skiing strategies: path-speed-force

[dn]

Bud got me thinking again about skiing strategy a month or so ago. I've been an advocate of efficiency, but that's still pretty hard to define. I've discouraged the wide-early style, but I've never been able to say clearly why or explain it in a way that was very convincing to its advocates. The attached pdf file is my latest attempt at explaining both, and I put forth a compromise ski strategy that may make more sense to both sides of the issue.

[ForrestGump]

Holy cow, that gives me a headache! Scoke will be salivating on it, though, I'm sure. LOL

[skidawg]

11 pages? Does anyone have time to work on this forum???

[Bud Man]

Awesome work David.

 

Just to clarify, those path lines are produced through mathematical formulas and you did not draw then. The lines are produced through the formulas of laws of math and laws of physics. Is that correct?

 

The reason I ask, is I actually drew what I thought might be an efficient path, (no math, just imagination) and even though it is not the exact same as your combined style path graph, I feel like it is very close and seeing your combined style path graph makes me think my imagination might be very close to what is actually going on. I will insert it below. It makes me feel good to think your education might actually back up my imagination.

 

I have my path drawn crossing centerline at 14m. Based on your findings, I might should try crossing a tad later. I think you suggest for me to try 17m. I might move my extra gates and give that a try. So far I have crossed center at about 14m on lines 14.25m – 10.75m (28 off - 39.5 off)

 

Think about this: I feel like I am coming out of the buoy too soon as I have said in another thread. If I can come out slower, as I think I need to do, that might set me up to cross where I need to cross.

 

In reading your study, I am even more excited about some theories I was posting on Wet Jacket before a wet blanket put out the thread before it could really get anywhere.

 

I am closer to getting started with my live testing, but still don’t have any volunteers to come ski their “wide and early” style.

 

Again David, very nice work and well presented.

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[Craig]

David,

 

Can you post the math? Thanks.

[Horton]

Holy Crap. I need new glasses. I thought I was a geek until I met you guys

[9400]

There's a guy that shows up at our lake sometimes. When he rides in the boat and I'm skiing, he starts throwing out "physics this, physics that, x component, y component," I immediately lose 2 passes. I understand some people need to think of it that way, but that gets way to complicated for me.

[Bud Man]

David,

In reference to the speed of the combined style illustrated on page 10: I am trying to balance my speed more than what you are showing on your graph. It shows the shortening of the rope, forces the speed to increase at 20m and decreasing at 31m. According to your calculations, what does a skier need to do differently to get the speeds more balanced in those areas as the line shortens? My thought is to load the line with less intensity but a slightly longer duration as the rope gets shorter. Is that correct? When I watch videos of myself, I think that is what I might be doing (sometimes anyway). Can you do the math that would produce that graph?

 

Thank you David.

This is really good stuff.

 

[dn]

thanks Bud - the graphs are not drawn, they are plotted directly from the math, as you thought.

 

You asked what a skier needs to do to keep the speed balanced. If you do as you suggest and load the line less but longer, you will cross the centerline later. That will bring you closer to the efficient path, and your speed will be more balanced. I don't think you can keep crossing up course and accomplish it - we can choose our actions but not the consequence - at least that's what I tell my kids.

 

... skidawg - this is something I do to relax, like some people watch tv. It's pretty tame compared to what I do for work - of course, when the water gets to 50F in a week or two, that's where I'll be doing my relaxing for the next 6 months.

 

 

[Craig]

David,

 

Would you be willing to share your analysis with me? Thanks.

[Bud Man]

David,

 

I saw in a DVD a while back that said; “speed gives you angle” which is not what I picture in my mind. I realize that things can be interpreted in different ways, but I just can’t seem to grasp that. As a matter of fact, I believe it is the exact opposite of that. I believe as for slalom skiing, the angle of the ski is what gives us speed. That is why I have tried to back off of my angle to slow down my speed and ski a shorter path. I felt like it was easier on my old body and more efficient.

 

Below is an excerpt from a post I put in the thread Efficient skiing (Path and speed).

 

“We do not have a motor to push us through the course. The boat pulls us, and if we never made our ski deviate from the straight path that the boat travels, then we would never go faster than the boat. The boat going faster does not give us angle. However, as soon as we angle the ski, we increase our speed. Therefore, I believe it is angle that gives us speed. The ski angle also gives us our path. A longer path gives us a faster speed. It requires more strength to hold more angle, which gives us more speed and a longer distance to go through the slalom course, and I do not believe that is efficient.”

 

 

David,

Which of these two would be supported by math and physics? (speed gives you angle) or (angle gives you speed)

 

[ForrestGump]

Bud, think about this. Angle has to have a velocity component great enough to keep the angle from stopping the ski. So in that regard, the higher your velocity from the apex, the greater the sustainable angle you can create. I believe that you are thinking along the lines of pure accelerating across course. And the speed/angle theory really is based on the apex back to the handle. This is something that my background in car racing makes easy to understand. In a car, much like on a ski, When you enter a turn you cannot just turn the wheel hard. If you do, you bleed off your forward momentum, then cannot get the car to bite, which means you push outward. But if you understand how to brake, turn in, roll the apex with the highest speed possible, you can exit the turn with a much steeper steering angle and be accelerating while doing it.

[DanE]

Bud, you can also give this a thought. An earlier line with steeper angle across the wake and higher speed compared to the path that gives you the slowest possible speed doesn´t have to equal higher load on your body. You create your speed in three stages, the pullout - the pull through the gates and maybe a little speed increase from bouy # 1 going to 2 depending of how close to your target speed you´ve nailed it through the gates.

From there on your set- if you´ve created a high speed situation it doesn´t take as much force to ski with a little steeper angle cross course and you can turn a little smoother without losing too much speed.

It´s the stop and accelerate situation you want to avoid- that´s what creates a high load situation not speed and angle.

Speed and angle however gives you a little more wiggle room to deal with less than desireble conditions.

Everything in moderation though- it´s very easy to bite off more than one can handle in the heat of the battle.

[Bud Man]

ShaneH,

You described that very well and I understand what you said. I just don’t understand that other person saying that speed gives you angle. Maybe it is as simple as he is trying to say something different than what my brain is interpreting from those four words.

 

When I speak of angle creating speed, I am referring to while being pulled by the boat. I realize that if there is no load, then a change of direction (ski angle) will slow you down.

 

What you said I feel fits into what I am trying to achieve in the slalom course.

• Slower average speed throughout the course by crossing wake with less angle and maintaining speed around the buoy.

• Longer arching turns at the buoys to maintain speed around the buoys.

• Try not to angle the ski anywhere in the course any more than is necessary.

 

I try to see the path I need to take through the course. I try to keep a mental image of the path I posted above. It seems to really help me.

 

I would still like to hear your response as well David.

 

Well said DanE.

 

[DW]

Bud, perhaps the way to interpret the comment is to consider it as "if you have or are skiing at a high speed (regardless of how you achieved it) you then are afforded the opportunity of being at a greater angle, or in all reality, the faster you are travelling on your ski the greater angle (from the direction of travel of the boat) you will need to keep the line tight or the downcourse velocity vector equal to boat speed". Personally, I would not worry about that statement as I really don't see the need to dwell on it.

[ral]

I guess that speed and angle are relative to the skier. I do not see this as an absolute optimum value for each line length. The "impossible line and speed " for Will Asher and Chris Rossi are VERY different than mine.

 

As with everything, if you ski near the limit of the angle you can handle, and near the limit of the speed you can handle, you are in trouble. One of the skiers in our lake, woman around 55 years, in very good shape, and with visually nice technique, skis up to 2 buoys 55 km 18 m. When skiing 52, she is extremely light on the line and has a low angle when crossing the gates, and running a later line, with little speed variation. Wheels fall of @ 55. And 52 is near the limit. She cannot handle more angle or speed, when she tries, she is in trouble.

 

On the other end of the spectrum, one of our decent open skiers, VERY strong, famous for breaking all equipment he uses, is able to run into 39. However, he falls @ 32 and 35 a lot. He goes out of the dock as if it was a contest for breaking the pylon. His limit is much different than the previous one described and, for him, getting down a notch should be beneficial.

 

In my view, we should ski at around 80 to 85% of the maximum we can sustain for all variables. When trying to get near 100%, you are in trouble. If targeting 50%, you are leaving buoys on the table.

 

Physical conditioning and technique improvement increase the maximum levels, so we can ski with more angle and speed.

 

Just MHO.

[Bud Man]

I agree DW, I should just put it right out of my head, right after David tells me if is possible or not. [smirk on my face]

 

OB, Good questions, but I don’t have the answers. I tried to ski a bit latter path tonight like the efficient path David plotted for all of us to study and did not do as well. When I cut to 11.25m, I overturned # 5 and sank before reaching the wake, but I ran all my other passes thought. I think there were 10, 12m passes in the set, but I have not reviewed the video yet, so I have not counted. I did not hit the water until 7:37PM, so it was about dark and those red buoys are hard to see that late. I felt very rushed, but that is normal for me when I am pushing darkness. Tonight would not be a fair judgment for me to make for the later path. I will try it again.

 

After studying David’s report, I’m suspicious that I might be skiing more wide and early than I thought, and you might be skiing less wide and early than you thought.

 

ral, those are good points.

 

[Bruce_Butterfield]

OB and Bud,

 

Let's turn this around for minute. Can you explain exactly why you consider speed and angle to be a bad thing?

 

With the laws of physics being the being what they are, if you are going to get out the end on a shorter rope, you are going to have more of both. Sorry, you might as well try to repeal the law of gravity as run a shorter rope with less speed and angle.

 

I think what is driving this train of thought is that many skiers get out of control when they get lots of speed and angle, or they will bite off more than they can handle and give it all back to the boat. This may not be as solid as the law of gravity, but its darn close.

 

So, I think a better answer is that you want absolutely as much angle and speed as you can get while maintaining control and being smooth. The bad news is that this is a lot harder than trying to ski “efficiently”, but will get you more buoys in the long run.

 

Food for thought.

[dn]

Bud asks does speed create angle. If you advocate that, you'd better ask what created the speed to begin with. I have not observed any skier where that is the case. I agree with Bud that angle creates speed. The skier comes around the buoy with with some speed and angle, consciously increases the angle of the ski, and that causes speed to increase. Then in the preturn speed can be used to maintain outward direction to the extent rope and boat position will allow.

 

I don't think anybody disputes that simple logic, yet I think I understand what people mean when they say speed creates angle, but strictly speaking, that's wrong. Angle is the cause which translates the force supplied by the boat into new direction, and speed is the effect, not vice versa.

 

Now on to the question others raised about whether you can add buoys by skiing with more angle and higher speed. Definitely! That's what my wide-early chart is all about. If your present limit is 38 off, and if you could muster more angle and speed, you could move up to the 39 off pass, etc. But that begs the question: if you're skiing that style and your limit is 38off, it's because you've reached your limit - so what makes you think you're going to be stronger or have faster reactions? For most of us it's wishfull thinking. Of course we could all do better if we were stronger and faster - but we all do have limits. So the question should be: how much better could you ski if you made better use of the strength you have? At first, you're likely to ski worse when you try a new style, because so many of your habits and reactions will be counterproductive. Tiger Woods didn't immediately improve when he took a few months off to change his swing many years ago, but he had faith, didn't get discouraged that he initially got worse, worked hard, and came back with a vastly improved swing. If the approach of skiing smarter not harder makes sense to you, then maybe you'll persist until you learn the new style and practice it enough to where you can match and then exceed your old style PB.

 

Last year when the Big Dawg came to my ski site, I found myself a perfect spot on the shore to sit and watch all those great skiers. Most of those guys don't say or perhaps know what style they ski. Most of those that will talk about it advocate a wide-early high angle high speed approach. So I watched them ski. At their 32off opening pass, judging by where they crossed course center, the majority of them looked like wide-early skiers, crossing well upcourse. Those that were crossing near midcourse even at 32off were clearly not having to work as hard, however. Then as the line shortened, the wide-early guys were crossing later and later, while the efficient skiers just kept crossing near midcourse and making it look effortless. At 39off they were all crossing within a meter of center. So even those that think they ski a wide early style were not. Even those guys don't have the strength and reaction time to take that style into very short line, so what chance do you and I have with a wide early style? I see the same thing watching the pros, except very few of them even start with a wide early style at longer lines. These observations, along with the forces I compute for the wide-early paths in my charts, are my justification for saying nobody is strong enough to ski all passes in a true wide early style. They may still be giving it all they've got and attempting that style, but why do that if somebody else can do as well with a lot less effort? If I learn to ski with less effort, I expect less wear and tear on my body, and thereby assure myself a lot more enjoyable years behind the boat.

 

 

[Bud Man]

I wrote this last night and then our internet went down until just now. I did not realize I would miss it as much as I did.

 

Bruce,

Just off the top of my head answer. It would appear that for 55kph, David Miller consistently gets more buoys, more angle and more speed than most if not all MM skiers, which supports what you are saying.

 

When I was younger, I had a turn and burn frame of mind and could only ski about six or eight passes every other day. I am turning 54 this year and have more of a target of minimum angle and speed frame of mind and can easily ski close to twenty passes in one set, mostly 12m line, every day if I choose. My typical daily sets this winter in my dry suit were; 1 - 14.25m, 1 - 13m and 10 or 12 - 35s. I’m still in my dry suit but a few days ago have switched to 14.25m, 13m, 12m, 11.25m and then some more 12s. Our weather here is SC is bouncing around a bit. High last Monday about 87° and calling for a high of 61° this coming Monday.

 

Anyway, my point is I don’t think my body can do what David Miller does. He looks like he is built out of steel. If a car hit him when he was crossing the road, he would be fine and the car would be totaled. In all seriousness, if I bend over wrong to tie my shoe, I will hurt my back where I can hardly walk. I love to ski and want to pace myself to ski until I am called Home.

 

By the way, I had miss remembered some things in your handle control article and went back and reread. I think it helps me ski better when I can keep it in mind. Good job on that.

Also, your staying open article helps me, when I can keep it in my mind. Another job well done.

In addition, the recent reprint of the old article you did about skiing in wind was also a very good job. You really do a lot of good for the sport. Thank you.

 

[baja]

Make an athletic move towards the ball... Works for baseball, golf, tennis... Slalom. Since my body is apparently incapable of performing like a CNC machine, I will be satisfied with what could best be described as a series of linked recoveries. These various recovery adjustments are required due to my individual experiences, physiological characteristics, and the persistent failure of the real world to provide me with perfect playing conditions. I'm going skiing.