Thermotherapy is the use of cold or heat on an injured area.
Cryotherapy is the application of cold, and is typically used during the period of acute inflammation which occurs 24-72 hours after a surgery or injury. It decreases pain and inflammation by causing a localized decrease in blood flow.
Heat therapy is employed after the first 36-72 hours post-injury and is often alternated with cryotherapy to increase and then decrease blood flow. It increases blood flow, relaxes muscles, and decreases pain. It also speeds healing by increasing enzymatic activity, improving muscle contractility and stretching capability, and increasing the extensibility of tendons.