Originally Posted by Jamt
The friction is largely related to how much snow you deform, and if you are forward the ski bends more and deforms more snow, so it is slower. However, In most cases line is more important than small changes in friction. Forward gets you a bit more turning and can help you with line. It is a trade off, and "forward a lot" is not the way to go all the time. Generally you need more forward when it is steep and less when not but there are as always exceptions depending on the course set.
Agreed, but as you transition to steeper slopes you need to move forward to maintain the fore/aft pressure relationship your skis have with the snow. That is one reason I'd rather discuss where the pressure being put on the snow in relation to the skis rather than try to agree on some definition of what constitutes forward or back.
When you are aft you also bend the ski more so in theory I suppose it could also mean you are turning more. However, my experience is that you turn less when you are aft than when you are fore.
Typically yes, but since you can lever a bend into your ski tails they can carve a very quick turn when your skis (or either ski) are(is) strongly edged. This bent tail will also work for carving straighter skis (much of the time), but not when very well for initiating a turn. However shaped skis with a good flare at the tails are another matter. I'm guessing that the difference is because shaped skis initiate the turn well from the tails when you put the skis on edge some at the transition. Then the tails flaring (out towards the tail) edges angle themselves off to one side some and thus pivot the boots (which are not restrained from pivoting because the ski tips are off the snow at that point) around because of the greater mass of the boots and legs that keeps them moving sideways slower than the ski tails are moving to the side.
Regarding the efficiency. The force line going between the center of BoS and through your CoM will pass a certain distance from you knee. This distance and the magnitude of the force will determine how much moment the knee will have to bear. The more moment the more the quads have to work. This means fore is more efficient from a quad point of view.
I agree it is probably harder on the quads and knees. I was warned by doctors (at a university science and medical exhibition) many decades ago that my sitting back and working my knees in moguls while the patella was being pulled tightly against the knee joint would quickly wear out my knees. Perhaps I have especially tough knees because so far I don't yet seem to have that problem.
In a turn with a lot of turning you may have about 3G in forces. If you are aft then the knee takes a lot of beating and the quads will burn in no time.
Your quads will burn if you hold them static and don't allow them to flush out the Lactic acid. When I'm doing this the only time the knees are that bent is during the transition. My legs straighten way out as the skis carve the outsides of the turning path even with tight snake like carved turns. Also since the G's are being taken near the end of the turn before I let my legs collapse some for the next transition (and the G load is for a very short period) even much higher G loads can probably be handled for these quick turns. Everything but the hips rotating the femurs to change edges is pretty relaxed in the transition. I just throw my knees over to the other side as fast as possible then by rotating the femurs but otherwise pretty much allow the skis to do their thing and follow along after them until the next transition.
When EB says that he is skiing faster and turning quicker and doing this with the thighs parallel to the ground I really get the impression that he is not really turning much at all. Quick turning means you are just letting the skis travel fast from side to side and the body is more or less going straight. The skis are turning and not the body, kind of like SL racers in a flush. If you have more patience and let the turn forces grow to 2-3G the advantages of EB's stance would be very few IMO.
I'm not claiming that being radically in the back seat has any advantages except to be able to turn quicker. You are correct, when snaking high speed multiple carved turns down the hill at high speed my head is not moving a whole lot side to side (or even up and down). It is a hell of a lot of fun though, and it is also great to be be able to turn that fast when I need or want to. It would be a shame if someone could benefit from this but is dissuaded because sitting back is "WRONG"! Personally, I don't mind if everyone ignores this. I'd get a lot less attention if doing this became a lot more common among good skiers. The slopes might be more dangerous if this technique falls into the hands of adolescent males who's brains haven't yet fully matured. One time this season I was buzzed by one of these guys schussing straight down within a few feet of me. I took off after him to let him know how close he came to dying back then because I was just about to make a sudden direction change toward where he came by and that because the carving maintains my speed I could easily have jetted out sideways for twenty or thirty feet as I often do at the end of a series of high speed quick carved turns.. Hopefully he thought about that after I told him of that danger.
Do you know that the level of lactic acid in GS skiers after finish is among the highest measured in any sport? .and they don't stay aft.
No, I didn't, but I can believe it. There is certainly a lot of violent muscle action taking place anaerobically among top ski racers. GS racers are probably having to keep their big quad and gluts held tense against G-forces longer than the other ski disciplines as well. Both would effect lactic acid levels from the reading i did about lactic acid when on the Quad Burn thread.
EB, you don't have video of yourself, but do you have any other video references to exemplify (except the Moscow circle).
The videos I've studied are mostly from World Cup ski races I've taped when I used to get Universal Sports on basic cable and from expert and extreme skiing videos I've picked up with the help of the Thrift Store Gods. Unfortunately, not something I can easily post even if I wanted to defy copyright laws. I appreciate the videos Tog has found and the ones of himself that Heluva posted.