On 6 October 1985 at the year's World Cup meet, Koch set the current 400 m world record of 47.60 seconds. That time is considered far out of reach of even the best of today's athletes. The meet was held at Bruce Stadium in Canberra, Australia, which is at 605 metres altitude. The world record 400 m run had been well planned, and her basic speed and speed endurance proven in several training runs in the weeks prior. One week prior to her 400 m world record run, anecdotal reports suggest that Koch had run the 200 m in 21.56 seconds (fully automatic time). This 200 m performance was never verified by the IAAF and remains unofficial.