A Biomechanical Analysis of Anterior Load Carriage

Details

• Personal Author:
  Anderson AM ; Brooks DJ ; Makrozahopoulos D ; McClure LR ; Meador KA ; Mirka GA
• Description:
  Front load carriage is a common occupational task in some industries (e.g. agriculture, construction), but, as compared to lifting tasks, relatively little research has been conducted on the biomechanical loading during these activities. The focus of this study was to explore the low back biomechanics during these activities and, specifically, to examine the effects of load height and walking speed on trunk muscle activity and trunk posture. Eleven male participants participated in two separate front load-carriage experiments. The first experiment called for carrying a barbell (with weight corresponding to 20% of elbow flexion strength) at three heights (knuckle height, elbow height and shoulder height) at a constant horizontal distance from the spine. The second experiment called for participants to carry a bucket of potatoes weighing 14 kg at the same three heights, but with no further restrictions in technique. In both experiments, the participants performed this task while either standing still or walking at a self-selected speed. As they performed these tasks, the activity levels of the right-side muscle of the rectus abdominis, external oblique, biceps brachii, anterior deltoid and three levels (T9, T12 and L3) of the erector spinae were sampled. Mid-sagittal plane trunk posture was also quantified using three magnetic field-based motion sensors at T9, T12 and L3. The results showed a significant effect of both walking speed and load height on trunk posture and trunk muscle activity levels in both the barbell and bucket experiments. In the barbell experiment, the walking trials generated 43% more trunk muscle activity than the standing trials. Trials at shoulder height produced 11% more muscle activity than trials at elbow height in the T9 erector spinae muscles and 71% more muscle activity in the anterior deltoid. In the bucket experiment, trunk muscle activity responded in a similar fashion, but the key result here was the quantification of the natural hyperextension posture of the spine used to balance the bucket of potatoes. These results provide insight into muscle activation patterns in dynamic settings, especially (load) carrying biomechanics, and have implications in industrial settings that require workers to carry loads in front of their bodies. [Description provided by NIOSH]
• Subjects:
  Agriculture Biomechanical Phenomena Construction Industry Ergonomics Musculoskeletal Diseases Musculoskeletal System Occupational Health Risk Assessment Risk Factors Safety
• Keywords:
  Agricultural-industry Author Keywords: Lumbar Biomechanics Construction-industry Electromyography Motion Analysis Musculoskeletal-system Musculoskeletal-system-disorders Physical-exercise Physical-stress Physiological-factors Physiological-response Physiological-stress Posture Risk-analysis Risk-factors Skeletal-disorders Skeletal-stress Weight-factors

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• ISSN:
  0014-0139
• Document Type:
  Text
• Funding:
  Cooperative Agreement ; Grant
• Genre:
  Journal Article
• Place as Subject:
  North Carolina ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  50
• Issue:
  12
• NIOSHTIC Number:
  nn:20033675
• Citation:
  Ergonomics 2007 Dec; 50(12):2104-2117
• Contact Point Address:
  The Ergonomics Laboratory, Edward P. Fitts Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, North Carolina, NC 27695-7906
• Federal Fiscal Year:
  2008
• Performing Organization:
  East Carolina University
• Peer Reviewed:
  True
• Start Date:
  20010930
• Source Full Name:
  Ergonomics
• End Date:
  20080929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1c3c119e95ca6b20ce0c509d4c242381758013c808b5281662a3a0ba81bd9bc20b533dfe02c0c6c80f844122c8e275bd3410833e335ce0cc6718df669f4b3eda
• Download URL:
  https://stacks.cdc.gov/view/cdc/189155/cdc_189155_DS1.pdf
• File Type:
  [PDF - 905.02 KB ]