Objectives
To describe the effect of direction of travel on measurements of peak vertical force (PVF) and vertical impulse (VI) obtained using a Tekscan walkway system.
Methods
Following acclimatisation, recordings were obtained for six healthy dogs walking twice in in each direction along the walkway. PVF and VI measurements were normalised and used to calculate left:right symmetry ratios for forelimb and hindlimb loading in each travel direction and for all recordings.
Results
Mean walking speed was 1.2 ± 0.14 m/s. Mean body mass was 25 ± 5 kg. No gross evidence of pulling to left or right was observed. Mean symmetry ratios for PVF and VI varied consistently but insignificantly with direction of travel. However, individual variation in symmetry ratios ranged from ±0.4–14 % for PVF and ±0.4–11 % for VI. Forelimb to hindlimb ratios of both PVF and VI varied by ±3-4 % with direction of travel.
Statement
Direction of travel may influence gait characteristics and thereby both determination of local reference intervals and discriminatory ability between normal and abnormal limbs. Consistent walkway room setup and use of multiple passes in both directions appear sensible in order to minimise error between measurements at different times, and to compensate for the effect of direction of travel on outcome measures.