Edited on 10/22/ for clarity, etc.
ydnar,
Thanks for the thoughtful response. I think you have been polite in your questioning of my posts and I hope you have found my responses the same. I think the interchange will be fruitful.
Some of what you say is true and I would agree with. For example that many people choose boots and fit their boots so that many functional aspects of the ankle movement is fatally restricted. These people are forced to use movements originating higher up. A change in equipment or fit would do more than a year of lessons to improve their skiing.
The difference with tipping is that inversion/eversion activates the turning design of the ski and so a little motion will do a lot. If you rotate/steer with movements higher up the chain they will have also have big effect to redirect the ski, but then there are other negative affects and consequences that you have to live with. If you have to do this because of an error or special circumstance (getting behind in the gates, obstacles, etc.) then you do, but what one does as a result of errors and special circumstances should not form the model what skills are most effective in the rest of our skiing.
ydnar wrote:I can only point so far without involving joints further up along the kenitic chain but I can only tip the foot so far without involving joints further up the kenitic chain, and isn't this the idea behind the kenitic chain.
Actually, I was trying to say that you can
not point your feet (rotate your legs) into the turn from the ankle. You must use movements that start high in the chain. Any rotation that has it's roots in the ankle (from the subtalar joint) are actually are in the wrong direction and are more of an idiosyncratic property of an individuals anatomy ( the tendency to pronate or supinate) than something that is controlled through skill. Why this is important will become clear in a bit.
Also, you are correct that other movements further up the chain help. However, active rotation is not one of them. The main issue is not whether movements higher up the chain are recruited in the tipping movements. Some movements are extremely important for facillitating the effect of tipping movemements started in the ankle. Leg flexion is a key one here. It frees up more range of external rotation of the femur so that the tipping that starts in the ankle can have a more efficient and bigger effect and it also makes plantar/dorsiflexion easier and more controlled-- the movemenst that control fore and aft movement.
[By the way, if anyone understands the topic on Epic about how pointing your toes at the start of the turn while keeping your shins pressured into your boot fronts, brings you forward (the ballerina turn). Please PM me about what movements could press your shins forward and bring you into the front seat while you are busy pointing your toes. Sorry for the digression.]
The main issue is in the causal direction of the movements. If the movements
start in the ankle they can do their job with little effect on balance. If the movements originate higher up, then they tend to be larger to begin with, harder to control, and have a bigger effect on balance. There is a dramatic difference between tipping done at the ankle with the leg is flexed enough to allow the other joints higher up to rotate passively and any
active rotation that must originate higher up.
If the causality is not taken into account then one will see no difference between active and passive rotation of the femur. However the difference between active and passive is everything.
In the case where the tipping is started in the ankle while the leg is flexed, both the lower leg and the femur passively rotate. The rotation of the bones is an effect of the tipping and flexion. They are not produced by rotation related muscles higher up and therefore, the rotation in the joints does not add rotational force or torque into the system as a whole. The rotation
"follows" the turning effect produced by the skis. Movements like flexion and counter action help allow the "following". In active rotation the leg rotation is
"leading" the skis
creating a rotational effect that disturbs the entire system. It isn't that one can't deal with the added and harder to control forces. People do it every day. However, even a casual analysis of their skiing shows that it's less efficient, harder to control, more susceptible to inconsistency (and injury), tends to disturb balance, and requires more athleticism (and its probably slower in the course, though that's not my real focus) -- all when there is an easier alternative.
In descriptions such as those given by Bob Barnes active and passive rotation are seen as essentially the same. See the "Most Basic Ski Movement Patterns" thread on epic -- where he chooses independent leg steering as "the most important, basic movement pattern of contemporary skiing, the one that applies in some form in nearly every good turn." I think his writing is clear and direct, so it's interesting to take a look at.
The argument is something like "even when one tries not to steer, there is passive steering. So, don't say steering isn't desirable or necessary." To use his favorite analogy of car steering, I would say that this kind of arguement would be like not making a distinction between passive changes in toe in/out as a result of castor and camber changes and active steering input from the wheel by the driver. Each affects direction, but they are radically different in nature (I am an avid motorsports enthusiest and work on all my own cars). Now, he also has other reasons for arguing for steering which aren't relevant here, so please don't respond saying I'm over-simplifying his position. If you throw both types of rotation into the same basket, I think this results in a vague and imprecise use of the term and fails to recognize the most important thing about the distinction. In another thread, Am I the only one ... ) he celebrates the vagueness in order to argue against Si's desire for more precision in ski terms. PMTS is more precise about these definitions. Active steering involves muscular effort in the direction of the turn. Passive rotation of the joints as a facilitating act is not steering. In fact not much is said about passive rotation in Harald's books or PMTS materials because it is not something one can control -- i.e., it's a passive effect. The thing that makes the turn are the other primary movements.
The description should help one see why even very good traditional skiers look to be almost flailing in their movements to a PMTS eye and why PMTS skiewrs look obsessively "hunkered down" to a traditional eye. In any case the difference in movement patterns is very noticeable.
With all this said I would point out a seemingly subtle though I think crucial difference in our interpretations of Harald's writing.
[Quote="ydnar"]Harald's first two books the idea was that a simple basic movement, a cue if you will, will serve to activate the kenitic chain and result in the necessary movements of the larger parts of the body without having to focus on conciously moving those large powerfull body parts with the added plus that recruitment of the large muscles in this manner means that they will be less likely to make overpowering movements.[/Qoute]
If I understand things correctly the point is not to avoid conscious use of rotation originating in muscle groups higher in the kinetic chain, so that you don't do it too much. The point is not to "use" those movements (muscles) at all to rotate into then turn. Any leg rotation that originates in the muscles of the leg that actively rotate the legs into the turn shoud not be used. If they happen passively, that's another issue.
The movements lower in the chain do not "lead" to "necessary movements of the larger parts of the body. " The lower chain movements are sufficient in themselves. They are primary. Movements higher up either facilitate or get in the way. I think they are referred to as "secondary movements" in the books and PMTS manual. It is not that movements in the foot and ankle "cue" the legs to actively rotate. The tippping and flexion effort is enough in itself to make the turn. This may seem like a small difference, but I think it's important. Maybe, Harald can comment of this.
By the way, a similar distinction is what is behind upper body movements in PMTS: turning to the outside of the turn early (counter action) and progressively
following the skis with the body until one is square to the skis at the transition. Again, this is opposite of the traditional notion of leading with the body into the turn (committing with the hips and shoulders and staying square to the fallline) and countering to stay square with the falline at the end. Maybe someone else will extend that discussion. The first is designed to prohibit and control rotation into the turn, the other attempts to actively use it.