From: "Telegraph Science Desk" Sat Apr 8 2000 To: "Sandra Savaglio" By Roger Highfield, Science Editor SCIENTISTS have discovered two fundamental laws that govern sporting performance, disproving the common belief that women are better than men at long-distance races. The laws can reveal whether an athlete is close to achieving the ultimate possible performance, and help coaches to determine the ideal distance at which a sportsman should compete. The findings have emerged from an analysis of world records, revealing that there is a fundamental difference between the American Michael Johnson and the great Ethiopian Haile Gebrselassie: the latter uses aerobic (oxygen burning) metabolism and the former uses anaerobic metabolism, when foodstuffs are burnt in the body, without the need for oxygen, to produce energy. The differences are already known but by analysing the performance of world beating runners and swimmers of both sexes, Dr Sandra Savaglio, of the Space Telescope Science Institute, Baltimore, Maryland, and Dr Vincenzo Carbone, of the Universita' della Calabria, Rende, Italy, have shown exactly where the different metabolisms rule. A transition from one metabolism to the other can be seen since records began in 1919, they report today in the journal Nature. 'We think that since this transition appears to be universal, it suggests that this might be a characteristic of the human body,' said Dr Savaglio. For running events below about 1,000 metres, where Michael Johnson excels, the average speed of a world-record performance declines sharply with increasing distance. But above this, where Gebrselassie has set long distance records, the slope is more gentle. The gentler the latter slope in an individual, the better they will be at long distance running. The key transition between the two slopes occurs as the body moves from 'anaerobic' (explosive, but only good for short bursts) and aerobic (steady, oxygen-burning) metabolism. The same rules apply for swimmers, where the transition occurs at about 400 metres. 'What's incredible is that there exist slopes that are universal, regardless of gender and sport,' said Dr Savaglio. 'The slopes can be used to help coaches to select the distances over which athletes can perform at their best.' Men and women are equally efficient - their average speeds decline at a similar rate - disproving the common belief that women are better than men at long-distance races. Although the rate of decline is the same, men are always faster than women. In other words, the slopes are the same but for men the speeds tend to start off slightly higher, said Dr Savaglio. The study also shows that the slopes are significantly steeper for running compared with swimming, perhaps because there is a small aerobic contribution even for the shorter races.