Hot and Cold medical supplies are great ways of treating injuries, be it on the track, field, at home or even the office.  Heat therapy is primarily used for taking the edge off of several different kinds of body pain. Those dull, persistent pains that you get with stiffness and cramping as an example.  As a general rule, cold therapy is used for sudden, acute injuries such as ankle sprains, muscle years, bruising and inflammation.  Items such as reusable ice packs, ice wraps, ice bags and treatments.