The emergence of Barry Word in Kansas City and Rod Bernstine in San Diego gives those teams unusually hefty running attacks. The Chiefs are especially blessed in this department, with Christian Okoye (260 pounds) and Word (240) at running back and Bill Jones (228) at blocking back. "We like to find backs who can run, block and catch," says K.C. coach Marty Schottenheimer. "If you get a big, strong guy with those qualities, he'll have an advantage over the smaller guy, unless the smaller guy is Barry Sanders." Marion Butts (248 pounds) and Bernstine (238), a converted tight end, give the Chargers a potent one-two punch. By averaging the weights of the top two rushers for every team in NFL history, the Elias Sports Bureau came up with this list of the five alltime heaviest backfield duos.