Slide out of rotation: from counter-switch to anti-bow

A very important principle in the sleek and mogul is that the upper body does not move, and the quality of the gliding depends to a large extent on what level you can fix the upper body to. Each time the expert's chic turns are the perfect combination of a solidified upper body and a flexible lower body. Everyone knows that the upper body must not move, but this statement is too general, then what is considered "immobile"? To clarify this issue, we need a quantitative description in the language of mathematics. The joints that can be exercised on the upper body include head, shoulders, elbows and wrists. From a geometric point of view, I think the so-called "upper body motionlessness" should include eight elements. In short:

Before or after, not left or right. Lift your shoulders and lift your wrists and elbows.

Here we combine specific examples to explore the true meaning of "immobility" and the road to cultivation.

1、Before or after - Start from standing

The correct standing stance of the ski is simple and important. From the side, we should include 3.5 movements. From bottom to top, we should bend the knees, knees, waist and head. Because the head bending is relatively small, it can only count 0.5.

When we discuss the upper body, we must first achieve "not before and after." This includes two aspects. First, the upper body should be straight, it must not be hunchbacked, and there must be no chest bending beyond 3.5 bends. Second, and most importantly, the angle between the upper body and the snow surface must be straight. Keeping it constant, if there is a change in the upper body before and after the gliding, then the included angle will also change, which will affect the quality of the gliding. The ideal degree of the included angle is 90 degrees, which is less than this value, but it means that the upper body of the person's upper body is thrown back, which leads to the overall center of gravity.

2, lock shoulder and elbow - "anti-twist" harvest

The upper body and lower body in skiing are like the male and female protagonists in a love story. Although the hearts are tightly linked to each other, they must be on the opposite path. Only in this way can the most beautiful stories be performed. The so-called upper and lower body's separation also has its aesthetic significance.

In continuous rotation, the direction of the snowboard always changes constantly. If no control is applied, the upper body will naturally follow the direction of the snowboard. To fix the upper body, we must first suppress this rotation. The simple method is to apply a reverse force refusal and let the upper body turn in the opposite direction to the snowboard. Just like twisting a towel, the left and right hands work in the opposite direction, not What moves is a towel, so this action is called "anti-twist", see Figure 2.

"Anti-twisting" is the middle stage and the most important stage for fixing the upper body. The correct "anti-tightening" may seem simple, but actually the specifications of the action are very demanding and should at least include the following three points: First, the shoulder line and the elbow line should be parallel to the snow course and perpendicular to the fall line; second, the point When the staff had only the arm and wrist movements, like hammering a nail with a small hammer, the upper arm could not participate, otherwise it became a wheel sledgehammer to beat the iron; the last and most easy to ignore is to raise his head and glide.

The practice of "anti-tightening" should implement the principle of gradual and orderly progress. Slowly slide and decompose on a gentle slope in a slow-slope manner. See Figure 2. Focus on the feeling of "screwing" and the positional relationship between shoulders, elbows, hands and heads. This stage must be slow, find the feeling in the slow, a quick brain is a blank, equal to no slip.

Figure 2: The "anti-twist" action at slow speed. Demonstration:veve, photography: very password

After slow gliding proficiency, gradually release the speed while firmly locking the shoulder line and elbow line. In Figure 2, the shoulder line (green line) of the veve is perpendicular to the roll-off line, but it is not inclined parallel to the snowy road. This is a common problem and must be corrected. The shoulder line is perpendicular to the roll-off line so that the upper body is facing the hill, parallel to the snow track to make the upper body upright. The elbow line is the same as the shoulder line. The fixed elbow line further restricts the upper body to have only the arm and wrist to move. In Figure 3, the “anti-tightening” of the Langke Jianxin is similar to that of a textbook: the shoulder line and the elbow line are in a harmonious position. The arm and the wrist form a hammer-type stick, which looks upright and the entire movement is regulated and smooth.

Figure 3: Standard "anti-twist" action. Demonstration: Lang guest Kenshin, photography: very password

3, not left or right - pull this bow of your body

Before and after, no rotation is all that is not moving? In a three-dimensional world, the upper body also has a dimension that moves to the left and right. In the Classical Swing, the upper body and the lower body as one body are dumped to one side so that the standing edge can make a turn. In Figure 4, the lower body axis (yellow line) of the LitoTejada-Flores basically coincides with the upper body axis (powder line), and the shoulder line and the elbow line are perpendicular to the roll-off line but not parallel to the snowy path. The participation of the upper body makes the standing blade simple and the gliding up is very easy. Therefore, the classical small swing is always so chic and calm, but at the same time, it is also doomed to a relatively slow rotation frequency and a large gyration radius, which is difficult to deal with steeper And more complicated ski trails.

Figure 4: Classical small swing action. Demonstration: LitoTejada-Flores, Photography: Breakthrough in Skiing

Modern small slewing (such as Ritchie's 6-step sleek slewing) further requires that the upper body should not tilt to the right or left, so that the upper body is completely solidified and cannot move in all dimensions. Since there is no participation in the upper body, the turn is completely driven by the tilt of the lower body to achieve the vertical blade. The inclined lower body axis and the vertical upper body axis form a wonderful angle, which is called "anti-bow". See Figure 5.

"Anti-bow" is the advanced stage of fixing the upper body, and it is also a technical realm that requires long accumulation to be achieved. The difference between anti-bow and anti-twist is the angle between the upper and lower body axes. The skiers in Figures 2 and 3 also achieve this angle, but this angle is too large, even close to a straight line, so it cannot be called "anti-bow." Only when this angle is reduced to a certain extent can it be counted as anti-bow.

The qt in Figure 5, with its perfect shoulder line and elbow line, sharp "anti-bow" angle, and wrist-typed stick, the entire movement stretches gracefully, slightly bowed but within an acceptable range. In addition, the snowboard and the fall-off line tend to be vertical, and the large amount of snow foam behind it proves that this is a powerful swing. The significance of anti-bow is here. Although I haven’t seen qt's video, I can imagine that his mogul gliding must be mellow and deep.

The path leading to the anti-bow is started from reverse twisting. Constant practice reduces the angle between the upper and lower body. This is a process from quantitative change to qualitative change, but it is not without shortcuts. The force passes through the bowstring, acting on both ends of the bow and pulling a bow. How do you pull the bow of the body? The principle is the same. The upper body's "anti-wrench force rejection" and the lower body's "knife edge force rejection" constitute two essential elements for pulling the bow. Among them, the upper body's anti-snaking has been talked about a lot, and it is relatively simple, difficult to be difficult to stand on the edge, standing edge The magnitude ultimately determines the magnitude of the anti-bow. So how to increase the blade edge rate? I think the trick is on mogul. It is not easy to raise the edge of the blade on a smooth snow surface, but it will become simple in mogul. Every snow bag is a guide for turning. When the double plate is firmly on the snow bag, you are standing on the edge. Its amplitude is equal to the slope of the snow pack, and the vertical edge of the moment is much more labor-saving than the plain, because the edge itself does not eat hard, all the bottom force, and then carefully observe the qt snowboard in Figure 5. The thing is so simple: the more you slide over a steep snowpack, the more likely it is to get a beautiful bow.

4, why the upper body can not move?

Before we all discussed how to make the upper body move, but did not answer why do it. In fact, the answer is not complicated, but it involves a bit of physical knowledge. In high school, we all learned momentum, which is the physical quantity that describes the motion of an object. Momentum = mass × speed (p = mv). The upper body of the human body occupies about two-thirds of the body weight. If this animal is not moved, then under the same momentum, the lower body, which accounts for 1/3 of the body weight, can obtain three times the speed of rotation (mv=1/3m× 3v) This means a higher gyration frequency; or at the same gyration speed, only the equivalent of 1/3 of the original momentum (1/3m × v) is used, which means a more effortless gliding.

Skiing is such a sport full of science. Behind every beautiful movement is a reasonable explanation of mathematics and physics, so the beauty of turning has always been part of the beauty of nature.