- Braking Snowplough
- Snowplough (Centre of Mass)
- Combining Pivot and Snowplough
- Dynamics 1 – Being Out of Balance – to Be in Control
- Skating/Adductors
- Dynamics 2 (Skis Parallel)
- Pivot
- Dynamics 4 (Advanced Angulation)
Braking Snowplough
We had to go for a complete reset of understanding and exercises for defining the basics of skiing. In this case, with time limited, we still had to build around the snowplough model. The key feature of a braking snowplough is that the adductor muscles (inside of upper leg) are totally relaxed – enabling a wider wedge directly from the hip joints. The wider the tails of the skis are apart the more edging there is just due to the angles of the legs with respect to the body.
Snowplough (Centre of Mass)
First turns are made by simply tightening the adductors in one leg only – to turn left it’s in the right leg. (With narrower ploughs then the adductors of both legs should be engaged -and if there is some speed then control becomes dependent on the turn shape and increased dynamics.)
Weight is always maintained on whatever ski is furthest down the mountain so that it can act as an effective brake. Changes of pressure on any ski are due to geometrical effects between the skis and the slope angle – not “transfer of weight”.
Starting a turn when traversing the slope in a plough requires only a slight movement of the Centre of Mass toward the downhill ski. This ski then slowly feeds the skier into a controlled turn. When facing directly down the fall line, the body being held constantly toward the inside ski of the turn, ensures the outside ski can takeover the completion of the turn. The pressure changes on the skis are automatic – just move the Centre of Mass toward the centre of the intended turn and keep it there from start to finish.
(There’s a tendency for habitual snowploughers to always push out the tail of the uphill ski to get it pointing downhill at the front. Better to push the tail of the downhill ski toward the upcoming turn centre, thus pulling the Centre of Mass that direction. This also reinforces the braking/pivoting action of that downhill ski.)
Combining Pivot and Snowplough
Snowplough provides an important platform for learning how a ski pivots.
While traversing the slope in a snowplough weight must be kept on the downhill ski.
Conventional ski instruction tells us to transfer weight to the uphill ski to start a turn – but that is only useful for race training advanced skiers. First of all a skier needs to know how to use the plough to generate complete control of speed – and that means NOT transferring weight. Weight is allowed to always be on whatever ski is further down the mountain. That ski will always be on its uphill edge and so it will act as a supportive brake. Through the first half of a turn this supporting/braking ski will gradually pivot (sliding sideways) as the plough comes around the turn. Meanwhile the outside ski in the turn requires the adductor muscles to be engaged – so as to shift the body (centre of mass) slightly towards the centre of the turn and edge the outside ski slightly more than the inside ski – to enable a deflection/turning force from the ski. When the plough is pointing directly downhill the outside ski in the turn will take over as being the furthest down the mountain – continue to keep the adductor muscles in that leg engaged until the turn is complete.
Dynamics 1 – Being Out of Balance – to Be in Control
When you are making a turn on skis you can feel a force trying to throw you out of the turn – it’s called centrifugal force. You are then told that to make this turn happen you are balancing against this force.
The only snag here is that it’s all an illusion – none of it is real.
Centrifugal force has a few other names – “inertial force”, “pseudo force”, “fictitious force”.
When you, the skier, observe your own turn you are experiencing what’s called a “rotational frame of reference” and it is also confusingly called a “non inertial frame of reference“.
Yes we can calculate centrifugal force – but it’s not real – it’s just mathematics! (The magnitude of the centrifugal force F on an object of mass m at the distance r from the axis of a rotating frame of reference with angular velocity ω is: 
Real forces can be seen from the outside of the system as if you were a drone observing from high above. There’s no force pulling you outwards just a force from the ski deflecting you inwards away from a straight line. This is called an “inertial frame of reference” and it has only real forces – no fictitious “inertial forces”. This real force is called “centripetal force” (inwards – toward the centre) and it is accompanied with an acceleration. The acceleration is a change in velocity (vector) but it’s only a change of direction not speed. Acceleration is the physics of disequilibrium – being out of balance – the official term in mechanics being “dynamics”.
Skating/Adductors
Skiing is just disguised skating. The main difference is the skis are wide and have two edges. When diverging the skis outwards at the tips into a skating stance the skis want to flatten on the snow and the stiff shaft of the ski boots will pull the knees outward. The adductor muscles need to be engaged to hold the skis on their inside edges. This is a pattern of muscle use – the adductors of both legs contracting – that should be maintained when skiing parallel. This is partly dependent on the skier’s morphology. If the femurs are naturally directed inwards less adductor use might be appropriate but if slightly bow legged there may be a need to consciously work the adductors.
Only when snowplough braking should the adductors be released to widen the spreading of the tails of the skis from the hip joints.
The other difference between skis and skates: – it’s just that skis bend and scribe arcs on the ground and are generally used on slopes not flat lakes. Skating actions are fundamental for a skier’s development because they involve independent leg action where only one leg at a time is really used. Although skiers can stand on two feet the body is oriented specifically on one hip joint at a time (when turning) and has to function as if standing on one leg. Skating exercises such as skating step turns are helpful in developing basic skills. Skating turns use diverging skis (opposite from snowplough) and incremental stepping of the centre of mass inward toward the turn centre. This is ideally the first sort of turning that any complete beginner should experience – on flat terrain
Dynamics 2 (Skis Parallel)
- Skis must be travelling forward – like a bicycle
- This is mainly about using the outside leg (start of new turn) to push the centre of mass into the centre of the new turn – for the whole duration of the turn
- There is no “balance” when skiing – dynamics is the physics of disequilibrium
- You are looking for stability from organised accelerations (ski technology!)
- Notice in the photos below the outside leg is essentially straight in a skating action (flexion for absorption and other purposes is primarily at the hip joint)
- The centre of mass goes down toward the snow – and to complete the turn it comes back up – like a motorbike in a turn
- There is no “Centrifugal Force” acting on the skier – only a deflection inward away from a straight line. This deflection is used to lift the skier up at the end of the turn – which involves “finishing” the turn – I.E. turning almost back up the hill.
- Remain square to the skis (follow the skis around the turn with your body) until you are really comfortable with movement of the centre of mass and clearly aware of moving it.
Model photos showing unambiguous dynamics…
Pivot
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. The other important element of this pivot is that both feet are kept downhill of the skier (vertically below 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 sideslipping 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 feel pressure on its outside edge but the adductor muscles of this leg should be pulling in the downhill direction. The ski will remain 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 only 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 the ski itself. This is why pole planting is only associated with pivoting – sideways motion – and not with dynamic – forward motion – skiing – where only a pole touch at most is required when entering a turn)
The adductor muscles of the outside leg continue to 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 (of the “outside” leg).
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 (torque) rather than the adductors (inside of the leg) being used to pull or tension the leg laterally.
When the pivot starts the skier (centre of mass) has to move downhill slightly from 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 will change 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 and 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.
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.
Pressure is initially felt on the inside edge of the foot with the adductors held tight (pulling uphill) and the ski is initially 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 – learning to link pivots is the ideal way to develop Angulation and Anticipation skills.
Linking Pivots
Linking the pivots 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 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 use your outside hip in the turn – pulling it backwards during the turn – to get your reflexes working and your core muscles protecting your back the most efficiently possible.
See…
Off Piste Fall line
Short Swings (Jump Turns)
Moguls
Angulation
Anticipation
The following “Advanced Angulation” module is just to show one of the key ways to “fall into” a turn. Ironically this angulation is often mistaken for a leaning to the outside of a turn (to be avoided).
Dynamics 4 (Advanced Angulation)
Creating “angulation” is exactly like dropping one cheek of your bottom onto a chair placed at the side of your body. This gives the impression of “facing downhill” in shorter turns – which is actually an effect not a cause or intention. The action is centred on a relaxation of the hip joint (outside leg) and a falling into the turn particularly in the second half of the turn . The turn initiation (short to medium radius) is with the skier’s upper body facing downhill – thrusting the upper body directly downhill while the skis travel across the hill.
