1 . You may have seen them coming quickly towards you or passing you swiftly. They’re moving steadily, swinging what looks like a ski pole in each hand.     1     These people aren’t skiing. They’re enjoying a type of exercise called Nordic (北欧的)walking. They use poles not for balance but to get their arms working. And their arms do work! In fact, in Nordic walking, the whole upper body gets plenty of exercise.

    2     Some of the time, they have to go up hills! They use their poles to help push themselves along. Nordic skiers were the first to use poles while walking. It was a way to train for their sport when there was no snow. Then other people, learning of the health benefits of the exercise, began to do it, too.

In the early days of Nordic walking, all walkers -- skiers and non-skiers alike- used ski poles. In 1988, an American company began making and selling poles especially for walking.     3     That’s because they usually aren’t used in snow. And they don’t stick very deeply into the ground. Some of them come with various tips, or ends, for use on different surfaces.

Although regular walking is healthy, studies have shown that Nordic walking is even healthier.    4     This produces strength in the muscles (肌肉) of the arms and chest. It makes the heart and lungs work harder. For young and old, Nordic walking is a great way to exercise the whole body outdoors.     5