The effects of altered distances between A-frame and the preceding jump on front limb dynamics in agility dogs

A high proportion of agility injuries associated with an obstacle are due to the A-frame, however, there is limited research into the kinetics and kinematics of dogs traversing this type of equipment. The aim of this research was to study the kinematics and kinetics of agility dogs negotiating an A-frame when the preceding obstacle (in this case a jump) was placed at 10 m, 7.5 m and 5 m ahead of the A-frame. Six competition standard agility dogs were recorded negotiating an A-frame after completing a jump with each dog attempting each distance three times. Inertial measuring units attached to each dog gathered maximum velocity, acceleration and deceleration between jump landing and the A-frame. Video analysis and pressure sensors gathered carpal hyperextension and peak vertical forces for both forelimbs at the dogs' contact with the A-frame. The study found no difference in either carpal extension or PVF data between the different distances. However, maximum approach velocity decreased (p < 0.05) with decreasing distance: 10 m (7.30 ± 0.40 m/s), 7 m (6.61 ± 0.34 m/s), and 5 m (5.74 ± 0.62 m/s). Acceleration was also decreased at the 5 m distance compared with 10 m distance (p < 0.05). A notable finding was the -1.57 m/s² decrease in deceleration found between the 10 m (-5.92 m/s²) and 5 m (-4.35 m/s²) distances (p < 0.05), with the 10 m distance having 36 % more deceleration than 5 m. As forelimbs have a role in deceleration, an increased distance between obstacles could be one of the factors involved in forelimbs injuries in agility dogs. In our study, positioning the preceding obstacle 5 m from the A-frame moderated speed, acceleration, and deceleration, and could potentially help to reduce reported injury rates, but additional studies are recommended to allow evidence-based guidelines.