Acceleration

[Deep11]

Acceleration

 

If you are still working out how to align and stack correctly then you should probably look away now.

 

There are many ways to run the course and most of the guys on here are in the "lock and load" category. I have been doing this for a few years (largely to perfect my stack) and it is (as it should be) a default position when things go wrong. I can run 14 and 13 all day long this way. 12 works as well, but less so, and then a few at 11.

At this time of the season I am setting goals and happy to deconstruct in order to ultimately move on.

This year I want to learn to accelerate properly, or at least see if I can.

 

Explanation: If you turn the ball and hook up in perfect alignment (stack), all acceleration will now come from the boat and any additional "lean" you put in (which you probably shouldn't as this increases drag also). In other words you can't introduce any additional acceleration. With this approach characteristically the "load" is applied into and through both wakes with a later edge change.

 

To be clear this is a great way to ski I just want to see if I can do it another way.

 

 

The alternative is when the boat starts to pull, you are NOT in your perfect stack position (in relation to the boat and pylon) but in a place that allows you to accelerate the ski under the rope (and ultimately behind the handle). The stack comes during this process, at just the right moment. As a result skiing this way the load comes on really early and the edge change is happening from before the first wake.

 

What I would like to know, from those who ski this way, is if they have any tips on how to get there, the "feel" they are looking for and any "visual" clues/goals (such as looking to shore/down the bouy line etc).

 

The skiers that I see really showing this are:

Nate, Seth, CP, Marcus Brown, TW

 

I realise that this may be quite an advanced topic, but don't think I qualify to post there just yet :(

 

Thanks in advance.

 

 

 

[Horton]

@Deep11 I am not on board with your basic premise. We talk a lot about stack on this forum because it is the number one problem for most skiers who do not run 38 (more or less)

 

I would say that there is never a time when you do not want your shoulders, hips and ankles aligned. Watch CP

 

As for when to load => many or most of the best skiers in the world carry speed through the turn so they can load late. They have time to be in the best possible position when the boat picks them up. The result is a very short but very efficient load.

 

Smith is maybe the best example of this. He picks up the load late and is in basically perfect position to get all his work done => over an extremely short distance.

 

Until he gets to 41 you can see Smith turn and glide toward the wakes before he loads.

https://youtu.be/2AXeYtFbxSI

[mwetskier]

@Horton -how old is that parrish vid? just asking because i didnt see any 55 gates which would date it quite a bit.

[Deep11]

Hi @horton, thanks for taking the time to reply and posting that video of Nate (I missed that one somehow).

I think we are on the same track - just different words.

To be clear, I totally agree about wanting to be aligned at all times. When I said the stack "wasn't perfect" I meant the point at which you are not quite in line with the pylon yet. (But still stacked / aligned over the ski)

It is the "short efficient load" I am seeking. My mistake was saying it was an early load, it isn't compared to the "turn and burn" off the bouy. It is however as you say all over very quickly with a huge amount of acceleration generated.

 

Carrying speed through the turn and the "glide" you mention, before the load, I think are important, (these guys don't drop into the turns or simply carve graceful turns they speed through them purposefully shortening the radius).

There is I hope more to it. When you mention that Nate is in the best position to get "all his work done over a short distance" - this is what I am getting at. Getting to the right point with right amount of speed is crucial but then what - what is the work he is doing?

Is it just a matter of falling away - really quickly, I don't think that will do it. Even if it was this you would have to be a bit more upright in order to have somewhere to fall to (which is probably a factor). In what ways are these guys inputting the energy to make the transition faster and more efficient? Do you think that this a "coached" action or the result of "just doing it for a long time"?

This is a video of Seth at 30mph showing the exact same thing - really efficient short load before the first wake. As you pointed out, he too is gliding to the point of contact but then power is injected.

He also talks about "getting the ski out from under him" in some other videos.

 

 

The handle collection (skiing to the handle rather than pulling in) and load are also very separate points.

 

The video of MB perhaps shows this quite well, the load from 4-5 looks like he falls away a bit too much, exaggerating what I am talking about, but when he picks up the boat he accelerates the ski from behind to in front really emphasising the "work".

 

 

If you stack off the bouy or even after the turn this does not happen. The video of MB mentions trailing arm again which is probably another factor. If you lean into your front shoulder the ski will be locked under you = longer load.

 

Interesting stuff and I hope we keep this conversation going as it's fun to have ideas to work with on the water, I really don't like simply going out skiing :)

 

Kevin

 

 

[ForrestGump]

I guess I'm not getting what you're defining as stack, because it doesn't seem to jive with what we've always defined it as.

[Horton]

@mwetskier 2014

[JAS]

Read once that all energy comes from the boat and all acceleration comes from ski. Skier is nothing more than conduit for energy transfer with anything less than optimal stack causing energy to be lost. When I see ski shoot forward I think in terms of skier getting ski into the orientation that creates max acceleration. With that in mind I think of it more as skier body is momentarily getting left a little behind rather than skier pushing ski forward. Would be great to add energy to the system but I can't make sense of how it might be done.

[mwetskier]

@JAS -i think sometimes the appearance of acceleration is actually just the loss of speed at a much slower rate than others. according of basic physics any turn will always slow the ski down unless there is some external force to add energy -but many skier turns burn off a lot more speed than these top pros. the term ' accelerating through the turn ' describes an impossible thing in my opinion but the *less* a skier *deccelerates* through the turn the better the result.

 

all just my opinion but definitely supported by known physics.

[Ed_Johnson]

@mwetskier ... As in Auto Racing 101, the slowest point of an ideal turn should be the Apex..This is the point you should commence acceleration.

 

What you are seeing with Nate, MB, etc, is that they are able to do this quite dramatically by dropping COM in the direction of travel significantly. By the Apex being the slowest point, you also have the tightest turning Radius which allows them to set a lot of Angle quickly without ZO knowing they are there yet..Next they get into a efficient forward COM stacked position which is the essence of acceleration..Without leading COM in the direction of travel, you will simply be leaning against the boat, and the ski stays with you...With COM Forward, the ski accelerates out ahead of you, then through the edge change, into the Reverse C position.

 

I hope this helps, since the Slalom Course is very similar to a six turn road course.

[mwetskier]

@Ed_Johnson -there is a big difference between auto racing and slalom skiing and that is the auto can accelerate out of the apex of a turn becasue it has an engine and a gas pedal. a slalom skier has neither. technically the skier can increase his velocity in a different direction because before the apex he was traveling zero mph or less in that direction. but this change in velocity is only due to the change in direction and to call it ' acceleration ' can easily confuse the issue for those who don't understand the difference between *speed* and *velocity*.

 

you are going toward the right side of the course through the gate, so your velocity toward the left side of the course is less than zero. as you approach the apex of the 1 ball turn your left ward velocity is increasing until it reaches zero at the apex. from there your left ward velocity continues to increase to its maximum value at or near the wake. but for whatever period of time you are in the turn with no load on the rope your pure speed -that is the speed of the water flowing under the length of your ski -is decreasing due to friction. anytime there is no load on the rope you are losing speed thats just plain physics. so the sense of accelerating out of a turn *before* the boat picks you up is not *acceleration* in the sense of an increase in speed but simply a change in velocity due to a change in direction. you cant increase your actual speed through the last half of the turn without some external force adding energy into the equation and that doesn't happen until the boat picks you up.

 

[Ed_Johnson]

@mwetskier ... OK, so first of all we can agree to disagree, and I'll use Nate Smith as an example..I had seen lots of videos of Nate skiing, but the first time I was there live to see Nate run 39 off, the perspective was drastically different from Video vs. Live.

 

When Nate came through the Gate he had plenty of outbound speed and angle, however, he really used that to his advantage by allowing the ski to carry out, and yes he was slowing...In fact what really stood out was how absolutely slow he appeared at the Apex for one ball...Then he shifted his COM cross course, and from my perspective "Accelerated" like no one else..It was like he hit first gear off the Apex to finish the turn, then leveraged more, hit second gear, more angle, more acceleration, and the rest is history.

 

Having driven everything from GT-1 Corvettes to Indy Cars, this totally reminded me of a trick we used approaching the Apex called Trail Braking...I have the same physical feeling at short line approaching the Apex that I did in the cars, where the G Forces are getting lighter, a last second feeling of almost floating, then nailing it off the Apex..The only difference to me is using weight shift in the direction of travel off the Apex instead of the throttle..The feeling is the same, and that "Feeling to me is Acceleration."

 

Also, the better I accomplish that, the resulting increase in speed allows for more angle, and the ability to sustain more load under acceleration, resulting in increased Angular Momentum, for the Reverse C and subsequent Carry Out, to the Apex, to repeat the process.

[mwetskier]

@ Ed_Johnson -I would argue with complete confidence that a device measuring the non linear speed of the ski at water level would show it does *not* begin to accelerate through the last half of the turn *until* the skier hooks up with the boat. theres simply no physical force involved making additional energy available and therefore such acceleration possible.

 

from shore and from the boat we see a skiers * side ways * velocity slow down to almost nothing and then see him go zooming away in the other direction but that is not the ' acceleration ' we are talking about here - that is a velocity shift due to the change in direction. the visual effect from most water level view points is very deceptive to the eye but the same illusion doesn't exist in overhead video where there is no water level perception of slowing toward the right and then accelerating toward the left.

 

Imagine your race car suddenly losing all power and all braking as you come into a turn so that you are entirely dependent on your current momentum to carry you through the finish of the turn. Except for some help from gravity out of a banked track are you saying that if you drove the corner *just right* your wheels would be turning faster at the end of the turn than at the apex?

[mrpreuss]

 

It's the first time I've noticed how high up on the boat Nate gets in the pull out for the gates.

 

It looks like that helps to allow him more room and time to accelerate

with more speed carried in from there VS instead of load from the boat later....

[Ed_Johnson]

@mrpreuss ... Exactly correct !!! Nate is an expert at generating "Cross Course Speed" for Angular Momentum to carry the ski out to it's widest point..Note this is Cross Course Speed and not Down Course Speed, which will make you fast at the buoy...By positioning himself "Up on the Boat" at the start, he is also in a position to generate the greatest angle, which he maintains very well throughout the pass..It's very hard to finish with angle if you didn't start with it.

 

@mwetskier .... You Stated, "there's simply no physical force involved making additional energy available and therefore such acceleration possible."

 

I believe you are not taking into account the rebound effect of using cross course speed and angle to carry the ski out to it's widest point, or the force of Gravity used by weight shifting COM in the direction of travel off the Apex.

 

Sorry, you will have a very hard time convincing me Nate is not accelerating off the apex and it is an illusion.

[mwetskier]

@Ed_Johnson -yes you already said we would have to agree to disagree. i dont want to be disagreeable so this is my last rebuttal unless you specifically ask me to reply. but i would like you to address my earlier question about taking a race car through a corner and losing all engine power right at the apex. the rolling friction of a well oiled racer ought to experience a lot less friction than a ski in the water so if you cant accelerate out of the corner with the unpowered car then you really shouldnt be able to with a ski.

 

i did consider the possibility of a rebound effect except that multiple slow motion videos -mapple and jaques and rossi for example - show that a slalom ski remains flexed and therefore loaded long after the apex. those same videos also show what almost amounts to a *pause* before the boat picks them up out of the finish of the turn. in videos of that nature i simply dont see any actual acceleration after the apex until that hook up.

 

shifting the com *does* cause a dramatic change in right to left velocity as i already discussed above. but i truly think its irrefutable that the friction of the ski in the water is pulling energy out of the ski at a far greater rate than ski flex rebound can put it back in. if that werent true you could simply pull hard through the gates then let go of the handle and sort of s-turn pump your way right on down the lake. the concept of acceleration by definition means over coming the drag of the ski in the water so why cant we just get a good fast start and then link a bunch of hard turns together to keep free skiing just a far as we want -no boat required?

 

at best the really great skiers like nate smith are just very very good at conserving energy and maintaining speed through the turn. but decelerating less than most other skiers is not equal to actually accelerating and physics dictates you have to add energy somehow to make that happen. moving your com forward when you walk or run is *not* what propels you forward. that com movement simply forces you to drive off your back leg as you extend your front leg in order to not fall on your face. its that repeated driving of the legs that allows us to walk or run and that leg action requires an input of energy. on a ski you cant drive yourself forward with your legs so instead the design of the ski makes it come around to catch up with your com but that *only* happens because the skier is carrying momentum around the corner.

 

as i said if that action of moving your com could impart enough energy into your ski to accelerate you against the drag of the water then you would be able to simple left right left right left right pump your self all the way down the lake on your own. but you cant -no one can.

[ToddL]

If the skier maintains a "tight line" through the turn, wouldn't the act of bringing the hip to the handle be a force which could initiate some _small_ amount of acceleration prior to the boat's influence?

[Than_Bogan]

Hm, pretty sure we completely lost Deep11's idea and question here. I don't have any great ideas about it, but am somewhat interested, so wouldn't mind a thread actually on that topic.

[Ed_Johnson]

@Deep11 ... asked what do you "FEEL" in order to position yourself into an accelerating stacked position...I was trying to explain that in order to do that it is a two stage process. First using leading COM off the Apex, for initial acceleration, as explained above, in Order to achieve, Stage 2, Leading COM weight transfer to the ski at hookup, in order to create the acceleration he was looking for.

 

I am convinced, especially at 35 and 38, after good cross course angle and speed, and you have reached the end of your rope literally, at the apex. If you drop your hips, COM, quickly into the turn, it feels to me like I am pushing off of something, and not only do you achieve immediate cross course angle, but a SURGE in acceleration. This SURGE buys me a extra tenth of a second to position myself into a LEADING stacked position BEFORE ZO is on me. Just coasting around a turn will not allow that to happen.

 

I have never experienced acceleration that moves the ski out ahead of you by just leaning against the boat. It has always taken Forward, Direction of Travel, Leading COM, to achieve that..... Once ZO is on you it's too late.

 

 

[Chef23]

@Deep11 I agree with @Horton. I don't think you ever want to start to pick up load when you aren't in a good stack. I just watched the Parrish video (I love watching him ski) and he is stacked when the boat picks him up. It may be a little later than the rest of us mortals because he and other top skiers are more efficient and carry more speed through the turn.

 

At the longer line lengths (32 and 35 for the pros) you do see a shorter work zone but I believe this is because good skiers are much more efficient and generate all the speed they need to carry them out to the ball in less space than I need for example. If you watch the videos at 39 and 41 the work zone seems to carry to the second wake. I am not sure why that is but it seems consistent across most videos I have watched.

 

The more efficient you are the shorter the work zone can be to create the speed needed to carry to and around the next ball. From my perspective efficiency is largely connected to the quality of your stack.

 

I think that video of Seth is misleading for most people struggling to run 30, 32 or 34 mph. If those folks could ski like Seth they wouldn't be struggling to run those speeds. Seth can ski those speeds the way he does because of the quality of his body position and the efficiency it delivers when the boat picks him up. While I find that video interesting I don't think it helps beginning skiers that much I think it confuses them.

[ToddL]

I think there was another thread about how Nate Smith is stacked but uber forward during his initial acceleration... In most cases, by the time the skier is behind the boat, the angle of the stack in relation to the rope has lined up (leading vs. neutral vs. trailing). Meaning that from apex to center-line, the stack is leading in the desired direction of travel but the ski is catching up with the stack until the ski and stack are eventually aligned at the center-line. You can also see the ski start to advance ahead of the stack from the center-line outbound.

 

(I have this idea that is a little hard to put into words, but I'll give it a try...)

 

Another way to think about it is ignore the rope. Think about the stack in relation to the center-line of the course. Position yourself at the end course and just in side the buoy line. Now, visualize that pro skier on a very short line. When he or she is at the point of initial stack before the acceleration starts, the skier is stacked and leaning away from your vantage point. Let's call this course-aligned stack lean. The skier maintains this stack orientation throughout the wake crossing. Only as the skier moves toward the center-line, the course-aligned stack converges in alignment with the rope.

 

When this course-aligned stack is viewed from the vantage of the boat at the initiation of acceleration, it looks like the skier's stack is significantly leading with COM.

 

What I am suggesting is that skiers who fight the boat are finishing their turns and trying to align their stack down the rope (leaning away from the pylon) while still out wide at the buoy. However, advanced skiers who efficiently exploit the boat finish their turns with a course-aligned stack away from the end of the lake and maintain this through the edge change. They finish the turn with course-aligned stack. The absolute best, in our sport can add a little bit more forward/leading COM to this and somehow stay in control.

[Chef23]

@ToddL if you watch the MB video when he is coming out of 4 ball I was thinking that he was stacked but his COM was much more forward than I think I am comfortable doing.

[ToddL]

 

This series of images was taken from the Wilson Bros' Bang Bang video. The camera angle is at the end course. It is very foggy, so a little hard to see, but I added a line showing the orientation of KC's stack. To me, this is course-aligned stack and what I was trying to explain above. The first image was at the moment the right hand came on the handle. The rest are as he approaches the center line. Notice that he isn't leaning forward toward the center-line of the course. Rather, he is course-aligned with his stack. This is all more visible because the vantage point is at the end course and not from the boat.

 

[ToddL]

@Chef23 - IMHO, even looking at the MB video if we try to visualize a line through the skier's front binding that is parallel to the center-line of the course, it still would appear to also be significantly aligned with MB's stack. He might be a degree or two leading, but it is not significantly leading. His wake crossings at the start of the video are totally course-aligned stack to me.

 

I tried to draw a line which (in my best judgement) is parallel to the course-center-line. Given this as a point of reference, he is not terribly forward with relation to course alignment. His is, however, extremely leveraged away from the end of the lake at a very wide location out of the buoy. That is clearly visible and gives the extreme perspective from the boat.

 

[Ed_Johnson]

@ToddL ... Thanks for posting that Video...For me that clearly demonstrates exactly what I was talking about..The slowest point being the Apex, then the 2 stages of acceleration @Deep11 was asking about...Stage 1..Apex to Handle..Stage 2..Stack Load...How can anyone say KC is not accelerating in stage one off of the apex and it is an illusion.

[Deep11]

 

@Ed_johnson and @ToddL I think we are on the same page. (Don't know if it's the right one, but definitely the same one).

@Chef23 I posted the video of Seth not for beginners to try and emulate but because it shows really well the efficient work zone at a slower speed. (Also when talking to Seth some of what I am asking becomes a little clearer in that he says it is the hand he collects the handle with which drives the acceleration of the ski (Trailing arm).)

 

It is clear that the shortest most efficient work zone for all pros is after their on side turn. What I have been told is that to have any chance of injecting power into the mix we should be trying to finish this turn with shoulders facing down course (I think TW mentioned this recently as well). I don't think, for me anyway, it's as simple as just dropping the hip - far too easy for it to fallback, which means finishing the turn with hips and shoulders rotated in the direction of travel. Which like Todd mentioned means stacking in line with the pylon from wide, which limits your, angle, acceleration and achieves a long load zone.

 

Without others chipping in on the "how to" yet, I'll let you know where I am with this. I am thinking that the only way of finishing the onside turn keeping shoulders facing down course is for their to be a degree of "disconnect" between upper body and hips and legs.

 

This is probably Ed's CoM and reverse C stuff, but I'll explain my thoughts:

 

If you are a stacked straight line on top of your ski and simply lean over to turn, you can stay stacked, but rely on centrifugal force to stop falling over. The turn is a carved slow and possibly graceful affair but if the timings off or you fall back on the ski at the end it's all over. This is turning using the upper body which I think is a bad habit.

Alternatively if you are tall and stacked over the top of the ski after the edge change and instead of leaning over to carve a turn, you instead try and keep your body upright and let the ski continue to move out - lower body disconnects. Then when the ski comes back in you have the opportunity to carve a tighter radius turn without falling away from the boat. You also can connect later with the trailing arm and hopefully (this is where I came in) inject some pace into your cross course direction. The Classic stacked position that we all talk about is still there just for a much shorter period of time. It's a position you accelerate through (from the boat perspective as Todd mentioned), rather than assume and hold.

What I'm finding really difficult is to keep my shoulders and hips facing down course whilst the ski comes round. I think I'm still quite flexible but this is tough, I'm hoping it's just getting used to the different view of the course and trusting that "everything will alright on the other side".

Keeping the body as upright as possible though is definitely a good thing.