the folly of 'fall' - Page 2

You're going to use gravity to move you and line to determine momentum's affect on your well being

If you're really cool you could skid some too !

Why not use it all? Huck, swoop, topple, they all have appropriate applications and should be in our quiver. Just like a variety of braking moves should be there. So here's a saying to ponder...

...there is no bad move, just a lot of innappropriate ones for a specific situation. The trick is to understand tactically which move works best for that unique situation and execute it without hesitation."

That's a fair statement JASP.  The bottom line is ,we make it happen to truly control line and momentum . We have a variety of tools to use  but need to selectively make use of them. Dealing with the aftermath of poor decisions usually means a price of some kind will be dealt with. The less we take from our future the more options we can make use of. The skill of cleaning up our misjudgments or new challenges is much easier when we can make the job less of an effort. 

Thanks Gary, To return to FOM's query about accurate verbiage, "topple" implies a pivot point down at the feet but doesn't address how much the legs flex, or how much angulation we hang onto through the transition. Which in my opinion is a very good thing! Way back in the sixties a rather famous toppling move existed (Jolbert called it the serpentine move since it resembled a snake striking it's victim). The uncoiling into an inclinated stance is even elemental to the arc to arc transition FOM mentioned. With the notable exception of the push to an edge moves, most parallel turn entries include the CoM projecting into the new turn. Always have. So regardless of what we call it, it has been around for a very long time. The fact that FOM suggested it was a new move coming down from above say to me that we haven't communicated the long history of the idea of projecting the core and the upper body into the new turn.

As a follow up thought, LeMaster did a tribute presentation a while back and I left that seminar with an deeper appreciation for Jolbert and how much of what he wrote is still valid today. I also have some books from the 1940's that explain ski moves as well as, or much better than most of what we write nowdays. Especially me...

I try to avoid falling while skiing.

I suppose it is partly a matter of what level skiing you aspire to. Falling implies a loss of control to me but I'll leave it up to you folks. If you want falling to be what you do while skiing well then so be it. If you aspire to something better then look at really high end skiing and I mean racers at the World Cup level you will see very early crossover and edge engagement. There are technical reasons for doing this that I won't go into now but if you examine the sequential photographs that Ron LeMaster publishes you can clearly see that they usually have crossed over their skis and are inclined down the hill way before the fall line. Usually the movement to achieve this has begun just after passing the gate. So, you might well ask, what is happening here that allows them to be inclined down the hill and strongly engaging their edges without falling over? Are they really falling down the hill? The answer is that they are balancing against forces much the same way that we always balance while skiing. In this case it is the force created by a forceful extension just as the skis roll onto their new edges that produce the force required to balance against during that very brief moment they are inclined down the hill. This is high energy, fast skiing. Try this while skiing slowly and you really will fall down the hill but try it at moderately fast speeds in the context of athletic skiing and you will find that you will be able to carve and even shape the turn somewhat before you even reach the fall line so that  the rest of the turn is just completing the arc and preparing to move into the next turn.

Sounds like Epicskiing!

Actually Oisin, Ron talks about a variety of cross over and turn entry options and goes on to explain why we would use each. Some include early edge engagement, some include it's polar opposite (a stivot). It all depends on what the racer wants to accomplish with that next turn, or series of turns. So it's impossible to suggest only one transition or where the racer engages their edges based on a few pictures from Ron. Same goes for the statements about alway using a strong extension move. What is actually keeping them from falling on their face is their inertial momentum. The push to a strong edge move is certainly an option there but again I must point out it's just one option. Nor is it accurate to suggest the strong shaping phase is alway that early, it can be in any third of the turn and again it depends on what the racer wants to accomplish and how the gates are set. What they are doing is getting set up for that next strong shaping phase regardless of where it is in the next turn.

What follows are  a couple of pics from Ron's web site that show how variable all of this is. The first is similar to the extensiont you described but the second shows a completely different tactic and extension much later in the next turn, in fact, it's just prior to the next gate.

This Stivot in the air should show why the strong edge engagement isn't necessary to be inclined into the new turn and prior to the strong shaping phase.

Here's an uphill step stivot where the body of the racer and the tail of the outside ski move uphill.

My point here is that I can use any of Ron's pictures to suggest something but overall they prove how variable skiing at that level can be. We must be careful not to suggest one tactic, or technique is universally appropriate.

With that theme JASP did this racer start the new turn on his inside ski?

Quote:

Originally Posted by justanotherskipro 

My point here is that I can use any of Ron's pictures to suggest something but overall they prove how variable skiing at that level can be. We must be careful not to suggest one tactic, or technique is universally appropriate.

Agreed, I believe I was thinking only of that technique which, visually at least, appears to be most like falling. Obviously there are a variety of techniques employed for various reasons. Nonetheless, however the turn is initiated there is often a phase in which the skier appears to be inclined down the hill, usually accompanied by extension. I don't disagree that you could fall down the hill at this point and play catch-up either. I'm just saying that is not usually what you are seeing.

Quote:

Originally Posted by justanotherskipro 

.......... What is actually keeping them from falling on their face is their inertial momentum. .............

 

Actually I think the inertial momentum ought to carry the skier's upper body down the hill in the direction it had been travelling. That helps to explain why the movement of the body down the hill is not only  the result of a muscular movement but does not, I think, explain what is keeping the skier from falling. 

Think about trajectories for a moment Oisin, A golf ball will rise after we hit it as long as it's inertial momentum is greater than the pull of Gravity. As that momentum fades the ball's flight will level off, then (slowly at first) begin to descend until eventually it will fall straight down along the vector defined by the pull of Gravity. Air resistance being the primary resistance the ball encounters, so ball manufacturers put dimples on the ball to control both the length of flight and amount of roll after the ball strikes the ground. All of this is based on controlling momentum.

So what does this have to do with skiing? Our momentum across the hill typically gets seperated into the momentum of the feet and skis and the momentum of the core. Notice I am avoiding the use of the term CoM since it's an abstract, global term. As we turn across the hill our two inertial momentums contains both a linear and angular component. (I think we all will agree that turns require angular momentum). If we release the body diagonally across the hill prior to releasing the feet the inclined stance will occur as both travel along their seperate paths. At this point as so you accurately pointed ou,t sufficient inertial momentum must exist (greater than the pull of gravity) for us to avoid falling down on our face. As the pictures I posted show, edge engagement and the strong pressure on that early platform you mentioned are not necessary since our momentums will carry both our body and our feet to the next strong shaping phase. At least in theory. If either has that flow interrupted that affected body part will arrive too late to produce the balanced stance we desire at the beginning of the next strong shaping phase. What we typically see in a world cup race is a lot of very dynamic recovery moves since they are operating on the ragged edge of control. What doesn't change is this interplay between momentum and Gravity. Gravity will alway pull us down the fall line but our edge platform allows us to redirect our momentum, or our two momentums diagonally across the hill.

Slider, yes it's a white pass stivot.

Quote:

Originally Posted by justanotherskipro 

Slider, yes it's a white pass stivot.

Thanks for the technical term. It's my understanding that every part of every turn should be addressed with impartiality .

Quote:

Originally Posted by justanotherskipro 

Slider, yes it's a white pass stivot.

No smiley ?  

Quote:

Originally Posted by justanotherskipro 

Think about trajectories for a moment Oisin, A golf ball will rise after we hit it as long as it's inertial momentum is greater than the pull of Gravity. As that momentum fades the ball's flight will level off, then (slowly at first) begin to descend until eventually it will fall straight down along the vector defined by the pull of Gravity. Air resistance being the primary resistance the ball encounters, so ball manufacturers put dimples on the ball to control both the length of flight and amount of roll after the ball strikes the ground. All of this is based on controlling momentum.

So what does this have to do with skiing? Our momentum across the hill typically gets seperated into the momentum of the feet and skis and the momentum of the core. Notice I am avoiding the use of the term CoM since it's an abstract, global term. As we turn across the hill our two inertial momentums contains both a linear and angular component. (I think we all will agree that turns require angular momentum). If we release the body diagonally across the hill prior to releasing the feet the inclined stance will occur as both travel along their seperate paths. At this point as so you accurately pointed ou,t sufficient inertial momentum must exist (greater than the pull of gravity) for us to avoid falling down on our face. As the pictures I posted show, edge engagement and the strong pressure on that early platform you mentioned are not necessary since our momentums will carry both our body and our feet to the next strong shaping phase. At least in theory. If either has that flow interrupted that affected body part will arrive too late to produce the balanced stance we desire at the beginning of the next strong shaping phase. What we typically see in a world cup race is a lot of very dynamic recovery moves since they are operating on the ragged edge of control. What doesn't change is this interplay between momentum and Gravity. Gravity will alway pull us down the fall line but our edge platform allows us to redirect our momentum, or our two momentums diagonally across the hill.

Well, you probably know a lot more about golf than I but your description contradicts what I have been taught regarding the trajectory of projectiles......but never mind I'm not sure it has much to do with skiing other than the concept of momentum.  What you describe I believe is the effect momentum plays upon your example of the skier who is making the turn relatively late. I was describing the turn in which crossover and inclination occur prior to arriving at the fall line. As your skis cross the fall line at this point your momentum (a resultant really) wants to pull your body  forward and down the hill. At least this is what I experience.  I take issue with your description of moving the body diagonally across the hill prior to releasing the feet. You can do this I suppose but it isn't what I see racers doing most of the time nor is it what I normally do. The effect of a forceful extension to achieve crossover is to release the edges simultaneous with the movement of the body across the skis. That's a pretty nitty point I must admit but consistent with good mechanics of skiing. Momentum will carry our body and feet to the next shaping phase as you point out but the angular momentum which tends to pull the body to the outside of a turn (giving us something to balance against) is a resultant of the forces of momentum and gravity. Gravity and momentum in the very early phase of the turn I am talking about are actually tending to pull the skier's body down the hill, (angular momentum is down the hill at this point, not towards the outside of the turn which would in fact be up the hill)  away from the feet, hence the role of extension in this brief moment in providing the force against the skis necessary to control them.  You see a movement from a very compressed stance at the end of the turn so part of the component resisting falling is an upward movement of the body as well as a movement toward the inside of the turn. This is I think what you are describing as a dynamic recovery move. I am trying to suggest there is something  going on in high end skiing that perhaps many of us have not experienced that affords a World Cup racer, if he chooses to employ it, a greater degree of turn shaping and control very early in a turn. This is my understanding anyway and it is generally what I experience when I choose to ski that way, such as I am able. 

Its been a long time since I studied physics so I hope you will forgive if I am a little loose with the terminology.

Huh? Remember the ball on a string experiment? How about discus throwing, shot put, or even David and his rock and sling. Releasing the centripetal force would produce linear movement on a line tangent to the circle. Not along a radial line. Simple Newtonian laws at work here. As that forward momentum dissipates our path would slowly turn into the fall line because the centripetal pull of Gravity would slowly become the greater force acting upon the skier. Edging and forcefully extending the leg(s) to create even more centripetal force is an option but not always a good one. In fact, it's usually a bad option since it limits what you can do in the rest of the turn. That's the folly of the early edge and strong pressure mantra.

BTW, angular momentum is about rotation around an axis, not centrifugal force. Svindal's stivot introduced just such an angular momentum. It was arrested by the strong edge engagement prior to the fall line. I wouldn't say he was late doing so. Most skiers wish they could do that turn as well as he did.

Quote:

Originally Posted by justanotherskipro 

Huh? Remember the ball on a string experiment? How about discus throwing, shot put, or even David and his rock and sling. Releasing the centripetal force would produce linear movement on a line tangent to the circle. Not along a radial line. Simple Newtonian laws at work here. As that forward momentum dissipates our path would slowly turn into the fall line because the centripetal pull of Gravity would slowly become the greater force acting upon the skier. Edging and forcefully extending the leg(s) to create even more centripetal force is an option but not always a good one. In fact, it's usually a bad option since it limits what you can do in the rest of the turn. That's the folly of the early edge and strong pressure mantra.

 

BTW, angular momentum is about rotation around an axis, not centrifugal force. Svindal's stivot introduced just such an angular momentum. It was arrested by the strong edge engagement prior to the fall line. I wouldn't say he was late doing so. Most skiers wish they could do that turn as well as he did.

Hmm, the term that eluded me was inertia. Quick question for you: when, as you were completing a turn across the hill and initiating a new turn, did you ever passively experience a force pulling you up the hill strong enough to balance against?

pelvic shift creates a countered position early in the turn that makes angulating to balance on the outside ski much easier.

from- http://www.yourskicoach.com/YourSkiCoach/Skiing_Into_Counter.html

Pelvic shift is a tool for moderating your rotational influences.  To allow for quick edging and reduction or elimination of unwanted pivoting. It removes the effect of counter through your edge changes that might cause them to hesitate to hook up .

Add a tipping of the new inside knee while flexing it as your body crosses your skis to lead you down the hill.

 To tie this in with Oisin's post above I think the uphill projection of his mass is from moving from one foot to the other  and is causing an "away " movement from his turn. Using the skill of pelvic shift  along with tipping the inside down the hill would focus his energy better into the next turn

I'm a bit confused by the question because it includes the qualifier "pulling" me uphill. Lifts do that but if I am trying to ascend on my own that usually incudes some active movements on my part.

Are you trying to discuss the snow pushing back at me and as we cross the hill it's vector is up the hill?

Quote:

Originally Posted by justanotherskipro 

I'm a bit confused by the question because it includes the qualifier "pulling" me uphill. Lifts do that but if I am trying to ascend on my own that usually incudes some active movements on my part.

 

Are you trying to discuss the snow pushing back at me and as we cross the hill it's vector is up the hill?

Well you seem to be saying that the skier, as he is inclined down the hill in this type of turn is supported by centrifugal force. Since gravity is pulling the skier's body down the hill, balancing against centrifugal force would seem to imply that centrifugal force is pulling him in the opposite direction. That would be up the hill.

It is hard to distinguish the body force of gravity acting on one's self and the role of momentum acting on one's self; we experience the combination of the two as a single experience.  At slow speeds, with mostly gravity acting, the movements that make use of gravity to "fall" into the turn seem inetficient and hence the OP's disaproval of "toppling".  However, at higher speeds, with more momentum available, the role of inertia dominates and it becomes the more efficient to draw power for our movements from the situation and the world around us rather than supply it all through our own muscular force, saving that for working the controls.

So if we throw a ball, what makes it continue to rise after we have let it go, Oisin? The air doesn't push it up, nor does Gravity, which would become a centripital force as it pulls the ball downward.

Something defies gravity only because there is an expense of energy  that motivated it to do so. There is no other solution

Quote:

Originally Posted by justanotherskipro 

So if we throw a ball, what makes it continue to rise after we have let it go, Oisin? The air doesn't push it up, nor does Gravity, which would become a centripital force as it pulls the ball downward.

The force of your throw (F=MA, I'm beginning to remember a little physics) propels the ball which is subject to frictional air resistance and gravity all  the while. These act upon the ball to cause it to alter its trajectory and speed and fall to earth. I don't believe gravity is described as a centripetal force.

The significance of  this to the discussion is?