H. Witte et al., GAITS OF HORSES - ARE THEY RULED BY OSCIL LATIONS .1. WALK IS DETERMINED BY PENDULUM MECHANISMS, Pferdeheilkunde, 11(3), 1995, pp. 199
For a basic understanding of the gaits of horses, the mechanical princ
iples for che analyses of oscillations are essential. They can be used
as efficient tools for diagnostic purposes. Movements, forces and mom
ents acting during locomotion are predictable using rather simple comp
utational models. In the model proposed here, the extremities move lik
e pendula. During ground contact they additionally are compressed like
springs. The body segment composed of head, neck and thorax performs
bending oscillations in relation to the lumbo-sacral segment. Standard
gaits make use of these components with different intensities: The wa
lk is governed by resonant oscillations of the pendula formed by che e
xtremities. Ar higher velocities, spring effects in individual legs le
gs are of growing importance. In the trot, the movements of the legs a
re too fast to be explained by the mechanisms of resonant pendula. Pow
er expenditure is minimized by temporary storage of elastic energy in
the legs' ''springs''. During ground contact two legs in parallel arra
ngement (the active diagonal) determine the resonance frequency (and t
hus the trot frequency). Gallop makes use of up to three ''springs'' a
t the same time. In addition, energy is stored in the bended beam (or
spring) of the trunk.