piston ring

i had burned the #5 piston ring in my 99' GT. i'm just curious b/c that engine only has 56,000 miles on it and i haven't done any really hard driving on it. i'm just tryin to find out how this could have happened. and just so no one asks, i didnt rebuild the engine, i ordered this engine from Jaspers. im gonna get them to replace it but im just trying to figure it out for my own knowledge for future reference. thanks.