When should you apply ice, heat or anti-inflammatories to that new or nagging injury? Injuries can be generalized as either acute - sudden onset and short-lived, or chronic - slow onset, and long-term.
Acute injuries are a result of sudden or recent trauma, characterized by mild to severe pain, redness of the skin, and swelling. Immediate treatment should be R.I.C.E.. Rest, Ice, Compression, Elevation. Rest and immobilize the injured site immediately and for the next 24-72 hours, icing the area for 15-20 minutes at a time, with an hour off in between, to allow the skin to return to body temperature, compress the site, and elevate at or above your heart, to reduce inflammation. NSAIDs - Non-steroidal, anti-inflammatory drugs can be taken as directed to further reduce swelling. If you are not showing signs of improvement within a few days, seek a sports-medicine professional.
Chronic injuries tend to be more subtle and slow to develop. They may be the result of an acute injury, but can not always be traced to a single incident. They are often the result of overuse or dysfunction, and are characterized by dull aching pain, soreness or stiffness. Heat, before activity, is the best treatment for these injuries, moist heat is best. Hot towels, heating pads or athletic hot packs applied to the affected area, promote circulation and elasticity of the joint or muscle tissues that do not suffer from inflammation. Icing after activity may aid recovery and prevent inflammation. Persistent pain lasting more than a week without improvement should be evaluated by a medical professional.