WORLDWIDE RUSH TO GET IN LINE

John F Kennedy Jr does it. Take That's Robbie Williams does it. Even the Duchess of Kent has been seen rollerblading.

For the uninitiated, rollerblades are like ice skates but with a line of wheels instead of blades. Fiendishly difficult to balance, they were developed for ice hockey players and introduced in the US in 1984 by two brothers who founded the company, Rollerblade, the first and still the largest manufacturer in the world.

The word Rollerblade is a company name and purists will tell you the correct name for the sport is called in-line skating.

While still dwarfed by the 16 million skaters in the US, last year 300,000 skates were bought in Britain, according to Rollerblade.

In-line skating has become the Nineties version of jogging, providing a good aerobic workout. It is also healthier than step aerobics or jogging, as it puts less stress on ankles, knees and backs.

According to sports shop Fagans, which sells Bauer skates, the sort of person to be found whizzing around London's Albert Memorial and falling over is in their "late twenties, doing it for fitness and enjoyment. It's a lifestyle sport - you have good fun and exercise at the same time."

However, to buy the skates can cost anything between pounds 99 and pounds 219 a pair, with an additional average cost of pounds 75 for the safety padding - essential helmet, wristguards, kneepads, and elbow pads.

In comparison, dress tends to be minimal - lycra shorts, cropped T-shirts, and bumbags. The better you are the more lycra you wear.