Mihaela Peneș was a swimmer and played handball and basketball before taking up athletics. She first competed internationally at the 1964 Olympics, where at only 17 years and 86 days old, she won a surprising gold medal. In the first round of the Olympic final, Peneș became the third woman to throw over the 60 m barrier, with 60.54. That result baffled the favorites Elvīra Ozoliņa, who had became the first woman to throw javelin over 60 m earlier in the year, at the Soviet Championships, and Yelena Gorchakova, who had broken that world record with 62.40 in the qualifying round, so that Gorchakova could only manage bronze, while Ozoliņa finished fifth. Ozoliņa was so distraught with her performance that she went to the Olympic Village hair stylist and had all her hair shaved off.
After her surprise victory at the 1964 Olympics, Peneș won gold at the 1965 Universiade and silver at the 1966 European Championships. She last competed internationally at the 1968 Mexico City Olympics, where she won silver. Peneș was also Romanian javelin champion from 1965-68. She finished her athletics career after the 1968 Olympics and then worked as an athletics coach and official. She joined the Romanian NOC in 1990, became the head of its international department in 1995, and in January-April 1999 served as its Secretary General.
Athlete Olympic Results Content