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Evaluating Methods to use the Virtual Corset™ Inclinometer for Trunk Posture and Spinal Compression Measurements
RS2007-DG02
Final Report Date:September 2010
| Principal Applicant: | Mieke Koehoorn (UBC) |
| Robin Van Driel, Catherine Trask, and Kay Teschke (UBC); Peter W. Johnson (University of Washington); Jack P. Callaghan and Kaitlin Gallagher (University of Waterloo) |
For more information about this project, please contact Mieke Koehoorn.
Issue
Back posture and spinal compression – the force that squeezes the bones in our spine together as we sit, walk, stand, play, and work – are recognized risk factors for back injury among workers. In order to learn more about the relationships between workplace risk factors and back injury, researchers need to able to evaluate back posture and spinal compression during work for large numbers of individuals. There are sophisticated methods that can measure these risk factors but they are costly, time consuming, and impractical in the field. Instead, field studies tend to use simplified, less accurate methods, such as observation tools. In the current study, researchers evaluated the use of a new device (the Virtual Corset™) to measure trunk angle (the angle of the torso in relation to either the pelvis or the ground depending on how many of the virtual corset devices are worn) and use the measurement data to estimate spinal compression. The Virtual Corset is more user friendly and less expensive than laboratory based methods.
Key findings
- The results support using the Virtual Corset as a direct measure of trunk angle. Best results (agreement with lab based methods) were obtained when two Virtual Corsets were used – one mounted on the torso and one on the pelvis.
- Estimates of spinal compression made with data from a single Virtual Corset did not agree well with lab-based estimates. However, the researchers recommend further research to evaluate using data from two Virtual Corsets (instead of one) to estimate spinal compression.
- The Virtual Corset has the potential to be used for measuring trunk angle in back injury research, and for prevention and rehabilitation purposes.
Objectives
- To evaluate the use of the Virtual Corset in measuring trunk angle and estimating spinal compression, in comparison with ‘gold standard’ laboratory measurement techniques.
Methods
Researchers measured trunk angle using both the Virtual Corset method (one torso-mounted and one pelvis-mounted) and the gold standard, an optoelectronic Motion Analysis system while participants performed lifting and lowering tasks in a laboratory setting. The tasks were modeled on work tasks observed by researchers during a large study of back injuries in heavy industries.
Using a number of statistical analyses, the measurements based on data from the two Virtual Corsets were compared with the Motion Analysis measurements to assess agreement on measured trunk angles. The researchers also compared the estimates of spinal compression based on data from a single Virtual Corset (torso-mounted) with lab-based estimates.
Results
- The double Virtual Corset method accurately measured posture with a high correlation and excellent agreement with the Motion Analysis system.
- Estimates of spinal compression based on posture data from a single Virtual Corset did not agree as well with the more sophisticated lab‐based method or measurements from a field study on back injury.
Conclusions and recommendations
The findings support using the Virtual Corset as a tool for directly measuring back postures, preferably when both a torso and pelvis mounted corset can be used. The researchers also note that the Virtual Corset has wide potential to be used in occupational back injury research, and for prevention and rehabilitation purposes.
Additional research is required to determine if data collected using the Virtual Corset can be used to accurately estimate spinal compression.
Future directions
The researchers’ ultimate aim is to use the Virtual Corset in future occupational back injury field studies to accurately measure trunk angle during work tasks for a large number of individuals. Future research may test whether this data can also be used to estimate spinal compression.
Publications and presentations
“Bending over backwards: looking for cheap and efficient ways of measuring trunk posture for research and practice.” Robin Van Driel, Catherine Trask, Yat Chow, Judy Village, Pete Johnson, Mieke Koehoorn, Kay Teschke. Spring 2010 School of Environmental Health Seminar Series, University of British Columbia, April 2010
“A Comparison of Trunk Posture Movements: A Motion Capture System and A New Data-Logging Inclinometer.” Robin Van Driel, Kay Teschke, Jack P. Callaghan, Catherine Trask, Mieke Koehoorn, Peter W. Johnson. IEA 2009, 17th World Congress on Ergonomics, August 2009. Beijing, China.
"A Comparison of Trunk Posture Movements: A Motion Capture System and A New Data-Logging Inclinometer". Robin Van Driel, Kay Teschke, Jack P. Callaghan, Catherine Trask, Mieke Koehoorn, Peter W. Johnson. 2009, Sixth International Conference on Innovations in Exposure Assessment, August 2009. Boston, MA, USA.
“A comparison between electromyography (EMG) and inclinometer predicted spinal compression.” Robin Van Driel, Catherine Trask, Yat Chow, Judy Village, Pete Johnson, Mieke Koehoorn, Kay Teschke. 38th Annual Conference of the Association of Canadian Ergonomists, Toronto, October 2007