The impact of fatigue factor on force plate vertical ground reaction forces in the dog

Force plate is a sensitive, accurate, and objective equipment which simultaneously display the changes of ground reaction forces during animal’s locomotion. It is widely applied in the evaluation of surgical outcomes and pharmaceutical effects. However, literatures have indicated many factors including breed, body weight, gait, pathologic changes, subject velocity, interday variance, intertrial variance, and starting distance could all contribute to the variables of force plate measurement. Researchers must carefully evaluation those factors in order to avoid unwanted bias.lthough force plate has becoming more popular in veterinary studies, due to the difficulty in patient control, numerous repetitions are often required to acquire valid data. According to a previous research, most dogs requires 45.3±4.7 and 57.8±6.0 trials to achieve 5 valid trials in walking and trotting gait. However, fatigue caused by repetitive trials may lead to variations in the measured ground reaction forces. he purpose of this study is to investigate the relationships between multiple trial repetitions and magnitude of the ground reaction forces. total of 9 healthy dogs (healthy group) and 9 dogs with natural occurring hindlimbs lameness (abnormal group) were included in the study. One hundred repeated trials were performed on each animal by the same handler in each session, the participants were maintained at a stable trotting gait while crossing the force plate system. Dogs were allowed to trot at their preferred speed, however only data obtained within±0.2 m/s were used for analysis. Peak vertical force (PVF) and vertical impulse (VI) of forelimbs and hindlimbs were collected. he collected data in each 100 trials were further divided into 4 distinct blocks, each containing 25 trials. Levene’s test for homogeneity and mixed regression model for repeated measurements were used to test the differences between blocks on each categories with the statistical significance level set at 5% (α = 0.05).ccording to the study, both the peak vertical force and vertical impulse remain consistent within a session of 100 repetitive trials in healthy and dogs with mild lameness. t is suggested that the fatigue factor under this condition affects minimally to the vertical ground reaction forces and could be ignored.