Despite what their PE teachers might have told them, for many of those who competed in a Chinese marathon earlier this month, it was not the taking part but the winning that counted.

Almost a third of the runners who finished in the top 100 have since been disqualified for cheating in the race in the southern port city of Xiamen.

Some of them hired imposters to compete in their place.

Some competitors jumped into vehicles part way through the route, Chinese media reported, while others gave their time-recording microchips to faster runners. Numbers 8,892 and 8,897 both recorded good times - but only thanks to number 8,900, who carried their sensors across the finish line.

Jiefang Daily, the Shanghai Communist party newspaper, said organisers caught the cheats when they scanned video footage. The paper said most of those involved had apologised, but that those showing an "unco-operative attitude" would be prevented them from competing in future events.

There was more than just prestige at stake in the marathon. Competitors stood to gain a crucial advantage in China's highly competitive university entrance exams. Those who finished in under two hours and 34 minutes could add extra points to their score in the gaokao, helping to explain why several of those disqualified came from a middle school in Shandong province.

The exams are so crucial to the future of Chinese children that both students and their families will go to extraordinary lengths to guarantee success. Last year, eight parents and teachers were jailed on state secret charges after using communication devices - including scanners and wireless earpieces - to help pupils cheat.

Organisers of the international event in Xiamen have vowed to increase surveillance in future, saying that they had only 200 monitors to oversee 50,000 runners in the marathon and accompanying races.

The problem is not a new one; in 2007, 19 competitors in Beijing were caught with multiple timing sensors.

Nor is such cheating restricted to China. Rosie Ruiz remains infamous in the United States for her victory in the women's race in Boston in 1980.

No one could understand how an unknown amateur runner had triumphed - until it emerged that she had ridden the subway almost all the way, joining the route barely a mile before the finish line.

The temptation to cheat in such a long race seems to have existed almost since the introduction of the modern marathon in the late nineteenth century.

Fred Lorz easily claimed the men's title in the 1904 St Louis Olympics with a time of three hours, 13 minutes. Officials soon discovered the secret of his success: the 11-mile ride he received in his manager's car.