[Ground reaction forces of the canine hindlimb: are there differences between gait on treadmill and force plate?]

Computer assisted gait analysis is based on the evaluation of kinematic parameters and the measurement of ground reaction forces by force plates or special instrumented treadmills. So far it is unclear, whether the canine gait of the hind limb differs fundamentally between the walk on treadmill and force plate.Thus, aim of this study was the comparison of ground reaction forces of the hind limb of dogs while walking on force plate and treadmill. Nine adult dogs of different breeds were used in the study and one hind limb of each dog was analysed on force plate and treadmill.The peak forces in direction of x, y and z and the vertical impulse (IFz) were evaluated. Considering the ground reaction forces of the hind limb, despite of the breaking forces, there were no significant differences between force plate and treadmill. Comparison of peak vertical force (Fz) shows magnitudes of 61.58% BW (body weight) on the force plate and 51.87% BW on treadmill. Vertical impulse (IFz) mounts up to 10.23% BW on treadmill and 11.49% BW on force plate. Fx and Fy forces showed only a low correlation, so these values were considered as uncomparable between treadmill and force plate. In summary it can be concluded that the vertical ground reaction forces of the examined dogs do not differ fundamentally on force plate and treadmill, whereas certain differences exist with regard to mediolateral and craniocaudal ground reaction forces. In the context of clinical gait analysis studies instrumented treadmills can be used increasingly to support the diagnostics of orthopaedic problems. The results of this study suggest that a direct comparison of the treadmill data with force plate measurements is only meaningful for the vertical ground reaction forces.