Types and causes of injuries include: Acute: These occur suddenly while playing or exercising. Signs and symptoms include, sudden, severe pain; swelling; inability to place weight on a limb, hand or foot; extreme tenderness in the area involved; extreme weakness in a leg or arm; a bone or joint visibly out of place. Chronic: These occur as a result of prolonged or repeated sports or exercise activity. Signs and symptoms include, pain when playing or exercising; dull ache at rest; swelling. Specific sports injuries are: €¢ Sprain: a sudden or violent twist or wrench of a joint causing the stretching or twisting of ligaments, and often rupture of blood vessels with haemorrhage to the tissues €¢ Strain: injury to a muscle, often caused by overuse, resulting in swelling and pain €¢ Fracture: a break in a bone or cartilage €¢ Dislocation: displacement of one or more bones at a joint €¢ Bruise (contusion): usually caused by blunt impact; capillaries are damaged, allowing blood to seep into surrounding tissue. Bruises are normally minor, but painful, and easily recognised by their characteristic blue or purple colour in the days following the injury.