230 Canine Sports Medicine and Rehabilitation
abdominal, quadriceps, and hamstrings) where
the 50th percentile represents the average
sedentary pet dog, greater than that represents
increasing degrees of fitness, and less than that
represents various degrees of muscle atrophy.
Over time, it becomes clear that many dogs
have significant imbalances in musculature. For
example, some dogs have large, well‐toned
quadriceps and weak, even atrophied ham
strings, while others have the reverse. Likewise,
many dogs have imbalances between the size
and fitness of the paraspinal and abdominal
musculature. The value of this kind of assess
ment is that specific muscle groups that are atro
phied or even just lacking size and tone compared
to their antagonistic muscle groups can be tar
geted with specific strength training exercises.
The core body muscles are important for
coordination of spinal and limb movements
and are critical when immediate responses of
the limbs are necessary. Since the thoracic limbs
generally bear 60% of the dog’s weight and all
the weight of the dog plus the effects of gravity
when a dog is jumping, cantering, or galloping,
the thoracic limbs get more exercise than the
pelvic limbs during routine daily activities and
performance training/competition. As a result,
canine rehabilitation professionals working
with canine athletes, particularly those that are
continuing to compete after their prime years,
should place special emphasis on exercises to
keep the pelvic limb and core muscles toned.
Body fat
A large proportion of dogs in North America are
overweight or obese (German, 2006). Dogs are
generally considered overweight when their
weight is greater than 15% above ideal, and are
obese when their weight is greater than 30% of
ideal (Gossellin et al., 2007), although these crite
ria have not been confirmed by rigorous epide
miological studies in dogs. Surprisingly many
active dogs, competition dogs, and even work
ing dogs are overweight, though it is less com
mon for them to be obese. Interestingly, recent
studies have shown that there can be a genetic
predisposition to obesity in certain breeds of
dogs (Miyabe et al., 2015; Davison et al., 2017).
There is strong evidence that people who are
overweight have an increased risk of cancer
and other systemic diseases as well as early
death, though the evidence basis in dogs is not
as rigorous (Cowey & Hardy, 2006; Martin et al.,
2006; Bach et al., 2007; Zou & Shao, 2008). The
increased prevalence of orthopedic disease in
obese humans suggests that obese dogs are
likely equally predisposed. Certainly, keeping
an animal in optimal to slightly lean body
condition has been shown to decrease the
risk of development of osteoarthritis (OA)
(Budsberg & Bartges, 2006).
While many veterinarians use visual body
condition scores in which dogs’ body condition
ranges from 1 (very thin) to 5 or 9 (very over
weight) to determine whether dogs are at a
correct weight, these systems have significant
limitations. They are not as helpful in coated
dogs, in which the coat can make a dog look
deceptively overweight, or in dogs such as
sighthounds that naturally have obvious ribs
and pelvic bones. A more important limitation
is the fact that visual scores do not adequately
differentiate between increased body size due
to fat versus muscle. In fact, a study sponsored
by Purina showed that the percentage fat in
dogs with a body condition score of 5 varied
from 13 to 22% (Brian Zanghi, 2017, personal
communication).
One way to assess whether dogs have excess
body fat is to palpate the thickness of the subcu
taneous fat. This is easily done in the area of the
dorsocaudal ribs, just ventral to the edge of the
latissimus dorsi muscle (Figure 10.1). In that
area, there is just a layer of skin and a layer of
subcutaneous fat overlying the ribs. When the
mobile skin and subcutaneous tissues in that
area are pinched and pulled away from the
body, the layer of subcutaneous fat slips
through the fingers first (Figure 10.2). In an
active dog, canine athlete, or working dog, that
layer should be as thin as tissue paper. There is
no advantage for an active, working dog (with
the possible exception of immediately pre‐race
long‐distance mushing dogs) to be carrying
extra subcutaneous fat.
This skin‐pinch system helps to determine
whether the dog is carrying excess fat on its body,
allowing for evaluation of body fat separately
from muscle. With experience, the canine sports
medicine/rehabilitation professional can closely
estimate the thickness of the layer of subcutane
ous fat and add that to the dog’s clinical records.