Improvement III — Clearing up counter/rotation, separation and anticipation
Introduction and definitions
To understand what's written on this page, you should first understand that what are called short turns, are actually often medium, sometimes even long turns. And that you can make very short turns within a very wide corridor. See About radius, corridor width and short and long turns for the explanation.
Then, if you've read or viewed material of or based on the Austrian and the American/Canadian schools on rotation, counter, counterrotation, separation and anticipation, chances are that you're confused. For a large part, that's due to different terminologies.
The international conference Interski, which is held every three years, should have synchronized that by now. But it hasn't, so I'll have to sort things here. And in the process, I'll make the definitions easy to remember and in line with general usage and the kinesiological sciences. The ones in red are used in Pro(fessional) Ski Instruction (PSI):
Anticipation
A term in some sources used for prerotation. Not used in PSI.
Counter
A term in some sources used for counterrotation. As a single term not used in PSI.
Counterflex
Short for the combination of counterrotation, forward flexion and lateral flexion/pelvic lean of the upper body. See also The benefits of counterflex.
Counterrotation
1. The movement wherein the skis and the shoulder girdle are rotating in opposite directions. 2. The posture wherein the shoulder girdle is facing the outside of the (old) turn, rather than pointing in the direction where the skis are traveling.
Where the shoulder girdle is facing/pointing is determined like this:
Thai greeting. Source: Wikipedia.
Double Twister
A Freestyle trick whereby the skis turn 90° to one side and the arms to the opposite, followed by the reverse movement, after which all return to their starting position. Compare Twister.
Frontal parallel axes (FPA)
The lines through the shoulders, hips, knees and ankles seen from the front being parallel. Compare transverse parallel axes (TPA).
FPA. Source: Learn How 2 Ski.
Postrotation
The continued rotation of the shoulders in the direction of the turn after the skis have completed it. Antonym of prerotation.
Postrotation. Source: YouTube.
Prerotation
The turning of the shoulders ahead of the skis in the direction of the (new) turn, to be followed by the skis. Antonym of postrotation. See also How to prerotate effectively.
Marcel Hirscher prerotating (as part of counterflexing) in a Slalom. Source: Wikimedia Commons.
Rotation
A term in some sources used for postrotation. In PSI: any rotary movement or position.
Separation
A term in some sources used for counterrotation. Not used in PSI.
Transverse parallel axes (TPA)
The lines through the shoulders, hips, knees and ankles seen from above (= in the transverse plane) being parallel. Compare frontal parallel axes (FPA).
Twister
A Freestyle trick whereby the skis turn 90° to one side and the arms to the opposite, and then return to their starting position. Compare Double Twister.
In PSI, the counterrotation tricks by Freestyle skiers are called Twister and Double Twister because those terms are intuitive and that's what they're called in that sport; see here and here:
For the rationales why the above terminology and definitions should be adopted by the global ski instruction community, see Causes of the confusion.
Instructions
To further improve the understanding of matters, we can look at what to do with the main rotary movements/positions that occur in good skiers. They occur in three circumstances:
Within a narrow corridor. In short- as well as in long-radius turns (both are possible in a narrow corridor), but the longer the turn, the less it's necessary and noticeable.
Within a wide corridor in short-radius turns. That concerns descending down a steep but wide slope.
Prerotated shoulders (i.e. counterflexed upper body) on a steep slope. Source: Dutch Ski Society.
Within a wide corridor in long turns. That generally concerns carving.
The basic instruction is then as follows:
1. Narrow corridor, long and short turns: Keep your shoulders facing the (intermediate) point where you want to go as much as possible. (More information.)
The location of the (intermediate) point depends on the course of the slope. On straight slopes, it should be at the bottom or on the line to it. On winding slopes, it should be at the turning point between the two winding slope parts.
'As much as possible' means for most people that in 120° turns within a narrow corridor, your rotary muscles will have to work very hard, because most people have a limited rotary flexibility. But you shouldn't force it for a prolonged time, to prevent repetitive strain injuries.
2. Wide corridor, short turns (steep, wide slopes): To make the turns as short as possible, your shoulders should be prerotated before each turn. In between turns: keep them there or turn them back in the direction of travel (restore the TPA).
3. Wide corridor, long turns (carving): Make your skis turn but keep your shoulders facing the outside of the turn. As your inside ski will move forward and/or your outside ski backward, that comes down to the shoulders staying in line with the feet, seen from above, but not with the direction where the skis are pointing (= counterrotation with TPA maintained).
There are a few exceptions to the instructions, but they concern turning arts that the intermediate or advanced leisure skier rarely practices (anymore):
In Plow techniques (Plow turning and Plow with parallel), the shoulders should turn with the skis (TPA is maintained throughout). As well as in an emergency stop:
Mikaela Shiffrin making a planned emergency stop. Although she's looking downhill, her shoulders are not facing downhill. Source: Eurosport.
In Slalom turns, the (single) poles are knocked down with the lower leg and the contralateral hand, called cross-blocking. You can therefore come across Slalom images in which the skier has neutral shoulders rotation relative to the direction of travel, and even prerotated shoulders relative to the feet:
Mikaela Shiffrin in a neutral to prerotation in a Slalom turn. Source: YouTube.
In Giant Slaloms, in which both arms go around the double poles, the shoulders are sometimes turned to the outside farther than the line through the feet (= counterrotation beyond TPA):
Alexis Pinturault counterrotating beyond TPA (i.e. counterflexing) in a Giant Slalom turn. Source: SWX Right Now.
That's done to go around the poles as close as possible and/or because of the next turn being sharp and close by (early prerotation). Furthermore, personal preference may play a role.
Counterrotation beyond TPA can even be seen in Slaloms, if the skier is forced to prerotate early/strongly for the next turn:
Marlies Schild counterrotating beyond TPA in a Slalom turn. Source: Merinet.com.
How to prerotate effectively
Prerotation can greatly improve turning, but it can be done in an effective and in ineffective ways. This is an extreme example of the mostly seen ineffective way:
Ineffective prerotation combined with bracing. Source: YouTube.
The effective way is as follows:
During the actual prerotation, have the weight-bearing ski(s) sufficiently edged on its/their uphill edge(s). That prevents the skis from turning prematurely, even though this phase can be very short.
Turn on the (new) outside ski, and if necessary push off with it. The (new) inside ski may touch the snow but should be unweighted and should follow the (new) outside ski.
The turning on the (new) outside ski is an active leg rotation, but can be a very quick movement.
After the skis completed the turn, restore the TPA or prerotate your shoulders in the other direction, for the next turn. In narrow-corridor turns, that means that the shoulders simply stay facing downhill.
How such a quick, short-lived movement can be so powerful is explained below.
Technical reference
Causes of the confusion
As said, the possible confusion is caused to a great extend by different terminologies. That's further explained here. And this section will show that the above suggested terminology and definitions should be adopted by the global ski instruction community.
Rotation
A number of sources use the term rotation for a movement that's actually postrotation. For two reasons, the latter term should be used for that: 1) the said sources use 'rotation' for other movements than postrotation as well, and 2) 'postrotation' is much more self-explanatory.
The term rotation should be used for any rotary movement or position, just as it is in common usage and all sciences. The textual context in which the term is used, and if needed a further description, will make clear exactly which rotation is meant.
Counterrotation and counter
All instructional sources have this in their definition of counterrotation: The movement wherein the skis and the shoulders are rotating in opposite directions. But the American and Canadian1-3 sources add that that rotation should be a short-lived and explosive movement. Such as seen in the Twister and Double Twister.
A slow counterrotation and a counterrotated position should be called counter according to them. But that creates an unnecessarily complicated terminology. Apart from that the differences between slow and fast movements and between movements and positions are very arbitrary, Twister and Double Twister were and still are perfectly suited names for the Freestyle tricks in question.
Separation
Another often used term for counterrotation on the North American continent is separation. That's a rather poor term, too, because postrotation (which is to be avoided) is separation as well. And because it needs the addition "of the lower and upper body in a rotary way" to make sense to beginners.
Anticipation
Furthermore, there's the term anticipation. That's used for prerotation, but it only makes sense to beginners with the addition "of the coming turn by prerotating the shoulders into the turn." After all, relaxing the legs to absorb a small bump is anticipation, too.
Less is more
Never increase, beyond what is necessary, the number of entities required to explain anything — William of Ockham (1285-1349)
The above should make clear that counterrotation is still the best main term, and together with prerotation and postrotation the only ones we really needed.
Counterrotation an error?
Unfortunately, there are more problems. The Austrians started labeling counterrotation an error at some point in time (see here, page 7, for the rather erratic history of the Austrian teaching plan). And some still do4. Which is illogical, because the same book gives this as movement description of the 120° turn within a narrow corridor:
Rhythmical turning of the skis under a steady upper body.
The kinesiology teaches us that in terms of muscle action there's no difference between the one end of a muscle being the fixed point and the other the mobile, or vice versa. So whether the upper body stays stable and the lower rotates or vice versa doesn't matter. It's essentially the same movement — caused by a contraction of the oblique abdominals, the spinal rotators and the leg rotators.
Therefore, labeling counterrotation an error is incorrect. Fortunately, another important, maybe even the most important, Austrian source6 doesn't do that anymore. It even says that the Prinzip der Gegenverwindung (principle of counterrotation in layman's terms) is important(!) for proper (short) turns. However, it still says that extreme counterrotation should be avoided.
While that's indeed true if it isn't necessary, there are circumstances in which it is. Such as in continuous 150° turns within a narrow corridor. As said, for most people that requires really powerful contractions of the rotary muscles, together with using all the rotary range of motion (ROM) they have. That's as extreme as it gets.
Prerotation can be powerful
The — three — mechanisms behind the power of prerotation are explained next, but to understand it, you first need to understand that there are two main mechanisms that make a ski turn: loading + edging the ski (indirect mechanism, long turns), and a rotary force around an axis (which may be a vector) perpendicular to the ski's surface (direct mechanism, enables short turns).
Although in prerotation, edging is used to prevent premature turning, the used main mechanism is direct turning. We'll be taking a turn to the left as example. The first mechanism has to do with the ROM of the internal and external rotation of the femur (= upper leg bone) in the hip joint:
External (L) and internal (R) rotation of the right femur in the hip joint. Source: Shut Up And Yoga.
In a stance with the feet pointing straight forward (= schuss posture), the ROM of the internal rotation of the slightly flexed right leg (hip joint, knee and ankle 30°) is only between 40° and 50°. But if you prerotate your pelvis to the left, the neutral rotation position of the femur moves with it, which makes that the foot can then get to the absolute 90° position with ease.
The second mechanism is that most muscles can deliver a faster contraction if they're slightly stretched prior to the contraction. And the pelvic prerotation to the left does that with the internal rotators of the right femur.
Together, these mechanisms make turning the feet much easier. Try it yourself:
Starting position:
on dry socks on a smooth surface,
hands forward,
feet pointing straight forward,
slightly flexed knees,
slightly raised heels.
While keeping your pelvis facing forward, turn your feet to the left and note the ROM of the right foot. In most of you, it will be between 40° and 50°.
Next, get back in the starting position. Now, first rotate your shoulders fully to the left, and then turn your feet. The right foot will get much further and the turning will feel much more powerful.
The third mechanism that makes prerotation so powerful is the so-called moment of inertia: a body that's in motion will keep moving unless it's stopped by a countering force, such as friction. That counts for rotary motions as well, and the friction between a flattened ski and a snowdeck is generally minimal.
Most of the prerotation actually takes place in the (uphill) hip joint(s) — it's a movement from the ground up, and the ankles and knees have much less rotary ROM. However, if one wants to prerotate the shoulders, the body automatically builds that from the ground up. And prerotation of the shoulders is a much easier movement than of the pelvis.
Benefits of counterrotation
Counterrotation serves several purposes. In combination with forward flexion of the trunk, it can:
compensate for a limited lateral flexion;
shift the load from the weaker lateral trunk flexors to the much stronger forward flexors;
lower the center of mass to improve stability;
make it possible to closely go around Giant Slalom and Super G poles.
And as said, the counterrotation in the current turn can serve as the prerotation for the next. In fact, counterrotation beyond TPA is generally only seen in case the next turn is sharp and nearby. And possibly in athletes with a personal preference for it; that I still have to investigate.
Counterflex
The human spine generally offers a limited lateral flexion. That means that just pure pelvic lean (= hips lean = lateral flexion = lateral angulation) is insufficient to create much edging. Fortunately, the human body does offer a big forward flexion.
However, to use that in the correct direction, the upper body must first counterrotate1. Adding counterflex to hips lean makes the pelvis move deeper into the turn, which makes the outside ski edge more, which makes it turn better.
Another big advantage of adding counterflex is that it lowers the body's center of mass, while nicely lining up the leg and pelvic bones. Together, that creates stability and power:
Ted Ligety combining hips lean with counterflex in a Giant Slalom. Source: Ron LeMaster, Ultimate Skiing. Note that for the exercises here, less is required.
And that's not all: it also prerotates the upper body into the next turn. That makes that turn easier, because due to the prestretching of the rotary trunk muscles, the lower body can follow with greater ease:
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