Running loops of an athletics track for 24 hours is most people’s idea of hell. But a brave band of souls – including our own Isaac Williams – have done just that as part of the Sri Chimnoy Self-Transcendance 24-Hour Race. But the undoubted master of the art is Yiannis Kouros.

On 4 October 1997, the Greek-born Australian Yiannis Kouros, one of the greatest ultrarunners of all time, ran a barely believable 303.5K in 24 hours.

In doing so, he set a 24-hour world record that, in his own words, is likely to “last for centuries”. The 41-year-old – who already held world records for ultra distances ranging from 100 to 1,000 miles, and times from 12 hours to six days – set a blistering pace from the off: reaching 100K in 7:15 and 150K in 11:05:02.

By the time 15 hours and 10 minutes had past, Kouros had broke the 200K world record and the pace – an astonishing average of 7:39min/miling – did not relent for the remaining nine hours. To put the extraordinary feat of endurance into context, no runner, almost twenty years on, has come within 27K of Kouros’ world record.

Hi secret? “When other people get tired, they stop,” he said. “I don’t. I take over my body with my mind I tell it that it’s not tired and it listens.”