Nike employs specialist doctors to produce 600-page documents on the anatomy of the foot, and next year will be introducing a shoe called Feet You Wear. The latest style of Footscape shoe, also by Nike and due for release here next year, is being touted as the most anatomically correct shoe ever. And Reebok's Ice range, its latest innovation, which uses a totally transparent sole, looks set to give the company new credibility when it arrives in the UK later this year.
The shoes in these pictures (far right) were all photographed on the street, not the sports field. The air pumps and ergonomic soles serve little function when all you are doing is bouncing around on a dancefloor or running for the bus. So, despite increasing use of technology, it is fashion, not function, that rules the market.
Sharon Tomkinson, the marketing manager for Cobra Sports, estimates that a high percentage of all the footwear the company sells is for leisurewear, not sportswear. And Paul Fox, the buying director of JD Sports, admits that a very small percentage of JD's shoes are sold for real sports activities - and there are 60 stores across the country.
People who wear trainers purely for fashion purposes can be split into two camps: those that want the latest hi-tech, skate and snowboarding styles before everyone else, and those that want retro styles that nobody else has got. It's the easiest form of fashion elitism. A pair of Adidas Trim Trab or Nike Air Total Max is far more accessible than the latest Prada jacket.
Retro or "authentic" (as they are known in the business), trainers have been farmed out for popular consumption and have saturated the market. Even Clarks now does a version in black, red and navy suede for only pounds 19.99.
In the UK alone, the athletic footwear market is worth in excess of pounds 850m a year, according to the market research group Mintel. Nike is the brand leader both here and in the US, and it is Nike's designs that are the most sought after by trainer connoisseurs.
The Nike Air Max in neon green and grey has become an instant design classic. Shops sold out of them (at pounds 109.99 a pair) in January and they are already changing hands for up to pounds 500 a pair in Japan and about pounds 200 in the UK (check Loot if you're interested).
The designers behind these trainers are anonymous, yet they have as much, if not more, power to dress style-conscious youngsters as big-name designers like Versace and Ralph Lauren.
Underlying the main trends for athletic footwear, a new hybrid has been emerging: the trainer/shoe. Kickers have produced a range of loafers and lace-up boots with moulded rubber trainer-style soles.
Kim Van Dooren, a designer at Kickers, says: "We've deliberately taken our influence for the soles from sportswear. It's a visual thing - they aren't running shoes."
The Majorcan shoe company Camper has a range called Mix. Camper has put rubber and polyurethane soles on to classic shoes and used high-performance fabrics such as Kevlar to make them waterproof, able to breathe (and bulletproof). The shoes are a perfect hybrid - a meeting of performance and classical shoes.
Looking to the immediate future, we asked five experts - the buyers for JD Sports, Office and Cobra, a trainer connoisseur and a footwear designer - to give their tips for the next big thing in trainer fashion.
Paul Fox, buying director for JD Sports
Paul Fox's 375 pairs of trainers occupy the spare room in his house - his four-year-old daughter owns 12 pairs and will only wear branded trainers.
"People think the 'authentic' movement has only been happening in the Nineties. They're wrong. It started on the terraces back in 1980 or 1981. The people that wear them today are those that wore them the first time around - and those that are wearing them for the first time."
Each year, Fox sees up to 2,000 different trainers from each of the major companies; in excess of 12,000 pairs a year. But he's not bored. "I still love selling in the shop where I started out, it's the biggest buzz. I get 12- to 13-year-old boys coming up to me who know nearly as much as I do from information available on the Internet."
The future for Fox is awaiting the next innovations from Nike, Adidas and Reebok. He doesn't think it's a con: "The technology gets better all the time." His hint is to keep an eye on Reebok; his favourite brand is Adidas ("I grew up with it"), but his tip for the next big thing is the Nike Air Total Max, on sale from 3 July.
Richard Wharton, buying director for Office and Offspring
"Whether it's old school, skate, or in your face, I don't know a person who doesn't have a pair." Office are a fashion footwear company, so Wharton is looking for cutting-edge trainers. "We don't buy safe bets, our customer doesn't want them," he says.
Before Wharton goes on buying trips, he looks at what is happening in fashion - from the latest Gucci collection to kids on their skateboards in the streets. He feels the next big step is a move away from retro, old-school trainers. "That market has become too mainstream," he says, "and when it's mainstream, I get out." He understands the mentality of the fickle fashion crowd who want exclusivity and elitism. He believes fashion and sportswear will merge eventually. But in the meantime, Wharton recommends the new Adidas Galaxy trainer in citrus and marine, which will be available from August.
David Lee, buying controller Cobra Sports
In his nine years at Cobra, David Lee has seen a huge change in consumer buying habits. "When I first started in this business, there were only two or three key trends. It was dominated by the 'casual' movement. But now trainer culture is so sophisticated and people are far more individualistic," he says.
Unlike Richard Wharton at Office, Lee has to cater to all tastes. Running shoes will always be available in Cobra, despite what fashion dictates. Lee knows what is going on at the fashion end of the market. He also knows that retro trainers have lost their ultra-fashionable edge. But like any canny store buyer, he knows they are well enough established to continue to sell among certain groups.
"Leading-edge consumers - those that set the trends - are buying hi-tech Nike and Adidas at the moment," says. Lee. His current favourites are the ACG (All Conditions Gear) range by Nike - "they're going to be really big" - specifically the Air Mada and Nike Air Terra Outback. He also believes, like Paul Fox, that the next big seller will be the Nike Air Total Max.
Fraser Cooke, trainer connoisseur
"If I see another pair of recycled Pumas I think I'm going to be sick." Cooke claims to be one of the people responsible for bringing the first wave of original deadstock trainers into London, in 1990. He bought 125 pairs of Adidas shell toes from Doctor Jay's (a shop in Brooklyn, New York) for $19 each, and sold them in Passenger, a now defunct shop that was the place for street style in London. They flew out of the shop.
Cooke is an "official" trainer expert, constantly being called upon for his advice. The shoes he wants now are no longer available: "Nike say they don't make their footwear for the fashion market, but they released a Nike Air Jordan *11 in New York in such limited numbers that they sold out in a day," he says.
He has sold many of his collectable trainers to the Japanese, who are the world's true fanatics. He believes that nobody comes close to Nike in terms of design. The ultimate trainer for him now would be the Jordan *11s. He also rates the ACG range by Nike and the new black and red Nike Air Footscapes, (the ones that lace up at the sides.)
Ruth Shaw, graduating with a BA Hons in design marketing and product development in footwear and accessories from Cordwainers College
Shaw specialised in fashion trainers for her graduation collection. Her designs are already being sold in Office, due to an industry placement that was part of the course.
Her collection is based on reconstructing the traditional idea of a training shoe, based on her belief that most young people go clubbing to keep fit. Her shoes have bouncy UVA foam-moulded rubber soles with traditional shoe styles on the top. Hence the brogue-style fake snakeskin and white patent trainer/shoe pictured here.
"I was trying to get away from the idea of a super hi-tech trainer by keeping the trainer style but flaunting convention by using unusual fabrics such as thick nylon, satin, towelling and hologram fabrics," says Shaw.
She sees the future of fashion footwear in the marriage of trainers and traditional shoes.
Footscape by Nike, pounds 79.99. Fraser Cooke's choice
Nike Air Total Max: pounds 109.99 by all good sports shops from 3 July. Recommended by Paul Fox at JD Sports and David Lee, Cobra Sports
Part of Ruth Shaw's collection: her trainer/shoe retails in Office for pounds 39.99. Inquiries 0181 838 4344
Adidas Galaxy, pounds 49.99, as recommended by Richard Wharton at Office shoes
Feet on the street: the trainer market is worth pounds 850m in the UK alone (top five pictures); Nike Air Max (above) is changing hands for up to pounds 500 in Japan