Development of a relative discomfort profile for repetitive wrist motions and exertions.
Lin L; Radwin RG; Snook SH
IEA '94, proceedings of the 12th Triennial Congress of the International Ergonomics Association, August 15-19, 1994, Toronto, Canada, Volume 2: Ergonomics in Occupational Health and Safety. Mississauga, Ontario, Canada: Human Factors Association of Canada, 1994 Aug; 2:219-221
Physical stress from repetitive exertions and motions was investigated using a psychophysical measurement of subjective discomfort in order to establish a relative discomfort profile for tasks which involve these stresses. Studies were performed using one female and two males between 21 and 25 years old. Wrist flexion was controlled between a neutral posture and 35 degree flexion or 65 degree flexion. Subjects turned a crank at two paces: 3 seconds/motion, and 15 seconds/motion. Subjects performed each combination of conditions for 1 hour; discomfort was measured after each session using an analog scale. Mean discomfort ratings for all eight conditions of pace, exertion, and angle were determined. Pace, exertion, and angle were all significant main effects. No significant interactions between pace and angle, or among the three factors were observed. The findings suggested a slope of 10 decibels/decade for frequency weighted filters for force, and a slope of 16 decibels/decade for frequency weighted filters for wrist flexion angle. The authors suggest that additional studies be performed in which a greater number of experimental levels, different wrist postures and motions, and different resistance directions are performed in order to understand the effects on the tasks performed involving a variety of postures and motions.
NIOSH-Grant; Musculoskeletal-system-disorders; Ergonomics; Human-factors-engineering; Repetitive-work; Task-performance; Humans
Industrial Engineering Univ of Wisconsin-Madison 1513 University Ave Madison, WI 53706
IEA '94, proceedings of the 12th Triennial Congress of the International Ergonomics Association, August 15-19, 1994, Toronto, Canada, Volume 2: Ergonomics in Occupational Health and Safety
University of Wisconsin Madison, Madison, Wisconsin