Cross-country skiing is one of the most physically taxing of all Olympic winter sports, with distances spanning up to 50 kilometres for men and 30 km for women.
"I call it drag-racing on skis," says CBC analyst Jack Sasseville. "Everybody has different strategies. If you go too fast, you're going to die a horrid death later - that happens a lot. If you go too slowly, you're going to give up too much time early, and you won't be able to get it back."
One technique a skier will use to conserve energy is "drafting," in which a skier follows directly behind another skier in order to have that person break the air for them. This method also helps the second skier to pace himself or herself through the race. In the shorter races, a stronger racer will go out as hard as he or she can from the start and hope nobody can keep up. Less powerful racers will draft behind the leaders, then try to slingshot past them on a downhill, a small uphill or a corner.
Classical vs. Freestyle
There are two basic techniques used by competitive skiers. The oldest is the classical style, in which the skis move parallel to each other through narrow tracks in the snow. When the skier is ascending a hill, the skis point slightly outward for traction. On level ground, good skiers can reach speeds in the range of 25 km/hr.
The newer style is freestyle, or "skating style," in which skiers do not keep their skis in narrow tracks. Rather, one ski points straight ahead, and the other is used like a skate to push off. Freestyle first appeared in Scandinavia in the late 1960s and made its debut as an Olympic discipline at the 1988 Winter Games in Calgary. Freestyle races are slightly faster than classical races, with average speeds of 30 km/hr.
The skis used for freestyle are shorter than those used in classical events, to allow for a more efficient "skating" motion and prevent tangling with other competitors' skis. The poles are also slightly longer.
The events: Use a program
In Olympic cross-country skiing, there are five types of events for both men and women: freestyle, classical, pursuits, sprints and relays. Depending on the event, one or both of the skiing techniques may be used, and the distances are usually shorter for the women's races.
It's a particular (and often confusing) quirk of Olympic cross-country racing that events and distances have varied wildly since cross-country's debut at the 1924 Winter Games - the list of discontinued, replaced and newly-introduced events could make the most attentive fan's head spin.
The 2010 Winter Olympics are no exception: they will feature a total of six cross-country skiing events each for men and women. Athletes will compete in the following: men's 15km freestyle and 50km classical events; women's 10km freestyle and 30km classical events; men's and women's combined pursuit events; men's 4x10km relay and women's 4x5km relay; men's 1.4km sprint and 6x1.4km team sprint; and women's 1.2km sprint and 6x1.2km team sprint.
In freestyle and classical individual races competitors ski in one style for the duration of the race. In freestyle races, skiers start individually, lining up in the tracks in 30-second intervals, with the order drawn by lot. In the classical events in which skiers are not confined to the same tracks, all competitors start at the same time in what's known as a mass start. In both cases, skiers race against the clock, and the winner is determined by overall time.
In classical events, a skier must give way when being overtaken, even when the second track is vacant. The skier in the rear yells a request to move, usually "Track!" This rule does not apply in the final 100m before the finish line or the exchange zone in a relay race.
The Pursuit
Pursuit racing, also known as combined pursuit, was introduced at the 1992 Albertville Games and combines a classical leg followed by a freestyle leg. Generally the order in which the competitors finish in the opening classical leg determines their starting order for the freestyle. During the Vancouver Games, there won't be a break between the two styles and competitors will have to change ski's in a designated area as fast as possible and then continue with the race. The first athlete over the finish line wins.
Sprints are short, fast, stadium-based races, which Sasseville likens to "NASCAR on skis." They range from 400 metres to 1.5km in distance and are extremely popular with spectators because of their furious pace.
Any style of skiing is permitted in a sprint race. The event progresses through several stages: competitors must first qualify for one of 30 finalist spots by racing the fastest times in an individual elimination round. The top 30 competitors then progress through the quarter-finals and semi-finals to qualify for the final round, in which the six remaining skiers have a flat-out race for the medals.
Relays
In relay racing, teams of four ski over a course of 10km for men and 5km for women. The first skiers on each team start as a group. The first two stages of the relay are skied using the classical style, and the last two are freestyle.
Exchanges between team members must take place in a clearly-marked 30m rectangular area of the course, and the arriving skier may touch any part of the next skier's body to pass on the race. Teams are disqualified for not completing the pass within the area, or for touching the next skier's pole or ski instead of the body. The first team to cross the finish line wins.
Equipment and facilities
With the exception of the sprints, which are held in a stadium, cross-country races take place on a set course that has a series of checkpoints and must include equal portions of ascents, descents and flat areas. Its easiest portion must be at the beginning, and the most difficult part must be in the middle.
Besides the obvious skis and boots, athletes wear a warm bodysuit, hat and gloves, as well as socks and underwear specially designed to draw moisture away from their bodies so their sweat doesn't chill them. Most skiers also wear goggles to prevent their eyes from watering in the icy wind.
In the relay and pursuit events, skiers are allowed to change one ski or binding if it is broken or damaged. Damaged equipment must be handed over to the race jury. Broken poles are fairly common in a relay event and can be changed an unlimited number of times.
A competitor may be handed new equipment, poles, waxes, accessories or refreshments while on the course.
A waxing game
The most critical equipment is the wax applied to the bottom of the skis. The wax a skier chooses can often mean the difference between winning and losing. Most international teams have computers to help them select the proper wax, as well as a large team of wax technicians whose sole job is to prepare skis for competition.
There are two types of wax: glide wax and kick wax, also know as grip wax. Glide wax is used to decrease the friction between the skis and the snow. Kick wax is used to increase friction between the skis and the snow in order to prevent slipping. For freestyle events, glide wax is applied to the entire underside of the skis. For classical events, glide wax is only applied to the front and back tips of the skis and kick wax is used in the middle.
Skis may not be changed in the midst of an individual race, and to prevent unauthorized switching of skis, both skis are marked prior to the race. Skiers are, however, allowed to re-wax their skis during the races. Proper wax selection at the starting line is crucial, in order not to lose time re-waxing.
Fast-twitch, slow-twitch
Besides being in top physical condition, cross-country skiers will be one of two different body types. Sasseville says distance skiers have to be able to sustain a high energy output for long periods, in some cases hours. "The sprinters have to go for three minutes as hard as they can. They have to have a whole bunch of fast-twitch [muscle] fibres, whereas distance skiers need to have more slow-twitch fibres."
Sasseville uses the analogy of the white and dark meats on a turkey. "The dark meat is the slow-twitch fibres: it has some fat, it has a lot of blood vessels. They move slowly but they can work for a long time. Fast-twitch fibres are the white meat - it's mostly sugar and carbohydrates for fuel, but it doesn't last for long. Good endurance athletes are generally 70 per cent slow-twitch fibres, and the [sprinters] are generally 90-95 per cent fast-twitch."
