Force platform analysis in clinically healthy Rottweilers: comparison with Labrador Retrievers.

OBJECTIVE: To (1) report ground reaction forces for healthy Rottweilers at a trot and (2) compare force platform data with values obtained for healthy Labradors. STUDY DESIGN: Prospective, clinical study. ANIMALS: Adult Rottweilers (n=9) and Labrador Retrievers (12) without orthopedic abnormalities. METHODS: Dogs were trotted over a force platform at controlled speed and acceleration. Peak vertical and craniocaudal forces, associated impulses, stance time, rising, and falling slopes were analyzed and forces, impulses, and slopes were expressed as percentages of body weight. The effects of weight and anatomic measurements on force platform values were re-evaluated with analysis of covariance (ANCOVA). RESULTS: In Rottweilers, peak vertical forces in thoracic limbs were significantly lower and vertical impulses in thoracic and pelvic limbs were significantly higher than in Labradors. Rising and falling slopes in thoracic and pelvic limbs were significantly smaller in Rottweilers. Body weight and anatomic measurements were significantly larger in Rottweilers. After removing the effect of relative velocity, functional limb length, and body weight by using ANCOVA, there were no significant differences between breeds. CONCLUSIONS: Ground reaction forces were significantly different between Rottweilers and Labradors when using standard methods of normalization. Based on ANCOVA differences were attributable to difference in conformation and body weight between breeds. CLINICAL RELEVANCE: Conformation and body weight have a significant influence on force platform values and this may cause bias when study results are compared.