YOU may be born with the right genes, train harder than your rivals, and pep up your performance with drugs. But don't expect that to be enough for Olympic success: the victors in Sydney may be divided from the rest by nothing more muscular than the economy in which they live.

That, at least, is the conclusion of a new study of past Olympiads*. It concludes that most of the differences between countries in the number of medals won can be explained by differences in their population and GDP. The authors assume that raw talent is evenly distributed around the world, so countries with a bigger population will, by definition, have more potential medal winners. The impact of GDP comes from turning the physical ingredients into gold, presumably through a combination of good nutrition, health care and education, better training facilities, the availability of sponsorship, and the ability to pay to get the athletes to the Olympics (though this time the hosts are paying).

Intriguingly, countries that host the Olympics do better than the econometric model forecasts as, to a lesser extent, do neighbouring countries. This might have something to do with the impact of the huge cost of getting athletes to the games, or perhaps of having plenty of supporters in the crowd. Australia will probably win a dozen or so more medals because it is the home team than it would do otherwise. Communist countries and one-party states also tend to perform better than economics and population alone would suggest—which may be good news for the Chinese this time, though not for the former Soviet block.

Who will emerge victorious in Sydney? America, the country with the highest GDP—even though its medal tally will continue a downward trend stretching back to 1992. China is tipped for the silver medal (85 medals compared with America's 90), and Germany the bronze (61).

In 1996, Britain performed badly compared with the economic forecast. Now the Brits are tipped to bring home perhaps 23 medals, up from 15 in Atlanta. Yet although the British economy might be in its best shape for years, are its athletes?