In vivo laboratory validation of the physiometer: a measurement system for long-term recording of posture and movements in the workplace

Abstract

Posture and movement are thought to be important risk factors for the development of work-related musculoskeletal disorders. Whole day occupational exposure assessment has typically used self-report or observation techniques, but the need for more accurate measurement is now recognised. The aim of this study was to compare the kinematic recordings of a frequently used field system (physiometer) with two laboratory-based systems (Fastrak and Peak) in vivo. Head, thorax and right arm kinematics were recorded simultaneously by the three systems whilst a subject performed 27 single and multiple plane physiological and simulated daily living task movement trials. Errors observed in the Fastrak and Peak data included gimbal lock and quadrant errors. Physiometer data errors included undervalues, overvalues and temporal errors of slow response and resonance. All three systems showed some cross-talk. Agreement between the physiometer and the other systems was generally high for physiological movements (R² > 0.8) and less for functional movements (R² > 0.5).

Statement of Relevance: The physiometer recording device can provide an indication of posture across time in the workplace; however, its accuracy is limited, particularly during functional movements. Further technology should be developed to unobtrusively capture accurate all day 3-D kinematics.

Keywords:

• field based
• in vivo
• motion analysis
• posture assessment
• validity

Acknowledgements

The authors would like to thank Sonia Ranelli for assistance during data collection and Paul Davey for technical support.