PIVOTING
Sideslipping
The main practical purpose of sideslipping is to get down the mountain without picking up speed.
Many learners are deprived of this skill because it is generally undervalued and has become even more neglected due to the complete domination of carving skis.
Wider and softer skis are easier for sideslipping in a greater range of conditions. Parabolic skis have some trouble gripping on ice during a sideslip but modern "double rocker" off-piste skis give a smooth and predictable sideslip.
The skis are kept on edge by the lateral stiffness of the ski boot shafts. Skis over 100mm wide underfoot begin to create problems on hard snow due to the extra leverage from the edge through the shaft of the boot due to the large offset of the edge from the centre of the foot. Those skis can be very unpleasant on-piste for some people. Anything wider than 110mm underfoot is best reserved for powder.
The skis are kept on edge by the lateral stiffness of the ski boot shafts. Skis over 100mm wide underfoot begin to create problems on hard snow due to the extra leverage from the edge through the shaft of the boot due to the large offset of the edge from the centre of the foot. Those skis can be very unpleasant on-piste for some people. Anything wider than 110mm underfoot is best reserved for powder.
In ski teaching the sideslip serves specifically for developing fall-line skiing. Fall-line skiing is where the skier's body travels directly downhill and not across the hill. This would apply to bumps, steep off-piste such as couloirs and deep powder snow. (Slalom is not "fall-line" skiing.) The mechanism of initiating the turn with a sideslip is called "pivoting".
The skier should be able to sideslip on either ski or both at the same time. It's normal to start off with both skis on the snow, skis parallel and with the majority of weight on the lower ski just to get a feel for it. The stance is normally quite narrow to prevent the uphill ski from catching the lower edge. Most beginners have trouble keeping the skis close together - especially if they have previously learned to
It should be noticed that only the uphill edges of the skis are in contact with the snow so the downhill edges are in the air. If the fronts of the skis are pulled downhill (or by moving the weight forwards slightly) then there will be no resistance from the downhill edges of the fronts of the skis and so the skier goes into a forward diagonal sideslip. Likewise if the tails are pulled downwards (of weight shifted backwards) during the sideslip then it turns into a backwards diagonal sideslip. Being able to alternate between straight down the fall-line and the two diagonals is a precursor to the skill necessary for pivoting in the fall-line.
It should be noticed that only the uphill edges of the skis are in contact with the snow so the downhill edges are in the air. If the fronts of the skis are pulled downhill (or by moving the weight forwards slightly) then there will be no resistance from the downhill edges of the fronts of the skis and so the skier goes into a forward diagonal sideslip. Likewise if the tails are pulled downwards (of weight shifted backwards) during the sideslip then it turns into a backwards diagonal sideslip. Being able to alternate between straight down the fall-line and the two diagonals is a precursor to the skill necessary for pivoting in the fall-line.
Both feet need to be rolled onto their inside edges inside the ski boots. This is not only an issue of "edge control" but of body management. Rolling the feet using the subtaler joints beneath the ankles and pulling inwards with the adductor muscles on both legs ensures the best options for control. Pulling both legs inwards keeps a narrow stance and when the skier practices sideslipping on one leg it ensures the that centre of mass can easily be placed above the appropriate hip joint.
Sideslipping is facilitated where possible by first of all working on posture and angulation (see ChiSkiing) Basically, keeping the bottom facing uphill creates "angulation" which helps to increase the edge hold and prevent sideslipping. Releasing this angulation by bringing the body square to the skis - bottom facing the tails of the ski across the hill - is usually enough to release edge grip and to allow the skis to sideslip.
Sideslipping can be practiced on the uphill ski only, with the foot rolled onto its downhill edge inside the ski boot - ski still on its uphill edge. This is preparation for learning to pivot.
Sideslipping is facilitated where possible by first of all working on posture and angulation (see ChiSkiing) Basically, keeping the bottom facing uphill creates "angulation" which helps to increase the edge hold and prevent sideslipping. Releasing this angulation by bringing the body square to the skis - bottom facing the tails of the ski across the hill - is usually enough to release edge grip and to allow the skis to sideslip.
Sideslipping can be practiced on the uphill ski only, with the foot rolled onto its downhill edge inside the ski boot - ski still on its uphill edge. This is preparation for learning to pivot.
Outside Ski, Outside Edge Pivot Initiation
The first pivot to learn - for beginners as well as advanced skiers - is the Outside Ski - Outside Edge Pivot Initiation.
After learning skating turns on the flat this is the way beginners should learn to turn for dealing with gradients. They should be assisted if required - by holding a ski pole at the side of the instructor and being physically led through all the moves - just like someone being led in a dance. Eventually the skill is assimilated due to the body being fed the correct feeling repeatedly. Some athletic beginners can cope with this manoeuvre on their own.
The reason for this pivot is to develop fall-line skiing skills. It's a "braking" form of turn which gives great control over speed - because of the skis only being used on uphill edges. (Surprisingly even the dreaded Snowplough can be done this way - but due to the severely inappropriate coordination it develops we will not be going there.) The other important element of this pivot is that both feet are kept downhill of the skier which is not only a fun and playful way to ski but is critical for safety on dangerous steeps such as in couloirs.
Most people are totally brainwashed in the skiing world into believing that a ski only turns because of its inside edge with its sidecut. Well it does, but not all of the time. The ski can also turn while on its outside edge during the first half of a turn. If someone has already worked on a forward diagonal sideslip then they already partly know the mechanism for this.
The skier has to stand on the uphill ski only, lifting the lower ski off the snow. The foot should roll over at the subtaler joint onto its inside edge with the ski still on its outside edge (due to the lateral support of the ski boot shaft preventing the ski from flattening). The downhill pole should be planted for support and so when the lower ski is lifted the body weight should be partially transferred to the pole. This requires the skier to face downhill and tilt forwards from the hips (angulation). Place the centre of mass downhill as much as possible with the use of support from the ski poles. Try to keep the ski on its uphill edge while the centre of mass moves downhill of it. The use of the pole here is to support and guide the centre of mass - which then pulls the ski tip downhill along with it. (In dynamics skiing with forward motion of the ski the pole is not required because the support for the centre of mass comes from the lifting up power of teh ski itself. This is why pole planting is only associated with pivoting and not with dynamic skiing - where only a pole touch is required when entering a turn)
The adductor muscles of the outside leg can then be engaged to allow the centre of mass to pull the front of the ski downwards in a sideslip into a turn. This trains the correct muscular coordination - pulling inwards towards the turn centre with the adductor muscles.
To check that the adductor muscles are being used the "Pole Stopper" exercise is useful. For this exercise I place a ski pole between the tips of the two skis. The skier lifts a ski a few inches off the snow and then pulls the tip against the pole. If the adductor muscles are being used then as the tip is blocked the tail should swing inwards at the back. If the tail swings outwards then the it's the muscles on the outside of the leg (abductors) being used to push and twist rather than the adductors (inside of the leg) being used to pull or tension the leg.
When the pivot starts the skier has to move downhill slightly with the ski but not too much because the ski must remain on the uphill edge for as long as possible. Moving the body too much downhill would change the ski edges far too quickly - for this effect the ski must be allowed to sideslip right from the beginning. The ski is best changing edges when it is in the fall-line, onto the new "inside" uphill edges for the last part of the turn. All the time - from start to end of the turn the skier needs to pull inwards or tension the adductors.
Completing the turn correctly requires the skier to avoid body rotation and to have the body in an anticipated and angulated stance, ready for another pole plant at the start of the next turn.
Most people are totally brainwashed in the skiing world into believing that a ski only turns because of its inside edge with its sidecut. Well it does, but not all of the time. The ski can also turn while on its outside edge during the first half of a turn. If someone has already worked on a forward diagonal sideslip then they already partly know the mechanism for this.
The skier has to stand on the uphill ski only, lifting the lower ski off the snow. The foot should roll over at the subtaler joint onto its inside edge with the ski still on its outside edge (due to the lateral support of the ski boot shaft preventing the ski from flattening). The downhill pole should be planted for support and so when the lower ski is lifted the body weight should be partially transferred to the pole. This requires the skier to face downhill and tilt forwards from the hips (angulation). Place the centre of mass downhill as much as possible with the use of support from the ski poles. Try to keep the ski on its uphill edge while the centre of mass moves downhill of it. The use of the pole here is to support and guide the centre of mass - which then pulls the ski tip downhill along with it. (In dynamics skiing with forward motion of the ski the pole is not required because the support for the centre of mass comes from the lifting up power of teh ski itself. This is why pole planting is only associated with pivoting and not with dynamic skiing - where only a pole touch is required when entering a turn)
The adductor muscles of the outside leg can then be engaged to allow the centre of mass to pull the front of the ski downwards in a sideslip into a turn. This trains the correct muscular coordination - pulling inwards towards the turn centre with the adductor muscles.
To check that the adductor muscles are being used the "Pole Stopper" exercise is useful. For this exercise I place a ski pole between the tips of the two skis. The skier lifts a ski a few inches off the snow and then pulls the tip against the pole. If the adductor muscles are being used then as the tip is blocked the tail should swing inwards at the back. If the tail swings outwards then the it's the muscles on the outside of the leg (abductors) being used to push and twist rather than the adductors (inside of the leg) being used to pull or tension the leg.
When the pivot starts the skier has to move downhill slightly with the ski but not too much because the ski must remain on the uphill edge for as long as possible. Moving the body too much downhill would change the ski edges far too quickly - for this effect the ski must be allowed to sideslip right from the beginning. The ski is best changing edges when it is in the fall-line, onto the new "inside" uphill edges for the last part of the turn. All the time - from start to end of the turn the skier needs to pull inwards or tension the adductors.
Completing the turn correctly requires the skier to avoid body rotation and to have the body in an anticipated and angulated stance, ready for another pole plant at the start of the next turn.
Inside Ski, Inside Edge Pivot Initiation
Turning on the inside ski is much harder to do - and for easier coordination it's best to use the preferred foot - eg. right foot for somebody who is right handed.
The foot still needs to roll onto its inside with the adductors tight but this ski is also on its inside edge (uphill). Strong pole support is necessary to get the centre of mass downhill of the ski and a lot of commitment to using the pole is required. It's much more difficult to get the centre of mass far enough downhill for a smooth pivot when standing on the lower leg. Whereas the outside ski pivot is a great way to start developing good angulation - the inside ski helps to develop more advanced angulation - by exaggerating the "end of turn" angulation requirements. People generally have the greatest trouble with angulation through the second half of a turn. This is mostily due to the hip being pulled forwards during the turn - so look at the ChiSkiing Page to see how to deal with that.
One Ski Pivot
The foot still needs to roll onto its inside with the adductors tight but this ski is also on its inside edge (uphill). Strong pole support is necessary to get the centre of mass downhill of the ski and a lot of commitment to using the pole is required. It's much more difficult to get the centre of mass far enough downhill for a smooth pivot when standing on the lower leg. Whereas the outside ski pivot is a great way to start developing good angulation - the inside ski helps to develop more advanced angulation - by exaggerating the "end of turn" angulation requirements. People generally have the greatest trouble with angulation through the second half of a turn. This is mostily due to the hip being pulled forwards during the turn - so look at the ChiSkiing Page to see how to deal with that.
One Ski Pivot
Linking the pivots... this is a true test of edge control and skillful directing of the centre of mass.
Two Skis (Close Stance)
Competition bumps skiers have their feet close together and many people swear by a "two footed" platform off-piste. This works because both skis pivot always on their uphill edge. The feet are always kept downhill of the body and so are the knees. Using the inside edges of both feet and the adductor muscles of both legs pulls the skis together and strengthens the stance. It's important however to always orient the body on only one hip - preferably the outside one. The hip is the biggest joint in the body and it is very close to the centre of mass. Any confusion around this area leads to confusion everywhere. Motion starts from the centre of mass - so pick your hip to apply it through - to get your reflexes working and your core muscles protecting your back the most efficiently possible.
For off-piste pivoting a seated stance is often needed in deep snow. This works because you are not skiing across the hill, you are skiing in the fall-line - so your bottom is "sitting" uphill. Imagine sitting on a chair on a slope, when facing downhill you would not have your weight falling backwards - it would even be hard to remain on the chair and all the forces would pass through the feet. This works even better with speed. The knees and feet being ahead of the body allow unseen obstacles to be absorbed. People tend to "lean back" when skiing off-piste to try to achieve a similar effect but that only locks up the leg muscles and tires them out. Just angulating and facing the bottom uphill - plus pulling the outside hip backwards (ChiSkiing) - when combined with inclination into the existing turn - can substitute for the seated stance and even permit the fronts of the skis to be used more strongly off piste - with relatively straight legs and without the threat of being pitched over the fronts.
For bumps the two ski pivot prevents the feet from diverging off in different directions - and it gives two edges for controlling speed in what is after-all a braking form of turning. The overall stance is similar to off-piste but is part of a "compression turn" which has it's own page here for reference (or soon will have). Avoid resorting to pushing out the heels - it's always a pulling inwards that's required.
Two Skis (Close Stance)
Competition bumps skiers have their feet close together and many people swear by a "two footed" platform off-piste. This works because both skis pivot always on their uphill edge. The feet are always kept downhill of the body and so are the knees. Using the inside edges of both feet and the adductor muscles of both legs pulls the skis together and strengthens the stance. It's important however to always orient the body on only one hip - preferably the outside one. The hip is the biggest joint in the body and it is very close to the centre of mass. Any confusion around this area leads to confusion everywhere. Motion starts from the centre of mass - so pick your hip to apply it through - to get your reflexes working and your core muscles protecting your back the most efficiently possible.
For off-piste pivoting a seated stance is often needed in deep snow. This works because you are not skiing across the hill, you are skiing in the fall-line - so your bottom is "sitting" uphill. Imagine sitting on a chair on a slope, when facing downhill you would not have your weight falling backwards - it would even be hard to remain on the chair and all the forces would pass through the feet. This works even better with speed. The knees and feet being ahead of the body allow unseen obstacles to be absorbed. People tend to "lean back" when skiing off-piste to try to achieve a similar effect but that only locks up the leg muscles and tires them out. Just angulating and facing the bottom uphill - plus pulling the outside hip backwards (ChiSkiing) - when combined with inclination into the existing turn - can substitute for the seated stance and even permit the fronts of the skis to be used more strongly off piste - with relatively straight legs and without the threat of being pitched over the fronts.
For bumps the two ski pivot prevents the feet from diverging off in different directions - and it gives two edges for controlling speed in what is after-all a braking form of turning. The overall stance is similar to off-piste but is part of a "compression turn" which has it's own page here for reference (or soon will have). Avoid resorting to pushing out the heels - it's always a pulling inwards that's required.
Short Swings
Placing a lot of weight on the pole for initiating the two ski pivot actually removes some weight from the skis - which then reduces the sliding resistance on the skis sideways into the new turn on their uphill edges. If a jump is made while moving the load onto the pole then there is zero resistance on the skis so the turn initiation is even easier. Coordination for this is tricky initially and usually work has to be done even on jumping correctly. Most people retract their heels when jumping but they should fully extend their leg in mid air to raise the centre of mass and then flex on landing to absorb the impact smoothly. When pivoting the soft landing helps to generate a smooth pivot. It's only necessary to swing the skis a few degrees in the air and then land on the uphill edges to continue a smooth pivot. The pressure cycle and dynamics of coming down into the turn from landing also help to drive the pivot once it has been initiated.
When turns like this are linked with a rebounding effect and fluent rhythm they are called short swings. Most people at the start are unable to keep their body from rotating or pushing out the legs so they are often unable to use their ski poles properly and unable to keep a good rhythm or accurate coordination.
Short swings should also be practised on one leg only.
The short swing can also be pivoted further around in the air with the jump to make the edge change in mid air and land on the new edges. When practised this way the aim is to leave clean edge to edge lines in the snow. When only one single turn is done like this it's called a jump turn - which may or may not be completed with a pivot on the ground. The jump turn is a safe way to turn in a steep couloir or in crusty snow. Make sure the bindings are set properly and the skis have a low swing weight! Having a ski fly off on its own in a couloir is not ideal. The aim in a couloir would be to minimise acceleration and the keep the feet completely below the body. The skier can almost jump uphill with this and leg retraction may be required with the skis being actively tilted downhill while in the air.
One useful exercise for "edge to edge" jump turns is to do a series of short swings that actually take you backwards uphill by using a strong jump.
Stivot
Carving skis are required for racing but they are deliberately restricted. The powerful carving effect is dominant and perhaps too dominant - certainly leading to injuries in young racers. The restrictions limit the carve radius - not too tight - in giant slalom and the ski length in slalom - not too short. One way to overcome this limitation in racing is to change the direction of the skis at the start of the turn by pivoting them. The pivot is frequently done in mid-air - partly through jumping and partly through a rebound. In any case as soon as the skier can the skis are locked onto their inside edges and carving recommences.
Powerful dynamics are used in racing turns so the turns always start with the centre of mass moving downhill of the feet relative to the perpendicular to the mountain. Even with very minimal pivot this means the turn is started on the inside edges (downhill edges) of the skis. The skier passes though "neutral" or a "flat ski" phase with the body perpendicular to the hill prior to the turn starting.
When turns like this are linked with a rebounding effect and fluent rhythm they are called short swings. Most people at the start are unable to keep their body from rotating or pushing out the legs so they are often unable to use their ski poles properly and unable to keep a good rhythm or accurate coordination.
Short swings should also be practised on one leg only.
The short swing can also be pivoted further around in the air with the jump to make the edge change in mid air and land on the new edges. When practised this way the aim is to leave clean edge to edge lines in the snow. When only one single turn is done like this it's called a jump turn - which may or may not be completed with a pivot on the ground. The jump turn is a safe way to turn in a steep couloir or in crusty snow. Make sure the bindings are set properly and the skis have a low swing weight! Having a ski fly off on its own in a couloir is not ideal. The aim in a couloir would be to minimise acceleration and the keep the feet completely below the body. The skier can almost jump uphill with this and leg retraction may be required with the skis being actively tilted downhill while in the air.
One useful exercise for "edge to edge" jump turns is to do a series of short swings that actually take you backwards uphill by using a strong jump.
Stivot
Carving skis are required for racing but they are deliberately restricted. The powerful carving effect is dominant and perhaps too dominant - certainly leading to injuries in young racers. The restrictions limit the carve radius - not too tight - in giant slalom and the ski length in slalom - not too short. One way to overcome this limitation in racing is to change the direction of the skis at the start of the turn by pivoting them. The pivot is frequently done in mid-air - partly through jumping and partly through a rebound. In any case as soon as the skier can the skis are locked onto their inside edges and carving recommences.
Powerful dynamics are used in racing turns so the turns always start with the centre of mass moving downhill of the feet relative to the perpendicular to the mountain. Even with very minimal pivot this means the turn is started on the inside edges (downhill edges) of the skis. The skier passes though "neutral" or a "flat ski" phase with the body perpendicular to the hill prior to the turn starting.
No comments:
Post a Comment