The effect of the A-frame on forelimb kinematics in experienced and inexperienced agility dogs

Abstract

Limited research has evaluated the kinematics of agility dogs over different equipment despite the growing popularity of recreational and competitive agility. A-frames are associated with a higher risk of injury; these risks could be related to how dogs approach the equipment. We hypothesised that forelimb (FL) and spinal kinematics would differ throughout the different phases of negotiating the A-frame: incline, apex, decline, and between experienced and inexperienced agility dogs. Eight agility dogs of mixed breed and age, all trained on the A-frame participated in the study. Participants were divided into two groups: inexperienced dogs (ID: <4 years training; n=4) and experienced dogs (ED: >4years training; n=4), and undertook 3 runs over the A-frame. Reflective markers were placed on each dog’s carpus (Ca), radiohumeral (RH) and scapulohumerus (SH) joints, Atlas, C3 and L3. Video footage was transferred to Dartfish™ to enable FL joint angles to be calculated for the approach (last stride), incline (FL contact), apex (FL over), decline (FL touchdown and FL departure). The range of movement (ROM) for spinal markers was also calculated. Wilcoxon signed rank analyses, with Bonferroni correction applied (P<0.02), indicated if kinematics differed for ED and ID between the phases. Similar kinematic patterns were observed through all phases for C3 and L3, however a greater ROM was found for ED: C3 and ID: L3. For Atlas, ED stayed in flexion for all phases whilst ID movement varied: approach-incline extension, incline-apex: flexion, apex to decline extension followed by flexion. No significant differences in FL joint angles existed (P>0.02). No significant differences in kinematic measures were seen between ED and ID dogs in any phase of the A-frame. ED demonstrate consistent movement patterns; ID vary their head and neck position more, and exaggerate their apex jump. Rounding the A-frame apex could encourage a less-extreme technique in ID.