Regardless of the specific structure affected, sports injuries
can generally be classified in one of two ways: acute or
chronic. Acute injuries, such as a sprained ankle, strained
back, or fractured hand, occur suddenly during activity. Signs
of an acute injury include the following: Chronic injuries
usually result from overusing one area of the body while playing
a sport or exercising over a long period. The following are
signs of a chronic injury: National Institute of Arthritis and
Musculoskeletal and Skin Disease (NIAMS) National Institutes of
Health