Pendular energy transduction within the step in human walking
Open Access
- 1 November 2002
- journal article
- Published by The Company of Biologists in Journal of Experimental Biology
- Vol. 205 (21) , 3413-3422
- https://doi.org/10.1242/jeb.205.21.3413
Abstract
During walking, the centre of mass of the body moves like that of a `square wheel': with each step cycle, some of its kinetic energy, Ek, is converted into gravitational potential energy, Ep, and then back into kinetic energy. To move the centre of mass, the locomotory muscles must supply only the power required to overcome the losses occurring during this energy transduction. African women carry loads of up to 20% of their body weight on the head without increasing their energy expenditure. This occurs as a result of an unexplained, more effective energy transduction between Ek and Ep than that of Europeans. In this study we measured the value of the Ek to Ep transduction at each instant in time during the step in African women and European subjects during level walking at 3.5-5.5 km h-1, both unloaded and carrying loads spanning 20-30% of their body weight. A simulation of the changes in Ek and Ep during the step by sinusoidal curves was used for comparison. It was found that loading improves the transduction of Ep to Ek during the descent of the centre of mass. The improvement is not significant in European subjects, whereas it is highly significant in African women.Keywords
This publication has 13 references indexed in Scilit:
- Penguin waddling is not wastefulNature, 2000
- Walking in simulated reduced gravity: mechanical energy fluctuations and exchangeJournal of Applied Physiology, 1999
- Energy-saving gait mechanics with head-supported loadsNature, 1995
- External, Internal and Total Work in Human LocomotionJournal of Experimental Biology, 1995
- 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
- The mechanics of sprint runningThe Journal of Physiology, 1971
- Mechanics of walking.Journal of Applied Physiology, 1966