The Gait
The gait is a coordinated rhythmic and automatic movement of the limbs and entire body of the animal ultimately resulting in progressive movement (Barrey 1999). The gait for bipeds and quadrupeds is divided into symmetric and asymmetric gaits. Symmetrical gaits demonstrate symmetry in the time and plane of limb movement and for the horse include the walk, tolt, pace and trot. Asymmetrical gaits show asymmetry in the time and median plane of the limb movement including the canter and gallop in the horse.
Gait |
walk |
tolt |
trot |
pace |
canter |
gallop |
Number of limbs in contact with ground at any time |
2-3 or 3-4 |
1-2 |
0-2 |
0-2 |
0-3 |
0-3 |
Table 1. Gait Defintions. The table shows gait classifications defined by number of limbs in contact with ground at any one time during a stride. Adapted from (Robilliard et al. 2006)
Figure 1 shows the phases of three gaits, the gallop, pace and trot. Asymmetrical gaits can be described in two phases; the stride stance phase and suspension phase as shown with the gallop. Symmetrical gaits cannot be divided into two phases. The pace is marked by alternative movement of the ipsilateral limb pair. The suspension phase of this motion indicates lift off of the limbs on the respective side of the body and the stance phase indicates ground contact with the respective limbs. The trot is marked by alternative movement of diagonal limb pairs. The right indicates the diagonal pair containing the right-hindlimb and the left indicates the diagonal pair with the left-hindlimb. Therefore, the stance phase represents the ground contact of the respective diagonal pair and the suspension phase indicates lift off of the respective pair (Leach et al. 1985).
Permission from Hillary Clayton (Leach et al. 1985) <br>
Figure 1. Shows diagrammatic representation of the horse at the gallop, trot and pace.
Speed is associated with a galloping racehorse. Barrey shows that a horse can increase velocity by a switch in gait from the walk to trot to canter to gallop. Yet, speed can be increased at each particular gait by an increase in stride length. This is accompanied by a decrease in stance time and swing time (Robilliard et al. 2006). This overall decrease in duration of the limb cycle repeats the limb movements more frequently.
Humans have classified the most common and identifiable gaits of the horse, some described above. Some argue that this may be an oversimplification of the locomotion of the horse as over 167 gaits have been defined (Leach et al. 1984). Others argue that the gait can be represented as a continuum and each commonly described gait will fall into a cluster on this continuum. Robilliard determined gaits from foot-fall patterns using a linear discriminate analysis (LDA) function based on stride time, speed, foot-on timing and stance time for each limb. This analysis allowed for the gaits to be categorically grouped based upon a given range.