Objective gait analysis is not commonly used in small animal clinical practice because it can be time consuming and requires expensive instrumentation. However, objective measurement and evaluation of gait variables are useful in distinguishing normal from abnormal gaits and for assessment of long-term outcomes for surgical procedures and nonsurgical interventions.1–3 To date, force plate analysis has received the most attention in both human and veterinary medicine,4–9 and it is widely considered to be the gold standard of objective gait assessment. In quadrupeds, the sequential use of 2 (or more) force plates has been shown to improve accuracy and efficiency of data collection.10
Pressure-sensitive walkways were introduced as a time-efficient alternative to the use of force plates. These walkways have the important advantage of providing both temporal and spatial information on the kinetics of all 4 limbs during the gait cycle.11 With a walkway of the appropriate length and width, it should be possible to collect data for 1 or 2 complete gait cycles from dogs of different sizes. Evaluations of various walkway systems, ranging from pressure-sensitive plates to full walkways, have been published.10–12 Determination of step length, stance phase, and swing phase allows walking trials to be divided into individual gait cycles, each consisting of a stance phase and swing phase. This permits simple comparisons of forces and paw contact areas across multiple strides and walking trials.
Pressure-sensitive walkways have some important limitations, the most important of which is that it is not possible to have precise control of the velocity at which the dog moves over the walkway. It has been shown that velocity is a key determinant of temporospatial variables for dogs,13 and thus, the inability to control velocity contributes to variability of data collected from pressure-sensitive systems that record over a fixed-length walkway. Walkways also require a large amount of floor space in the gait analysis laboratory or clinic (typically at least twice the length of the walkway is needed to allow animals time to reach a stable walk or trot before reaching the walkway and then slow down after stepping off of it). Finally, pressure-sensitive instrumentation can be very expensive, even relative to force plates, and it can easily be damaged if the sensors are not handled carefully.
Instrumented treadmills were introduced in the late 1980s as a space-efficient and cost-effective alternative to instrumented walkways.14,15 Instrumented treadmills are available that make use of force sensors16,17 or pressure sensors.18,19 Although introduced initially for the human market, instrumented treadmills are becoming more common in the veterinary market. Brebner et al20 reported on the use of a forcesensitive treadmill for assessment of dogs with and without lameness, and Assaf et al21 recently compared gait analysis results measured with a pressure-sensitive walkway and a pressure-sensitive treadmill for a group of healthy dogs. Although there was some concern that dogs (or people) might have different gait patterns over ground, compared with the patterns detected when walking or running on a treadmill, 1 study11 of 5 mixed-breed dogs found no significant differences between overground gait patterns and those assessed on a treadmill. An investigation of 40 adult human subjects also indicated that differences in most gait variables are no longer detectable after approximately 6 to 7 minutes of acclimatization to a treadmill.6
The purpose of the study reported here was to assess the repeatability of gait analysis results for healthy dogs determined by use a of pressure-sensitive treadmill designed to measure temporospatial and kinetic gait variables in this species. We hypothesized that the instrumented treadmill would provide repeatable intrasession and intersession measurements of kinetic and temporospatial variables in the study sample.
The instrumented treadmill was provided by Zebris Medical GmbH. No direct financial support was provided for this study. Dr. Häusler serves as a consultant for Zebris Medical GmbH.
Presented in abstract form at the 10th International Symposium on Veterinary Rehabilitation and Physical Therapy, Knoxville, Tenn, 2018.
Ground reaction force
Intraclass correlation coefficient
Interquartile (25th to 75th percentile) range
CanidGait, Zebris Medical GmbH, Isny im Allgäu, Germany.
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