Friday, March 16, 2012

John, Susan Day 1

Initial Assessment

Stance is quite good and there is a natural motion of the body into the turn. It is obvious however that the outside leg is being pushed away from the body and the is a general lack of movement. On flat terrain such as in the video clip this will work, but on steeper terrain there will be a lack of control. This is all that is visible at this stage. Despite John finding that his legs would tie up in cramp that cannot be predicted from looking at his skiing. 

The stance is confused with pressure on the front of the boots but the body being left behind in the vertical plane. Weight tends to be on the inside ski and there is a two footed push outwards of the ski linked to an attempt to keep the upper body facing downhill. In spite of those issues there is still a natural tendency to move the body into the turn. Susan would be unable to ski off piste or on ice with her current technical form.

Dynamics Part 1
With both skiers being able to ski we went straight from warming up into learning dynamics. John was familiar with the classic concept of snowplough turning and weight transfer by moving the body over the outside ski. For John the explanation of dynamics presented him with a clear alternative, opposite to his previous training. I provided physical support for him to lean against to feel the different effects of moving the Centre of Mass - and specifically accelerating the centre of mass in the direction of the turn to generate pressure on the supporting (outside) leg.

Susan believed that she was entering a turn by standing on the inside ski while "edging" the outside ski. That's quite original, but not as crazy as it might sound to some people. This was happening to her because of her two footed stance but the actual understanding is likely to have been a corruption of something that she was taught in the past. It took a couple of repetitions of the explanation of dynamics before Susan was able to snap out of her original understanding and fully understand the new one. 

Both skiers were able to progressively integrate the new movement, beginning with "swings to the hill" and eventually linking turns in both directions. I explained and demonstrated that "dynamic range" is a skier's real limitation. Most skiers believe that they have to stand up in "balance" and not fall over. In fact when they try to fall over (using dynamics) they cannot get more that around 20° towards the snow. The better the skier the further this range can be extended.  

John initially had trouble pushing against my shoulder because he was not able to grip with his ski edges - so we had to work on the basics of rolling the feet and using the adductor muscles on the inside of the leg just so that he could have a basic platform to move his centre of mass.

I explained how the centre of mass is an abstract point that we learn to physically identify - like the point of a pencil against paper - and to specifically move to direct our skiing.

There were a few problems with the skis catching on edge and carving unintentionally. To overcome this tendency I taught about pushing the feet forwards to tighten the turn radius (and stop the ski from jamming on edge). This was done statically with the skis off. The inside leg was used as a support to pivot around the heel and using the poles pointed downhill for additional support the weight had to be moved directly over this foot and the other leg pushed forwards to make a line arcing in the the snow. This feeling of resistance on the boot sole is the feeling that accompanies "pushing forward" of the outside ski during a turn. Pushing the foot forward during a turn makes the ski cut more actively in front of the skier's trajectory and tightens the turn radius - the ski doesn't actually move ahead while this happens - the turn tightens instead. On steeper terrain bigger dynamics with a quicker push forward of the outside foot guarantees control over speed and a sharp turn.

I asked Susan to avoid trying to face downhill and pushing her heels out to the side. She had to follow the skis around as if on a bicycle for the time being - toppling sideways into (and out of) the turns. I also asked her to ski with the feet slightly further apart so that she could feel the legs working independently and the pressure effects of dynamics on the outside ski.

We went indoors to remove ski boots and look at how the feet need to work in the ski boots. The basic message was to lock the ankles and rock the sub-taler joints below the ankles to rotate/rock the feet from edge to edge. I showed that the easiest way to do this is to be on the heel - but that there were other options. The main thing is to avoid collapsing the ankle and leaning on the ski boot, which both were doing to some extent (Susan more than John). The rolling of the feet was linked to the adductor muscles pulling inwards when a foot was placed on its inside edge. This pulling inwards of the adductor muscles and rolling of the foot is combined in practice with the motion of the centre of mass towards the turn centre - everything moving towards the turn centre and assisting the directional force of the ski towards the turn centre. We went back out onto the piste and applied this to turns.

Dynamics Part 2
John was having trouble from accelerating off downhill at the start of the turn and then having to brake suddenly to bring speed under control. The "foot forward" process wasn't enough to prevent this at this stage. To attempt to bring John's speed under control we moved on to working on the dynamics of the second part of the turn - that is - how to exit a turn. I explained how a turn resembles a motorbike turn on the flat. The bike drops down into the turn and comes back up out of it. In skiing this is more complicated because it isn't on the flat. If the turn finishes with the skier going across the hill he must come right out to the perpendicular to the mountain to get the skis flat and truly complete the turn. Most people stop short in the vertical with the skis still on the uphill edges and so they find it hard to start the next turn. I demonstrated "hanger turns" where I obviously stayed on the lower ski as it brought me up and out of the turn to at least the perpendicular then just changed leg to fall into the next turn. This once again helped John and by now Susan's stance had improved - she had automatically become centred over her skis and was supporting herself on one foot. Her stance was slightly wider and stronger. John's stance had gone from being wide to becoming narrow and was looking better too. Both were now about hip width apart and looking more natural with good dynamics on gentle terrain. 

On steeper terrain John was not holding it together yet and he was aware of a great deal of tension in his muscles. We did an exercise with the arm to demonstrate how you become paralysed when all the muscles are tightened and there is limited selective use of the muscles. John was not at the stage yet where he could relax enough to avoid this happening to his legs.

I explained the illusion of "centrifugal" force and how the only real force is centripetal (towards the centre) and how we have to act to work with such forces and not to resist imaginary "outward" forces. When all the muscles pull inwards towards the turn centre (along with the force from the skis) then we can avoid unnecessary "resistance" and tension.

Pivot Intro
In one last effort to help John to avoid losing control and accelerating off downhill at the start of the turns we took a quick look at pivoting. John was able to execute a pivot from the uphill edge of his uphill ski surprisingly well for a first effort. Unfortunately he was too tired by now to hold this together when skiing. One of the greatest fallacies of traditional teaching is to place people on the inside edges of the skis in a snowplough and brainwash them to thinking that all turns are made on the inside edges. This causes a lack of control over accelerations and makes "fall line" skiing impossible. Not only does the snowplough have this effect but it teaches the wrong muscle coordination - pushing outwards - from the start. John was not ready for pivoting just yet and we had not even looked at "skating" and other basic skills - but sometimes people can pick up the pivot very quickly and gain a major level of control over speed - so it was worth trying at this stage. We will look at pivoting in much greater detail tomorrow.

No comments:

Post a Comment