Sochi 2014: Why are Dutch so good at speed skating?

The Netherlands finished fifth in the medals table at the winter Olympics in Sochi, with 24 medals including eight golds, all from the skating rink.

So why are the Dutch so good at speed skating - and how do they dominate the sport so comprehensively?

The BBC's Anna Holligan went to the ice rink where the Olympic champions train, in Heerenveen, to try to discover the secrets of their success.