Walking in simulated reduced gravity: mechanical energy fluctuations and exchange
- 1 January 1999
- journal article
- clinical trial
- Published by American Physiological Society in Journal of Applied Physiology
- Vol. 86 (1), 383-390
- https://doi.org/10.1152/jappl.1999.86.1.383
Abstract
Walking humans conserve mechanical and, presumably, metabolic energy with an inverted pendulum-like exchange of gravitational potential energy and horizontal kinetic energy. Walking in simulated reduced gravity involves a relatively high metabolic cost, suggesting that the inverted-pendulum mechanism is disrupted because of a mismatch of potential and kinetic energy. We tested this hypothesis by measuring the fluctuations and exchange of mechanical energy of the center of mass at different combinations of velocity and simulated reduced gravity. Subjects walked with smaller fluctuations in horizontal velocity in lower gravity, such that the ratio of horizontal kinetic to gravitational potential energy fluctuations remained constant over a fourfold change in gravity. The amount of exchange, or percent recovery, at 1.00 m/s was not significantly different at 1.00, 0.75, and 0.50 G (average 64.4%), although it decreased to 48% at 0.25 G. As a result, the amount of work performed on the center of mass does not explain the relatively high metabolic cost of walking in simulated reduced gravity.Keywords
This publication has 17 references indexed in Scilit:
- Force treadmill for measuring vertical and horizontal ground reaction forcesJournal of Applied Physiology, 1998
- Teaching the Spinal Cord to WalkScience, 1998
- A Theory of Metabolic Costs for Bipedal GaitsJournal of Theoretical Biology, 1997
- COMPARISON OF GAIT MECHANICS AND FORCE GENERATION DURING UPRIGHT TREADMILL AND SUPINE LBNP EXERCISE 520Medicine & Science in Sports & Exercise, 1996
- Scaling Body Support in Mammals: Limb Posture and Muscle MechanicsScience, 1989
- The determinants of the step frequency in walking in humans.The Journal of Physiology, 1986
- Energetic cost of carrying loads: have African women discovered an economic way?Nature, 1986
- The mechanics of walking in children.The Journal of Physiology, 1983
- Ballistic walkingJournal of Biomechanics, 1980
- The sources of external work in level walking and running.The Journal of Physiology, 1976