|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online January 8, 2007
Journal of Experimental Biology 210, 208-216 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.02645
Ground forces applied by galloping dogs
Biology Department, University of Utah, Salt Lake, UT 84112, USA
* Author for correspondence (e-mail: walter{at}biology.utah.edu)
Accepted 9 November 2006
The gallop differs from most other quadrupedal gaits in that each limb plays a unique role. This study compares the ground forces applied by the four limbs and uses force differences between limbs to address the question of why the gallop is the fastest quadrupedal gait. Individual ground forces were recorded from each of the four limbs as six dogs galloped down a runway at constant speed. Trials were videotaped at high speed using a camera positioned perpendicular to the runway, and velocity was measured using photosensors. The trailing forelimb applied greater peak vertical forces than the lead forelimb, however the vertical impulses from the two forelimbs were similar because the lead forelimb had a longer contact interval. The trailing forelimb and lead hindlimb applied greater peak accelerating forces and accelerating force impulses than their contralateral limbs despite their tendency to have shorter contact intervals. The accelerating impulse of both forelimbs combined did not differ significantly from that of both hindlimbs. The forelimbs applied a greater decelerating impulse than the hindlimbs, such that their net fore-aft impulse was decelerating whereas that of the hindlimbs was accelerating. The greater accelerating impulse applied by the trailing forelimb and greater decelerating impulse applied by the lead forelimb are consistent with the forelimbs acting as elastic struts rather than being actively retracted. In contrast, greater accelerating forces were produced by the lead hindlimb while the center of mass was lifted, suggesting that the hindlimbs are more actively extended or retracted during stance. The differences in ground forces measured between paired limbs suggest that the lead forelimb and trailing hindlimb are limited in their ability to apply forces by their positions in the stride cycle rather than by their muscular capacity. Although a bound or half-bound would allow more limbs to produce their maximal forces, a gallop may generate higher speeds because it is more efficient. Galloping could be more efficient than other gaits involving sagittal bending if the increased number of ground contact intervals decreased either the decelerating forces applied at the onset of ground contact or the vertical motion of the center of mass.
Key words: locomotion, gallop, ground force, gait, biomechanics, dog
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
Related articles in JEB:
This article has been cited by other articles:
|
|
 |
|
  R. M. Walter and D. R. Carrier Rapid acceleration in dogs: ground forces and body posture dynamics J. Exp. Biol., June 15, 2009; 212(12): 1930 - 1939. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. E.A. Bertram and A. Gutmann Motions of the running horse and cheetah revisited: fundamental mechanics of the transverse and rotary gallop J R Soc Interface, June 6, 2009; 6(35): 549 - 559. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. B. Williams, J. R. Usherwood, K. Jespers, A. J. Channon, and A. M. Wilson Exploring the mechanical basis for acceleration: pelvic limb locomotor function during accelerations in racing greyhounds (Canis familiaris) J. Exp. Biol., February 15, 2009; 212(4): 550 - 565. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. D. Maes, M. Herbin, R. Hackert, V. L. Bels, and A. Abourachid Steady locomotion in dogs: temporal and associated spatial coordination patterns and the effect of speed J. Exp. Biol., January 1, 2008; 211(1): 138 - 149. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Blackburn GALLOPING, DOG STYLE J. Exp. Biol., January 15, 2007; 210(2): i - ii. [Full Text] [PDF]
|
|
