New shoes spring into Olympic action

BEIJING (Reuters) - Two athletes in Sunday's marathon will have an extra spring in their step -- quite literally.

Angola's Joao N'Tyamba and Ecuador's Franklin Tenorio have both opted to race in the controversial Spira Stinger shoe that has a two stainless steel springs bedded in its sole.

U.S. track and field authorities have banned the distinctive yellow footwear, saying it gives athletes an unfair advantage, while the international athletics federation has yet to rule on the issue, opening the way for the Spira's debut at an Olympics.

The shoe's creator says other contesters could still protest about its use and criticized the continuing confusion.

"My shoe certainly provides no more of an advantage than the Speedo swim suit and no one is saying Michael Phelps should be barred," Andy Krafsur, CEO of Spira Footwear, told Reuters in a telephone interview from his home base in El Paso, Texas.

Phelps and countless other swimmers broke a slew of world records in Beijing swimming in the space-age Speedo garb.

Wearing the right shoes is vital in a marathon.

They have to be tough enough to get the runner round the 26.22-mile (42.195-km) course, gentle enough to protect the hard pressed feet and light enough to keep tiredness at bay.

Other racers on Sunday are also opting for unusual footwear, including the fancied U.S. athlete Ryan Hall, who will be using innovative Asics shoes which have rice husks meshed into the sole to absorb water and improve traction.

Krafsur said that all the runners' shoes would have been made to help athletes get round the course and he did not see why the inclusion of springs should cause any especial concern.

"The shoe returns energy, but all shoes return some energy. It is not spring loaded and not motorized. It is mechanized and common sense tells you it should not be banned," he said, adding that the idea was simply to help prolong athletes' careers.

"The energy the shoe returns reduces the stress on the body. That means you are more likely to avoid injury."

Angola's N'Tyamba is 40 and will be one of the veterans on Sunday. He said the shoe might enable him to stay in competition.

"At my age, one's muscles change. This shoe is helping me a lot and I don't see why anyone could think that is a bad thing," he told Reuters.

The shoe made its first appearance at the Games on Tuesday when Belgian athlete Axel Zeebroek donned them in the triathlon. Ranked 57th in the world, he finished the race in 13th place.

Critics have accused Krafsur of cashing in on the U.S. ban to generate publicity for his range of consumer products, with his average customer being 55-year-old women.

He says he is trying to make inroads into a market dominated by giants like Nike and accuses the track and field authorities of failing to keep pace with technology.

"The oversized driver in golf and the metal tennis racket were banned when they were introduced, but over time they came to increase participation in the sport," he said.