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Slalom sequence test #2

post #1 of 23
Thread Starter 
Here are a couple more slalom sequences from the Copper Mountain World Cup this fall. They show winner Laure Pequegnot and Kristina Koznick, who finished 6th in the same turns. With a little luck, the frames should synchronize....


Best regards,
Bob Barnes
post #2 of 23
Thread Starter 
OK--so they don't quite synchronize automatically. To view the animations in synch, let them load completely, then click on the "Back" button and then the "Forward" button on your browser to return to the page. At least that works on my IE browser.

Any other suggestions? Dchan?

Best regards,
Bob Barnes
post #3 of 23
GREAT STUFF!!! Using the back and forward buttons synced the pics up for me.
These two sequences are interestring to watch. Looks like the first turns are similar, seconed turn look a little cleaner from Laure and look as if Koz uses a little more rotary and gets some snow flying off the skis. Third turn looks as if the Koz is on it! Skis are slicing and moving forward while the body is moving down the course and very quite. Look as if Laure gets the skis skidding and and when they bite she is left behind for a second. Looks like she is making a good recovery by the end of the sequence.
The only problem that I had with the pictures is the speed that they appear. I found that they were just fast enough to make it hard to compare frames before the next overlay appeared. This may be my problem! Again, Great Stuff!! It sure make for an great chance to examine the differences in turn shapes and styles!
Well Done! [img]smile.gif[/img]
post #4 of 23
: God! I hate being around people with talent, dedication and the time to do it all..... makes me feel like a real slug!

Bob: Thanks for all of the energies that you put into this stuff! [img]smile.gif[/img]
post #5 of 23
This is the way to watch world cup racing. I'm assuming that the frames were taken at equal intervals. If so P is clearly ahead after the third turn.

I notice that K has a much more hunched over style and that her A-frame is very evident. P, on the other hand seems to be in the back seat between turns but has no A-frame at all. Her legs seem to stay perfectly parallel.

Hitting the Stop button at various times during the sequence allows you to look at and compare the relevent positions in the same turns.

Bob, great job on this.

post #6 of 23
Hey, if I look at this sequence every day, will I be able to ski like Laure?
Thanks Bob!!!
post #7 of 23
Laure's torso seems to be facing downhill more throughout the sequence, also angulation seems a bit better.

yea or nay?
post #8 of 23
Wow, Bob.

These are just outstanding. Thanks for posting them.

Considering that there must not be much more than about 1.5 seconds between gates (wouldn't that be about right?), Laure gets unbelievable extension/flexion in her turns.

I'm probably wrong, but it also appears that Laure has a little different hip thing going on at the rise line than Kristina. Laure seems to be leading a bit more with her uphill hip, which perhaps allows the downhill hip to drop fractionally lower and increase the angles a little?

Anyway, these are a kick to see. Gorgeous turns.

Women making slalom turns look more cool than men - just like in soccer and volleyball.


post #9 of 23
Hey, Bob. An echo here. Thanks for taking the time to do that. Truly appreciated. I really like and seem to gain further understanding from SEEING this stuff; really "hooks up" with the vocabulary of it. 'Specially the staying "aimed" downhill.

<FONT COLOR="#800080" SIZE="1">[ December 19, 2001 09:00 AM: Message edited 1 time, by ryan ]</font>
post #10 of 23
Thanks Bob, I can't believe how similar these two racers are.
post #11 of 23
Great job on the photo sequences, Bob.

I can't get both of the sequences on my screen at the same time, but it looks like the two skiers' positions in the course match up perfectly through the 9th image where they have both raised their right hand and are (or are about to) block the gate. Image 10 seems to show snow being thrown up from Kristina's skis, but not from Laure's. By the 11th image, and certainly by the 12th where they're both crouched in their transition, Laure is perceptivly ahead.

What do people think? Am I viewing this correctly and is a conclusion that Kristina first starts to lose time at the second turn correct? More importantly, if so, what is causing this?

Bob.Peters, I've been counted the gates in the five or six WC slalom races I've managed to tape off free TV during the last three or four years. Both men and women seem to average close to 0.8 seconds per gate. Given that the flushes and hairpins are probably faster than others, I'd guess that WCers average less than a full second for each "ordinary" gate.
post #12 of 23
Thread Starter 
Thanks for the comments, everyone! I agree with those who see Koznick losing some speed in that first left turn (second turn on the sequence, frames 10-11). Lots more snow flying from her skis, which go sideways, rather than launching forward like Pequegnot's skis do from their clean edgeset. This also accounts for Koznick's bent-over stance in the 12th frame. She has made the move forward with her body that would have kept her in balance when those skis shot forward. Since the skis went sideways instead, she ends up folded at the waist.

What looks like a lot of "back seat" positioning in the transitions of both skiers is really a similar move to the old "jet turns." The skis shoot forward from their edgeset, while the body takes a shorter line into the next turn. For a moment, it looks like the skier is way back, but there is no tail pressure to speak of here (when it's done perfectly, that is--perfect balance in such a dynamic move is not a given!).

For those interested, the images are shot at 5 frames per second, consistently throughout both sequences (actually, it's every 6th frame from a digital video camera). Each of those turns, then, took about a mere second to complete!

Playback is at one frame per second, so the skiers are going 1/5 of actual speed. This is easily adjustable--what do you all think? OKSkiBum suggests that it might be preferable to slow it down more--I'll try that when I get a chance.

Thanks again everyone! I'll put up more as time allows.

Best regards,
Bob Barnes
post #13 of 23

Thanks for the stats on elapsed time between gates.

I actually was going to guess closer to a second, but when you look at all that's going on in those frames during a single SECOND (one thousand one), it just doesn't seem possible. To go from being fully flexed on carving ski(s) to a direction change to full extension and back to flexed in a second - all while staying on line in a WC slalom course - borders on being inhuman.

Man, what talent.

post #14 of 23
A very interesting dynamic here. Normally, you would want to start a turn with the body ahead of the skis, because the skis will accelerate as they turn into the fall line, and will catch up to the body at the end of the turn. In the turns above, the skis start the turn ahead of the body, because the turn is so short that the body catches up to the skis at the end of the turn.
post #15 of 23
Bob: Thanks for the exciting sequences. This is really great to see hear at Epic. Since a picture is a thousand words, it's great to watch the differences between skiers.

The efficiency Laure exhibits is a cleaner line with more precise movements through all turns. Kristina appears to be in a "catch up" mode after turn #2.Once she starts into the catch-up mode you can see her try to step up in the sequence, to get a higher line in preparation for the next turn, from turn two to three, in particular.During that sequence you can see her skis start to diverge at the start of each step.

The acceleration in Laure's turns is evident with the extreme rebound. It appears so strong that at first the upper body appears to be somewhat rotated turn to turn, however her knees continue to drive toward each new turn.

Great job. Keep it coming. I agree with OKskibum in that a little slower sequencing may provide more time for comparisons. Thanks. Whtmt : : : :

<FONT COLOR="#800080" SIZE="1">[ December 19, 2001 08:29 PM: Message edited 2 times, by whtmt ]</font>
post #16 of 23
Thread Starter 
<BLOCKQUOTE>quote:</font><HR>Since a picture is a thousand words, it's great to watch the differences between skiers. <HR></BLOCKQUOTE>

Thanks Whtmt--and since I'm the first one to go to those 1000 words when I don't have a picture, these montages should save us all a good bit of time....

Here's another one--Annemarie Gerg of Germany, who came 14th in the Copper slalom. She was almost 2 seconds slower than Pequegnot in this run. Same set of turns, with a 2 second delay between frames this time.

Best regards,
Bob Barnes

<FONT COLOR="#800080" SIZE="1">[ December 20, 2001 04:20 PM: Message edited 1 time, by Bob Barnes/Colorado ]</font>
post #17 of 23
words saved, and only a few gates. Lots to talk about here. I don't see the retraction that was so prevalent once I see lots of extension and little flexion. In the original sequence I see that american girl stays much more blanched through her run never reveling her bib number. The French girl gave up her number around PIC number 9 or so. After that she was all done. The German looked much more square to the skis and I would bet she made bigger mistakes on other parts of the course. Watch for the retraction move though it is not what it once was.eek: :
post #18 of 23
Awesome stuff. I'm a full time IT guy and have to admit I wouldn't know where to begin putting something like this together.

I just noticed something interesting about their heads. Pay attention to the yellow frame on LP's helmet. She appears to be focused downhill in every frame whereas KK appears to be looking across the hill between each gate. LP seams to be looking much further ahead than KK, or maybe she just saw Bob with his camera and was trying to catch his eye.

post #19 of 23
Thread Starter 
Hah! Great observation, Gary. As much as I'd LIKE to think Laure P. was "trying to catch my eye," I'm pretty certain she didn't even know I was there. I was standing in the crowd, using a fairly long lens.

Best regards,
Bob Barnes
post #20 of 23
So everyone,

Is Koz going to do it. Suggest we send messages of encouragement to the Koz@koz.com

Bob you amy want tosend your observations as well.

Go to the website and you can email to her through it.

So let us all think SLC,Koz and the GOLD !!!!
post #21 of 23
: : Bob, This work is outstanding, you should get a job for the network for the Olympics and help Brooker do analysis! Laure obviously grew up on a "flat" hill. She wins this section of the course (other than having the advantage of being on Salomon 3Vs!) by squirting the tail and accellerating away between gates, look at her perpendicular spine exiting the turns compared to Christinas staying(leaning) forward. Keeping the spine perpendicular to the ground drives force down throught the heel to pressure the tail without leveraging the rear boot cuff too severely. This "hanging" on the tail for an instant is developed by training on the flats and works great if you can recover fast enough not to get caught in the back seat. Great Stuff!!- Thank you

<FONT COLOR="#800080" SIZE="1">[ December 24, 2001 08:35 AM: Message edited 3 times, by Michal Grau, PNS Race Staff ]</font>
post #22 of 23
Wow, BOB that is great stuff.

Koznick's turns reveal more spray from the skis after the gate than Laure, and Gerg is obviously turning much too early.

I'm curiously comparing the 'parallelness' of Laure's and Kristina's skis. There seems to be some difference there, but I'm not completely sure what it is.
post #23 of 23
Thread Starter 
Hi Roto--

Good eye! Yes, Koznick clearly throws a lot of snow and loses some speed on that left turn. Her skis go sideways rather than jetting forward, and her upper body then folds over. Pequenot is the superior glider, at least in these seqnences. Koznick appears slightly over-active with her inside ski, which accounts for the slightly less parallelness of her skis--the slight divergence of her tips at times. This not only scrubs a little speed, but it also prevents her inside ski from helping the clean carve when the outside ski breaks away.

Tiny little things really show up clearly in sequences like these, don't they? I agree too that Gerg "turns too early" in these turns. This shows up clearly in the 8th frame, where she has turned her skis strongly to set up for the left turn. The little stem ("abstem") that appears as she rounds the gate (9th frame) is probably due both to struggling to set that edge again after she threw it into a skid, and also perhaps to needing to DELAY the edgeset slightly because she overturned her skis in the previous frame. It happens in the other turns as well, but shows up most clearly in that left turn. In any case, Gerg appears to pivot her skis more strongly ("set a stronger steering angle") than either Pequegnot or Koznick as she sets up for these turns.

Merry Christmas!
Bob Barnes
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