The race to snaffle the latest hip trainer baffles the designers themselves. What makes a particular style "cool" is a mystery.
Whether worn as a fashion statement or not, trainers generally look a certain way. "The public have a perception of what a sports shoe should look like and therefore have a vocabulary of expectations," says Mark Batsford, product development manager at Hi-tec.
Often the "look" of a trainer will be the initial attraction - the colour, the lines, the design. For the serious athlete, however, other issues come into play such as comfort and suitability for the job. There is an element of "psychological caressing" adds Mark Batsford. "Sports shoes can have a positive effect, making the wearer feel she or he can run faster or jump higher. "
Cutting-edge scientific research and up-to-the-minute technological advances also play their part, enhancing the shoe's performance, comfort and look. "As new cushioning and even shoe-making and material technologies are evolved, design of athletic footwear can be pushed to greater aesthetic heights, " says Henry Besanceney III, women's training-shoe designer at Reebok.
Nike has spent millions on research into impact absorption, and the Ministry of Defence has shown an interest in this study to help them improve soldiers' boots. New materials allow moisture to be absorbed away from the foot and evaporate outwardly, keeping the foot dry, cool and blister-free.
With so much to consider it's important to focus on the essential ingredients. "A sports shoe should be lightweight, durable, not too expensive, simple enough in its appearance not to go out of date too quickly, and suitable for more than one activity," Mark Batsford says.
So what about the trainer of the new millennium? Despite suggestions in the Press that trainers have had their day, designers are confident they're here to stay, and have started work on collections for 2000. "Far less white, more obvious synthetics, lots of mesh fabrics and less apparent technology - basically a simpler, cleaner look," predicts Mark Batsford.
Henry Besanceney says the shoe will be, "Simple in its look, but on second and third looks it reveals a fabulous level of detail in materials and execution. "
"Designers of sports shoes will make an effort for the millennium, just as they did with the World Cup - trainers will probably look quite spacey with lots of shiny materials - very synthetic looking," adds Graham MacLellan, design director at Arrow.
At the leading edge of fashion, Jessica Good is the head designer at Shellys in London. "Our trainer-inspired footwear is for fashion only, we are very clear about that. We have to be careful not to include the word 'sport' anywhere on the shoe or the packaging because you will always get someone who thinks it's okay to wear them to their aerobics class."
One of Shellys best-selling shoes is the high-heeled wedge trainers that the Spice Girls made famous. These platforms are obviously not appropriate for jogging but the "look" is heavily influenced by performance sports shoes.
"I always look to Nike for inspiration," says Jessica, "but we are lucky because we can use crazy fabrics and be more daring in the construction of the shoe itself."
Set to change perhaps, but trainers are here to stay - in all their various guises!
Stephanie Wyatt works within the Design and Manufacture Department at De Montfort University in Leicester. All interviewees are footwear design graduates from De Montfort University