As Reebok's Director of Research Engineering, he warns that without decent trainers many of us who do aerobics, running or other sports would be hobbling around injured. "Your foot bone is connected to your leg bone, and so on up the chain," he says. So are they really necessary? I put this heretical idea to Spencer White, a genial American boffin who runs a hi-tech laboratory in Boston peopled by jogging robots in Reeboks and professors from MIT. After all, the ancient Greeks didn't wear trainers to run the original marathon. Not so hard for their parents, who may still remember a time when daps served just as well, weren't scorned as totally "sad" and didn't cost a fortune.

Impossible, perhaps, for this generation of teens, whose very identity can depend on what they have on their feet. Imagine a world without trainers. The Design Museum, 28 Shad Thames, London SE1 (0171-378 6055).Stride is available from Offspring, 60 Neal Street, London WC2; Aspecto, 85 Bridge Street, Manchester; branches of Cobra Sports; branches of JD Sports and Hip, 9 & 14 Thorntons Arcade, Leeds.. Deakin is passionate about keeping them reasonably priced - and pounds 69.99 (or pounds 64.99 for the girls) is a small price to pay for an instant design classic.Stride will be on show at the Review Gallery at the Design Museum until August. "I wish I'd bought more of them, they appeal to everyone: it's not a black thing or a gay thing, although both groups are buying them, it's a fashion and club thing."He is waiting for the red, white and blue variations on the current styles to come out next month, and will increase his order Until then, catch them if you can. Richard Wharton, from Offspring, a shop in Covent Garden dedicated to trainers, has been selling them for the past few weeks and watching them leave the shop in droves.