workstations were developed that combine a computer workstation with light physical activity. The goal of this study was to investigate two dynamic workstations in comparison with conventional workplaces with systematic laboratory measurements. The project was performed in cooperation with the Dutch TNO Work and Employment Institute.

Activities/Methods:

Twelve participants were required to complete a standardized battery of five office tasks in a laboratory setting at two conventional workstations and two dynamic workstations (treadmill and semi-recumbent elliptical machine station), with each dynamic workstation tested at two different intensity levels. The sequence of workstations and tasks were randomized. Physical activity was analyzed with use of the CUELA activity system in addition to heart rate and muscular activity measurements of two back muscles. From the measurements, work performance during the various tasks, body postures and movements, physical activity indices (PAIs), energy expenditure and muscular activity were determined. The dynamic workstations were subjectively assessed with standardized questionnaires.

Results:

The body postures measured at the dynamic workstations were similar to their corresponding conventional counterparts (conventional sitting compared to the ergometer workstation and conventional standing compared to the treadmill workstation). At the dynamic workstation and conventional seated workplace, similar postures with the typical curvature of the back and pelvis angles were observed. The two investigated muscle groups (m. erector spinae and m. trapezius) seem to elicit higher muscular activity at the dynamic workstations with the higher intensity levels. However, in comparison to the conventional workstation conditions, only the walk station at the higher intensity elicited a significantly greater muscular activity. The lowest muscle activities were measured at the conventional seated workstation. The measurement of heart rate and physical activity yielded significant increases at most dynamic workstations compared to the conventional seated workstation. As expected, the heart rate and physical activity increased with higher intensities at the dynamic workstations. The energy expenditure measured yielded significantly higher values for most of the dynamic workstations (except the treadmill at low intensity). Participants stated that their work performance declines at the dynamic workstations, but this subjective feeling was not confirmed by the objective evaluation of work performance. Only for the mouse dexterity task during the treadmill with higher intensity a significant decline in speed (16%) and accuracy (12%) was determined. The performance of all other tasks was significantly unaffected. The limited differences in the selected EMG muscle activity and posture are not necessarily to be concluded as negative findings. Office work will have prerequisites in posture in order for the work to be performed, which would suggest that certain facets or characteristics of office-based VDU work needs to remain unchanged. However, on the basis of these results it is questionable whether “dynamic” alternatives will be completely included in the working environment and replace the conventional office workplaces. The dynamic workstations tested showed a number of deficits in their design and would therefore require alterations pertaining to the ergonomics and safety during use. The workstations are however being constantly further developed and more recent versions of dynamic workstations with improved ergonomic designs and which occupy less space in use have appeared on the market. It is conceivable that in future, through the use of the dynamic workstations, physical activity at the office can be increased either through the individualized temporary use or through the sharing of communal workstations. A detailed presentation of the study is currently being compiled in an IFA Report.

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