The collective benefits of aquatic exercises include assisted weightbearing; improved strength and endurance, cardiovascular
fitness, range of motion, agility, balance, and proprioception; as well as decreased joint effusion and peripheral edema.38,42,44,45 Be sure to monitor the patient closely and ensure its safety. Floatation devices may be used, and a handler should be with
the patient at all times. A patient that tires suddenly or experiences acute anxiety may require immediate attention.
Water temperature may also affect the cardiovascular response to exercise. Peripheral vasoconstriction occurs in people when
they are submerged in cool water. Blood moves centrally, enhancing venous return, which results in increased stroke volume
and decreased heart rate, increasing exercise efficiency.46 Blood pressure decreases slightly as well when working in cooler water. Because of these physiological effects of water temperature,
it has been recommended that whirlpools and underwater treadmills be kept in the range of 78.8 to 82.4 F (26 to 28 C) to prevent
heat-related complications.32 People who exercise in water that exceeds body temperature have higher cardiovascular demands that result in increased blood
pressure47; this may hold true for dogs as well. One study suggests that slightly warmer water temperatures ranging from 86 to 94 F
(30 to 34.4 C) had negligible influence on heart rate, respiratory rate, and rectal temperature.48
It is recommended to wait until after suture removal in an uncomplicated wound or incision before beginning aquatic therapy.
Some clinicians believe that it is only necessary to wait until the wound is sealed by fibrin. The cleanliness of the water,
urgency of the therapy, availability, and the patient's overall health may be factors to consider when determining when to
initiate aquatic therapy. In conditions that necessitate early aquatic therapy before the wound is sealed, surgical sites
can be temporarily covered and protected with water-resistant bandages, dressings, or wound sealants.
Neuromuscular electrical stimulation
NMES is a common modality used in physical rehabilitation. Most NMES units use surface electrodes to excite nerves, which
in turn, stimulate muscles to contract. The depolarization of the motor nerve results in skeletal muscle contraction. Three
types of currents are commonly used: continuous direct, continuous alternating, and pulsed currents. Most NMES devices are
pulsed current, which consists of unidirectional or bidirectional flow of DC or AC electrical current that stops for brief
periods. NMES is used in a variety of orthopedic and neurologic conditions, including cranial cruciate ligament pathology,
fractures, and spinal cord trauma.49 The benefits of NMES include increased joint mobility, decreased joint contracture, decreased edema, improved circulation,
improved muscle strength, and pain relief.2,32,50,51 Patients that should not receive electrical stimulation are those with pacemakers or seizure disorders. It should also not
be used over a carotid sinus, a gravid uterus, or areas of thrombosis or neoplasia.
Therapeutic ultrasound is a deep tissue heating modality that may be an effective adjunct when rehabilitating musculoskeletal
conditions such as restricted range of motion resulting from joint contracture, pain, and muscle spasm. It also appears to
be helpful in stimulating tissue healing at lower intensities. The degree of heat production and penetration depends on the
intensity, frequency, and duration of ultrasound and the size of the treatment area. The tissue type being treated is also
an important factor. High collagen content tissues (bone, cartilage, and tendons) are affected more than those with less collagen
(fat, blood vessels, and muscles).
The temperature of the tissues being treated can be raised 1 to 4 C (1.8 to 7.2 F) through the use of ultrasound. Some treatment
protocols have been extrapolated from experimental studies done in people.52-54 One study that looked at the effects of various ultrasound treatments on caudal thigh musculature in dogs showed significant
heating during 3.3 MHz ultrasound.26 Another study demonstrated a significant increase in hock flexion and tissue heating with 10 minutes of continuous ultrasound
at 1.5 W/cm2 applied to the calcanean tendon.27 The effects were transient and suggest a need to apply other stretching and range of motion exercises immediately after heating.
The skin over the target tissue must be clipped so that the ultrasound waves are not attenuated.55