Nordic walking is a form of exercise: walking with ski pole-like poles. Poles are used the same way as in nordic skiing, that is, to push yourself forward, giving more intense upper body muscular activity. Increased activity raises the heart rate to an aerobic level at which fat is burned. Nordic walking can be up to 40% more efficient (about 400 calories burned per hour) than walking without the poles (about 280 calories per hour). It also causes less strain to joints and knees than running or jogging. Walking around with poles may look a bit awkward but is actually a great way to release muscle tension in the neck and shoulder region, often experienced by people doing office work. In Finland, more than 300 000 people walked this way by the end of year 2000.
The poles come in many varieties: some are made of aluminium, some of carbon fiber. There are solid poles and telescopic models with adjustable length. Many kinds of accessories make walking more convenient and safe: comfy straps, ergonomic pole grips, spikes for slippery confiditions and rubber paws for walking on paved roads. More and more sports equipment manufacturers like Exel, Exerstrider and Leki also make walking poles.
Finnish sports company Exel has put up a site for this sport: www.nordicwalking.com, which includes technique and exercise tips, especially for stretching and warm up. There's also information about the poles made by the company and a length calculator which helps you find the best matching poles. If you're interested, you should also see the About.com story: http://walking.miningco.com/recreation/walking/library/weekly/aa071000a.htm