Biomechanical comparison of standing posture and during trot between German shepherd and Labrador retriever dogs

Abstract

It is widely accepted that canine breeds stand and move differently. The prevalence of various musculoskeletal disorders such as hip and elbow dysplasia is also different between breeds. German shepherd dog (GSD) and Labrador retriever dog (LRD) are two large breeds with different conformations that have high prevalence of these disorders. This study quantifies the movement and standing posture of twelve healthy GSDs and twelve healthy LRDs to identify biomechanical similarities and differences that may be linked to sub-optimal hip and elbow mechanics. A pressure walkway and a motion capture system obtained measures of kinetics, kinematics and conformation during standing and trot. During standing, LRDs carry a greater percentage of the weight on the forelimbs (69%±5% vs. GSDs: 62% ±2%, p<0.001) and their body Centre of Pressure (CoP) is located more cranially (p<0.001). GSDs had a greater pelvic tilt (79˚±8 vs. 66˚±9˚, p = 0.004), more flexed stifles (44˚±9˚vs. LRDs: 34˚±10˚, p<0.05) and hocks (58˚±11˚vs. 26˚±9˚, p<0.01) and more extended hips (-10˚±11˚vs. 30˚±12˚, p<0.001). During trot, the GSDs' CoP had a longer anterior-posterior trajectory (151%±22% vs. LRDs: 93%±25% of the withers height, p<0.001). Stride parameters and loading of limbs were similar when normalised to the size and weight of the dog, respectively. The LRDs had a more extended thoracolumbar angle (p<0.001) and a less flexed lumbosacral angle (p<0.05). The LRDs' hip remained flexed during trot whereas the GSDs' hip joint was less flexed during swing (p<0.001) and more extended in late stance and early swing (p<0.001). In conclusion, the LRDs and GSDs differ in the way they stand and move and this would result in different loading pattern of the joints. Further investigation is required to determine the extent to which biomechanical differences are linked to musculoskeletal problems presented clinically.

Effect of Femoral Head and Neck Osteotomy on Canines’ Functional Pelvic Position and Locomotion

“…Static weight bearing was, on average, 15.6% of the total body weight on the FHO limb versus 20.3% on the contralateral limb, which sums close to the 37.5% reported to be a normal front/hind body weight distribution ratio in dogs [25], with breed variations from 31% to 38% [26]. This indicates that the dogs are mainly offloading weight to the contralateral hind limb, and not so much to the front limbs.…”

Evaluation of Variability in Gait Styles Used by Dogs Completing Weave Poles in Agility Competition and Its Effect on Completion of the Obstacle

“…Even within the Border Collie breed there is variability in conformation, with differences in shoulder angulation, length of back and loin, and rear limb angulation being notable. Variability of conformation has been shown to affect movement within breeds ( 24 ). This effect may be even greater when performing highly physical activities such as agility, compared with walking and trotting.…”

Biomechanics of the Canine Elbow Joint

“…Only sex was shown to be a significant factor altering that ratio, with females being below the mean value throughout different breeds [94]. Another study comparing kinematic and kinetic data of orthopedic healthy Labrador retrievers and German shepherds reported that Labrador retrievers carry a higher percentage of the weight on their forelimbs compared to the German shepherd (69% vs. 62%, p < 0.001) [66]. If this breed specific mechanical overload plays a role in the pathogenesis of DED and contributes to the high rate of Labrador retrievers with developmental elbow disease, in particular MCD, is not known.…”

“…The ratio between swing and stance phase depends from the gait pattern and the dog's velocity [28,29,70,71]. At the walk the swing phase of the forelimb accounts for 39 to 43% of the whole gait cycle [60] and increases to approximately 50% to two thirds of the whole gait cycle during the trot, depending from the trotting speed [28,43,45,58,62,64,66]. During running the swing phase is further prolonged and accounts for approximately 75% of the gait cycle [62].…”

“…Range of motion is influenced by different parameters like breed, limb and body segment length, gait, velocity, exercise, age, contralateral limb amputation and concurrent orthopedic disease. With increasing speed of the gait the range of motion of joints increases [29,45,57,62,66,68,69]. Obese dogs show an increased range of motion as well, especially during the stance phase [57].…”