The role of the upper body in human locomotion

• Main Author: Baird, Jennifer L
• Language: ENG
• Published: ScholarWorks@UMass Amherst 2012
• Subjects: Biomechanics
• Online Access: https://scholarworks.umass.edu/dissertations/AAI3545899

The arms and thorax are integral parts of the human body for locomotion. However, the legs have been the focus of study in a majority of research on human walking and running. The human body functions best when all the parts work together as a cohesive unit. The overall aim of these studies was to analyze changes in arm, thorax and pelvis interactions under various manipulations, and to relate those findings to angular momentum control. Manipulations used were: gait speed, arm and thorax kinematics (removal of arm swing and reduction of axial rotation), age and mode of locomotion (walking and running). In the first study, manipulating arm swing and axial rotation led to changes in thorax-pelvis coordination and upper and lower body angular momentum that were designed to maintain angular momentum control through adapted arm swing. Walking without arm swing resulted in an increase in the range of whole-body angular momentum. This increase in angular momentum could potentially lead to problems in maintaining balance. In the second study, older adults demonstrated a smaller change than young adults did in thorax-pelvis coordination with increasing speed. However angular momentum differences were apparent at slower speeds but not faster, indicating that older adults regulate angular momentum independently of coordination, and do so differently than young adults. In the third study, walking and running locomotion modes led to a different organization of thorax-pelvis coordination and arm swing. This resulted in an inverse relationship between coordination and angular momentum regulation. The more out-of-phase coordination pattern in walking had smaller arm swing, while a more in-phase coordination pattern in running was associated with greater arm swing. In both modes of locomotion, arm swing was used to generate angular momentum to counter that of the legs. The general finding from these studies is that angular momentum is a factor of human locomotion that is regulated regardless of the degree of thorax-pelvis coordination in order to allow the momentum of the arms to counter that of the legs. This balance of angular momentum is likely important for the energetics and control of walking, and is an indirect result of the linking of upper and lower body movements. Arm swing is important for regulating angular momentum and plays a key role in countering the momentum generated by the legs.