Measurement of the work done by the foot into the sand during one step of walking

Moving about in nature often involves walking or running on a soft yielding substratum such as sand, which has a profound effect on the mechanics and energetics of locomotion. Force platform and cinematographic analyses were used to determine the mechanical work performed by human subjects during walking and running on sand and on a hard surface.  Oxygen consumption was used to determine the energetic cost of walking and running under the same conditions. Walking on sand requires 1.6-2.5 times more mechanical work than does walking on a hard surface at the same speed. On the other hand, running on sand requires only 1.15 times more mechanical work than does running on a hard surface at the same speed. Walking on sand requires 2.1-2.7 times more energy expenditure than does walking on a hard surface at the same speed; while running on sand requires 1.6 times more energy expenditure than does running on a hard surface. The increase in energy cost is due primarily to two effects: the mechanical work done on the sand, and a decrease in the efficiency of positive work done by the muscles and tendons..

More information: Patrick Willems

Principal publication of the lab on that topic : LEJEUNE T.M., WILLEMS P.A. & HEGLUND N.C. (1998) Mechanics and energetics of human locomotion on sand. J. exp. Biol. 201: 2071-2080

Return to the main page

Responsable : Philippe Gérard - Contact : pHg