When you do physical exercise to excess, you may experience sudden pain and swelling around a joint or a muscle. This may occur when you stretch too far, change direction or slow down abruptly, land awkwardly, or collide with another player during a sporting event. The injury you have may be a sprain or a strain.

Here's the distinction:

• Sprain
  A sprain is a stretching or tearing of ligaments. Ligaments are tough bands of fibrous tissue that connect one bone to another. They help to stabilize joints, preventing excessive movement. Sprains are frequently caused by rapid changes in direction or by a collision. Common locations for sprains are your ankles, wrists and knees.
   

• Strain
  A strain is a stretching or tearing of muscle. This type of injury often occurs when muscles suddenly and powerfully contract — or when a muscle stretches unusually far. This is called an acute strain. But overuse of certain muscles over time can lead to a chronic strain. People commonly call muscle strains "pulled" muscles. Hamstring and back injuries are among the most common strains.

Treatment depends on the severity of the injury. Many times, self-care measures and over-the-counter supports and pain medications are all that you'll need.