Mechanical work for step-to-step transitions is a major determinant of the metabolic cost of human walking
Open Access
- 1 December 2002
- journal article
- Published by The Company of Biologists in Journal Of Experimental Biology
- Vol. 205 (23), 3717-3727
- https://doi.org/10.1242/jeb.205.23.3717
Abstract
In the single stance phase of walking, center of mass motion resembles that of an inverted pendulum. Theoretically, mechanical work is not necessary for producing the pendular motion, but work is needed to redirect the center of mass velocity from one pendular arc to the next during the transition between steps. A collision model predicts a rate of negative work proportional to the fourth power of step length. Positive work is required to restore the energy lost, potentially exacting a proportional metabolic cost. We tested these predictions with humans (N=9) walking over a range of step lengths(0.4-1.1 m) while keeping step frequency fixed at 1.8 Hz. We measured individual limb external mechanical work using force plates, and metabolic rate using indirect calorimetry. As predicted, average negative and positive external mechanical work rates increased with the fourth power of step length(from 1 W to 38 W; r2=0.96). Metabolic rate also increased with the fourth power of step length (from 7 W to 379 W; r2=0.95), and linearly with mechanical work rate. Mechanical work for step-to-step transitions, rather than pendular motion itself, appears to be a major determinant of the metabolic cost of walking.Keywords
This publication has 22 references indexed in Scilit:
- Mechanical and metabolic determinants of the preferred step width in human walkingProceedings Of The Royal Society B-Biological Sciences, 2001
- Stabilization of Lateral Motion in Passive Dynamic WalkingThe International Journal of Robotics Research, 1999
- Simple Models of Human MovementApplied Mechanics Reviews, 1995
- Three Uses for Springs in Legged LocomotionThe International Journal of Robotics Research, 1990
- Passive Dynamic WalkingThe International Journal of Robotics Research, 1990
- A possible energy‐saving role for the major fascia of the thigh in running quadrupedal mammalsJournal of Zoology, 1989
- Comparison of mechanical work and metabolic energy consumption during normal gaitJournal of Orthopaedic Research, 1983
- Ballistic walkingJournal of Biomechanics, 1980
- Optimization of energy expenditure during level walkingEuropean Journal of Applied Physiology, 1974
- Arbeitsphysiologische StudienPflügers Archiv - European Journal of Physiology, 1927