Injuries can take your training to a standstill. With a better understanding of your injury and proper treatment, you can get back in the game faster than before.
As health care provider, I suggest icing an acute injury and heating a chronic injury. Unfortunately, most of us do not understand the difference between acute and chronic so we self-treat with whatever we think feels good. Enhancing your body's physiology with the proper use of ice and heat at the proper time can help shorten a recovery episode.
The physiology of ice can be best explained as follows:
Ice constricts blood flow to muscles. As the muscle cools, the amount of blood in the muscle diminishes as the constriction process pushes it out. This is great to help reduce bruising, swelling and discomfort.
As the muscle warms and the blood vessels expand, new blood comes rushing in and cleans the debris left behind from the injury and stimulates the healing process. It is recommended that ice is only applied for 10 minutes every hour. The more often the cycle is allowed to transition, the faster one's body can recover from an acute muscle injury (injury having severe onset and a short course). Always place a towel between the body and the ice to prevent trauma to the skin. Note that the increasing the icing time has a negative effect on the body.
Moist heat is a great treatment tool for chronic muscle injuries (injuries persisting for a long time). Moist heat applied to the injury site opens up the blood vessels allowing blood to flow more freely. Typically, chronic injuries have some sort of ischemia (lack of blood) associated with them. The ischemia is detrimental to healing and the moist heat helps reduce it. Apply moist heat for up to 20 minutes every hour and always place multiple towels between the body and the moist heat to prevent trauma to the skin.
What happens if you place heat on an acute injury or ice on a chronic injury?
Think of this scenario. You burn your mouth on a hot cup of coffee (acute). Do you suck on an ice cube or drink more hot coffee? Ice reduces the inflammation to the burn and diminishes the nerve response allowing some sense of a good feeling. It's a little different with a muscle injury in that the heat initially feels good even though it is adding inflammation and swelling. Then, once the heat is removed the injury site is typically more irritated than if you just left it alone. Ultimately, you are extending your symptoms and delaying the healing cycle when heat is applied to an acute injury. With a chronic injury, applying ice when heat is suggested can delay the therapeutic effects that heat offers.