Comparisons of physical exposure between workers harvesting apples on mobile orchard platforms and ladders, part 2: Repetitive upper arm motions. (November 2020)

• Record Type: Journal Article
• Authors: Thamsuwan, Ornwipa; Galvin, Kit; Tchong-French, Maria; Aulck, Lovenoor; Boyle, Linda Ng; Ching, Randal P.; McQuade, Kevin J.; Johnson, Peter W.
• Is Part Of: Applied ergonomics. Volume 89(2020)
• Publication Date: 2020-11
• Subjects: Accelerometer -- Agriculture -- Productivity -- Repetition; Human engineering -- Periodicals; 620.82
• DOI: 10.1016/j.apergo.2020.103192
• Languages: English
• ISSNs: 0003-6870

Abstract

Abstract: Farmworkers are exposed to physical risk factors including repetitive motions. Existing ergonomic assessment methods are primarily laboratory-based and, thus, inappropriate for use in the field. This study presents an approach to characterize the repetitive motions of the upper arms based on direct measurement using accelerometers. Repetition rates were derived from upper arm inclination data and with video recordings in the field. This method was used to investigate whether harvesting with mobile platforms (teams harvesting apples from the platform and the ground) increased the farmworkers' exposure to upper arm repetitive motions compared to traditional harvesting using ladders. The ladder workers had higher repetitive motions (13.7 cycles per minute) compared to the platform and ground workers (11.7 and 12.2 cycles per minutes). The higher repetitions in the ladder workers were likely due to their ability to work independently and the additional arm movements associated with ladder climbing and walking. Highlights: A computer algorithm was developed to measure repetitions from the accelerometer data. Arm repetition was calculated from field-based directly measured acceleration data and was counted from video observation. There was agreement between the video- and accelerometer-based repetition estimations, but limitations were identified. Mobile orchard platforms did not increase the work repetition of the upper arms. Harvesting by ladders involved other arm motions that increased repetitions.