It's a little harder than usual to concentrate on making fashion notes when your mouth has just fallen open and your head is cricked back at 45 degrees, and the "model"—the champion trampolinist Bryony Page—has just rotated her body in a perfect circle in midair 30 feet above you. But such were the thrills taking place at Linley Hall in Victoria—transformed overnight into "Stella's Gym," complete with Olympic athletes including Allyson Felix and Victoria Pendleton—at the launch of Stella McCartney's Spring Adidas collection.

"We like to push it a bit further each season," said McCartney, who in recent years has streaked ahead of the field in transforming the aesthetics of women's performance sportswear. Now the collection spans running, gym, yoga, dance, tennis, golf, swimwear, and accessories, all characterized by a sharp eye for fashion detail and, this season, popping with neon pinks, grass green, yellow, and periwinkle blue. In one corner were gymnasts performing on the balance beam in leotards and yoga sweats; in another, the tennis team knocked balls about in scalloped-edge dresses over orange shorts. Elsewhere, runners warmed up on treadmills wearing high-tech spray-painted leggings. What gives McCartney the edge? Personal commitment, of course. Strolling around looking super-toned, she pointed to a group of girls working out on an apparatus devised by her personal trainer, Tracy Anderson, the woman who's given Madonna her body. Anderson has consulted on the development of McCartney's gym line, and if that's the first step to looking that good, we're in.