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Ergonomic considerations of manually harvesting Maine wild blueberries (AIHCE extended abstract).
Estill CF; Tanaka S; Wild DK
Am Ind Hyg Assoc J 1996 Oct; 57(10):946-948
A field study consisting of a symptom questionnaire, limited physical examination, and ergonomic analysis was conducted to determine if blueberry raking may cause cumulative trauma disorders of the wrist. To extract berries from the plant, the raker grips the rake handle, places the tines of the rake under the bush, and pulls the rake up through the plant. Anywhere from 10 to 100 raking motions are needed to fill a rake, depending on the plant thickness and quantity of berries on the plants. For the ergonomic analysis, each of ten workers was viewed for 10 minutes. Nine of 14 harvesting crews in various fields were visited during the study and 134 rakers completed the survey questionnaire. Most rakes used had 55 to 60 tines with the average weight being 1.7 kilograms. The average number of lifts per minute was 32 with a standard deviation of 13. Of the ten rakers observed, seven used both hands at once to rake the blueberries. The posture was stooped. The worker's torso was bent over most of the time while the wrist, arm, and shoulder were used to move the rake through the berries. The force required to pull the rake through the blueberry bushes averaged 87 newtons (N) with a standard deviation of 17.5N for three attempts. Of the 134 rakers participating in the study, a history of tendinitis in the hand or wrist was reported by 12% and a history of carpal tunnel syndrome was reported by 5%. Back pain was reported by 27% of those surveyed, hand and wrist pain by 20%, and elbow pain 11%. Based on specific criteria, 4% of the participants had carpal tunnel syndrome, another 4% had de Quervain's disease, and 2% had both.
NIOSH-Author; Musculoskeletal-system-disorders; Repetitive-work; Carpal-tunnel-syndrome; Cumulative-trauma-disorders; Food-processing-workers; Agricultural-workers
Issue of Publication
American Industrial Hygiene Association Journal
Page last reviewed: March 4, 2022
Content source: National Institute for Occupational Safety and Health Education and Information Division