Ice packs or cryotherapy are generally more effective in terms of depth of penetration than other superficial thermal modalities. Intramuscular temperatures can actually be reduced by 3-7 degrees C. This is helpful in reducing local metabolism, inflammation, and pain. The analgesic effects of ice result from a decreased nerve conduction velocity along pain fibers and a reduction of the muscle spindle activity responsible for mediating local muscle tone. It is usually most effective in the acute phase of treatment ( usually the first 72 hours) , though the client can use it for their pet after physical therapy or the home exercise program to reduce pain and the inflammatory response. It is applied over an area for 15-20 minutes, 3-4 times per day initially and then on an as needed basis. Superficial Heat:
Superficial heat can produce heating effects at a depth limited to 1-2cm. Deeper tissues are generally not heated due to the thermal insulation of subcutaneous fat and the increased cutaneous blood flow which dissipates heat. It has been found to be helpful in diminishing pain and decreasing local muscle spasm. Superficial heat, such as the hydrocolater pack, should be used as an adjunct to facilitate an active exercise program. It is most often used during the acute phases of treatment when the reduction of pain and inflammation are the primary goals. Heat therapy is used later in the healing process to increase blood flow, increase muscle flexibility, decrease pain and increase healing.