Mechanics of dog walking compared with a passive, stiff-limbed, 4-bar linkage model, and their collisional implications

Usherwood, James R.; Williams, Sarah; Wilson, Alan M.

doi:10.1242/jeb.02647

Cited by 38 publications

(65 citation statements)

References 18 publications

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“…At slower than normal speeds, the metabolic cost of transport increases ( Langman et al 1995) with decreasing mechanical energy recovery (figure 13a), which is consistent with previous force plate and modelling measurements of other quadrupeds Griffin et al 2004a;Usherwood et al 2007). This may explain why elephants do not habitually move very slowly (indeed it is difficult to convince them to maintain very slow speeds), as their energy-conserving mechanisms may be less effective in this speed range.…”

Section: Discussionsupporting

confidence: 86%

“…The fluctuation amplitude of vertical acceleration was approximately 3 m s K2 at 1.37 m s K1 , and increased only moderately to 7 m s K2 at 3.07 m s K1 . Both the horizontal and vertical CM accelerations at slow speeds broadly matched previous force plate and modelling data for slowly walking dogs and other quadrupeds Griffin et al 2004a;Usherwood et al 2007). The torso angular velocities (roll u x , yaw or heading u z and pitch u y ) all oscillated cyclically around zero with small amplitude, and increased only slightly when speed increased to 3.07 m s K1 .…”

Section: Resultssupporting

confidence: 78%

“…This is consistent with the inference that an inverted pendulum mechanism is very effective during this period in elephants. Just before each forelimb's touchdown, there was a burst of positive power, presumably to reduce the touchdown collisional losses Elephant locomotor dynamics L. Ren and J. R. Hutchinson 201 and hence save energy (Kuo 2002;Ruina et al 2005;Usherwood et al 2007). This positive power continued until slightly before the next forelimb lift-off, raising the elephant's CM to its highest position presumably via the trailing forelimb's push-off.…”

Section: Resultsmentioning

confidence: 99%

“…Their maximal energy recovery may appear to be lower than that of typical walking quadrupeds (approx. 60-75%; Griffin et al 2004a;Usherwood et al 2007), but this may be explained by their relatively smaller vertical CM displacement, which leads to small potential energy fluctuations. This will reduce the transduction between the potential and kinetic energies when they are out of phase, and hence result in small energy recovery.…”

Section: Discussionmentioning

confidence: 98%

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The three-dimensional locomotor dynamics of African (Loxodonta africana) and Asian (Elephas maximus) elephants reveal a smooth gait transition at moderate speed

Ren

Hutchinson

2007

J. R. Soc. Interface.

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We examined whether elephants shift to using bouncing (i.e. running) mechanics at any speed. To do this, we measured the three-dimensional centre of mass (CM) motions and torso rotations of African and Asian elephants using a novel multisensor method. Hundreds of continuous stride cycles were recorded in the field. African and Asian elephants moved very similarly. Near the mechanically and metabolically optimal speed (a Froude number (Fr) of 0.09), an inverted pendulum mechanism predominated. With increasing speed, the locomotor dynamics quickly but continuously became less like vaulting and more like bouncing. Our mechanical energy analysis of the CM suggests that at a surprisingly slow speed (approx. 2.2 m s K1 , Fr 0.25), the hindlimbs exhibited bouncing, not vaulting, mechanics during weight support. We infer that a gait transition happens at this relatively slow speed: elephants begin using their compliant hindlimbs like pogo sticks to some extent to drive the body, bouncing over their relatively stiff, vaulting forelimbs. Hence, they are not as rigid limbed as typically characterized for graviportal animals, and use regular walking as well as at least one form of running gait.

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Section: Discussionsupporting

confidence: 86%

Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 98%

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The three-dimensional locomotor dynamics of African (Loxodonta africana) and Asian (Elephas maximus) elephants reveal a smooth gait transition at moderate speed

Ren

Hutchinson

2007

J. R. Soc. Interface.

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“…

SOJ Veterinary Sciences

Open Access Research Articlebegin to walk at a faster pace, the limbs begin to impact with the ground and in so doing behave elastically [5]. Clearly, there is then an inverse relation between limb stiffness and an ability to convert potential energy into kinetic energy thus stiffness decreases as speed increases.

In the trot, the body's center of mass behaves differently.

…”

mentioning

confidence: 99%

Seroprevalence of Infectious Bursal Disease in Backyard Chickens of Six Districts of North Shewa Zones of Oromia and Amhara Regions, Ethiopia

Girma¹,

Kebede²,

Megarsa³

2017

SOJVS

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SOJ Veterinary Sciences Open Access Research Articlebegin to walk at a faster pace, the limbs begin to impact with the ground and in so doing behave elastically [5]. Clearly, there is then an inverse relation between limb stiffness and an ability to convert potential energy into kinetic energy thus stiffness decreases as speed increases.In the trot, the body's center of mass behaves differently. Rather than being raised in the first half of the stance phase, it is lowered and the body moves as a wave, often with minimal oscillation in those breeds of dogs that are used to trotting for long periods of time [6]. Here potential energy is converted into elastic energy and stored upon impact with the ground by passive stretching of tendons and muscles, to be released later on in the stance phase. This is the spring-mass model described by Blickhan [3]. The study undertaken by Gregersen and colleagues not only confirms this spring-mass model, it also reveals that the work performed by every joint of the fore-and hind-limbs is more efficient due to a reduced "cost" of physical activity resulting from the release of elastic energy [7]. Indeed, in the trot three quarters of the work performed by dogs is recoverable [7].Muscles used in locomotion are stretched prior to shortening while producing a force. Compared to concentric contractions (shortening), eccentric contractions (lengthening) result in the highest force with the lowest energy costs due to the higher energy absorption [7,2]. Subsequently, the stored energy can be converted back to kinetic energy in the rebound [1,2]. One of the situations in which this is used to great effect is in the very rapid protraction of a horse's fore-limb during periods of galloping, when elastic energy stored in the biceps muscle is released as a burst of energy that results in a catapult action propelling the fore-limb forward [8].Acoustic Myography (AMG), which directly measures muscle contractions, was recently documented as being a useful diagnostic tool for rapidly determining muscular injury in the veterinary clinic [9,10]. Indeed, this technique has been used in the assessment of veterinary clinical diagnosis and monitoring of such dysfunctions or diseases as lameness, kissing spine, crookedness and muscular atrophy as well as post surgery/ trauma monitoring (distance measurement) or retraining/ healthy daily training (http://www.myodynamikequine.com/ AbstractIt is generally known that muscles have the ability to store and convert energy making certain types of movement highly efficient with regard to muscle work. The principle behind this concept is summarized in what has become known as the "spring-mass" model. Whilst evidence of a change in gait from walk to trot has been documented for more than 35 years, quantitative measurements of comparable changes in muscle function remain elusive. In a study involving 11 Labrador dogs, looking at muscle function as assessed by acoustic myography, changes in muscle efficiency/coordination as well as both spatial-(fiber recruitment) a...

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Locomotion in Small Tetrapods

Biknevicius

Reilly

Kljuno

2016

Understanding Mammalian Locomotion

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Mechanics of dog walking compared with a passive, stiff-limbed, 4-bar linkage model, and their collisional implications

Cited by 38 publications

References 18 publications

The three-dimensional locomotor dynamics of African (Loxodonta africana) and Asian (Elephas maximus) elephants reveal a smooth gait transition at moderate speed

The three-dimensional locomotor dynamics of African (Loxodonta africana) and Asian (Elephas maximus) elephants reveal a smooth gait transition at moderate speed

Seroprevalence of Infectious Bursal Disease in Backyard Chickens of Six Districts of North Shewa Zones of Oromia and Amhara Regions, Ethiopia

Locomotion in Small Tetrapods

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