Article

OBJECTIVES: To test the hypothesis that reducing vertical center of mass (COM)
displacement will lower the metabolic cost of human walking. To examine changes
in joint work associated with increasing and decreasing vertical COM movement
during gait. DESIGN: Randomized repeated measures. SETTING: Human Neuromechanics
Laboratory, University of Michigan. PARTICIPANTS: Able-bodied subjects (N=10).
INTERVENTIONS: Subjects walked at 1.2m/s on a treadmill and overground. Subjects
manipulated vertical COM displacement either by adjusting stride length or by
using visual feedback to reduce COM movement. MAIN OUTCOME MEASURES: We measured
kinematic and kinetic data to calculate vertical and lateral COM displacements,
joint torques, and work. In addition, we collected oxygen consumption to
calculated metabolic power. RESULTS: Increasing and decreasing vertical COM
displacement beyond subjects' preferred range resulted in increases in the
metabolic cost of walking. When vertical COM displacement was reduced,
corresponding increases in positive ankle and hip work and negative knee work
were observed. CONCLUSIONS: Humans are capable of walking in a manner that will
reduce COM displacement from normal. Decreasing vertical COM movement results in
increases in metabolic energy costs because of greater mechanical work performed
at the hip, knee, and ankle joints. Thus, reducing vertical COM movement is not a
successful strategy for improving either metabolic or mechanical energy economy
during normal walking by able-bodied subjects.

Langue : ANGLAIS

Tiré à part : OUI