Lightweight blade designs - improving jumps?

[tstop4me]

tstop4me, short and long track speed skates do not usually have full contact with the bottom, because they do have rocker curvature. (See https://www.danielyeow.com/2011/inline-to-ice-1 for some speed skate rocker curvatures). But I'm not sure how much that affects your argument. Especially since this forum isn't devoted to speed skating.

What I wrote was that the statement "a thinner blade would cut deeper into the ice" would hold only if the blade has a flat bottom and the flat bottom is in full contact with the ice:

But note that that "the contact area is a function of the thickness of the blade" holds only for a limited scenario: for a speed skate blade ground with a flat bottom (no hollow) oriented such that the flat bottom is in full contact with the surface of the ice; i.e., the sides of the blade are orthogonal to the plane of the ice. If orthogonality is not strictly maintained, the contact area will no longer be dependent on the thickness of the blade (here I'm excluding ice so soft that the blade sinks in).

I made no comment as to how often this scenario actually occurs in practice. I used the example of a speed skate blade ground with a flat bottom because AFAIK no figure skate blades and no hockey skate blades are ground with flat bottoms. So a limited scenario for a limited blade geometry means that "a thinner blade would cut deeper into the ice" is even more of an outlier. So my analysis is not affected at all. And, in the context under discussion (dependence on the thickness of the blade), we're talking about full contact across the transverse direction of the blade (nominal inside to outside edges) not across the longitudinal direction (toe to heel). My analysis would still hold, e.g., for a figure skate blade ground with an infinite ROH (still a longitudinal rocker, but no transverse hollow), if we were comparing the same local longitudinal section of a blade with different thicknesses.

 

[FSFan1999]

To comment on the original post (I know the thread has moved on a bit), I saw somewhere that somebody weighed the blades, with a combined weight of 654grams gold seal vs 512grams revolution. This doesn't account for variations in amounts of sharpen, blade life left etc. Whilst that reduction looks significant % wise, really it's 142 grams.

if you drink a glass of water this makes the same difference. Of course weight distribution would be different, but takeoff timing will have 50x the influence on height and rotation speed than this small amount of weight.

That's not to say revolutions are bad blades, it's just that the weight reduction isn't worth the money or providing advantage for the majority of people and there are other compromises to consider - I.e. catch foot spins being more difficult.

 

[tstop4me]

Anyway, I doubt if discussions of physics theory interests many people here.

[Strange comment coming from you, given the contents of your posts so far in this thread.] True, but I'm addressing the OP, not a general audience:

I am a PhD student and I am curious about lightweight blade designs.

<<Emphasis added.>>

The o.p.'s original question was about how the weight of blades affected jumps.

Again true, but I didn't introduce the segue into the discussion of blade thickness. Others, including you, did. I chimed in to correct what I think is a major error: in the vast majority of scenarios (excluding extreme outliers), it's the edge geometry, not the blade thickness per se, that affects how deep you cut into the ice and how fast you glide. That's all.

 

[Query]

To comment on the original post (I know the thread has moved on a bit), I saw somewhere that somebody weighed the blades, with a combined weight of 654grams gold seal vs 512grams revolution. This doesn't account for variations in amounts of sharpen, blade life left etc. Whilst that reduction looks significant % wise, really it's 142 grams.

if you drink a glass of water this makes the same difference.

Must be a fairly small glass. E.g., 1 U.S. cup is 240 ml, or about 240 grams of water.

But what about the psychological issues of making due with equipment perceived as being 2nd rate? This could be almost as bad as not having a Snoopy dog blade guard, or no glitter.

 

[Timskate]

I assume you reach this conclusion along the following line of reasoning. Pressure Exerted by the Blade on the Ice = (Total Weight of Skater and Gear)/(Contact Area of Blade on Ice). The greater the pressure, the deeper the cut. The contact area is a function of the thickness of the blade. The thinner the blade, the smaller the contact area. The smaller the contact area, the greater the pressure.

But note that that "the contact area is a function of the thickness of the blade" holds only for a limited scenario: for a speed skate blade ground with a flat bottom (no hollow) oriented such that the flat bottom is in full contact with the surface of the ice; i.e., the sides of the blade are orthogonal to the plane of the ice. If orthogonality is not strictly maintained, the contact area will no longer be dependent on the thickness of the blade (here I'm excluding ice so soft that the blade sinks in).

Figure skate blades are ground with a hollow to produce two distinct edges, an inside edge and an outside edge. During a straight glide on a clean, proper ice surface, the blade will leave a double trace | | (two traces, one from each edge, spaced apart); not a single wide trace with a width approximately equal to the thickness of the blade. So the contact area is not a function of the thickness of the blade (here I'm excluding ice so soft that the blade sinks in). And of course, during a curved glide on a single edge, the contact area is not a function of the thickness of the blade.

With blades ground with a hollow, you need to take into consideration the blade edge angles, and the dependence of the blade edge angles on the radius of hollow (ROH) and the blade thickness. Many skaters know that they can vary the sharpness of the edges by changing the ROH. Many don't realize, however, that for a fixed ROH, the degree of sharpness will vary with the blade thickness. This has been discussed in a previous thread: https://www.goldenskate.com/forum/threads/how-different-radius-of-hollow-affect-skating.81787/. Here are my key posts from that thread (to simplify the discussion, I'm describing blades with no side honing, but the basic concept holds for other geometries):

Thank you for your detailed insights!

I now understand that blade performance and speed depend more on edge geometry and sharpening (ROH) than on thickness alone. I also get the point that tapered and parabolic blades can use varying thickness strategically—changing along the blade's length to alter edge sharpness in different sections. For example, thinner near at places for better bite on turns and thicker elsewhere to enhance glide. However, I wonder why manufacturers don’t clearly explain this on their websites, including detailed options to help skaters get the most out of these blade designs.

Considering the significant role of edge geometry in skating performance, have there been any empirical studies directly comparing the effects of blade thickness versus edge configuration on speed and maneuverability? Additionally, how would you propose conducting such a study?

Since your points highlight that blade performance depends more on edge geometry and sharpening (ROH) than just thickness, what’s your opinion on why manufacturers emphasize thinner blades for increased speed? Isn’t that misleading? Lastly, could you share your thoughts on why most manufacturers claim benefits like increased jump height or cushioned landings without providing test data? Do you think they care about validating these claims?

 

[FSFan1999]

Must be a fairly small glass. E.g., 1 U.S. cup is 240 ml, or about 240 grams of water.

But what about the psychological issues of making due with equipment perceived as being 2nd rate? This could be almost as bad as not having a Snoopy dog blade guard, or no glitter.

Counter point - in MK Gold Star blades Boyang Jin was one of the best jumpers in the world. In Revolutions he hasn't produced the same (of course I'm not blaming the blades).

But I guess it gives Adam sio him fa and Shun sato an excuse...

 

[Flying Feijoa]

For example, thinner near at places for better bite on turns and thicker elsewhere to enhance glide.

Just jumping in again - if I understand @tstop4me correctly, for a fixed ROH the thinner section of the blade would bite less, not more, because the angle of the metal would be less acute. That might make sense for a parabolic blade since the thin part is in the middle (the gliding section) while the thicker parts would be nearer to where forward/back turns are done.

By the way, if you don't mind sharing, what approximately is your field of study?

 

[Mathematician]

providing test data?

I didnt read the entire discussion here, but could you elaborate on what sort of test you would like to see? I cant formulate an experiment in my mind that would be able to entirely validate or disprove the claims of these manufacturers. Firstly the study would have to be rather long term, IMO. It would be unreasonable, even assuming maximum efficacy of the product, to find a detectable increase of performance immediately. It would still need time for the athlete to adapt before they can analyze if their potential peak has changed at all (since also, athletes are looking at peaks, which occurs for many only at certain times of the season). This makes placebo isolation enormously difficult, and longer time adds a whole new dimension to extra variables and influences. Not to mention the natural state of such testing to begin with... obviously there exist too many variables between individual skaters and different sorts of jumps. It would be literally impossible to just list the innumerable amount of other influences nevermind experimentally isolate them. Athletes are not looking for an entire extra rotation, or half a second of air time, or inches of height; more like, at absolute most, improving an often UR'd jump or perhaps stabilizing their exits/entries. Otherwise, usually it would likely be hoped to incrementally improve general skating quality, or ease, including jumps, which would be very subjective to study. Ultimately I think, relative to what exists in the sports world, these blades should be the last of our worries when it comes to scientifically dubious products, since many such exist that are also extremely harmful, not just useless. I am not familiar with the exact claim of the manufacturer. Jump height, as in, distance from the ground to the apex of your jump, sounds like a rather peripheral factor when considering holistic jump quality. If thats the exact claim, it sounds gimmicky, but I doubt thats such a myopic pitch is the entire suggestion when selling to a professional.

 

[tstop4me]

For example, thinner near at places for better bite on turns and thicker elsewhere to enhance glide.

Just jumping in again - if I understand @tstop4me correctly, for a fixed ROH the thinner section of the blade would bite less, not more, because the angle of the metal would be less acute. That might make sense for a parabolic blade since the thin part is in the middle (the gliding section) while the thicker parts would be nearer to where forward/back turns are done.

@Flying Feijoa , you are correct; @Timskate got it reversed. To re-iterate, for a blade with a fixed ROH and whose thickness varies longitudinally (pick to heel):

smaller thickness --> larger included edge angle --> less bite & more glide

larger thickness --> smaller included edge angle --> more bite & less glide

 

[tstop4me]

Since your points highlight that blade performance depends more on edge geometry and sharpening (ROH) than just thickness, what’s your opinion on why manufacturers emphasize thinner blades for increased speed?

<<Emphasis added>> But do they? I will refocus the discussion to figure skate blades. I've checked the current websites of the major figure skate blade brands: Wilson, MK, Jackson Ultima, Riedell Eclipse, and Paramount (Note: Wilson and MK were originally separate companies, but are now owned by the same parent, HD Sports). None of them emphasize thinner blades for increased speed. In fact, none of them explicitly list blade thickness as a specification or give numeric values for blade thickness.

MK does give a brief discussion of tapered and parabolic thickness profiles. [Caveat: Jackson Ultima gives a brief discussion of "tapered design", but that refers to dovetail edges, not tapered thickness profile.] MK also has a brief discussion of their MK Dance Blade, featuring their slimline design [no explicit details on their website, but the blade thickness along the region of the edges is less than the blade thickness in the remainder of the blade body (e.g., towards the stanchions)]:

"At Pyeongchang 2018, 85% of all Olympic Ice Dance athletes used the MK Dance for its slimline design, allowing the skater to move from one edge to the other much quicker. Essentially, the unique configuration of this blade allows skaters the advantage of employing less body lean to change their edges."

Note the emphasis on quick changes of edge; no mention of faster speed.

What is prominently promoted by all these manufacturers is lighter weight: there's a race to the bragging rights of "We have the lightest blades!" One easy way to achieve lighter weight (regardless of its significance) is via a thinner blade. As an aside, a thinner blade reduces materials costs (the initial raw plate stock is cheaper if you start out with thinner plate); and maybe manufacturing costs since you don't have as much material to cut through (this is speculation on my part).

 

[Timskate]

I didnt read the entire discussion here, but could you elaborate on what sort of test you would like to see? I cant formulate an experiment in my mind that would be able to entirely validate or disprove the claims of these manufacturers. Firstly the study would have to be rather long term, IMO. It would be unreasonable, even assuming maximum efficacy of the product, to find a detectable increase of performance immediately. It would still need time for the athlete to adapt before they can analyze if their potential peak has changed at all (since also, athletes are looking at peaks, which occurs for many only at certain times of the season). This makes placebo isolation enormously difficult, and longer time adds a whole new dimension to extra variables and influences. Not to mention the natural state of such testing to begin with... obviously there exist too many variables between individual skaters and different sorts of jumps. It would be literally impossible to just list the innumerable amount of other influences nevermind experimentally isolate them. Athletes are not looking for an entire extra rotation, or half a second of air time, or inches of height; more like, at absolute most, improving an often UR'd jump or perhaps stabilizing their exits/entries. Otherwise, usually it would likely be hoped to incrementally improve general skating quality, or ease, including jumps, which would be very subjective to study. Ultimately I think, relative to what exists in the sports world, these blades should be the last of our worries when it comes to scientifically dubious products, since many such exist that are also extremely harmful, not just useless. I am not familiar with the exact claim of the manufacturer. Jump height, as in, distance from the ground to the apex of your jump, sounds like a rather peripheral factor when considering holistic jump quality. If thats the exact claim, it sounds gimmicky, but I doubt thats such a myopic pitch is the entire suggestion when selling to a professional.

Well, firstly, if I claim to sell a faster car with improved acceleration, I need to be able to measure its speed to substantiate that it is actually faster. How else could I assert that a product has a performance advantage if it cannot be measured or is out of reach to verify? Based on your reasoning, how can blade manufacturers claim that their products enable higher jumps? Therefore, perhaps the right question to ask is how the manufacturers tested and proved that their lightweight blades increase jump height.

As mentioned earlier in this discussion, marketing claims must be accurate, substantiated, and backed by evidence. For instance, if a product claims to enhance performance—such as enabling “higher jumps” or “cushioned landings”—these statements should be supported by verifiable data. In this discussion, I questioned a specific claim, but I understand that there are many other dubious claims that one might challenge. Generally, misleading claims that influence a consumer’s decision could potentially lead to lawsuits, and I have the right to question these claims if the only empirical evidence available suggests that they are misleading. In the United States, the Federal Trade Commission (FTC) enforces truth-in-advertising laws.

On another note, jump heights, lengths, and other performance metrics can be measured very accurately, and there are numerous papers and methods detailing how to assess the impact of equipment, shoes, flooring, and so forth on athletic performance. For example, there are studies on how different shoes affect stride and speed, and how various figure skating boots influence landings. Typically, controlled, randomized studies are conducted where participants are blinded to avoid bias. Statistical software, such as G*Power, can be used to determine the required sample size to achieve sufficient statistical power. These studies do not have to be long-term or overly complicated, as you suggested. For example, look at the methods of the 2022 study on different blades (https://www.tandfonline.com/doi/full/10.1080/14763141.2022.2063757) where researchers tested different blades and found no differences in jump height between traditional and lightweight blades.

Equipment can have a direct effect on an athlete without requiring a lengthy adjustment period—such as special swimsuits that increased swimming speeds (which were subsequently banned) or running shoes with carbon fiber springs that improved running speeds (now regulated). An extreme example is comparing a solid blade weighing 5 kg to a lightweight blade weighing 50 grams: you would likely see a direct effect on jump height. However, with the current weight difference of just about 100 grams between solid and lightweight blades, there appears to be no difference in jump height.

 

[Mathematician]

Well, firstly, if I claim to sell a faster car with improved acceleration, I need to be able to measure its speed to substantiate that it is actually faster. How else could I assert that a product has a performance advantage if it cannot be measured or is out of reach to verify? Based on your reasoning, how can blade manufacturers claim that their products enable higher jumps? Therefore, perhaps the right question to ask is how the manufacturers tested and proved that their lightweight blades increase jump height.

As mentioned earlier in this discussion, marketing claims must be accurate, substantiated, and backed by evidence. For instance, if a product claims to enhance performance—such as enabling “higher jumps” or “cushioned landings”—these statements should be supported by verifiable data. In this discussion, I questioned a specific claim, but I understand that there are many other dubious claims that one might challenge. Generally, misleading claims that influence a consumer’s decision could potentially lead to lawsuits, and I have the right to question these claims if the only empirical evidence available suggests that they are misleading. In the United States, the Federal Trade Commission (FTC) enforces truth-in-advertising laws.

On another note, jump heights, lengths, and other performance metrics can be measured very accurately, and there are numerous papers and methods detailing how to assess the impact of equipment, shoes, flooring, and so forth on athletic performance. For example, there are studies on how different shoes affect stride and speed, and how various figure skating boots influence landings. Typically, controlled, randomized studies are conducted where participants are blinded to avoid bias. Statistical software, such as G*Power, can be used to determine the required sample size to achieve sufficient statistical power. These studies do not have to be long-term or overly complicated, as you suggested. For example, look at the methods of the 2022 study on different blades (https://www.tandfonline.com/doi/full/10.1080/14763141.2022.2063757) where researchers tested different blades and found no differences in jump height between traditional and lightweight blades.

Equipment can have a direct effect on an athlete without requiring a lengthy adjustment period—such as special swimsuits that increased swimming speeds (which were subsequently banned) or running shoes with carbon fiber springs that improved running speeds (now regulated). An extreme example is comparing a solid blade weighing 5 kg to a lightweight blade weighing 50 grams: you would likely see a direct effect on jump height. However, with the current weight difference of just about 100 grams between solid and lightweight blades, there appears to be no difference in jump height.

Well, you could know more than me. I do find the vehicle example as a false equivalency for hopefully obvious reasons... I'm also not convinced by the methods of that experiment, like at all, though its interesting. Like I said, I'm no expert, but the methods in that experiment sort of confirm to me my original suggestion about the complexity of such a study.

The weight difference, 100g. Yea, I agree in and of itself its nothing. At that level though you are looking for a compounding effect with all the different measures taken though. Its a single step which would be part of a greater push for a few kilograms off. You like car examples so imagine the F1 mechanics who take off a few grams here or there. Sounds like nothing for a huge chunk of metal, but...

Its not about inches or rotations here, but delicate minutia for the professional.

Yea, its best we had verification for everything. But its sort of idealistic. Peer review studies and experiments can be... their own world. I dont think you're objectively wrong necessarily I am just interested in your particular focus with this product. This is peanuts by sports advertisement standards. It seems peculiarly specific. Are you looking for a niche area to study as a thesis or something?

 

[Timskate]

Well, you could know more than me. I do find the vehicle example as a false equivalency for hopefully obvious reasons... I'm also not convinced by the methods of that experiment, like at all, though its interesting. Like I said, I'm no expert, but the methods in that experiment sort of confirm to me my original suggestion about the complexity of such a study.

The weight difference, 100g. Yea, I agree in and of itself its nothing. At that level though you are looking for a compounding effect with all the different measures taken though. Its a single step which would be part of a greater push for a few kilograms off. You like car examples so imagine the F1 mechanics who take off a few grams here or there. Sounds like nothing for a huge chunk of metal, but...

Its not about inches or rotations here, but delicate minutia for the professional.

Yea, its best we had verification for everything. But its sort of idealistic. Peer review studies and experiments can be... their own world. I dont think you're objectively wrong necessarily I am just interested in your particular focus with this product. This is peanuts by sports advertisement standards. It seems peculiarly specific. Are you looking for a niche area to study as a thesis or something?

You misunderstood the analogy with the vehicle example. It was about the measurement approach, not the car itself. Let me try again: I can’t claim that a special bracelet absorbs dark matter for an athlete’s well-being if we currently have no technology to detect dark matter. Such a claim would obviously be false.

So, if measuring jump height in different blades is such a complex and difficult task, how did the manufacturers conduct their experiment—especially if you believe that a double peer-reviewed study involving scientists from multiple institutions did not approach it well? The study in question is well-conducted, credible, and peer-reviewed, which means it was accepted by the scientific community.

As with any claim—such as one asserting enhanced performance, like blades enabling “higher jumps”—it must be supported by verifiable data. Based on the methods manufacturers use to conduct their experiments, anyone should be able to replicate those tests and obtain reasonably similar outcomes, namely higher jumps with lightweight blades.

Well, we all have different interests. Mine currently lie in figure skating and marketing claims, and you seem interested in my particular focus on this product. Accurate product claims matter to me, as you can see from this discussion. I also question other claims in other industries, but since this forum is about figure skating, that’s why I placed this question here. Or maybe what I really want is just blades that make me actually jump higher

 

[Mathematician]

You misunderstood the analogy with the vehicle example. It was about the measurement approach, not the car itself. Let me try again: I can’t claim that a special bracelet absorbs dark matter for an athlete’s well-being if we currently have no technology to detect dark matter. Such a claim would obviously be false.

So, if measuring jump height in different blades is such a complex and difficult task, how did the manufacturers conduct their experiment—especially if you believe that a double peer-reviewed study involving scientists from multiple institutions did not approach it well? The study in question is well-conducted, credible, and peer-reviewed, which means it was accepted by the scientific community.

As with any claim—such as one asserting enhanced performance, like blades enabling “higher jumps”—it must be supported by verifiable data. Based on the methods manufacturers use to conduct their experiments, anyone should be able to replicate those tests and obtain reasonably similar outcomes, namely higher jumps with lightweight blades.

Well, we all have different interests. Mine currently lie in figure skating and marketing claims, and you seem interested in my particular focus on this product. Accurate product claims matter to me, as you can see from this discussion. I also question other claims in other industries, but since this forum is about figure skating, that’s why I placed this question here. Or maybe what I really want is just blades that make me actually jump higher

Oh come on please dont go there. Peer review is a good system, as long as we all remember its necessarily open to interpretation; especially experimental papers. Thats the whole point! They are peer reviewed for DATA not CONCLUSION. Conclusion is effectively an opinion section, within reason of course, and outside of data-recap. I accept their data entirely. Its useful. Their conclusion is ambiguous, it seems they are well aware of their limitations. All they claim is that they couldnt evidence height increase (but they could evidence shock absorption), I already agreed with that, that is my entire thesis that its not an experimentally valid question. If you are a Ph.D student you know well its dishonest to just withdraw and claim "well its accepted science bro" "oh you think you know better than science?" etc... I can show you a peer review paper that says 2/3 peer review papers are wrong. Appeal to consensus is just disrespectful on the level of discussion were trying to have, right? The methodology there was NOT good for what WERE looking for or YOUR specific claim/extrapolation. That isnt an attack on the scientists or the paper. It is an intelligent and interesting experiment. But the aforementioned nature of this issue physically doesnt allow a convincing and universal study. The fact that these intelligent and hard working people found that was the best way to try for a conclusion is extremely telling. I mentioned I think isolating such a variable is impossible. The study supports that hypothesis in my personal interpretation. If you disagree thats ok, thats the whole point.

Anyways, thats not my main idea, so lets agree to disagree. And lets analyze as follows:

You make another claim/question, this one actually being very valid, if its not provable scientifically why do they make the claim? Thats is the main crux of the discussion, right? So lets stick with that.

Yes, a good question, and I answered earlier by half-conceding to your claim that marketing is at play big time. But I still think we need to understand further. We can take a lawyer's approach instead of a scientist's, since you mentioned lawsuits and false marketing laws.

Lets remember the F1 car weights. Take a few grams off a car - will you see an increase in lap time? No. And if you did, it wouldnt mean anything, because it would be so insanely minuscule you wouldnt be able to isolate the factor of simply a better performance by the driver. So you would have to test for car efficacy holistically after many changes. What IS evidenced already though is that lighter weight will move faster (with diminishing return), and after enough changes we would experimentally evidence that. So, would it be dubious for the engineers to claim the original few gram reduction is useless, or let it not be deceitful? Is a lighter steering wheel, taking off a few grams, a dubious product? I dont think that attack would hold up in court. Its marketing, yes, embellished, but not really malicious, or even wrong at all.

So, maybe I am being a little pedagogic with you. You have a valid question. I also shouldnt be so judgemental if you have this niche interest you want to study - I apologize for that. I am known for also getting hyper-specific with skating analyses that few users want to engage about. But, I really disagree with your expectation of some scientific proof for such a specific and delicate, professional product. I also really disagree with your level of criticism in their marketing. Its standard non-malicious marketing. In absolutely no way is it breaking the law or deceitful (as was implicitly suggested). Its just desirably presenting an extrapolation of an established physical cause-effect relationship (less weight, more height), to sell the product. Its not dishonest IMO. Of course, not to mention the blade shape differences which help otherwise that others were discussing, that I am not expert enough to engage about, and we of course also agree have nothing to do with that study you linked. Also factors presumably reasonably deduced from established physical knowledge.

 

[Timskate]

Oh come on please dont go there. Peer review is a good system, as long as we all remember its necessarily open to interpretation; especially experimental papers. Thats the whole point! They are peer reviewed for DATA not CONCLUSION. Conclusion is effectively an opinion section, within reason of course, and outside of data-recap. I accept their data entirely. Its useful. Their conclusion is ambiguous, it seems they are well aware of their limitations. All they claim is that they couldnt evidence height increase (but they could evidence shock absorption), I already agreed with that, that is my entire thesis that its not an experimentally valid question. If you are a Ph.D student you know well its dishonest to just withdraw and claim "well its accepted science bro" "oh you think you know better than science?" etc... I can show you a peer review paper that says 2/3 peer review papers are wrong. Appeal to consensus is just disrespectful on the level of discussion were trying to have, right? The methodology there was NOT good for what WERE looking for or YOUR specific claim/extrapolation. That isnt an attack on the scientists or the paper. It is an intelligent and interesting experiment. But the aforementioned nature of this issue physically doesnt allow a convincing and universal study. The fact that these intelligent and hard working people found that was the best way to try for a conclusion is extremely telling. I mentioned I think isolating such a variable is impossible. The study supports that hypothesis in my personal interpretation. If you disagree thats ok, thats the whole point.

Anyways, thats not my main idea, so lets agree to disagree. And lets analyze as follows:

You make another claim/question, this one actually being very valid, if its not provable scientifically why do they make the claim? Thats is the main crux of the discussion, right? So lets stick with that.

Yes, a good question, and I answered earlier by half-conceding to your claim that marketing is at play big time. But I still think we need to understand further. We can take a lawyer's approach instead of a scientist's, since you mentioned lawsuits and false marketing laws.

Lets remember the F1 car weights. Take a few grams off a car - will you see an increase in lap time? No. And if you did, it wouldnt mean anything, because it would be so insanely minuscule you wouldnt be able to isolate the factor of simply a better performance by the driver. So you would have to test for car efficacy holistically after many changes. What IS evidenced already though is that lighter weight will move faster (with diminishing return), and after enough changes we would experimentally evidence that. So, would it be dubious for the engineers to claim the original few gram reduction is useless, or let it not be deceitful? Is a lighter steering wheel, taking off a few grams, a dubious product? I dont think that attack would hold up in court. Its marketing, yes, embellished, but not really malicious, or even wrong at all.

So, maybe I am being a little pedagogic with you. You have a valid question. I also shouldnt be so judgemental if you have this niche interest you want to study - I apologize for that. I am known for also getting hyper-specific with skating analyses that few users want to engage about. But, I really disagree with your expectation of some scientific proof for such a specific and delicate, professional product. I also really disagree with your level of criticism in their marketing. Its standard non-malicious marketing. In absolutely no way is it breaking the law or deceitful (as was implicitly suggested). Its just desirably presenting an extrapolation of an established physical cause-effect relationship (less weight, more height), to sell the product. Its not dishonest IMO. Of course, not to mention the blade shape differences which help otherwise that others were discussing, that I am not expert enough to engage about, and we of course also agree have nothing to do with that study you linked. Also factors presumably reasonably deduced from established physical knowledge.

I understand that isolating a single factor, such as blade weight, in complex athletic performance is challenging. However, complexity doesn’t justify making claims without credible evidence. The peer-reviewed study that found no significant improvement in jump height with lightweight blades serves as a useful reference point—even if you believe its methodology is limited. The key issue is that the manufacturers have not provided their own verifiable data to support their marketing claim.

While subtle effects are possible, good-faith advertising should rely on demonstrable evidence, not just assumptions. If the claim is that lighter blades enable higher jumps, there should be a replicable, data-driven test confirming that result. Without such evidence, it’s fair to question the validity of the claim. Yes, marketing often involves some embellishment, but when it influences consumer choices—especially those of parents investing in their children’s equipment—accuracy matters. Dismissing the need for scientific backing only encourages further misinformation in the marketplace.

Peer review isn’t only about data. In reality, peer reviewers assess the methodology, the interpretation of data, and whether conclusions logically follow from the results. Arguing that “2/3 of peer-reviewed papers are wrong” is both overly broad and irrelevant. Rigorous peer review remains the best system available for evaluating and validating scientific claims. This doesn’t mean we accept everything unquestioningly, but it does mean that the study in question has passed a certain standard of scrutiny.

It seems you’re comfortable with the idea of manufacturers making performance claims without verifiable evidence. This stance is problematic because it normalizes misleading marketing. Even if a claim is subtle, it should still be supported by data. The comparison with F1 mechanics shaving off grams doesn’t hold, since those teams aren’t selling consumer products with performance claims to everyday buyers. Moreover, an F1 team’s incremental changes are measured and quantified in lap times; they don’t advertise these tweaks as guaranteed performance enhancements to consumers. Small effects can still be tested with proper methodology, even if it’s difficult. Dismissing the possibility undermines the need for honesty in advertising.

 

[Mathematician]

I understand that isolating a single factor, such as blade weight, in complex athletic performance is challenging. However, complexity doesn’t justify making claims without credible evidence. The peer-reviewed study that found no significant improvement in jump height with lightweight blades serves as a useful reference point—even if you believe its methodology is limited. The key issue is that the manufacturers have not provided their own verifiable data to support their marketing claim.

While subtle effects are possible, good-faith advertising should rely on demonstrable evidence, not just assumptions. If the claim is that lighter blades enable higher jumps, there should be a replicable, data-driven test confirming that result. Without such evidence, it’s fair to question the validity of the claim. Yes, marketing often involves some embellishment, but when it influences consumer choices—especially those of parents investing in their children’s equipment—accuracy matters. Dismissing the need for scientific backing only encourages further misinformation in the marketplace.

Peer review isn’t only about data. In reality, peer reviewers assess the methodology, the interpretation of data, and whether conclusions logically follow from the results. Arguing that “2/3 of peer-reviewed papers are wrong” is both overly broad and irrelevant. Rigorous peer review remains the best system available for evaluating and validating scientific claims. This doesn’t mean we accept everything unquestioningly, but it does mean that the study in question has passed a certain standard of scrutiny.

It seems you’re comfortable with the idea of manufacturers making performance claims without verifiable evidence. This stance is problematic because it normalizes misleading marketing. Even if a claim is subtle, it should still be supported by data. The comparison with F1 mechanics shaving off grams doesn’t hold, since those teams aren’t selling consumer products with performance claims to everyday buyers. Moreover, an F1 team’s incremental changes are measured and quantified in lap times; they don’t advertise these tweaks as guaranteed performance enhancements to consumers. Small effects can still be tested with proper methodology, even if it’s difficult. Dismissing the possibility undermines the need for honesty in advertising.

Whats your program and what was your undergrad?

 

[Timskate]

Whats your program and what was your undergrad?

I won’t be sharing any personal information with you due to your 'judgmental' approach.

 

[Mathematician]

I won’t be sharing any personal information with you due to your 'judgmental' approach.

Im caught off guard TBH. I felt my last response is diplomatic and friendly. Well I suppose things get lost in online interactions.

BTW, of course peer review looks at method, I did also say peer review is a fine process. I qualified that their goals are different so it can still be irrelevant to our analysis regardless. I suggested you'd disagree, and said its fine so we can move on. I also conceded that its fine you are really interested in the marketing side and I apologized for seeming confused by the interest at first. I just mention its not super scientific, though you seem to want to approach it from that angle, instead now it seems moreso to be based on suggestions about how things "should" be this or that, or it "should" be done this or that way, etc... in an idealistic way. I actually did also even preemptively say thats fine too but its just hard to engage with in any objective analysis.

 

[Query]

It seems to me that to sue a seller for false advertising, you would need to prove they are lying. Which would be a combination of proving that what they say is untrue, and that they know it is untrue.

The manufacturer, on the other hand, doesn't have to prove what they are saying.

Also, I believe most statisticians would say that it is the statistical method, not the software that implements it, that matters. Also, that the statistical method should depend on known facts about data, such as statistical distributions of data and noise.

But many scientific publications require or expect papers to use statistical techniques based on fairly specific statistical assumptions, that are often incorrect.

Because of these kinds of statistical issues, I suspect that a moderately large fraction of scientific publications come to incorrect conclusions.

"Evidence based science" comes up especially often in medicine. But medicine is another field where relatively few of the common statistical assumptions I mentioned are actually valid, because bodies are extremely complex incompletely understood systems, and many variables are strongly interdependent. On top of that, companies that develop medical studies routinely sponsor many small studies, then select those whose results are allowed publication. The net result is that the "evidence base science" may very often be incorrect.

In any event, conclusions for ice skating equipment may also be biased by sponsorship and free equipment given to some of the best athletes and coaches. So correlation studies between performance and models will be strongly biased. And "double blind" tests are impractical in sports like skating where you sometimes need to look down at the equipment while practicing.

So "evidence based science" on sports equipment is nearly impossible. It is fairly safe to make almost any claims one wishes, knowing suits regarding such claims are unlikely to succeed.

 

[Mathematician]

It seems to me that to sue a seller for false advertising, you would need to prove they are lying. Which would be a combination of proving that what they say is untrue, and that they know it is untrue.

The manufacturer, on the other hand, doesn't have to prove what they are saying.

Also, I believe most statisticians would say that it is the statistical method, not the software that implements it, that matters. Also, that the statistical method should depend on known facts about data, such as statistical distributions of data and noise.

But many scientific publications require or expect papers to use statistical techniques based on fairly specific statistical assumptions, that are often incorrect.

Because of these kinds of statistical issues, I suspect that a moderately large fraction of scientific publications come to incorrect conclusions.

"Evidence based science" comes up especially often in medicine. But medicine is another field where relatively few of the common statistical assumptions I mentioned are actually valid, because bodies are extremely complex incompletely understood systems, and many variables are strongly interdependent. On top of that, companies that develop medical studies routinely sponsor many small studies, then select those whose results are allowed publication. The net result is that the "evidence base science" may very often be incorrect.

In any event, conclusions for ice skating equipment may also be biased by sponsorship and free equipment given to some of the best athletes and coaches. So correlation studies between performance and models will be strongly biased. And "double blind" tests are impractical in sports like skating where you sometimes need to look down at the equipment while practicing.

So "evidence based science" on sports equipment is nearly impossible. It is fairly safe to make almost any claims one wishes, knowing suits regarding such claims are unlikely to succeed.