Changes in the amount and structure of motor variability during a deboning process are associated with work experience and neck-shoulder discomfort

Appl Ergon. 2009 Sep;40(5):887-94. doi: 10.1016/j.apergo.2008.12.006. Epub 2009 Feb 4.

Abstract

In this field study, the size and structure of kinematics variability were assessed in relation to experience and discomfort during a deboning task. Eighteen workers divided in groups with low/high experience and with/without neck-shoulder discomfort participated. Standard deviation and coefficient of variation (amount of variability), as well as approximate entropy and sample entropy (complexity) and, correlation dimension (dimensionality) were computed for head-shoulder, shoulder-hip and elbow-hip displacement in the vertical direction. A longer work experience was associated with shorter work cycle duration and decreased amount of variability while complexity increased for the head-shoulder displacement, P<0.05. Shorter work cycle, lower amount of variability and, lower dimensionality for the head-shoulder displacement were found in relation to discomfort, P<0.05. While the amount of variability, complexity and dimensionality increased for the elbow-hip displacement, P<0.05. These findings suggest a functional role of experience via learning effects and discomfort through compensatory mechanisms on the size and structure of motor variability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cross-Sectional Studies
  • Denmark / epidemiology
  • Ergonomics*
  • Humans
  • Linear Models
  • Male
  • Meat-Packing Industry*
  • Motor Skills*
  • Neck Injuries / epidemiology
  • Neck Injuries / etiology
  • Neck Pain / epidemiology
  • Neck Pain / etiology*
  • Nonlinear Dynamics
  • Occupational Exposure / adverse effects*
  • Occupational Health*
  • Posture*
  • Shoulder Pain / epidemiology
  • Shoulder Pain / etiology*