Extension of the ergonomics laboratory for the measurement of internal musculo-skeletal stresses

Status:

completed 05/2005

Aims:

The institutions for statutory accident insurance and prevention (BG) need for consultation and the resulting need for research in the field of ergonomics and biomechanics have increased continuously in recent years owing to the growth in prevention activities aimed at the avoidance of work-related diseases of the musculo-skeletal system. In the light of the present discussion of further occupational diseases of the musculo-skeletal system, such as carpal tunnel syndrome (CTS), repetitive strain injury (RSI) and gonarthrosis, the BG Institute for Occupational Safety and Health (BGIA) anticipates an increasing need by the BGs in the coming years to address complex biomechanical issues. Such issues particularly include organization of the workplace, loading of the spine associated with lifting, carrying, pulling and pushing activities and with trunk flexion, and with loading of the hand, arm and shoulder. Facilities are also to be set up for analysis in the area of Personal Protective Equipment (PPE) in the fields of tripping and slipping and in relation to the wearing of protective equipment (acceptable load, physiological load). In order to provide facilities for quantitative assessment of the loads of the musculo-skeletal system and to extend the existing facilities in the above areas, the ergonomics laboratory was to be upgraded.

Activities/Methods:

The following measurement systems were procured and installed: optoelectronic motion analysis system employing eight cameras, two three-component force measuring platforms, handles for triaxial action force measurement employing piezoelectric technology, four-channel electromyography recording system, further in-house developments for combination with CUELA, and multichannel recording and analysis of analogue measurement signals. Following commissioning, the new measurement systems were tested in conjunction with the existing measurement systems and synchronized with them in laboratory measurements. This activity was conducted in the first instance on a test arrangement for the analysis of pulling and pushing activities. A special measurement facility (CUELA in combination with force measurements) and an adjustable inclined plane for analysis of loading on inclined surfaces were set up for this purpose. The CUELA system was to be calibrated with the aid of the optoelectronic movement sensor system, and a calibration routine developed for future applications.

Results:

An optoelectronic motion analysis system employing eight cameras and two three-component force measuring platforms was installed for routine analyses of stress upon the musculo-skeletal system. The measurements can be supplemented by electromyographic recordings of exposed muscles and by synchronous recording of further variables such as hand forces, acceleration, or signals from other electrical sensors. The associated software can now be used to generate suitable biomechanical models of the locomotor apparatus for measurement of internal musculo-skeletal loading, such as joint and spinal stresses. Initial tests involving lifting/carrying and pulling/pushing activities have been completed very successfully. Comparative measurements with the CUELA system were performed in the laboratory in the context of repetitive tasks (assembly of halogen spotlamps). The BGIA thus now possesses a very precise and flexible laboratory facility for efficient study of ergonomic and biomechanical issues.

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