At first glance, they appear to be cross-country skiers. They're propelling themselves through the German countryside with the aid of metal poles. But there's no snow in sight - and no skis on their feet.
Instead, this group of sports enthusiasts is part of a Scandinavian walking craze that has spread like wildfire across Europe. Where joggers and inline skaters once held sway, now Nordic walking enthusiasts are everywhere - forest trails, city streets, parks, and beaches.
Walking with ski poles is not new. For decades, it was a summer training method for Finnish cross- country skiing teams. But in 1997, a firm introduced the first walking poles - shortening them to make up for the fact that the athlete, without skis, has a shorter stride - and Nordic walking as a fitness sport was born.
In Finland, it caught on quickly. Today, almost one-quarter of the population there regularly engages in it, experts say. Over the past two years, the Scandinavian craze won over an estimated 3.5 million European walkers who are encouraged by some 3,000 instructors.
Germany, with an estimated 2 million participants, is where the trend has become most entrenched, according to Nordic Walker, a new magazine in Hamburg dedicated to the sport.
"Nordic walking is growing phenomenally in Germany, and I think it's here to stay," says Uta Engels, a sports researcher with the German Sports Association in Frankfurt. "It's for all age groups and for all levels. You can jump in without having done any sports. Old and young, it's for the whole family."
Businesses are noticing, too. Increasingly, hotels, leisure resorts, and nature reserves are advertising Nordic walking trails. Travel agencies offer Nordic walking tour packages at home and abroad. In a recent edition, Nordic Walker listed the 50 top German parks with Nordic walking trails.
Meanwhile, the number of certified instructors is booming. Three years ago, Peter Braun was trained as a Nordic walking instructor and opened a Nordic walking school near Frankfurt. Nordic walking, Mr. Braun stresses, is more than just walking with poles. Proper use of the poles and arm motion encourages good posture and assures a complete workout.
But most active Nordic walkers say there are bonuses to their sport beyond the fitness aspect.
Siglinde Weiss took up Nordic walking in the quest to lose weight, but has found she enjoys it for many other reasons: "Where [else] do I get to be in the fresh air, exercise, and spend time with my friends?"
Bettina Klump, an insurance agent in her mid 30s, says she likes the way Nordic walking helps her forget her problems.
"A sport has to be fun," says Diana Reuter, an executive with a busy schedule. The sport's simplicity and effectiveness are what led her to start a few weeks ago.
"No need to make an appointment with somebody, no big plans," Ms. Reuter says. "You just get your poles and take off."