Page 109 - Canine Lameness

5.5 Strength Testing 81

(B)

Figure 5.7 (A) The Gulick tape measure is used to
measure limb circumference. (B) The device
contains a 4-oz spring-loaded tension indicator
that allows the tester to standardize the amount of
(A) tension applied. The appropriate tension is applied
when one red bead is visible (white arrow).

5.5 Strength Testing

Whereas flexibility testing evaluates the passive extensibility, or stretch of a muscle, strength test-
ing evaluates the force‐producing capacity of the muscle to determine if weakness is contributing
to lameness. Strength testing can only tell the tester if the muscle is strong or weak, not the under-
lying reason why. If the evaluator finds muscle weakness during the strength test, further diagnos-
tics to determine the cause should be pursued.
Prior to strength testing, the quantity of muscle bulk should be estimated to determine if muscle
atrophy has occurred, even though muscle circumference is not necessarily directly correlated
with muscle strength. Muscle mass can be estimated by direct palpation or by measuring the limb
circumference with a Gulick tape measure. Direct palpation certainly is subjective, and several
authors have also called into question the validity and reliability of Gulick measurements. Namely,
the ability to replicate positioning of the tape measure on the limb (particularly from one session
to another), hair regrowth (if used during convalescence from surgery), and systemic weight gain
or loss is a factor that influences these measurements (Smith et al. 2013; Bascuñán et al. 2016).
Therefore, the clinician should understand the correct use of a Gulick device and take note of the
area measured to improve the accuracy of subsequent measurements (Figure 5.7).

5.5.1 How to Perform Strength Testing
Strength testing in people is performed using validated tests, such as the manual muscle test
(MMT) to determine hip extensor muscle strength (Perry et al. 2004). These tests rely on commu-
nication with the patient (e.g. asking the patient to maintain a certain joint or limb position while