Clean Run - April 2017 - 16

How Harnesses May Alter Gait

Balance HarnessTM

Some gait characteristics can be altered
significantly while wearing a harness.
Most owners and handlers do not observe an obvious alteration in gait while
their dog is wearing a harness. However,
visually observing subtle changes in
gait can be difficult. Pressure-sensing
walkways have been validated to analyze gait characteristics in dogs and can
detect subtle gait alterations. Pressuresensing walkway measurement systems
objectively analyze gait data quickly and
provide a number of temporal (timing)
and spatial (distance) gait parameters.
See Table 1. This form of objective gait
analysis can be used in a clinical setting
to aid in diagnosing orthopedic, muscular, and neurological disorders that affect gait. It also can be used to analyze
the effects of various factors, such as
harnesses, on gait characteristics.
A recent study was conducted at Veterinary Orthopedic & Sports Medicine
Group in Annapolis Junction, Maryland to evaluate how five commercially available harnesses affect canine
gait characteristics at the trot using a
pressure-sensing walkway. The restrictive harnesses used for the study were
the ComfortFlex® Sport Harness, the
PetSafe® Easy Walk® Dog Harness, and
the Julius-K9® IDC® Harness. The nonrestrictive harnesses were the Balance
HarnessTM and the Dog-Games® Original Fleece-Lined Harness. The Balance
Harness has both a front and rear clip
for the leash, but only the rear clip was
used in the study.
To control for different sizes and styles
of movement of different breeds of
dogs, and because the breed is so commonly used for agility, this study used
10 healthy Border Collies. For each dog,
three passes trotting across a pressuresensing walkway were recorded either
with the dog on a leash and collar or
on a leash attached to the harness. In
all cases, the leash was held loosely so
that the dog was not pulling. For each
dog and each harness, the following
variables were measured or calculated
for each passage: total pressure index
percentage (TPI%), stance time percentage (ST), stride length (SrL), and
step length (StL) (Table 1).
16

Dog-Games® Original
Fleece-Lined Harness

These are examples of non-restrictive harnesses, which cross the body above
or in front of the shoulder joint. The fleece-lined harness has a large surface area
in contact with the dog's body.

Table 1. Temporospatial Gait Analysis Parameters
Temporal (timing)
Gait Parameters

Spatial (distance)
Gait Parameters

Gait Cycle Time is the elapsed
time between the first contacts of
two consecutive footfalls of the
same foot, measured in seconds.

Total Pressure Index Percentage
is the sum of peak pressure values recorded from each activated sensor by a paw during mat
contact (e.g., how much pressure
a dog is placing on each paw).

Stance Time is the time elapsed
between the first contact and
the last contact of one identified paw, expressed in seconds
(e.g., the amount of time the
dog spends with their paw on
the ground).

Stride Length is measured on the
line of progression between the
heel points of two consecutive
footprints of the same foot (e.g.,
left front foot to left front foot).
Step Length is the distance between the heel point of one foot
to the heel point of the contralateral foot (e.g., left front foot to
the right front foot).

The results of this study demonstrated that wearing a harness affects gait. Interestingly, regardless of the harness type, some dogs were found to be highly reactive
to wearing a harness. In fact, even dogs who had been wearing harnesses most of
their life and that were thought to be well accustomed to wearing a harness were
still found to have significant alterations in gait while wearing a harness, regardless
of the type of harness. Overall, wearing a harness was also associated with a longer
forelimb stride length, shorter forelimb step length, a greater forelimb total pressure index percentage, and a shorter forelimb gait cycle.
In this study, some harnesses were shown to affect gait characteristics more than
others. In particular, dogs reacted most strongly to the Julius-K9 IDC Harness, which
was classified as a restrictive harness, and the Dog-Games Original Fleece-Lined
Harness, which was classified as non-restrictive. Interestingly, these two harnesses
had the most surface area touching the dog's bodies. In contrast, the Balance Harness, which was the most adjustable harness and also covered the least amount of
the dog's body surface area, appeared to affect gait characteristics the least.
Clean Run | April 17

Table of Contents for the Digital Edition of Clean Run - April 2017