Kenya has a reputation for producing many of the world's best long-distance runners, but that proud heritage has been tainted by a spate of doping cases involving high-profile athletes in recent years.

In May, the head of Kenya’s Olympic Committee said urgent action was needed to tackle the "cancer" of doping among the country's athletes.

Ahead of next week's African Championships, Kenyan runners have been filmed taking this oath against the use of performance-enhancing drugs.