Development of a Novel Gait Phase Classification for Dog Forelimbs: Advancing Kinesiological Integration and Physiotherapy

This study aims to develop and validate a gait phase classification system for dog forelimbs to enhance kinesiological understanding and establish a solid foundation for targeted physiotherapeutic interventions.

Eight clinically healthy beagles (ages 4–8 years) were selected to ensure consistency in gait patterns; beagles are commonly used in veterinary research due to their genetic uniformity. After treadmill acclimatization, kinematic data were collected for 10 gait cycles at 0.7 m/sec using a motion analysis system (Kissei Comtec Co., Ltd., Matsumoto, Japan, 60 fps). The ten gait cycles were analyzed to minimize variability due to habituation. A single observer conducted a frame-by-frame analysis of video data, classifying gait cycles into phases by adapting the human eight-phase gait classification to dog forelimbs. The dog gait phases were defined as initial contact (IC) and five subsequent phases: loading response (LR; from IC to when the contralateral forelimb is lifted from the floor), middle stance (MidSt; to when the contralateral forelimb makes contact with the floor), pre-swing (PSw; to ipsilateral forelimb lift-off), early swing (ESw; to when the carpal joint is opposite the contralateral forelimb), and late swing (LSw; to next IC). The reduced number of gait phases compared to humans reflects morphological differences, such as the digitigrade locomotion of dogs. Intraclass correlation coefficients (ICC) were calculated to assess intra-rater reliability of phase timing. Statistical analyses were performed using R software. All procedures were approved by the Animal Research Committee of Rakuno Gakuen University.

The mean durations of the gait phases (with one gait cycle considered as 0–100%) were as follows: LR (16.2 ± 0.3%), MidSt (33.7 ± 0.4%), PSw (16.8 ± 0.3%), ESw (7.8 ± 0.4%), and LSw (25.5 ± 0.4%). The ICC values for phase transitions were 0.83 (LR to MidSt), 0.86 (MidSt to PSw), 0.80 (PSw to ESw), and 0.93 (ESw to LSw), indicating excellent intra-rater reliability and confirming the robustness of our classification system.

We developed a novel classification for dog forelimb gait phases by adapting the human gait cycle. The validity was confirmed through good intra-rater reliability of gait phase timing. This classification integrates previously fragmented findings in dog kinematics, kinetics, and muscle activity, offering a robust framework for future research and physiotherapeutic interventions.

Clarifying the functional roles of each gait phase will facilitate the development of precise, phase-specific physiotherapeutic interventions, enhancing the quality of therapy in veterinary practice. Future studies should investigate this classification's applicability across different breeds, ages, and in dogs with gait abnormalities, potentially advancing dog physiotherapy significantly.