Front Matter

Chapter 8 Therapeutic Exercise 189

Specific exercises

In this section, specific exercises are described;
each one includes a goal, a technique, and a
progression.

Walking

For the patient who is post‐injury or postopera­
tive, initiating proper walk training is the most
important and the easiest first step to take.
Goal: Maintain a correct gait pattern through­
out the exercise.
Technique: The patient with concurrent car­
diac disease may simply go out to sniff and mean­
der for a set period of time, while the metabolically
healthy patient may be asked to maintain a speed‐
walking pace. Progression would involve chang­
ing the terrain (ramps and hills) or the substrate
(sand or gravel). Increasing the speed is also a
form of progression. The patient that has had sur­
gery for CCL insufficiency is started with short
toileting leash walks b.i.d. to t.i.d. for the first
week, then the exercise is made more difficult by
adding one block (approximately 0.1 mile) for
each week after surgery for up to 6 to 8 weeks.

Proprioception

For the healthy canine athlete, proprioceptive
exercises can enhance neuromuscular control
and functional joint stability, thus decreasing
the risk of injury. For the injured canine patient,
proprioception work is vital to ward off repeat
injury. For this reason, it is imperative that the
rehabilitation therapist be well versed in the sci­
ence of proprioception. Sherrington described
the proprioceptive system as “afferent informa­
tion from proprioceptors (mechanoreceptors)
located in the proprioceptive field that contrib­
utes to conscious sensations, total posture, and
segmental posture” (Sherrington, 1906; Lephart
et  al., 2000). Hewett and colleagues (2002)
expanded the definition to include the complex
interaction between the afferent and efferent
systems. Dynamic joint stability is the result of
neuromuscular control and proprioception
while postural control requires the integration
of visual, vestibular, and proprioceptive inputs
(Ghez, 1991; Shumway‐Cook & Woollacott,
1995). Any disruption in mechanoreceptor input

that affects proprioception will negatively affect

dynamic joint stability and therefore posture.

Mechanoreceptors

Mechanoreceptors (articular, cutaneous, and

muscle receptors) are located in connective

tissues throughout the body. Golgi tendon

organ‐like receptors are the largest of the arti­

cular mechanoreceptors. They are slow to

respond to stimuli, have a high activation

threshold, and are active only during dynamic

joint states, thus sensing the extremes of the

joint’s normal movement range (Zimny, 1988).

The role of cutaneous receptors in initiating

reflexive responses, such as the flexion with­

drawal reflex in response to potentially harmful

stimuli, is well established (Hulliger et al., 1979).

The muscle spindle and the Golgi tendon organ

(GTO) are the two primary types of muscle

receptors (Hulliger et al., 1979). Sensory output

from the muscle spindle detects joint position

throughout the range of motion (Matthews,

1981; Caraffa et  al., 1996). GTOs are located at

musculotendinous junctions. During a muscle

contraction this junction is stretched, distorting

the receptor endings of the GTO afferent neu­

rons. Activation of the GTO afferents leads to

inhibition of the motor neurons to the stretched

muscles and excitation of the motor nerves to

the antagonistic muscles. This feedback loop is

referred to as the inverse myotactic reflex.

In human sports medicine, several propriocep­

tive training programs have been shown to be

effective in reducing injury rates (Caraffa et  al.,

1996; Hewett et  al., 1999; Wedderkopp et  al., 1999;

Heidt et  al., 2000; Myklebust et  al., 2003). These

programs incorporate several steps to retraining

the injured athlete, as described by Caraffa and col­

leagues (1996). Their perturbation training pro­

gram for nonsurgical anterior cruciate ligament

(ACL) patients involves an early phase, exposing

the athlete to perturbations in all directions with

the goal of eliciting an appropriate muscular

response to applied perturbations (no rigid co‐con­

traction). The middle phase introduces light sport‐

specific activity during perturbation techniques,

with the goal of improving athlete accuracy in

matching muscle responses to perturbation inten­

sity, direction, and speed. The late phase involves

increased intensity of perturbations by using sport‐

specific stances. The goal is to obtain accurate,