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# PMTS Camp at Hood - Page 8

Quote:
 Originally Posted by HarveyD Max, What you may not appreciate is that the PSIguy's crossbar (analogous to the pelvis) is mounted loose. There is a parallel stop bar more like a thick wire) that prevents him from tipping over completely, although inevitably, he does. Gravity pulls his crossbar downhill, causing his struts (legs) to tip and putting his skis on edge. He represents an early conceptual model of what skiing would be like on shaped skis. I too have seen him in action.
Its a cool model. I did notice him getting wobbly and then tipping over. I tip over sometimes too but normally I bobble instead of wobble before I fall.
Max, when psiman is pointing his skis straight down the hill, centripetal force trys to push him over his skis, and the component of gravity perpendicular to the snow surface trys to keep him from going over his skis and the downhill component of gravity doesn't care if he goes over his outside ski or not. When psiman has his skis pointing across the hill, both the centripetal force and the component of gravity directed downhill gang up on the component of gravity perpendicular to the snow and over he goes.
Quote:
 Originally Posted by Ghost Max, when psiman is pointing his skis straight down the hill, centripetal force trys to push him over his skis, and the component of gravity perpendicular to the snow surface trys to keep him from going over his skis and the downhill component of gravity doesn't care if he goes over his outside ski or not. When psiman has his skis pointing across the hill, both the centripetal force and the component of gravity directed downhill gang up on the component of gravity perpendicular to the snow and over he goes.
Yeah, I finally got that after watching the video. Bascially he doesn't have much edge resistance to speak of. What I was pointing out earlier is that in a real world situation if you have a strong edge you need to do something to release it or you carve back up the hill.
Let's bring the thread all the way back to the topic.

One thing I forgot to mention regarding extension. If you don't extend you will decrease the ability to flex for the next release. You may have seen this happen to skiers in the bumps. They don't extend after absorbing the bump and in one or two more bumps then end up getting thrown in to the air because they didn't have any flex range left in the legs to absorb the bump with. The same thing happens in normal turns and once you run out of flex you have to do something else to release (like a big up move).

### What happens to that inside ski

Ich bin eine PMTS'er (but just barely).

However, I have often thought about the physics Dchan describes with regards to the inside skis need to scribe a shorter turn since it is in a smaller diameter circle.

Here's what I think happens, but it's not something that I think about when skiing.

There are a number of "little things" in PMTS that seem to have larger effects. One of the emphasis early in the progression is pulling the heel of the "free foot" closer to the stance foot (where together is a relative term). One of the drills, in fact, is having an instructor push your downhill (free foot) heel away and showing how much effort you might need to exert to draw the heel in. The goal of the drill isn't about maintaining a certain separation, but rather in creating early awareness that some effort is required to keep the feet in the right spatial relationship. Another precept/drill is pulling the free foot (inside foot) back and not letting it drift ahead of the stance foot.

I believe the combination of these two moves effectively shortens the radius of the inside ski by putting a little extra weight on the tip of that ski and by slight dragging (not sure what a right word might be) of the tail of the inside ski next to the stance ski.
Quote:
 Originally Posted by Max_501 Let's bring the thread all the way back to the topic. One thing I forgot to mention regarding extension. If you don't extend you will decrease the ability to flex for the next release. You may have seen this happen to skiers in the bumps. They don't extend after absorbing the bump and in one or two more bumps then end up getting thrown in to the air because they didn't have any flex range left in the legs to absorb the bump with. The same thing happens in normal turns and once you run out of flex you have to do something else to release (like a big up move).
But MAX! In-depth discussions about a little toy making turns is so much more fun!

And Max question:
Why a race camp? Do you Race?
Was the camp geared towards SL? GS? Both. Did you end up on actual Race course?
Quote:
 Originally Posted by MTT Why a race camp? Do you Race?Was the camp geared towards SL? GS? Both. Did you end up on actual Race course?
My kids race so I knew a race camp would be a good thing for me. It was focused on SL which is great since I enjoy short turns (slalom skis are my favorite). We ran a course that was set with brushies. No real gates. I'll probably start masters racing next season just for the time in the gates.
Quote:
 Originally Posted by Max_501 My kids race so I knew a race camp would be a good thing for me. It was focused on SL which is great since I enjoy short turns (slalom skis are my favorite). We ran a course that was set with brushies. No real gates. I'll probably start masters racing next season just for the time in the gates.
OK.
I have found that little things like Gates and Ruts have a pretty big impact on most of what has been discussed here. However a Race clinic that allows you to ski with and emulates superior skiers while having fun is a worthy cause.
Quote:
 Originally Posted by MTT OK.I have found that little things like Gates and Ruts have a pretty big impact on most of what has been discussed here. However a Race clinic that allows you to ski with and emulates superior skiers while having fun is a worthy cause.
Having to make turns that someone else dictates makes a HUGE difference, no doubt about it. Also, skiing in ruts really keeps you on top of things. The last day we were joking about how crazy it was that were disappointed that the course was coming down when 4 days earlier we would have avoided a rutted up run like that at all costs.
Quote:
 Originally Posted by Max_501 My kids race so I knew a race camp would be a good thing for me. It was focused on SL which is great since I enjoy short turns (slalom skis are my favorite). We ran a course that was set with brushies. No real gates. I'll probably start masters racing next season just for the time in the gates.
Another one who has caught the bug....

Ice is fun, really!
Finally got to watch the PSIman on my high speed connection. Quite a cool gadget. I see I'm too late though.
PSIman's Center of Gravity is down at or below his knees I wonder what a skier built that way would look like? :
Quote:
 Originally Posted by SLATZ PSIman's Center of Gravity is down at or below his knees I wonder what a skier built that way would look like? :
LIke this?

Skier: Hermann Maier
Image: Ron LeMaster
By the way Bob,

Thanks for giving Ron credit..

FYI for those of you that want to use images from Ron LeMaster's website, please feel free to do so, as long as you put credits for him. Epicski has a standing letter of permission from Ron to use and post images from his website as long as they are credited to him and the electronic watermark is still visable. I don't want to violate that agreement and lose the great resource.

Now back to the conversation.

### Another fine mess...

Just to add some more goo to the stew, we might note the following:

As someone who spends a great deal of his time concerned with circular arcs, tangency, etc. while designing little things such as roads, I might suggest that the curves carved by a skier (including PSIman) making the appropriate progressive and continuous moves are not circular arcs of constant radius. To carve a constant radius circular arc would require an abrupt transition followed by a very static and rigid "park and ride."

In practice, we continuously increase or decrease edge angle, while at the same time adjusting many other parameters of our skiing. Some of the moves are conscious, some are not. Despite our best efforts, our shins are not perfectly parallel, and the two skis do not have exactly the same edge angle against the snow at the same instant.

We might also note that there is a range of edge angle in which the "pure carve" curve is very sensitive to the edge angle. A slight change in the edge angle can create a large change in the line.

The resulting curves are probably a complex hybrid combination of pieces of circular arcs, spirals, parabolas, and hyperbolas. The inside curve will be similar, but different from, the outside curve. Both the radii and the many various center points or focal points will be different. The inside curve will not be a simple exact offset of the outside curve.

As has been pointed out here already, there are a variety of things the skier can do to get the inside ski to lay down a line that appears roughly concentric with the trench carved by the outside ski. The fact that it isn't exactly concentric or parallel, and that neither line is a pure circular arc (and they don't need to be) gives the skier a good deal more latitude in adjusting the line of either ski and, in general, moving effectively.

Go play!

### Actually, PSIA Man's Skiing Sucks

PSIA Man's skiing is created by the CM dumping over in a pendulum fashion and leading (causing) the skis to edge into a park and ride. The causal path here is from the top down. In fact good skiing happens using the opposite causal path. The feet tip, the legs flex to facilitate tippng, and the upper body adjusts (counter balance and counter movement) against the direction of tipping and turning to create balance and grip.

While I agree that PSIA Man makes an interesting toy, and I do see lots of skiers skiing this way, it is not a model for effective and efficient skiing.
Quote:
 Originally Posted by SkierSynergy PSIA Man's skiing is created by the CM dumping over in a pendulum fashion and leading (causing) the skis to edge into a park and ride. The causal path here is from the top down. In fact good skiing happens using the opposite causal path. The feet tip, the legs flex to facilitate tippng, and the upper body adjusts (counter balance and counter movement) against the direction of tipping and turning to create balance and grip.
SS, that's one way of looking at it, but I disagree with you, as I don't believe that starting by tipping feet is always the best (or only) way of making a good turn. Sometimes I see better turns where the upper body makes the first move, and other times I see great turns where the lower body is working completely independently of the upper.
Quote:
 Originally Posted by SkierSynergy While I agree that PSIA Man makes an interesting toy, and I do see lots of skiers skiing this way, it is not a model for effective and efficient skiing.
Of course not... but that's not really the point, is it? It seems interesting to me that a toy can make carved turns in a way that seems to some to be impossible. No pushing, pulling, lifting, flexing, etc. necessary. I find that interesting.

The only way to turn? Nope. The "right" way to turn? Nope. A way to turn? Yeah, I think so. And I think that fact alone is very interesting.
Quote:
 Originally Posted by SLATZ PSIman's Center of Gravity is down at or below his knees I wonder what a skier built that way would look like? :
I'm not sure why you'd say this. Why do you think it's below his knees?
Alright

This thread is back on track. In-depth disscussions about a little toy sliding down a snowbank :
Quote:
 Originally Posted by MTT Alright This thread is back on track. In-depth disscussions about a little toy sliding down a snowbank :
thank you.

and thanks, max.
Were there any other PMTS or camp specific questions?
yes.

the hands.

anything?

disregard if nothing, thanks.
Quote:
 Originally Posted by Max_501 Were there any other PMTS or camp specific questions?
Anyone . . . Anyone. . . .the ____________ curve . . .

Quote:
 Originally Posted by Max_501 ... camp specific questions?

Yes:
1. Did you enjoy yourself?
2. Has the camp allowed you to have more fun on the slopes?
MAX_501,

I am talking about pulling the foot back as you are. I should have said that if the inside ski is too far advanced when you transfer weight your balance point will be over the tail and the ski can jet out.

So, by pulling my inside foot back I manage the fore and aft pressure distribution I will soon be experiencing.

Telling someone to "stay centered" is the same thing, and probably an easier instruction to understand. But how do you know you are "centered"? By the pressure distribution on the bottom of your foot!

Balance is highly correlated with pressure control... of course there is way more to pressure control than balance, like flexion and extension.....
Quote:
 Originally Posted by ryan the hands....anything?
Wow, I can't believe I didn't say a word about that in the orginal post. We talked about them plenty. The basic idea is that you need to keep a strong inside arm position which is hand up and a bit forward...if you let your hand drop and fall back it will reduce (or eliminate) counter balance and counter rotation. You should be able to see both hands in your peripheral vision at all times.

Related to this is the timing of pole plants which is very important for fast short turns. As soon as the left pole touches the snow the right pole should be moving forward and visa versa. That way you don't have to rush to get the pole forwards for a plant. Personally the correct timing is a challenge for me. I still rush doing too much of my forward pole movement too late.

The movement is subtle. You don't want large arm movements.

One drill I like for the strong inside arm is the pole push. After you plant the pole you keep a strong arm and the pole tip pushes against the snow as you make the turn. This keeps the inside arm from dropping down or back.
Quote:
 Originally Posted by Wear The Fox Hat Yes: 1. Did you enjoy yourself? 2. Has the camp allowed you to have more fun on the slopes?
Oh yeah I had a great time. We had good snow, decent weather, and a great group of people.

The training I received definitely supercharged my short turn so yeah, I think I'll have even more fun on the slopes.
Quote:
 Originally Posted by Max_501 Oh yeah I had a great time. We had good snow, decent weather, and a great group of people. The training I received definitely supercharged my short turn so yeah, I think I'll have even more fun on the slopes.
Then !
To me the "how you do it" is less relevant than the amount of fun you have (while respecting others)
Quote:
 Originally Posted by jhcooley Just to add some more goo to the stew, we might note the following: As someone who spends a great deal of his time concerned with circular arcs, tangency, etc. while designing little things such as roads, I might suggest that the curves carved by a skier (including PSIman) making the appropriate progressive and continuous moves are not circular arcs of constant radius. To carve a constant radius circular arc would require an abrupt transition followed by a very static and rigid "park and ride." In practice, we continuously increase or decrease edge angle, while at the same time adjusting many other parameters of our skiing. Some of the moves are conscious, some are not. Despite our best efforts, our shins are not perfectly parallel, and the two skis do not have exactly the same edge angle against the snow at the same instant. We might also note that there is a range of edge angle in which the "pure carve" curve is very sensitive to the edge angle. A slight change in the edge angle can create a large change in the line. The resulting curves are probably a complex hybrid combination of pieces of circular arcs, spirals, parabolas, and hyperbolas. The inside curve will be similar, but different from, the outside curve. Both the radii and the many various center points or focal points will be different. The inside curve will not be a simple exact offset of the outside curve. As has been pointed out here already, there are a variety of things the skier can do to get the inside ski to lay down a line that appears roughly concentric with the trench carved by the outside ski. The fact that it isn't exactly concentric or parallel, and that neither line is a pure circular arc (and they don't need to be) gives the skier a good deal more latitude in adjusting the line of either ski and, in general, moving effectively. Go play!
YAY
Thankyou ...
especially the centrepoint/focal point one.... I never got why everyone was so obsessed that both skis were on a circle with the SAME centre.... unless you skied the whole 360degrees out you would be quite happy for their centres to be about ... say... "hip width" away from each other...
Quote:
 Originally Posted by Max_501 Cool, do you have any footage without all the editing? Makes it nearly impossible to analyze what is happening. BTW, what causes the little guy to do tight turns vs wide turns?
Here's Bob Barnes' video. Again it is highly edited but gives you some more to look at.

http://ourworld.cs.com/BBRNZ/PSIMAN01.wmv
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