Title: Joint loading, muscle co-contraction, ligament force and peak knee contact forces when walking on railroad ballast

Authors: Hang Xu; Andrew S. Merryweather; Donald S. Bloswick

Addresses: Department of Mechanical Engineering, University of Utah, 50 S Central Campus Dr, Rm 2110, Salt Lake City, UT, USA ' Department of Mechanical Engineering, University of Utah, 50 S Central Campus Dr, Rm 2110, Salt Lake City, UT, USA ' Department of Mechanical Engineering, University of Utah, 50 S Central Campus Dr, Rm 2110, Salt Lake City, UT, USA

Abstract: Knee contact force (KCF), muscle co-contraction and ligament forces at the knee were determined for eight railroad workers walking on ballast. Independent variables included: surface condition [no ballast (NB), walking ballast (WB), mainline ballast (MB)], configuration (level, 7° lateral slant), and uphill/downhill limb. KCF was not affected by surface condition or surface configuration. Muscle co-contraction was higher for WB than NB, and higher in the uphill than downhill limb. First peak KCF in the anterior cruciate and medial collateral ligaments were higher and second peak KCF in the lateral collateral ligament were higher in the lateral slant condition than the level condition. Force in the medial collateral ligament was higher for the uphill than for downhill limb. Force in the anterior cruciate and lateral collateral ligaments was higher for downhill than uphill. This suggests that railroad worker gait may include compensatory mechanisms to reduce peak KCFs and knee instability.

Keywords: railroad ballast; knee contact force; peak KCF; ligament force; muscle co-contraction; joint loading; walking on ballast; railroad workers; railway workers; ligaments; downhill walking; uphill walking; worker gait; compensatory mechanisms; knee instability.

DOI: 10.1504/IJHFMS.2014.062356

International Journal of Human Factors Modelling and Simulation, 2014 Vol.4 No.2, pp.87 - 101

Available online: 05 Jun 2014 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article