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Influence of velocity on Weimaraner trotting stride mechanics
The large size of the Weimaraner assists in the breed performing the tasks of a sporting dog. However, the size may also make the breed more susceptible to hip dysplasia. Nevertheless, the Weimaraner compared to other large dog breeds demonstrates a lower rate of dysplasia, which may be due to the preferred slower speed of this breed and resulting stride mechanics. Although kinematic research has been done on other large breeds, gait analysis of the Weimaraner is lacking, and thus, the objective of this study was to determine the influence of velocity on the trotting stride mechanics of the Weimaraner. Six American Kennel Club (AKC) registered Weimaraner dogs were led by the same handler at a slow (st velocity: 1.2-1.7 m/s) and fast (ft velocity: 1.9-2.3 m/s) trot on even, natural footing. Strides (n=10) were selected for each dog for each trot based on soundness and correctness of gait, consistency of speed, and noticeable foot placement and lift-off. Stride variables were determined by frame-by-frame analysis with video frames of foot placement and lift-off documented. Stride variables were given as a % of stride. Means (SD) were determined for stride variables and t-tests (P<0.05) were performed between velocities. Both trots were produced with a diagonal footfall sequence and a similar stride duration (st-0.53±0.10 msec, ft-0.47±0.07 msec) and frequency (st-1.94±0.13 str/sec, ft-2.12±0.09 str/sec), alternating between periods of diagonal bipedal support (st-88±2%, ft-75±5%) and suspension (st-12±1%, ft-25±3%) with less than half of the stride cycle of each limb spent in stance (Fore: st-44±4%, ft-38±2%; Hind: st-44±5%, ft-38±4%). Although stride length significantly increased with speed (st-0.90±0.02 m, ft-0.99±0.04 m; P<0.05), the diagonal limbs remained paired on contact (diagonal advanced placement: st-0±0%, ft-0±0%). The use of suspension at all velocities and the dependence of stride lengthening to increase velocity are distinguishable characteristics of the Weimaraner from other large breeds studied including the Labrador Retriever and German Shepherd. Understanding of canine locomotion through the analysis of the stride mechanics as was done in this study will assist in the clinical examination of gait and the assessment of veterinary locomotive rehabilitation.
Keywords: kinematics, trot, Weimaraner