A Method for Characterizing Repetitive Upper Arm Motions in Apple Harvesting and a Comparison Between Working with Ladders and Mobile Platforms

Details

• Personal Author:
  Aulck L ; Galvin K ; Johnson PW ; Thamsuwan O
• Description:
  The US tree fruit industry is facing market pressure due to labor shortages and price competition from foreign producers. In response to these market pressures, harvest-assisting mobile platforms were introduced in some apple orchards to replace conventional ladders. The platform is semi-autonomous and can carry 2-6 workers. Relative to traditional harvesting with ladders, the goal of this study was to determine whether the platform could lead to increased repetition and/or non-neutral upper-arm postures. Methods characterizing upper- arm postures are quite robust; however, methods for characterizing repetitive movements are less developed. This study aims to develop systematic methods for characterizing upper-arm repetition and apply these methods to evaluate the effect that mobile platform use has on upper extremity posture and repetition. Tri-axial inclinometers were used to continuously monitor upper-arm inclinations among 12 platform and 8 ladder workers over a full day of harvesting. Repetitions were counted based on different thresholds for changes in upper- arm inclination (5, 10, 15, 20, 25 and 30 degrees) (computational method) and were also calculated from a subset of workers that were video-taped (observational method). Differences in upper-arm repetition between computational and observational repetiton methods were compared and differences in repetition and posture between platforms and ladders were assessed using RANOVA. There were differences in upper-arm posture, in terms of the percentage of time in overhead posture, between the platform and ladder harvesting methods. With respect to the repetition rates counted from the videos, rates using the computational method were best approximated using 10-degree changes in upper-arm inclination. Using 10-degree changes in upper-arm inclination, repetitions were high (>15 repetitions/minute) for both platform and ladder use. Working on the platform exposed workers to less repetition than using ladders (18 +/- 0.49 VS 29 +/- 0.43 rep/min; p<0.0001). The method in this study differs from other lab-based studies which define repetitions based on movements passing through an anatomical or postural cut-point (e.g. Spielholz et al., 2001). Rather than relying on these cut points, which typically don't occur in field settings, this method may facilitate determining repetition rates in other types of occupational settings. [Description provided by NIOSH]
• Subjects:
  Agriculture Ergonomics Farmers Musculoskeletal Diseases Musculoskeletal System Occupational Health Safety
• Keywords:
  Agricultural Industry Agricultural Machinery Arm Injuries Exposure Assessment Farm Workers Ladders MSD Musculoskeletal Disorders Repetitive Work Upper Extremities
• Publisher:
  Canadian Centre for Health and Safety in Agriculture
• Document Type:
  Text
• Funding:
  Cooperative Agreement
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 10 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  43
• NIOSHTIC Number:
  nn:20053371
• Citation:
  Proceedings of the 7th International Symposium: Safety & Health in Agricultural & Rural Populations: Global Perspectives (SHARP), October 19-22, 2014, Saskatoon, SK, Canada. Saskatoon, SK, Canada: Canadian Centre for Health and Safety in Agriculture, 2014 Oct; :43
• Federal Fiscal Year:
  2015
• NORA Priority Area:
  Agriculture, Forestry and Fishing
• Performing Organization:
  University of Washington
• Peer Reviewed:
  False
• Start Date:
  20010930
• Source Full Name:
  Proceedings of the 7th International Symposium: Safety & Health in Agricultural & Rural Populations: Global Perspectives (SHARP), October 19-22, 2014, Saskatoon, SK, Canada
• End Date:
  20270929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c6c7b175eda5049a3698954b56493e1288344386df6fb33f9b4c6b70707aaa6a390a33d36e1d3c0a614b7191045877bb78816c59edb2b0bc7434c7e0305bd1a9
• Download URL:
  https://stacks.cdc.gov/view/cdc/216139/cdc_216139_DS1.pdf
• File Type:
  [PDF - 405.15 KB ]