How Cross-country Skiing Works


Alpine skiing not for you? Try one of the Nordic varieties instead. See more pictures of winter sports.
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When most people think of snow skiing, typically alpine, or downhill, skiing come to mind. However, there are different forms of skiing, and the oldest -- and best, if you ask its practitioners -- is cross-country skiing.

In alpine skiing, a skier generally takes a chairlift to the top of a steep run and skis down it -- both the toe and heel of the ski boot are bound to the ski. But in cross-country skiing, the heel of the boot isn't attached to the ski, allowing the skier to raise his or her heel with each step to approximate a normal walking motion. This enables skiers to travel across a variety of terrains without downward momentum, meaning they can move uphill as well.

Cross-country skiing, which is also known as ski touring, XC skiing or Nordic skiing, has been around for a long time. In fact, Norway is home to a 4,000-year-old rock carving that clearly shows a man standing on very long skis, the fronts of which are curved upward. About 1,000 years ago, cross-country skiing made a shift from a necessary mode of transport to a sport, and eventually it spread to other parts of the world as an enjoyable way to spend a snow-filled day. However, people who live in arctic conditions still use cross-country skis as a means of transportation.

If you have a Nordic trainer at home, you're probably aware of how good an aerobic workout cross-country skiing provides. A casual observer may simply note the coordinated use of the arms and legs, but nearly every other part of the body is getting worked as well, including the abs, buttocks, back and hip flexors.

Cross-country skiing usually takes place in the wilderness or on a well-worn track. In fact, part of the sport's appeal lies in its ability to let skiers commune with nature and escape into a meditative state -- instead of facing hoards of skiers at an over-crowded resort.

But as easy as it looks, there are many factors at play when it comes to moving oneself across a snowy terrain, and we'll examine some of them in the next section.

The Physics of Cross-country Skiing

Cross-country skiers must take certain physics principles into account, including the following:

  • Friction - Cross-country skiers have a love-hate relationship with friction -- it's produced when skis make contact with snow, and it can either help or hinder a cross-country skier. When skiing downhill, less friction is better -- the skier can increase speed and distance with less effort. However, when attempting to move along a level plane, especially when trying to make uphill progress, friction is needed so the skis can grip the snow and allow the skier to push off and move the other ski forward.
  • Gravity - While gravity pulls us down to the ground, it doesn't necessarily pull us downhill -- it must be overcome through power and momentum so the skier can move forward on a downhill plane. Gravity also allows the cross-country skier to keep his or her balance and remain grounded while skiing uphill.
  • Drag - Air molecules surround us, and when we move, those molecules must get out of the way. The rearrangement of these molecules creates drag, or wind resistance, which slows down skiers. You can reduce drag by making yourself smaller by crouching down and using controlled arm and leg motions.
  • Force - Force is generated from the cross-country skier's legs and his or her poles, which are used to push and pull the skier forward. The pole's horizontal range of motion affects speed, but vertical motion doesn't.
  • Mass - Skiers come in all shapes and sizes, and body mass plays a big part in the physics of cross-country skiing. Larger skiers will encounter more friction between the ski and the ground because of body weight. However, if those skis are waxed, the extra weight can help increase the skier's downhill speed. A smaller frame, on the other hand, will produce less drag and may not be able to reach the same downhill speed.
  • Velocity - Velocity in skiing is mostly determined by stride frequency and stride length. The length of the stride has more impact on a skier's speed than the frequency of his or her strides.

So what kind of gear do you need to begin cross-country skiing? Keep reading to find out.

Cross-country Skiing Gear

Don't forget your poles.
Don't forget your poles.
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Cross-country skiing doesn't require much in the way of equipment. Plus, cross-country equipment is both lighter and less expensive than alpine equipment.

If you'll be skiing on maintained courses, you'll want skis that are light, fast and thin. If you'll be blazing your own trails, you'll want backcountry skis that are heavier and several millimeters thicker. Combination skis are also available. Skis come in different lengths, but short and mid-length skis are most popular. If you're unsure which ski length you're most comfortable with, try renting skis first to determine which is the best fit for you.

Poles are light and normally have basketlike attachments at the ends -- these enable them to grip the snow's surface before the tip plunges to the ground. Poles typically reach from the ground to the skier's chin, and they have straps that keep the pole attached to the skier's wrist.

Boots for cross-country skiing are lighter and less block-like than alpine ski boots, and their bindings match the ski, leaving the heel free to rise and fall.

Plan to dress in layers when you're skiing -- some clothes will inevitably be shed as the exercise heats you up. Think about what clothing you would wear if you were to go jogging on a very cold day. Ski gloves and sunglasses typically round out the cross-country skiing ensemble.

When you place a ski on a flat surface, you'll see that the front and back end touch the ground, while the span between them, the camber, arches off the ground. When one ski is gliding, it does so on the two points of contact. However, as the other leg pushes down for the kick, the middle of the ski is pressed down, and this middle portion provides grip. This is often enhanced by grip wax, while the front and back tips of the ski are covered in glide wax.

Waxless skis have raised patterns manufactured into the length of the ski to provide grip, eliminating the need for grip wax. However, these skis aren't always ideal for all conditions, and they don't allow for adjustment in terms of applying different types of wax.

Keep reading to learn about the finer points of cross-country skiing.

Cross-country Skiing Techniques

There are two different styles of cross-country skiing: ski skating and classic skiing, which is also known as striding, diagonal or traditional. Classic skiing is planting one ski down and pushing it back in order to propel the other ski forward. For example, as you put your left ski down, you'll simultaneously use the pole in your right hand to help balance you and push you forward. When you push down and back with your right ski, your left pole will be put into action -- hence "diagonal." Despite this moniker, the resulting motion is a smooth forward glide.

This method will also enable you to perform a diagonal climb and ski uphill, using shorter strides and assuming a more vertical posture. Steeper hills may require using the herringbone technique in which the skis are arranged into a "V" shape and the skier walks uphill by planting the inside edge of the ski into the snow.

Ski skating utilizes a motion that resembles rollerblading or ice skating -- you push out with one ski while gliding ahead on the other, and the two skis are always pushing away from each other. If both skis stayed on the ground, you'd likely find yourself spread-eagled on the snow, but your one grounded ski maintains your forward motion.

Alpine skiers don't have a monopoly on downhill descent -- such drops are no problem for cross-country skiers as long as they utilize the telemark turn. This turn involves bending one leg behind the other, pointing the forward ski into the turn and pointing the tip of the rear ski into the side of the leading ski. This is a free-heeled method of making wide controlled turns as you descend a hill.

On slight hills, skiers may opt for a double-pole technique in which they hold their skis in a fixed position facing forward and use both poles simultaneously to reach ahead and pull themselves forward. On flat or slightly uphill terrain, you can combine the double-pole technique with alternating kicks.

Don't strap on your skis just yet. Keep reading to learn some helpful cross-country skiing tips.

Cross-country Skiing Tips

Talk about a workout.
Talk about a workout.
©iStockphoto.com/DOUGBERRY

To an observer, it may look easy to gracefully glide across the snow on skis; however, learning the techniques needed for cross-country skiing takes time. You may have no trouble getting up and gliding your first time out on skis, but you'll intuitively pick up some tricks for better skiing as you gain experience. Cross-country skiing requires a mix of different techniques, motions and rhythms that can be mastered only through practice.

While you may be proficient enough on your first outing to get from point A to point B, it may be helpful to take some skiing lessons. A skilled instructor can help you learn proper techniques and prevent you from developing bad skiing habits.

There's a good reason why most gyms feature Nordic machines: Cross-country skiing is an excellent cardiovascular workout. If you're not in decent shape before trying cross-country skiing, you may be in a for a long day of huffing and puffing. If you have a trip planned, try to get in shape beforehand so you can enjoy the sport.

While you're skiing, try to keep your knees and ankles flexed and your upper body forward. It's also important to work on establishing a rhythm as you kick, stride and glide -- move your arms and body forward, not side to side, and prolong the forward glide. When first starting out, you may feel more comfortable on wider and slower skis. After you get the hang of cross-country skiing, you can experiment with different types of skis that can provide you with a speedier and more agile experience.

For more information on cross-country skiing, see the links on the following page.

Related HowStuffworks Articles

Sources

  • American XC Skiers. "Beginners." (Dec. 3, 2009)http://www.xcskiworld.com/beginners.htm
  • American XC Skiers. "Classic Technique Basics." (Dec. 3, 2009)http://www.xcskiworld.com/training/Technique/classic.htm
  • Cazeneuve, Brian. Cross-country skiing: a complete guide. W. W. Norton & Company, 1996. ISBN 0393313352, 9780393313352.http://books.google.com/books?id=qVcmVhhvHrAC&pg=PP1&dq=cross+country+skiing&lr=&as_brr=3#v=onepage&q=&f=false
  • Cross Country Ski Areas Association. (Dec. 3, 2009)http://www.xcski.org/
  • Forde, Olav. "Winter sports in Norway." (Dec. 3, 2009)http://www.reisenett.no/norway/facts/nature_outdoors/winter_sports.html
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  • Lund, Morten. "A short history of alpine skiing." Skiing Heritage, Winter 1996.http://www.skiinghistory.org/history.html
  • Older, Jules. Cross-Country Skiing for Everyone. Stackpole Books, 1998. ISBN 0811727084, 9780811727082.http://books.google.com/books?id=nvjkxEzOPewC&printsec=frontcover&source=gbs_navlinks_s#v=onepage&q=&f=false
  • Rusko, Heikki. Cross Country Skiing. Wiley-Blackwell, 2003. ISBN 0632055715, 9780632055715.http://books.google.com/books?id=he7-eY86uIcC&printsec=frontcover&source=gbs_navlinks_s#v=onepage&q=&f=false