Wednesday, April 18, 2012

Thomas, Melanie day 1

Weather fluctuating between bursts of heavy snow and cold air then bursts of boiling hot sunshine. You have to dress for winter in case the sun doesn't come out - but when it does you just melt and turn to slush along with the snow on the pistes. On the bright side it's the best on-piste snow I've ever seen at this time of year. The off piste will certainly be excellent too but not for the usual "transformed Spring snow" but for powder. Perhaps we'll find some of that tomorrow!

Warm Up
The warm up run was intended to be a shuss and skate across the flats into Val d'Isère, but questions were already primed and firing: How do you stand in the boots? You said before that you don't "lean forwards". Which leg does the weight go on? I always thought it was the downhill one... etc..
Well I like questions - it means that the people in front of me are participating fully and every question provides an insight into that person's current understanding and perception of skiing.

Remove the planet from under your feet and you are "free floating" in space. America's top physicist John Wheeler describes in his book (A Journey Through Spacetime and Gravity) that this state doesn't change even when we are within the Earth's atmosphere. Only the pesky "elastic force" of the Earth manages to block our freefloat that normally follows the geometry of spacetime. We feel this as pressure on our feet when standing or walking. It's so common that you don't think about it at all - unless you are only a few months old and you have just left the comfort of freefloat in the womb and walking still hasn't been mastered. To stay upright we have to stay more or less vertical - that means "in line" with this geometry (gravity). For the past few million years humanity (or neanderthality and homo erectusality) was quite happy with this state of affairs - but then some thoughtless Norwegian about 7000 years ago strapped skis to his feet and changed everything. Skiing is an intermediate state somewhere between freefloat and standing. As a rule human beings like "freefloat" - we like water - and some of us float high in the sky in our dreams - I know that I've done that a lot. Anyway - getting back to the point... 

When you stand across the hill on skis your skis are horizontal and you are both vertical and standing perpendicular to the direction of travel. You feel the pressure under the feet and it is your full body weight - say 70kg. There is no need to lean on the boots - you just stand up. At this point it's a good idea to feel light contact with the shin against the front of the boot just to sense where it is. Always aim to feel this or to return to this when skiing. The boots don't have to be tight and it's best if the feet can wriggle a bit to make shapes inside the boots. Good boots need to have stiff shafts but they don't need to compress the legs. When you ski off downhill on a slope at say a very steep angle of 45° - then half of the effect of gravity goes into accelerating you and so only half of it is pulling you into the hill. You would feel like you weigh only 35kg  (not quite weightless yet!) and this comes from an elastic force still perpendicular to the slope - but no longer (effectively) vertical - the body is now 45° from the vertical. We are now allowed some measure of freefloat so to stay on our feet we have to recognise that the remaining "elastic" force is deflecting us horizontally as well as vertically. We have to stand perpendicular to the slope and despite feeling 50% lighter we should feel everything else identical to when on the flat - NO LEANING against the boots. During the change of slope form horizontal to 45° you have to physically move and even anticipate this move so that you remain centred over your feet and skis and perpendicular to the new slope. It is a very active and conscious (but natural) adjustment. Eventually air resistance comes into the picture and balances the acceleration.

Still not finished the "warm up" I had to explain "dynamics". I asked Thomas and Melanie to put their weight on their right (uphill) foot and to do so both moved their centre of mass directly to the right over the foot. This is called "balance" and is part of "statics" in mechanics. It is what is taught in ski schools with exercises to move the body over that foot and then turn on that foot - right foot to turn left. IT IS WRONG! We need to use "acceleration" which is part of "dynamics" in mechanics. To get the pressure on the right foot we need to accelerate the centre of mass to the left. When I'm standing there acting like a wall then it's easy to accelerate against me! It's also easy when moving forwards because the ski maintains the acceleration (angular acceleration) by cutting beneath you and lifting you back up even more powerfully than I can. This is a natural movement for anyone "standing" and moving around. You are running along and someone shouts "go left" - you don't move over to the bl**dy right do you? (unless you are one of those people who always get "right and left" muddled). We just get confused because we are in this weird intermediate state between standing and freefloat where we find the wonderful but completely absurd world of "national ski instruction bodies". They have responded by linking and freezing every instruction to a permanent unchanging state of "balance" and pinning a national flag to it. It kind of resembles an animal playing dead when under threat. The idiots actually say that if you take a photo at any point in the turn all the forces would be balanced. WWWWRRRRROOOOOOOOOOOONG! 

To sum up :- When you want to go right move right. 

Skiing Backwards
Before going too far I had both Thomas and Melanie skiing backwards. In this case the reason was not to re-centre them in their boots - but to prepare them for sideslipping exercises - which is part of the development of "pivoting".

Thomas struggled with this fundamental skill. It doesn't take a lot of practise to improve but it is a commonly neglected skill - especially in this age of "carving skis". It's like we have forgotten to tell people that skis also go sideways - in fact that's what they mostly need to do. Likewise Melanie was very uncomfortable on the ice - but had more control in general. I explained that to go backwards (backwards diagonal sideslip) you had to slide the tails of the skis to point slightly downhill and to go forwards (forwards diagonal sideslip) you had to slide the tips of the skis slightly downhill. In this manner we were incrementally building the control and feeling needed to be able to "pivot" later on.

Video Clips (Dynamics)
The video clips here were taken at the start of the exercise. The dynamics were in place but needed to be developed. The interesting thing here is to see the different issues emerging. Melanie has a very strong upper body rotation into the turn. Any rotation inhibits dynamics and causes the skis to be thrown sideways outwards from the turn. It also stops the centre of mass from staying inside the turn at the end of the turn creating instability. Thomas was not rotating but he was not managing to stay in the perpendicular and he was pushing his feet out and twisting them into the turn - with a significant upper ski stem  - using the lower ski as a platform. The clear common denominator here was a distinct lack of use or awareness of the adductor muscles and feet.

Skating with Gravity
As we were exploring our "intermediate freefloat state" I suggested that we get connected with it through skating. Thomas said that he used his quads for power for skating, running and walking. I suggested that we might use gravity instead. This resembles tacking against the wind in sailing. We use gravity to displace us forwards by falling forwards and dropping the recovered leg underneath the body. There is no need to "push off". Thomas got this straight away. Melanie was skittering around unable to grip enough with the skis. This is where I explained about the adductor muscles and the rolling of the feet onto their inside edges - together. Melanie got it straight away. 

Dynamics with Adductors
When the adductors and feet were used in the correct way both Melanie and Thomas felt more control, grip and tightness in the turns with Melanie's rotation coming under control. I explained that when the outside foot was rolled onto its inside edge the forefoot actually turned away from the turn - it didn't twist inwards. To make this work properly it is best to first roll the uphill foot during the traverse, then engage the adductor muscles, then slightly lift the lower ski from the snow to commit 100% to the top ski BEFORE initiating the new turn. The lifting of the lower ski will then serve to cause the dynamics of "falling" into the next turn. This is important to feel because gravity is powerful so we want to use it. Just as gravity propels us in skating it gives us the initial dynamics in skiing in precisely the same way - but with the bonus of the slope thrown in.

I explained how snowplough and stemming train people in the wrong coordination - pushing the skis outwards instead of pulling inwards - and that this tendency becomes unconscious and ingrained. There is also the overwhelming illusion of centrifugal force that causes people to push outwards to brace against a non-existent force. The only force we experience other than the elastic force of the ground is the directional force of the ski. This is always"inwards" never outwards. We need to resist  the emotional tendency to brace and push outwards - locking up the legs and losing the support of the skis. We need to always pull inwards with rolling the foot, tensing the adductors and directing the centre of mass.

Centre of Mass
I explained that the centre of mass is an abstract point normally found between the navel and pelvis in front of the spine. It moves around and we can "feel it" like we feel the tip of a pencil when drawing. We use this point to design and control our movement - DIRECTLY. This is probably the single most important thing in skiing.

Independence of the legs
Thomas had a tendency to stem and be generally two-footed so we did the "skating into skiing" exercise. This involves skating with gravity - downhill on a gentle gradient. As speed picks up the "fall" can be prolonged as the ski generates angular accelerations and the skating converts into skiing - one leg at a time and with the correct coordination, use of muscles and timing. Skiing is a one legged activity and the sensation of being on one leg is sustained through accurate angular accelerations from the ski. We remain on one leg precisely due to this organised "disequilibrium".

Introduction to Pivoting
We spent a moment developing the pivot. I explained that this is for "fall line" braking skiing when you control your speed with short turns or linked sideslips straight down the hill. In a steep couloir there is no choice but to do this - other than a Kamakazi attack straight down the hill. In a mogul "zip" line it's the same story, or just even linking a few very short turns. The difference is that the turn is initiated from the uphill edge of the support ski - not the downhill edge as has been the case up until now with everything from snowplough onwards. To make this happen it is generally necessary to use the ski pole planted downhill for support. The body has to move inwards towards the pole to be able to complete the pivot. Melanie got this after a few attempts. Thomas had it straight away. The same fundamental skills are used for pivoting as for turning on the inside edge. The foot had to be rolled onto the inside edge while the shaft of the ski boot kept the ski on its uphill edge. The lower ski had to be lifted out of the way. Dynamics had to be used and the adductors actively engaged. Due to having worked on all of those things already - including the sideslip - the pivot was easy to do straight away.

When we hit ice Thomas started "bracing" his outside leg and I had to remind him to pull inwards no matter what his instinct tried to make him do. Next we hit slush and Melanie started to rotate again and get into difficulty. I explained that the skis generate their own mini "velodrome" banked track and so they don't ever need to be "turned" in the slush. Slush makes a great medium for skiing if you see it in three dimensions and use it in this way. 

Tomorrow I want to work more directly on Melanie's tendency to rotate through changing her awareness of how the hip and pelvis move. At the same time I want to correct Thomas's posture to put his back into a better alignment. 

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