Published

Journal of Biomechanics 46 (2013) 2522–2528
Article history: Accepted 28 June 2013

Authors

  • Amy Silder
    Department of Orthopaedic Surgery, Stanford University, CA, USA
    Department of Bioengineering, Stanford University, CA, USA
  • Scott L. Delp
    Department of Bioengineering, Stanford University, CA, USA
    Department of Mechanical Engineering, Stanford University, CA, USA
    Department ofMechanicalEngineering,StanfordUniversity,USA
  • Thor Besier
    Auckland Bioengineering Institute, The University of Auckland, New Zealand

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Abstract

Although numerous studies have investigated the effects of load carriage on gait mechanics, most have been conducted on active military men. It remains unknown whether men and women adapt differently to carrying load. The purpose of this study was to compare the effects of load carriage on gait mechanics, muscle activation patterns, and metabolic cost between men and women walking mechanics at their preferred, unloaded walking speed. We measured whole body motion, ground reaction forces, muscle activity, and metabolic cost from 17 men and 12 women. Subjects completed four walking trials on an instrumented treadmill, each five minutes in duration, while carrying no load or an additional 10%, 20%, or 30% of body weight. Women were shorter (p<0.01), had lower body mass (p=0.01), and had lower fat-free mass (p=0.02) compared to men. No significant differences between men and women were observed for any measured gait parameter or muscle activation pattern. As load increased, so did net metabolic cost, the duration of stance phase, peak stance phase hip, knee, and ankle flexion angles, and all peak joint extension moments. The increase in the peak vertical ground reaction force was less than the carried load (e.g. ground force increased approximately 6% with each 10% increase in load). Integrated muscle activity of the soleus, medial gastrocnemius, lateral hamstrings, vastus medialis, vastus lateralis, and rectus femoris increased with load. We conclude that, despite differences in anthropometry, men and women adopt similar gait adaptations when carrying load, adjusted as a percentage of body weight.