Immediately after suffering a muscle injury, is it ice or heat?
The rule of thumb is captured in this acronym: RICE.
First, stop all activity that involves the the injured area to provide rest. Second, apply ice for at least 20 minutes to reduce swelling that can cause secondary injury to the muscle fibers. Apply compression with a wrap to the injured area to prevent swelling. Finally elevate the injured area to prevent blood from pooling and creating additional swelling.
If you have severe pain, broken skin, or are unable to use the injured area at all, seek medical help immediately.
So when would you use heat? Heat is useful in non-acute situations or after an injury is well into healing (usually after 72 hours). Notice that the main intent of the RICE treatment is to reduce swelling. Heat increases blood flow and swelling, so is counter productive with an acute injury.
Overworked, fatigued and tired muscles respond well to heat. The additional blood flow helps to free up muscle fibers and increase movement for these conditions. The key in using heat is to move the affected area by gently stretching or walking after the application of heat. This helps prevent the return of the original condition after the heat is removed.
If you’re using heat as part of your rehabilitation of an injury (after the 72 hour acute phase), always follow up the application of heat with a round of ice therapy.