In the world of downhill skiing, there is nothing more thrilling than skiing a series of high-speed linked turns. However, because speed and turning do not complement to each other, it is easier said than done. According to Newton's laws of motion-an object with a higher speed has a higher momentum, and a higher momentum has a higher inertia to resist the changing of direction-at a higher speed, a skier cannot change the direction as quickly as at a lower speed. The skier must travel longer distance to achieve the same rate of turn as at a lower speed, thus loses some of efficiency in turning. On the other hand, to change direction quickly, the skier has to sacrifice speed. In either case, the skier is locked in the predicament. Thus, to ski fast and to turn well at the same time becomes the challenge of the downhill skiing.
To ski fast in downhill skiing is not difficult; pulled by gravity, a skier can accelerate rapidly. The difficulty is how to slow down. Downhill skiing has no conventional braking devise; to slow down, the skier has to dissipate the speed either by skidding the skis or by turning uphill. Thus, turning in downhill skiing serves not just changing direction but also a mean for speed control. In order to ski well, the skier has to turn well. In the high level skiing, two turning techniques stand out-telemark-turn and parallel-turn.
Telemark-turn is used on the skis with loose-heel bindings (e.g. cross-country skis), and the techniques are based on the [cross-country skiing's] diagonal-stride. With minor difference in timing and a curved path, the whole turning sequence is not much different from that of a diagonal-stride. A telemark-turn begins at the pole-planting. However, instead of helping the skier to make kick [as it does in cross-country skiing], the pole-planting is now aiding the skier to maintain the balance. After the pole-planting, the rear ski is slid forward and crosses in front of the forward ski so that both skis form an asymmetric wedge. Then the leading ski is weighed and edged to produce the turn.
The pressure on the leading ski depicts the curvature of the turning path. The pressure on the rear ski serves a dual purpose of maintaining the skier's balance and a mean to effect the pressure on the leading ski, thus changing the curvature of the turning path.
Due to the asymmetric wedge, the path of the skis is naturally curved; however, increasing the pressure on the leading ski, the turn will be tightened, and increasing the pressure on the rear ski, the turn will be relaxed. By shifting the weight fore and aft to change the pressure on the skis, the skier can thus ski a desired path.
The fore and aft telemark stance is very flexible, thus stable. With a strong longitudinal stability, telemark-turn makes a sensational long carved-turn. Longitudinally stable, the carved-turn provides the skier a strong technique to ski powder and open slopes. Flowing with gravity, telemark-turn is fast, and a graceful way to turn.
Based on telemark-turn, telemark-skiing is an exhilarating way to ski. With the lightweight cross-country skis and loose-heel bindings, telemark-skiing gives the skier a tremendous sensation of speed and angular acceleration. Nevertheless, while stable longitudinally, the telemark stance offers little lateral stability. Telemark-turn is less stable when speed is slow. With little ability to skid and to make short radius turn, telemark-skiing is weak on icy and narrow slopes. Because the loose-heel bindings, the feet-together parallel stance will not help neither. To improve the lateral stability, the skier needs a device to lock the heels. So, locked-heel bindings are utilized.
The locked-heel bindings increase the skier's ability to push heels, which makes skidding turn easier, which in turn enhances the skier's turning ability, thus makes short radius turn possible. With locked-heel bindings, skiing starts to change shape. Skidding requires a strong lateral movement, thus stiff boots are used to give ankles more support and power. With stiff boots and locked-heel bindings, the skier is indeed becoming stable laterally, however, the fore and aft telemark stance is no longer possible. Telemark-skiing is out, parallel-skiing is in.
The parallel-skiing is based on the technique of parallel-turn. Due to the locked-heel bindings and stiff boots, parallel-turn has a more rigid structure than telemark-turn has. (Although less efficient, however, parallel-turn on loose-heel binding is the same as that of locked-heel binding.) In analyzing the parallel-turn techniques the skier finds that there are four definite phases to execute a turn: (1) pole-planting, (2) unweighting, (3) weight-shifting, and (4) traversing.
A parallel-turn begins at the end of the previous turn. The pole-planting marks the beginning of the turn. With the aid of the pole-planting, the unweighting follows. While unweighted, the weight is shifted from the downhill ski to the uphill ski and at the same time skis are pivoted into a new direction. By rolling the pressure off the uphill edges to the downhill edges, the traversing follows to finish the turn. If done in a precise and fluid manner, parallel-turn is a quick way to turn with little speed lost. However, it has its own share of problems.
In parallel-turn, poles are used as a timing device, and as a supporting device. However, used as a timing device, misusing a pole means a missed timing; used as a supporting device, miss-planting a pole costs the skier's balance.
The time and place they fail are usually when the skier needs them the most. In order to avoid such failures, the skier needs to pay attention to where and when the skier uses poles. While the skier needs all the concentration to ski the terrain ahead for an all-out performance, pole-planting diverts much needed concentration.
Meanwhile, carrying poles creates an aerodynamic drag which slows us down; during a turn, the three foot pole creates a undesirable leverage on the outside pole which holds the skier's outside shoulder back also delays turning, further contributes undesirable side effect. Poles have their places in downhill skiing, however, at times, they create more problems than they solve. the skier pays a high price for carrying poles.
Pole-planting also restricts down-unweighting; the natural consequence is up-unweighting. Up-unweighting fights against gravity, thus reduces momentum which reduces speed. Moving the body up and down also increases fatigue, and contributes instability in turning.
Weight-shifting can be executed only after first two steps are executed properly; otherwise, the skier would not have the balance to continue the turn, and weight-shifting would only compound the problem. Pivoting creates skidding, and skidding further reduces the speed.
After the weight is shifted to the uphill ski, the traversing begins by rolling the pressure off the uphill edges, and resetting it on the downhill edges (which are now the uphill edges in the coming turn) to change the direction of travel. Because the edge pressure is directly tight to the quality of the turn, the switch has to be decisive and precise.
During a turn, due to the skier's maneuvering pressure, the skis are arced upward. It is such arc that generates the turning force which causes the ski to change direction. If the skier relaxes the pressure on a ski, the ski bounces back, the arc is reduced, which changes the turning dynamic, the skier slows down and becomes unstable. The skier suffers a poor quality turn. If the skier maintains the pressure on the ski, the turning dynamic locks the skier in place, which makes fine directional adjustment difficult.
The traversing needs to be executed more precisely still, so the skier will be able to arrive to a proper position to initiate the next turn. Due to the timing requirement on each phase, the whole turning sequence is complicated and difficult to execute properly. Parallel-turn leaves more to be desired.
Clearly, the culprit is the pole-planting. Due to the timing requirement of the pole-planting and the consequence that follows, the pole-planting depicts a very rigid structure for the skier to follow. To free the skier from such a restriction, a new style of skiing is evolved-Tai Chi Skiing. Tai Chi Skiing skis without poles. By not carrying poles, the skier is freed from the structure that is imposed on by the pole-planting; the skiing starts to lose its form and begins a new transformation.
By not carrying poles, the skier assumes a cleaner aerodynamic configuration which reduces drag. To further reduce the drag, a sideway stance is adapted. A sideway stance favors riding on the uphill edges of skis. Riding on the uphill edges of skis reduces the friction which gives the skis a cleaner speed, thus achieving a faster speed. Riding on the uphill edges also favors carved-turn. Carved-turn reduces skidding, thus preserves the speed better, which gives a higher speed in turning. However, the catch-22 question remains: with a higher speed, can the skier still maintain the skier's turning efficiency?
By not using poles, the pole-planting is no longer needed, the turn can be initiated at anytime. By "stepping" from the downhill ski onto the uphill ski directly, the skier achieve pole-planting, unweighting, and weight-shifting all in one move, which simplifies the turning procedure, thus reduces the time needed to make a turn. The result is a faster rate of turn. The sideway stance makes the uphill ski more in-line with the fall-line. The weight shifting in essence is a down-weighting, which generates an extra pressure for the angular acceleration that is needed for the turn; the skier is accelerated out of the turn. A higher speed turning is achieved. With simplified turning procedure and high speed turning, the skier achieve a faster turn. However, during the high speed turn, the skier may still get locked in the motion.
To free such immobility and the unwanted turning tendency, slipping and skidding are used to enhance the turning performance. Slipping is an under-turn which causes the skier to slide downhill with little directional change. On the contrast, skidding is an over-turn which enables the skier to change direction rapidly without losing much of elevation.
Both prolonged slipping and skidding are not efficient techniques as far as turning concern, however, due to their ability to upset the turning force, they are effective techniques to change the curvature of a turning path and to maneuver the skier around a tight spot.
Slipping and skidding are inefficient because the friction they generated robs the speed of the skis; however, the speed in skiing is determined by how fast the skier travel [downhill] not that of the skis, when executed properly, their adverse effect may be negligible.
When slipping, the skis travel sideway, thus slow down, but because the under-turn, the skier's path becomes more downhill than in a balanced turn, the skier's speed remains high. When skidding, because the over-turn, the skier's path becomes more uphill than in a balanced turn, the skier's speed maybe slow down, but because the speed of the skis remains high, the skier's momentum is preserved, which can be converted back to speed easily once the need of skidding is over.
In either case, the negative effect on the over all speed may be minimum. When executed in a ever small duration and alternated fashion, slipping and skidding enable us to eliminate the unwanted turning tendency caused by the arced skis and still to retain the ability to change direction; slipping and skidding are viable techniques. With slipping and skidding, the immobility during a turn is alleviated.
To further enhance the technique, a technique called "tracking" is also developed. Tracking is to ski a "line" instead of skiing a random path. Because a line has a narrower definition, a more precise mean of skiing is needed. To track a line at will, the skier has to be "one with the line." In order to be "one with the line," the skier needs to know what a line is, and why a skier turns, and how to make it happen.
Contrary to the common belief, a skier turns is not because the skis have turned nor the skier ourselves have turned but the path of the skis has turned. The path of the skis can be explained scientifically as the result of the net force of the centripetal force, the centrifugal force, and gravity. To the skier, however, the path of the skis is the direct respondent of the skier's maneuvering pressure. By exerting pressure on a ski, the skier directs the ski to go where the skier wants it to go.
Mechanically, when the uphill edge of a ski is pressed, it digs into the snow, which increases the centripetal force, thus causes the path of the ski to turn. After the turning passes the fall-line, if the same pressure is still applied, the ski travels uphill thus slows down. When the pressure on the uphill edge is relaxed, gravity pulls the path of the ski downward. The ski changes its direction to downhill and speeds up. On the other hand, when the bottom of a ski is pressed, the ski speeds up, and when the pressure is relaxed, it slows down. Then, how much a ski will change its direction and speed is determined by the combining factors: the net force of the edge pressure, the bottom pressure, and the overall pressure on the ski.
In short, for a given overall pressure, the ski turns when the edge pressure is emphasized, and speeds up when the bottom pressure is emphasized. That is the turning mechanics of one ski.
In a balanced turn, the pressures on both skis are in some way balanced for the given turn. When the uphill ski is pressed, it speeds up; pulled by gravity, it steers the path of the skis downhill, the skier speed up; at the same time, the turning is relaxed. When the downhill ski is pressed, it speeds up as well; however, pulled by the centripetal force, it steers the path of the skis uphill, the skier slow down, and the turning is tightened.
In other words, when turning downhill the uphill ski predominates, and turning uphill the downhill ski predominates. Thus, to turn downhill, the skier presses the uphill ski, and to turn uphill, the skier presses the downhill ski. Turning downhill, the skier speeds up, and turning uphill the skier slow down.
By constantly adjusting the position of the skis and the pressure on and between them, the skier achieve both speed control and direction control. The complicated skiing is simplified only as weight shifting for speed control, and knee action for edge control. With such a technique of ski control, the idea of two separated skis starts to fade as they merge into one single variable ski that is operated by a single maneuvering pressure that is generated by the skier's coordinated mind and body.
As the skier, skis, and the line merge into one entity, the "line" perceived in the skier's mind becomes the vehicle that takes the skier down. As the maneuvering pressure balances out the turning force of the selected line, the skier skis through the slope anywhere riding on a "line."
Ultimately, tracking enables the skier to ski a selected line instead of a random path on the slope. While to ski a random path has the advantage to turn at anytime the skier wants, tracking trades such freedom for a discipline that is staying on the line. More concentration is needed to stay on a line than to ski a random path; such concentration intensifies the skier's inner awareness, which is vital for an all-out performance.
As the performance approaches to all-out, the concentration intensifies as well. As the total concentration [to bring the external world in] and the maximum awareness [to feel the world outside] merge into one harmonized reality, the skier is no longer skiing but being skied as the skier is only a media which reflects the spirit and beauty of gravity; the skiing has lost its form and becomes formless.
Since gravity is the ultimate driving force in downhill skiing and anything the skier does creates drag and friction that undermine the power of gravity; then, the lesser the skier does, the better off the skier is. At an all-out performance the skier may not have extra strength to fight the gravity, but the skier can always channel gravity to the skier's advantage by yielding if the skier has the equilibrium.
Fighting gravity is futile, yielding to it thrives. Then, for a better performance, the strategy is not to fight gravity but to find a path that is equilibrium to gravity for a chosen speed, then to ride the line out. By yielding, the skier ski "like water flow, never resist, but ever persist." That is a principle of Tai Chi. Tai Chi Skiing is fully fledged.