The first Enhanced Games take place in Las Vegas, with athletes in track, swimming and weightlifting taking performance-enhancing drugs and aiming to “beat” world records. Organisers say competitors have spent months training in Abu Dhabi using combinations of substances such as testosterone, human growth hormone, peptides and anabolic steroids, which are banned in Olympic-level competition. The event is streamed online and offers large cash prizes, including bonuses tied to record performances.

Sports governing bodies and anti-doping agencies denounce the event as dangerous and contrary to the spirit of sport. Health experts warn the long-term effects of some substances are not well understood and could involve serious risks including cardiovascular, liver and kidney problems. Enhanced Games officials respond that all medications are approved by the U.S. Food and Drug Administration and that emergency medical staff are on standby; the chief medical officer says he is “reasonably confident” nothing will happen.

Organisers also expect records set on Sunday to be unofficial because specific international bodies will not accept them. In the swimming, Greek swimmer Kristian Gkolomeev wins the men’s 50m freestyle and records an unofficial “world record” time, while several other races feature near-misses and some personal bests. A small number of athletes compete without drugs and win events.