Citation

Garg A, Moore JS, Kapellusch JM. Ergonomics 2016; 60(8): 1033-1041.

Affiliation

a Occupational Science & Technology , University of Wisconsin - Milwaukee , Milwaukee , WI , USA.

Copyright

(Copyright © 2016, Informa - Taylor and Francis Group)

DOI

10.1080/00140139.2016.1246675

PMID

27734756

Abstract

The Composite Strain Index (COSI) quantifies biomechanical stressors for complex tasks consisting of exertions at different force levels and/or with different exertion times. The Cumulative Strain Index (CUSI) further integrates biomechanical stressors from different tasks to quantify exposure for the entire work shift. The paper provides methodologies to compute COSI and CUSI along with examples. Complex task simulation produced 169,214 distinct tasks. Use of average, time-weighted-average (TWA) and peak force, and COSI classified 66.9%, 28.2%%, 100% and 38.9% of tasks as hazardous, respectively. For job rotation the simulation produced 10,920 distinct jobs. TWA COSI, Peak task COSI, and CUSI classified 36.5%, 78.1%, and 66.6% jobs as hazardous, respectively. The results suggest that the TWA approach systematically underestimates the biomechanical stressors and peak approach overestimates biomechanical stressors, both at the task and job level. It is believed that the COSI and CUSI partially address these underestimations and overestimations of biomechanical stressors.

Practitioner Summary: Composite Strain Index quantifies exposure when applied hand force and/or duration of that force changes during a task cycle. Cumulative Strain Index integrates physical exposures from job rotation. These should be valuable tools for designing and analyzing tasks and job rotation to determine risk of musculoskeletal injuries.

Language: en