Title: Impact of military footwear type and a load carriage workload on slip initiation biomechanics

Authors: Harish Chander; Sachini N.K. Kodithuwakku Arachchige; Samuel J. Wilson; Adam C. Knight; Reuben F. Burch V; Daniel W. Carruth; Chip Wade; John C. Garner

Addresses: Neuromechanics Laboratory, Department of Kinesiology, Mississippi State University, Mississippi State, MS 39762, USA; Human Performance Laboratory, Center of Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA ' Neuromechanics Laboratory, Department of Kinesiology, Mississippi State University, Mississippi State, MS 39762, USA ' Department of Health Sciences and Kinesiology, Georgia Southern University, Statesboro, GA 30460, USA ' Neuromechanics Laboratory, Department of Kinesiology, Mississippi State University, Mississippi State, MS 39762, USA ' Department of Industrial and Systems Engineering, Mississippi State University, Mississippi State, MS 39762, USA ' Human Performance Laboratory, Center of Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA ' Department of Industrial and Systems Engineering, Auburn University, Auburn, AL 36849, USA ' Department of Health and Kinesiology, Troy University, Troy, AL 36082, USA

Abstract: The impact of military footwear and workload on slip incidence and severity have been previously reported. Further analysis of slip initiation biomechanics is warranted in attempt to prevent slips. Sixteen participants were tested with two military boots, standard (STD) and minimalist (MIN), before (PRE) and after (POST) a load carrying task during normal gait (NG), unexpected (US) and expected (ES) slips. Joint kinematics, ground reaction forces and muscle activity from the slipping leg were analysed using a 2 (MIN-STD) × 2 (PRE-POST) × 3 (NG-US-ES) repeated measures ANOVA. Results revealed significant gait modifications due to footwear and gait. STD exhibited greater ankle dorsiflexion and knee flexion, lowered ground reaction forces and increased muscle activity compared to MIN. US and ES elicited greater plantar flexion and knee flexion angles while requiring a greater muscle activation compared to NG. Findings can aid in understanding slip initiation biomechanics, for footwear design and promoting safety.

Keywords: military footwear; slips; falls; lower extremity kinematics; ground reaction forces; lower extremity muscle activity; load carriage.

DOI: 10.1504/IJHFE.2020.109560

International Journal of Human Factors and Ergonomics, 2020 Vol.7 No.2, pp.125 - 143

Received: 26 Dec 2019
Accepted: 21 Feb 2020
Published online: 15 Sep 2020 *

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