GAIT is the pattern of movement of the limbs of animals, including humans , during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed , terrain , the need to maneuver, and energetic efficiency. Different animal species may use different gaits due to differences in anatomy that prevent use of certain gaits, or simply due to evolved innate preferences as a result of habitat differences. While various gaits are given specific names, the complexity of biological systems and interacting with the environment make these distinctions 'fuzzy' at best. Gaits are typically classified according to footfall patterns, but recent studies often prefer definitions based on mechanics. The term typically does not refer to limb-based propulsion through fluid mediums such as water or air, but rather to propulsion across a solid substrate by generating reactive forces against it (which can apply to walking while underwater as well as on land).
Due to the rapidity of animal movement, simple direct observation is rarely sufficient to give any insight into the pattern of limb movement. In spite of early attempts to classify gaits based on footprints or the sound of footfalls, it wasn't until Eadweard Muybridge and Étienne-Jules Marey began taking rapid series of photographs that proper scientific examination of gaits could begin.
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* 1 Overview * 2 Variables * 3 Physiological effects of gait * 4 Differences between species * 5 Energy-based gait classification * 6 Energetics * 7 Non-tetrapod gaits * 8 See also * 9 References
Milton Hildebrand pioneered the contemporary scientific analysis and the classification of gaits. The movement of each limb was partitioned into a stance phase, where the foot was in contact with the ground, and a swing phase, where the foot was lifted and moved forwards. Each limb must complete a cycle in the same length of time , otherwise one limb's relationship to the others can change with time, and a steady pattern cannot occur. Thus, any gait can completely be described in terms of the beginning and end of stance phase of three limbs relative to a cycle of a reference limb, usually the left hindlimb .
Gaits are generally classed as "symmetrical" and "asymmetrical" based on limb movement. It is important to note that these terms have nothing to do with left-right symmetry . In a symmetrical gait, the left and right limbs of a pair alternate, while in an asymmetrical gait, the limbs move together. Asymmetrical gaits are sometimes termed "leaping gaits", due to the presence of a suspended phase.
The key variables for gait are the duty factor and the forelimb -hindlimb phase relationship. Duty factor is simply the percent of the total cycle which a given foot is on the ground. This value will usually be the same for forelimbs and hindlimbs unless the animal is moving with a specially trained gait or is accelerating or decelerating . Duty factors over 50% are considered a "walk", while those less than 50% are considered a run. Forelimb-hindlimb phase is the temporal relationship between the limb pairs. If the same-side forelimbs and hindlimbs initiate stance phase at the same time, the phase is 0 (or 100%). If the same-side forelimb contacts the ground half of the cycle later than the hindlimb, the phase is 50%.
PHYSIOLOGICAL EFFECTS OF GAIT
DIFFERENCES BETWEEN SPECIES
Play media A hamster walking on a transparent treadmill. Play media Alternating tripod gait of walking desert ants.
Any given animal uses a relatively restricted set of gaits, and
different species use different gaits. Almost all animals are capable
of symmetrical gaits, while asymmetrical gaits are largely confined to
mammals , who are capable of enough spinal flexion to increase stride
length (though small crocodilians are capable of using a bounding
gait). Lateral sequence gaits during walking and running are most
common in mammals, but arboreal mammals such as monkeys , some
opossums , and kinkajous use diagonal sequence walks for enhanced
stability. Diagonal sequence walks and runs (aka trots) are most
frequently used by sprawling tetrapods such as salamanders and lizards
, due to the lateral oscillations of their bodies during movement.
ENERGY-BASED GAIT CLASSIFICATION
While gaits can be classified by footfall, new work involving
whole-body kinematics and force-plate records has given rise to an
alternative classification scheme, based on the mechanics of the
movement . In this scheme, movements are divided into walking and
In spite of the differences in leg number shown in terrestrial vertebrates , according to the inverted pendulum model of walking and spring-mass model of running, "walks" and "runs" are seen in animals with 2, 4, 6, or more legs. The term 'gait' has even been applied to flying and swimming organisms that produce distinct patterns of wake vortices .
* ^ Tasch, U.; Moubarak, P.; Tang, W.; Zhu, L.; Lovering, R. M.;
Roche, J.; Bloch, R. J. (2008). "An Instrument That Simultaneously
This article includes a list of references , but ITS SOURCES REMAIN UNCLEAR because it has INSUFFICIENT INLINE CITATIONS . Please help to improve this article by introducing more precise citations. (August 2009) (Learn how and when to remove this template message )
* Hildebrand, M. (1989). "
Vertebrate locomotion an introduction how
does an animal's body move itself along?". BioScience. 39 (39):
JSTOR 1311182 . doi :10.1093/bioscience/39.11.764 .
* Hoyt, D. F.; Taylor, R. C. (1981). "
* v * t * e
Animal locomotion on land
* v * t * e
Fins , limbs and wings