Miklós Németh, Hungary
World Record: 94,58m (310' 4") Montreal, Canada 26 Jul 1976
Miklos Nemeth is the only athlete to have set a world record and won an Olympic gold medal and to have had a father (Imre, hammer thrower) who had achieved these same distinctions.
Miklos had been something of a boy wonder, throwing 87.20 meters (286'1") when he was barely 20, but he did not seem to progress over the years. At the Mexico City Olympics he was troubled by an elbow injury and did not make it through to the final. At the Munich Olympics he was seventh with 81.98 meters (268'11"). Nor did he have much success at the European Championships. He was fifth in 1966, ninth in 1971 and seventh in 1974.
Finally when everyone had given up on the wunderkind, Nemeth finally did himself justice at the 1976 Olympics. In the first round he unleashed a killer throw, 94.58 meters, a new world record. That throw finished the competition, and he won by over 6.6 meters (21'8"), a huge winning margin.
He later became active in the design of javelins. His Nemeth javelin of the late 1980s had a special roughened area behind the grip, which increased the surface area. It led to several new world records, but these were later disallowed by the IAAF, which banned the implement.
source: World Record Breakers in Track & Field Athletics