Influence of height, body weight and body weight-to-height ratio on jump kinematics in agility dogs

Abstract

Recent studies have described the jumping biomechanics of agility dogs and identified key variables that optimize jumping performance. Although the potential influence of morphometric variables on biomechanics of jumping dogs has been acknowledged, few studies have examined their actual relationships. The aim of the present study was to investigate the influence of height at the withers, body weight and body weight-to-height ratio on the linear, angular and temporal biomechanical variables of the agility jump. Eleven agility dogs were analyzed jumping over a 60-cm single hurdle. Inter- and intra-individual variability and correlation analyses were performed. Morphometric variables, particularly body weight and body weight-to-height ratio, significantly influenced jump kinematics. Heavier dogs, and those with higher body weight-to-height ratio, tended to exhibit greater jump heights at take-off, over the hurdle, and at landing, as well as shorter jump distance in front of the hurdle and total jump distance. In contrast, lighter dogs, and those with lower body weight-to-height ratio tended to show lower jump heights at take-off, over the hurdle and at landing, and longer jump distance in front of the hurdle and total jump distance. The body weight-to-height ratio significantly affected jump trajectory: dogs with higher ratios showed shorter, steeper trajectories, whereas those with lower ratios showed longer, flatter ones. These results suggest that performance differences may exist among dogs in the same agility category based on their height at the withers but differ in body weight-to-height ratio, supporting consideration of this variable when defining competition categories.