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Quadrupedal Mechanics - Anatomy & Physiology (view source)
Revision as of 07:14, 29 November 2013
, 07:14, 29 November 2013→The slow walk
All animals use the slow walk at times when stability is important, for example when walking over rough terrain and by animals bearing awkward loads. It is visualised by a gait diagram in Fig. 10.10 a.
All animals use the slow walk at times when stability is important, for example when walking over rough terrain and by animals bearing awkward loads. It is visualised by a gait diagram in Fig. 10.10 a.
[[File:QMFig 10.8.png|thumb|'''Fig 10.8 Support triangles''']]
:::::'''Fig 10.8 Support triangles'''
:::::'''Fig 10.8 Support triangles'''
:::::When a horse stands on all four feet, its centre of gravity lies as shown diagrammatically in dorsal view (a), cranial to the diagonals between the feet. Either hindfoot can now be lifted without change in weight distribution, because the centre of gravity lies within the triangle of support formed by the other three feet (b, c). Raising the head as in Fig.10.3 a directs the centre of gravity caudally. In (d), either forefoot can now be lifted. The centre of gravity need not be directed so far caudally if the head deviates to the side; if it deviates to the left, the right forefoot can be lifted (e).
:::::When a horse stands on all four feet, its centre of gravity lies as shown diagrammatically in dorsal view (a), cranial to the diagonals between the feet. Either hindfoot can now be lifted without change in weight distribution, because the centre of gravity lies within the triangle of support formed by the other three feet (b, c). Raising the head as in Fig.10.3 a directs the centre of gravity caudally. In (d), either forefoot can now be lifted. The centre of gravity need not be directed so far caudally if the head deviates to the side; if it deviates to the left, the right forefoot can be lifted (e).
[[File:QMFig 10.9.png|thumb|'''Fig 10.9 Head, neck, trunk and tail movements during the slow walk''']]
:::::'''Fig 10.9 Head, neck, trunk and tail movements during the slow walk'''
:::::'''Fig 10.9 Head, neck, trunk and tail movements during the slow walk'''
:::::If protraction of the left hind limb in (a) produces the axial displacement shown in (b), the left forefoot can be lifted and the limb protracted. Forelimb protraction straightens the body axis and prepares it for the same movement on the opposite side of the body (c, d). Using this slow gait, even a highly adapted cursorial animal uses to some extent the same axial movements for locomotion as an animal with only rudimentary limbs.
:::::If protraction of the left hind limb in (a) produces the axial displacement shown in (b), the left forefoot can be lifted and the limb protracted. Forelimb protraction straightens the body axis and prepares it for the same movement on the opposite side of the body (c, d). Using this slow gait, even a highly adapted cursorial animal uses to some extent the same axial movements for locomotion as an animal with only rudimentary limbs.
==='''The fast walk'''===
==='''The fast walk'''===