Overview
Keywords: Workplace Demands; Psychophysical; Upper Extremity; Biomechanics; Worker Capability
Timeline: 2009 - 2010
Researchers: Steven Fischer (Principal Investigator and student researcher, University of Waterloo), Richard Wells (University of Waterloo), Clark Dickerson (University of Waterloo)
Funder: Centre of Research Expertise for the Prevention of Musculoskeletal Disorders (CRE-MSD)
Project type: Seed grant
Sector/Workplace type: All
Theme:
Theme
3
Risk
assessment
and
hazard
identification
Background/rationale
Allowing workers to self-select their maximum acceptable demands for work is an approach commonly used for setting exposure limits in the workplace. However, research to support that these self-selected forces are appropriate is lacking.
Research question/objectives/methods
The objective of this study was to better understand this self-selection process by answering the following two questions:
- Do workers self-select acceptable forces in proportion to their maximum capability?
- Is this proportionality related to the internal mechanics of the body?
17 male workers were hired to complete nine different simulated workplace tasks. In each task they were asked to apply as much force as possible, and then they were given 30 minutes to self-select the amount of force they felt was acceptable if they had to continue that job for an entire day. Several parameters were also measured which allowed the internal mechanics of the body to be determined. These measures were used to determine if workers were more likely challenged by whole-body balance, or joint strength, while performing their maximum exertions in each of the nine simulated tasks.
Key findings
Workers did self-select forces in proportion to their maximum capability. In addition, when strength was identified as the internal factor most likely challenging the worker, the self-selected force was 67% of the maximum capability; conversely when balance was most challenging the proportion was 80%.
Implications for the prevention of MSDs
These findings provide scientific support to demonstrate that self-selected work demands are chosen, in part, based on the internal mechanics of the body. Further, this proportional relationship may be exploited in the future to develop better approaches to more readily predict acceptable work demands in the workplace.
Knowledge dissemination
Fischer, S. L., Brenneman, E. C., Wells, R. P., & Dickerson, C. R. (2012). Relationships between psychophysically acceptable and maximum voluntary hand force capacity in the context of underlying biomechanical limitations. Applied ergonomics, 43(5), 813-820.