It seems that rules really differ from sport to sport too. For instance the likes of the US can get multiple medals at some of their strong events with several swimmers or athletes in the same race - as can the Kenyans, Jamaicans etc in the athletics. Yet the rules were changed in the velodrome this year to allow only one entrant per country - suppposedly at least partly in response to Britain's dominance 4 years ago. Had the best riders been allowed to compete then I'm sure Britain may have filled the podium in some races. Of course other events have restrictions too but the change in this one has afected Britain somewhat