While it looks easy, crosscountry skiing is one of the toughest Winter Olympic sports. Indeed, the demands of striding and poling tax an athlete's cardiovascular system more than any other winter sport. Like top runners, crosscountry skiers have little body fat, powerful legs and wiry bodies. Contestants consider the 50km (about 33 miles) the most taxing.

NORDIC COMBINED

The two sports of Nordic combined make opposing demands on athletes' bodies. On the first of two days, competitors each take three jumps off of the 70 meter hill. Next day comes the 15 km cross country race. In the jump he needs the muscles of a sprinter. For the crosscountry he needs endurance muscles. Skiers vie for the highest cumulative point total. Scoring is usually slow and complex. CLASSICAL STYLE

Using skinny skis, long ski poles and wearing sleek nylon racing skins, crosscountry skiers try to be the fastest over a snow-covered, usually wooded course. This should be one-third flat, one-third uphill and one-third downhill. When using traditional crosscountry stride, skier plants pole then kicks with one ski and glides forward on the opposite ski. Events include: men's 15km and 30km and women's 5km and 10km. FREE TECHNIQUE

In the early 1970s, skiers discovered that it was possible to go much faster by using the same leg motions as an ice skater. In this method, skier pushes off the inside edge of his weight-bearing ski. Half the races at Calgary will be freestyle, which means that the winner will likely skate instead of using the classic technique. Events include: Men's 50 km and 4

10 km relay. Women's 20km and 4

5 km relay. WAXING SKI BOTTOMS

is both science and art. Temperature readings are posted at the start to help skier assess snow conditions -- a critical factor in choosing waxes. SKI WAXES

There are four main waxes that each competitor mixes into a brew that he believes will give him the edge. SOURCE: ABC Sports, Winter Games Access