Page 56 - Canine Lameness

28 2 Objective Gait Analysis

2.4.2 Animal Handlers
It has been shown that differences in handlers can affect gait data. Therefore, clinicians should try
to limit the number of people who leash walk patients for gait analysis and when possible have the
same person walk an individual patient at each examination time.

2.4.3 Velocity and Acceleration
Changes in movement velocity (e.g. speed) and acceleration have some of the most profound
effects on both kinematic and kinetic gait data. Clinicians should select an acceptable velocity and
acceleration range prior to data collection and only collect trials that conform to that range. Ideal
velocity ranges for walking and trotting may vary between animals of differing sizes. In the author’s
experience, a walking velocity of 0.9–1.2 m/s, a trotting velocity of 1.7–2.1 m/s, and an acceleration
2
range of −0.5 to 0.5 m/s are appropriate for most medium‐ to large‐breed dogs. Information
regarding the merits of wider or narrower velocity ranges for trotting dogs can be found elsewhere
(Hans et al. 2014).

2.4.4 Marker Application

Much of the easily preventable error in kinematic analysis is related to errors in initial marker
placement or marker replacement (Kim et al. 2017; Torres 2018). Clinicians can minimize this by
designating a point person(s) to attach the markers to animals standing in a natural position as
well as establishing consistent protocols for marker placement. Standard marker locations have
been established for most models and many rely on marker application over easily palpable bony
landmarks to help ensure repeatability.

2.4.5 Comparing Averages

For kinetics and kinematics, single gait measurements should not be used for comparison.
Instead, clinicians should compare an average value from repeated measurements. An average
of five measurements or data from five trials are most commonly used for comparison. For PSW
systems where multiple and repeated measurements can occur during one pass, often the
results from five passes are averaged for comparison. Although the clinical benefit of using
more than five passes is unclear, clinicians should avoid using less than three measurements
for comparison.

2.5 Evaluating Gait Data

The appropriate analyses of data in kinetics and in kinematics often rely on similar methods. The
built‐in equipment software programs often can perform data comparison to varying degrees.
However, it is more common that data is exported into a spreadsheet program or a stand‐alone
statistical program for comparison.
In veterinary medicine, single‐point values such as PVF, VI, MAX, MIN, and ROM are most
commonly evaluated (Figure 2.3) and provide clinicians with a single value that is easier to inter-
pret and compare. Other methods may use the entire gait waveform for comparison (Torres 2018).
However, these methods are more complex and time consuming thereby limiting their usefulness
in a clinical setting.