Study finds common sports injuries could be lethal.

A study presented at the annual American Heart Association meeting in Chicago, Ill., in November found that a hard blow to the chest of a child athlete can result in sudden death despite wearing appropriate protective gear.

Particularly susceptible are children who play hockey, football, lacrosse or baseball. Specifically, a blow to the heart at a specific point during its beating cycle can cause ventricular fibrillation, a condition where little or no blood is pumped, resulting in collapse and sudden death if medical help is not provided immediately.

Dr. Barry Maron of the Minneapolis Heart Institute Foundation, the study's author, tracked 184 cases of the condition since 1995. Of these, 47 percent occurred during practice or competition in organized sports and 53 percent occurred during recreational sports or other activities. Thirty-nine percent suffered fatal chest blows while wearing protective gear--10 deaths occurred when the projectile directly hit the chest protector. The average age of these athletes was 15 years old.