Vocabulary: sports 詞匯：體育運動

Can we expect many world records at the Games? Some experts aren't holding their breath.

Meaningful world records have only been achieved in a few Olympic sports. At the Beijing Games, world records were broken in 33 separate events: one in women's team archery, four in weightlifting, five in athletics (of which Usain Bolt set three), two in track cycling and the remainder in swimming.

Yet swimming world records might be scarce in the London Aquatics Centre. In the aftermath of Beijing 2008, the sport spent a year involved in technological warfare as rival companies vacuum-packed their swimmers in ultra-aerodynamic suits to give them a competitive edge. Then the world governing body, FINA, rewrote the rules on swimsuits and restored some order, but by then the damage to the record books had been done.

Since 2009, wearing considerably slower suits, only Ryan Lochte in the men's 200m medley and China's Sun Yang in the men's 1500m freestyle have set new world records, both at last year's World Championships. No woman has broken a world record since the 2009 suits were banned.

In the 1980s mostly Eastern Bloc athletes set records. In the years since, a succession of doping revelations has left the authenticity of many from that era in doubt.

David Moorcroft, Britain's former 5,000m world record-holder, thinks records are more credible now and we're getting performances more representative of what athletes are naturally capable of.

Some are betting the hunt for records at London 2012 may come from the Olympic Velodrome. "It's going to be an extremely fast venue," said British Cycling's performance director, Dave Brailsford. "Hopefully we'll see some records fall."