A concussion is a head injury that affects your brain function. It can be produced by a bump, blow, or jolt to the head or body (with force transmitted to the head). Concussions are a national epidemic in athletics, especially in contact sports – from youth football, soccer, and lacrosse to the NCAA and professional leagues. An estimated 1.6 to 3.8 million sports-related concussions occur each year (Source: CDC).