| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
,1 Harvard Division of Health Sciences and Technology, and 5 Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge 02138; 3 Concord Field Station, Museum of Comparative Zoology, Harvard University, Bedford 01730; 2 Division of Engineering and Applied Sciences, Harvard University, Cambridge 02138; 4 United States Army Research Institute for Environmental Medicine, Natick 01760; and 6 Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, Massachusetts 02114
Mammals use the elastic components in their legs (principally tendons, ligaments, and muscles) to run economically, while maintaining consistent support mechanics across various surfaces. To examine how leg stiffness and metabolic cost are affected by changes in substrate stiffness, we built experimental platforms with adjustable stiffness to fit on a force-plate-fitted treadmill. Eight male subjects [mean body mass: 74.4 ± 7.1 (SD) kg; leg length: 0.96 ± 0.05 m] ran at 3.7 m/s over five different surface stiffnesses (75.4, 97.5, 216.8, 454.2, and 945.7 kN/m). Metabolic, ground-reaction force, and kinematic data were collected. The 12.5-fold decrease in surface stiffness resulted in a 12% decrease in the runner's metabolic rate and a 29% increase in their leg stiffness. The runner's support mechanics remained essentially unchanged. These results indicate that surface stiffness affects running economy without affecting running support mechanics. We postulate that an increased energy rebound from the compliant surfaces studied contributes to the enhanced running economy.
biomechanics; locomotion; leg stiffness; metabolic rate
Deceased 14 February 1999.
This article has been cited by other articles:
|
|
 |
|
  S. Grimmer, M. Ernst, M. Gunther, and R. Blickhan Running on uneven ground: leg adjustment to vertical steps and self-stability J. Exp. Biol., September 15, 2008; 211(18): 2989 - 3000. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Trimmer and J. Issberner Kinematics of Soft-bodied, Legged Locomotion in Manduca sexta Larvae Biol. Bull., April 1, 2007; 212(2): 130 - 142. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Segers, P. Aerts, M. Lenoir, and D. De Clerq Dynamics of the body centre of mass during actual acceleration across transition speed J. Exp. Biol., February 15, 2007; 210(4): 578 - 585. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Daley, G. Felix, and A. A. Biewener Running stability is enhanced by a proximo-distal gradient in joint neuromechanical control J. Exp. Biol., February 1, 2007; 210(3): 383 - 394. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. J. Butler, I. S. Davis, and J. Hamill Interaction of Arch Type and Footwear on Running Mechanics Am. J. Sports Med., December 1, 2006; 34(12): 1998 - 2005. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Vanhooydonck, A. Herrel, and D. J. Irschick Out on a limb: the differential effect of substrate diameter on acceleration capacity in Anolis lizards J. Exp. Biol., November 15, 2006; 209(22): 4515 - 4523. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. A. Cavagna The landing-take-off asymmetry in human running J. Exp. Biol., October 15, 2006; 209(20): 4051 - 4060. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Daley, J. R. Usherwood, G. Felix, and A. A. Biewener Running over rough terrain: guinea fowl maintain dynamic stability despite a large unexpected change in substrate height J. Exp. Biol., January 1, 2006; 209(1): 171 - 187. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. P. Ferris, Z. A. Bohra, J. R. Lukos, and C. R. Kinnaird Neuromechanical adaptation to hopping with an elastic ankle-foot orthosis J Appl Physiol, January 1, 2006; 100(1): 163 - 170. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. S. Marigold and A. E. Patla Adapting Locomotion to Different Surface Compliances: Neuromuscular Responses and Changes in Movement Dynamics J Neurophysiol, September 1, 2005; 94(3): 1733 - 1750. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. A. Cavagna, N. C. Heglund, and P. A. Willems Effect of an increase in gravity on the power output and the rebound of the body in human running J. Exp. Biol., June 15, 2005; 208(12): 2333 - 2346. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. T. Moritz and C. T. Farley Human hopping on very soft elastic surfaces: implications for muscle pre-stretch and elastic energy storage in locomotion J. Exp. Biol., March 1, 2005; 208(5): 939 - 949. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. T. Moritz and C. T. Farley Passive dynamics change leg mechanics for an unexpected surface during human hopping J Appl Physiol, October 1, 2004; 97(4): 1313 - 1322. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. T. Moritz, S. M. Greene, and C. T. Farley Neuromuscular changes for hopping on a range of damped surfaces J Appl Physiol, May 1, 2004; 96(5): 1996 - 2004. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kohlsdorf, R. S. James, J. E. Carvalho, R. S. Wilson, M. Dal Pai-Silva, and C. A. Navas Locomotor performance of closely related Tropidurus species: relationships with physiological parameters and ecological divergence J. Exp. Biol., March 1, 2004; 207(7): 1183 - 1192. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Lindstedt SPRINGS IN LEGS AND RUNNING SURFACES J. Exp. Biol., January 1, 2003; 206(1): 8 - 8. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
