Some say it is the high-tech swimsuits that allow swimmers to break old records. Others say top athletes train differently today. But whatever the reason, the number of world records broken in Beijing is unprecedented.
Is it the suit that gives swimmers their record breaking speed?
World-class swimming is drowning in record-breaking performances.
More than 60 new records have been set so far in the 2008 season, and the Olympic competition in Beijing isn't even over yet.
Feats like those in China's capital -- where 16 world records fell alone in the first of four days of Olympic finals -- have not been seen since the Olympics in 1976 in Montreal.
Could it be doping? New technologies? Scientific discoveries? Around the edge of the swimming pool at Beijing's futuristic "Water Cube" swimming venue, there are many theories.
"What's happening here, under normal circumstances, is not statistically possible," Germany's top coach, Oerjan Madsen, said. "The times the swimmers are clocking here are knocking the long-term statistics on their head."
Experts in the sport are having a hard time coming up with an explanation. Several factors taken together could be the cause, they say.
"For one thing, there is the suit," Madsen said, referring to Speedo's high-tech, full-length "silver bullet" LZR Racer.
"I think the main reason, though, is to be found in training based on science," Madsen said. "Fewer mistakes are made because of it.
More full-time professionals
Top US swimmer Michael Phelps (center) broke five world records
"There are also more and more full-time professionals in many countries who live from swimming and are able to pursue the sport in a completely different way."
German International Olympic Committee vice-president Thomas Bach struck a similar line, speaking of a combination of the new suits and improved sports science.
"The flood of world records was already expected before the Games started," Bach said.
Dirk Lange, the German coach of South Africa's Olympians, named another reason that has always proved a winner at past Olympics: "The top people have a killer instinct."
Five world records for Phelps
A combination of all these factors must be what allowed the US teams in the 4x100m and 4x200m freestyle relays to smash the records by huge margins of 3.99 and 4.72 seconds respectively.
The US athletes have worked for years to achieve the perfect butterfly kick. As a result, top US swimmer Michael Phelps, who by dint of physique and many other characteristics already is the best all-around swimmer of his time, has achieved unbelievable high speeds on his turns and has had world records in all his five events so far in Beijing.
With perfect starts and turns and low-drag, high-buoyancy racing suits, "it became clear we would see a deluge of records," Lange said.
Some downplay suit's effect
Italian coach Alberto Castagnetti has called the LZR Racer "technological doping."
But American swimming legend Mark Spitz, the seven-time gold medal winner from the 1972 Munich games, would have none of it.
"If it was the swimming suit, then I'm buying Tiger Woods' golf clubs because it means no matter who the swinger is, I am going to be able to score like that," he argued.
A high-tech suit could give a swimmer mental confidence but it would be only a part of a winning equation, argued Britta Steffen, a German swimmer who has broken records wearing Adidas products.
"In all the discussions, you should not forget that a suit does not swim on its own. A person is in each one, and that person can have a good day or a bad day, be well or poorly trained," she said.
Zimbabwean two-time silver medalist Kirsty Coventry, who herself got one of the records, simply referred to the fun factor. "The crowd is creating conditions where it is enjoyable to swim.
"The swimmers can just have fun and the pool is very fast," she said.