Explained: A woman running the NYC marathon for charity dies 2 miles from the finish

Rachel Apa, 24, of Lewisberry, Pennsylvania, collapsed near the 24-mile mark of the New York City Marathon and later died.

rhabdomyolysis

A rare condition in which muscle tissue breaks down during extreme exertion, releasing substances that can poison the body.

Division I

The top competitive level of college athletics in the NCAA system.

five-borough format

The marathon route covering all five New York City boroughs, as opposed to earlier editions run only in Central Park.

defibrillator

A device that delivers an electric shock to the heart to try to restore a normal rhythm.