Should I get Carv

[Erik Timmerman]

So does CARV stand up to repeated insertion of lace-up liners? Just asking for a friend.

 

[geepers]

Says who?

Says me.

If we're swirling an object (like a skier) around on a rope the centripetal force as measured at the boot will be same to that measured via the tension in the rope.

In this year's update to their software (hintertux), they claim that "terrain became the north star for our Data Science team. If you sent it down a steep pitch, or braved the bumps, we wanted you to be fairly rewarded [...]"

It has been noted by innumerable others that the best CARV Ski IQs (for those interested) were obtained on smooth groomers. As I understand it this season's software release is an attempt to rectify that situation so that those whose skiing tends to retain form on more challenging terrain are rewarded.

Remains to be seen how well that works.

Static sensor orientation is irrelevant to a dynamic sport like skiing. IMUs estimate the sensor orientation by fusing the estimate of the gravity vector's orientation and the angular speed. The estimate of the gravity vector's orientation is completely off when you spend most of your time not at 1g, in high-vibration environments or at non-zero angular velocities. The angular speed integration can only work for so long before drifting.

Fair bit of my time skiing is spent sitting on chair lifts. Roughly 1g and only as noisy the nearest boombox.

Maybe the CARV engineers and data analysis ppl have more experience plucking meaningful information out of noisy data sets.

It is not what their marketing says when they compare Ted to other skiers. They show the full time history of the measured/calculated values.

So you reckon those graphs are for one turn?

Wrt variability of terrain...oh look...

The anatomy of a Ted Ligety turn

Improve your skiing technique with real-time audio coaching. Carv uses pressure and motion analysis to score your technique and help you improve.

getcarv.com

Sure, these numbers also mean that skier B is going 30% faster on the same course. No need to spend any money on Carv to assess that. A good old stopwatch should have plenty of resolution!

Nice if there's a race course. And we can get all the world's CARV skiers to run it on the one day. (Then again it may be a bit of a rut-fest after the 1st 200 or so...)

I free ski like a multitude of others. No gates, no course, no stop watch. Have to fork out $$$'s to get educated eyes on. CARV may provide objective feedback when not in workshops.

 

[Wade]

So does CARV stand up to repeated insertion of lace-up liners? Just asking for a friend.

Take a look at the ZipFit thread. It came up there today.

 

[Mike King]

Again that is great, but from a marketing perspective it is not selling me.

I think the raw data they generate is really interesting, but just one piece of the puzzle. I would be much more inclined to invest say $1K in carve if the purchase came with say a 3 day clinic where they analyzed your Carv data, worked with you on the now to improve form .. etc. and identify drills you could then do yourself to continue to improve your skiing. It would also be nice if the filmed you at the start and end of the clinic, with the Carv data showing how improvements in your form and technique changed the data. This could be a really interesting model where Carv partners with resorts to deliver this higher value immersive clinic ... just saying this would be a much higher value offering IMHO as it addresses the missing elements that technology cannot deliver on its own

carvperformanceinstitute.com

 

[Mike King]

There you go!

https://www.carvperformanceinstitute.com/

Can't wait for you to review how these camps are!

It is just $1700 + you have to get your Carv system/subscription. Just a bit more than what you hoped for!

Nope. Thomas will set you up with a Carv system for the camp. If you want to buy afterwards, go for it.

The reviews for the camps are stellar. But why wouldn't they be? You will be skiing with demo team members with decades of teaching experience.

You can see the testimonials from those who attended the camps.

Mike

 

[Mike King]

It is important when you claim that you can measure the fore-aft and left-right force distribution, as well as the early weight transfer onto the ski. All of these are important factors to consider to improve your skiing.

The accelerometer measures the acceleration at the foot. It is not the acceleration we care about (it is like if you measure the acceleration of your wrist... who cares?). F=ma only works when applied at the center of mass... real basic physics!

Nobody has really been able to measure the real edge angle using an IMU. There are multiple papers about it. What you get is the angle with respect to the inertial reference frame. The problem is that you don't know the slope angle. The edge angle is the angle between the ski base and the slope. It is only possible to estimate the slope angle when the slope is long and constant over multiple turns. There is no chance of getting a good measurement of the edge angle in moguls.

But again, the role of a business is not to find the truth. It is to find useful things to do with what they have...

excuse me, but who cares if it is "truth" if it in fact provides a reliable proxy that estimates ski performance? Did you look at the post from Carv that goes into some of how they develop their algorithm? And the statistical tests of the correspondence between the predictions from the algorithm vs the scoring of video by demo team evaluators?

Carv also claims to have identified a method to estimate slope angle from the data that they have (over 340 million ski turns).

And Jamie did complete his Ph.D.

Mike

 

[AlexisLD]

Says me.

If we're swirling an object (like a skier) around on a rope the centripetal force as measured at the boot will be same to that measured via the tension in the rope.

This is not the case when you have a massive rope (i.e., your leg) with springs/dampers between segments (i.e., your muscles/tendons).

We were also not talking about tension, but about acceleration. The acceleration is not constant at each point along the rope, which is what is measured by the accelerometer.

Fair bit of my time skiing is spent sitting on chair lifts. Roughly 1g and only as noisy the nearest boombox.

You get only a few seconds of validity out of integrating these small mems gyros. Your chairlift ride will only provide a reset between runs, but that won't be good for long...

It has been fun to debating physics and sensors with you, but it is clearly going nowhere. If you believe that Carv can provide accurate force distribution on the skis, true edge angle and accurate acceleration of the center of mass, or that is none of this is needed, then good for you!!

 

[AlexisLD]

excuse me, but who cares if it is "truth" if it in fact provides a reliable proxy that estimates ski performance?

I agree with you that it doesn't need to be the truth to be useful (and I said it numerous times). However, doing so often makes things shaky or not work in different conditions (e.g., on more complex terrain).

Did you look at the post from Carv that goes into some of how they develop their algorithm? And the statistical tests of the correspondence between the predictions from the algorithm vs the scoring of video by demo team evaluators?

Yes. And there is very little technical info on how they develop their algorithm.

As for the correspondence with video scores, there is very little detail on how it was done. It is fairly easy to find correlations (e.g., the speed of these skiers is also probably as highly correlated with their Ski:IQ and video scores). Also, if you look at their data, an intermediate/advanced skier can be rated as bad as a beginner and almost as good as a Demo team member. Another way of looking at it is that 50% of the intermediate video-rated skiers have a Ski:IQ as high as 50% of the advanced video-rated skiers. That is a pretty large overlap! This can all be caused by not doing the right or complete measurements to start with... and that is why we should care!

Carv also claims to have identified a method to estimate slope angle from the data that they have (over 340 million ski turns).

There were 2-3 research groups claiming they could calculate the edge angle at the last International Conference on Skiing Science last year. By the end of the conference, they all recognized that they were not really calculating that. More data would not have helped.

And Jamie did complete his Ph.D.

Where is his thesis? They are typically available online but I can't find it...

 

[geepers]

A physicist and an engineer are given a challenge. There's a beer on a table 2 meters away. To get the beer they are allowed to take a 1st step of up to 1 meter but each successive step must be half the length of the previous step. The physicist refuses to participate claiming that it will take an infinite number of steps to reach the bar and he won't live that long. Meanwhile the engineer strides 1 meter, steps half a meter, hops a quarter of a meter and reaches to grab the beer saying near enough is good enough.

Just so we can be clear on how this applies to this discussion there's some here - the 'phyicists' in the story - throwing up with all sorts of 'reasons' a system like CARV can't work. Meanwhile the folk at CARV - the 'engineers' in the story - have come up with concept, developed a product, started a business, and in 2023 had over 20,000 members across 58 countries. And we know at least some of those members must be happy given they offer a 100 day money back guarantee and would surely be out of business by now if it was a total con. (Heck we even have long time posters here who seem happy with the product.)

 

[Noodler]

A physicist and an engineer are given a challenge. There's a beer on a table 2 meters away. To get the beer they are allowed to take a 1st step of up to 1 meter but each successive step must be half the length of the previous step. The physicist refuses to participate claiming that it will take an infinite number of steps to reach the bar and he won't live that long. Meanwhile the engineer strides 1 meter, steps half a meter, hops a quarter of a meter and reaches to grab the beer saying near enough is good enough.

Just so we can be clear on how this applies to this discussion there's some here - the 'phyicists' in the story - throwing up with all sorts of 'reasons' a system like CARV can't work. Meanwhile the folk at CARV - the 'engineers' in the story - have come up with concept, developed a product, started a business, and in 2023 had over 20,000 members across 58 countries. And we know at least some of those members must be happy given they offer a 100 day money back guarantee and would surely be out of business by now if it was a total con. (Heck we even have long time posters here who seem happy with the product.)

But the "faithful" are under this assumption that the product will help them become better skiers. That's really all that counts in the end. That's why there is the "sub-thread" within this thread about whether there's actual proof of the product being useful to actually improve skiing. And that's where the rub is as far as I'm concerned. The product was built and marketed under the guise that you can determine "good skiing" from the data they are currently collecting. I know, from extensive coaching and my own skiing experience, that this is simply not the case. What's happening at the soles of my feet and the angles of my legs aren't even half the story. So just because they have 20K members after 5+ years isn't surprising. The real test will be where they are in 5 more years.

 

[pchewn]

Unless you are racing, skiing is mostly about emotions -- how do you feel when you are skiing. If the CARV product makes the user feel better about his skiing, then the product is a success. Lots of rec skiers use recreational drugs to feel better about their skiing. Is their skiing objectively better? Probably not. But they feel like they are enjoying the ski day more -- so that is a success.

 

[geepers]

A few have pointed out that SkiDad does a pretty good job trenching the groomers. Interesting to see how CARV does assessing his skiing off-piste.

But the "faithful" are under this assumption that the product will help them become better skiers. That's really all that counts in the end. That's why there is the "sub-thread" within this thread about whether there's actual proof of the product being useful to actually improve skiing. And that's where the rub is as far as I'm concerned. The product was built and marketed under the guise that you can determine "good skiing" from the data they are currently collecting. I know, from extensive coaching and my own skiing experience, that this is simply not the case. What's happening at the soles of my feet and the angles of my legs aren't even half the story. So just because they have 20K members after 5+ years isn't surprising. The real test will be where they are in 5 more years.

Good to see you are keeping an open mind on this product.

 

[Noodler]

Good to see you are keeping an open mind on this product.

To clarify, I think there is some good data in what they're collecting. The problem is marketing this as providing "sufficient" data to tell you whether you're making good turns or not. That's simply an exaggeration (moving rapidly toward an outright lie). They need to quit overselling the value and effectively pulling the wool over the eyes of their membership. Like I said before, either they're too ignorant to realize the shortfalls of their system or they know, and they don't care and are only in it to sucker more folks into believing things that cannot be true about what this product can provide.

And with that, I'm done discussing CARV. Unless things change with the product, I'm not adding any additional value to these conversations. Anyone with a CARV system is welcome to come share some turns with me and dig deeper into what it's showing versus the actual on-snow performance you're getting.

 

[James]

A few have pointed out that SkiDad does a pretty good job trenching the groomers. Interesting to see how CARV does assessing his skiing off-piste.

Ah so that explains skidad making turns with Ligety, and why Tom Gellie is commenting on skidad’s videos.

 

[DavidSkis]

[You assert (without any support) that Carv is a flawed system. Yet the system itself arose out of the CEO's Ph.D. dissertation -- clearly it had a sufficient theoretical and empirical basis and result for his work to be able to stand the examination by his dissertation committee. And there's considerable development of the hardware, software, data, and algorithms since. With lots of review and development assistance by demo team members from around the world as well as several FIS level ski racers.

So show me the evidence that it contributes to ski improvement.

So far there is no objective evidence. We have testimonials from skiers who self-assess, and videos of people like Tom Gellie giving lessons that improve a skier and the carv metrics--but no videos of a "before and after" Carv user absent top-shelf instruction.

The product is several years old, so if it were effective in creating skier improvement, we should have the evidence. But there is nothing showing that Carv improves skiers in practice. If it were useful, I absolutely would buy it. But there's no evidence to show that it's helpful, and the burden of proof falls on Carv here.

 

[Mike King]

So show me the evidence that it contributes to ski improvement.

So far there is no objective evidence. We have testimonials from skiers who self-assess, and videos of people like Tom Gellie giving lessons that improve a skier and the carv metrics--but no videos of a "before and after" Carv user absent top-shelf instruction.

The product is several years old, so if it were effective in creating skier improvement, we should have the evidence. But there is nothing showing that Carv improves skiers in practice. If it were useful, I absolutely would buy it. But there's no evidence to show that it's helpful, and the burden of proof falls on Carv here.

Carv asks its users if Carv contributed to improvement in their skiing. Those data show that users believe it has done so.

 

[TheWombat]

I have been using Carv now for 3+ seasons, and it has absolutely helped me improve my skiing. But to be clear, I wanted to improve, I looked at many YouTube videos, I review the data from Carv, I try things, I reflect, I learn. I spend time with Carv on the monitors e.g. indivual turn Ski-IQ/Edge Angle etc, to understand the correlation between a good Carv score and what a turn feels like, and to help push me to try and edge more etc. I also found the Train with an Olympian program good.

The first season I had Carv I was getting a Ski-IQ of 90 or so, then 120s the next season, last season was 130s and this season I am breaking into the 140s.

I have Outdoor Tech 3.0 speakers in my helmet. I have Zipfit liners and Carv is fine with the daily taking in/out of the liners. I always have Carv on, I just sometimes switch off the audio and just let it capture the data in the background.

If you want to improve, and are willing to use Carv properly, e.g. the drills/monitors etc, then I think it is a very effective tool. However it won't suit everyone.

I also found getting an InstaCam 360 X3 this season, and videoing myself also really helped to get the connection between what Carv captures as metrics, how the skiing feels to me, and importantly how I look visually. e.g. my left turn was scoring lower on edging metrics and from using the video I realized I don't move my left knee in as much so my shins were not parallel - whereas for my right turn I was fine.

Carv is a tool, just like any other. It won't make you a better skier unless you actively use it to improve.

 

[Phishnerd]

I have been using Carv now for 3+ seasons, and it has absolutely helped me improve my skiing. But to be clear, I wanted to improve, I looked at many YouTube videos, I review the data from Carv, I try things, I reflect, I learn. I spend time with Carv on the monitors e.g. indivual turn Ski-IQ/Edge Angle etc, to understand the correlation between a good Carv score and what a turn feels like, and to help push me to try and edge more etc.

This tracks. I think the software update has simplified the concepts and it's a little easier to mentally process the data better. I've let it run in the background a lot, but when you ski with the audio it can do some cool stuff. If it's in readout mode you can easily get the feedback through just using a target number -- e.g., I want to hear edge angles over 40. I'm using it more this year and I get the sense that I'm improving, how much can be attributed to the tech, idk.

Coincidentally, it looks like they just pushed an update called Active Coaching which might be a bit to gameified https://getcarv.com/blog/introducing-active-coach

 

[Phishnerd]

While the early adopters continue to defend the product (and their justification for the investment) in the face of overwhelming evidence that it wasn't a great purchase decision.

Also tracks. But I got in at the kickstarter and the lifetime free premium turned out great, LOL #humblebrag

It was a cool product concept. I think I paid $199 up front, waited idk 2 years to get it. The software has gotten better as it has gone on. When the trackers got messed up they sent brand new ones.

$199 for the real-time audio and some video is a lot tho.

 

[TheWombat]

When I compare the cost of Carv (assuming you got the life time one-off price like I did) then it is very good value for money compared to the cost of a couple of private ski lessons. To be clear Carv doesn't replace ski lessons, but it can supplement them and/or reduce the number you buy. It is a tool and just like any tool how well it works for you depends on what you are after, what you want to achieve, how much you want to improve, etc etc etc.

I like the fact that they are continuing to improve and enhance it, and that you can decide if you use it, have it running quietly in the background, use it actively with the inbuilt drills/training mode/coaching etc.