Method for quantitatively assessing physical risk factors during variable noncyclic work.
OBJECTIVE
Assessing exposure to physical risk factors during variable noncyclic work can be problematic. The purpose of this study was to modify an existing data reduction method for directly quantifying physical exposures during variable noncyclic work.


METHODS
Myoelectric activity of the finger flexors of two groups of workers, heavy equipment operators (N=25) and mechanics (N=25), was sampled to determine the intensity and duration of forceful exertions during normal tasks. Data were reduced with a modification of the exposure variation analysis (EVA), called clustered EVA (CEVA), using three intensity and two duration categories. A two-way, mixed-effects, repeated-measures analysis of variance evaluated the percentage of sampled work time in each CEVA category.


RESULTS
CEVA was able to quantify variable noncyclic work, and it contrasted the work of the two groups, with simple effects significantly different for all the exposure categories. The mechanics performed high-intensity short-duration contractions 9.1% of the time, whereas the operators had similar contractions only 1.8% of the time. Conversely, the operators used low-intensity contractions of prolonged duration over 81% of the time, compared with only 43% for the mechanics.


CONCLUSIONS
CEVA is a useful modification of EVA for contrasting the noncyclic work typical of understudied industries like construction. A simplification of electromyography with summary measures such as CEVA provides a comprehensible, yet accurate measure of forceful exertions during worktasks.
Anton
Dan
D
Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242-5000, United States. dan-anton@uiowa.edu
Cook
Thomas M
TM
Rosecrance
John C
JC
Merlino
Linda A
LA
D000328:Adult; D001696:Biomechanical Phenomena; D015984:Causality; D003430:Cross-Sectional Studies; D004576:Electromyography; D005385:Fingers / Q000502:physiology*; D005542:Forearm / Q000502:physiology; D006801:Humans; D018482:Muscle, Skeletal / Q000502:physiology*; D012307:Risk Factors