Range of motion
There are a number of factors to consider before using exercise to increase range of motion. Do you want to improve active or passive range of motion? What joint is being treated? Which tissues around the joint are affecting range of motion? In what condition are the joint surfaces, articular cartilage, joint capsule and ligaments? Keep in mind that it may or may not be possible to restore a "normal" range of motion depending on the lesions affecting the joint. When you are working to increase range of motion in a canine patient, the goal is to gain function.
Range-of-motion exercises can be applied actively or passively. In an active range-of-motion exercise, the patient is encouraged to perform exercises that cause the joint to assume the desired range. An example is using a physioball to get a postoperative elbow-fracture patient to extend the elbow. The dog is lifted onto the ball with its forelimbs draped over the front. As the ball is gently rocked forward, it will reflexively extend its forelimbs to protect itself from falling on its nose. In a passive range-of-motion exercise, the therapist creates the motion. An example is using gentle flexion and extension of the stifle in a postoperative anterior cruciate ligament repair patient. The success of both active and passive range-of-motion exercises is determined by using a goniometer to measure joint range of motion before and after therapy.
There is an important distinction between range of motion and flexibility. Range of motion is associated with joint osteokinematics. Flexibility relates to muscle and tendon elasticity. It is interesting to note that issues related to flexibility commonly appear in two muscles surrounding the same joint rather than in just one. Therapeutic exercises that focus on stretching can be initiated once these muscles have been identified.
Not unlike their owners, dogs should always warm up before beginning any stretching work. (In the case of non-ambulatory patients, E-stim or therapeutic ultrasound can be used for this purpose.) Therapeutic stretches can be active or passive. An active stretch is initiated by the patient. In a common stretching technique, cookies are used to encourage the dog to reach into positions that will stretch the affected muscle. Active stretching also can be accomplished with exercises such as walking through weave poles or around cones set in a tight pattern. Passive stretches are done by the therapist. An example is advancing the forelimb to stretch the latissimus dorsi and teres major muscles. The patient needs to be comfortable with the therapist and relaxed and cooperative in order to benefit from passive stretching exercises.
Building endurance is equally important in debilitated patients and canine athletes. Dogs recovering from an extended period of recumbency have very low endurance. This is because the first fibers lost when a muscle is immobilized are the slow-twitch fibers, most common in muscles of posture or gravity-resistance. Early endurance work for these patients may involve little more than assisted standing, with a focus on postural muscles rather than on the cardiovascular system.
On the other hand, building endurance in a canine athlete is focused on the cardiovascular system. Land routines, treadmills and water can all be utilized to increase strength, speed and duration of effort in these dogs. Heart rate, respiratory rate and how fast each recovers after a maximum effort are monitored on an on-going basis. Resistance can be used to augment the effects of any exercise program, which can be done using weighted vests, sleds, resistance bands, hill work and water.
The emphasis in strength training is primarily on resistance. In a debilitated patient, strength training starts slowly, such as moving from down to a sit, and a sit to a stand. Gravity is the only resistance needed here. External resistance can be added as the patient progresses.
Many different types of weights can be used in veterinary rehabilitation. If the focus is on strengthening a single limb or set of muscles, leg weights can be used. Adding core strengthening can help prevent thoracolumbar and lumbosacral injuries, especially in canine athletes and chondrodystrophic breeds.
Many canine rehabilitation patients struggle with awareness of body position, or proprioception. Therapeutic exercise can address this problem in a number of ways. In debilitated patients, proprioception training can be as simple as assisted standing, progressing to standing with the addition of gentle perturbations by the therapist. When the patient is able to resist these movements without losing balance, more challenges can be added such as rocker boards, wobble boards and other unstable surfaces.
A rocker board is a platform with a rounded rail on the underside that rocks from side to side when a dog stands on it. The patient must work to resist this movement to maintain balance. Once the dog has mastered the rocker board, it can progress to a wobble board — a platform with a hemisphere on the underside that can rock in any direction. The size of this hemisphere can be increased to increase the challenge.
More active proprioception exercises include walking through a pile of PVC rails or over cavaletti rails set at irregular heights and distances. Walking the dog on an air mattress also can improve proprioception. The more inflated the air mattress, the easier it is for the patient. As the dog gains skill on this surface, gentle perturbations can be added, either to the patient or to the mattress surface. Balance blocks are another proprioception tool. The dog can be placed on these blocks and asked to stand. The blocks can then be slid apart, forward or backward, requiring the dog to reestablish its balance.
Design of the therapeutic exercise program
A canine rehabilitation therapist evaluates the patient and identifies the structures involved and the stage of recovery of the tissue. From this evaluation, goals are set and a therapeutic exercise program is designed to meet them. The patient is evaluated at each visit to measure progress made and to make adjustments to correct for any deficits. The rehabilitation therapist must be able to recognize when the patient is ready to progress from early exercises to those that are more challenging. The goal, once again, is to improve functioning and quality of life for the patient.
Many therapeutic exercise options can be used in canine rehabilitation — exercises that increase joint mobility, flexibility, strength and endurance. Treadmills, pools, cones, poles, boards, weights — even cookies — can help dogs achieve health and fitness goals. Ultimately, however, the skills and training of the therapist are what bring the benefits of therapeutic exercise to canine patients.
Dr. Van Dyke is the founder and CEO of the Canine Rehabilitation Institute in Wellington, Fla., with locations in Fort Collins, Colo., and Annapolis Junction, Md.