I am size 13, my Adidas Adios Pro 2's have the stack height listed as 39mm on the side of the shoe.
If you wear size 7 shoes, and they also have the legal stack heigh of under 40mm in the heel, isn't that much more cushion/foam under foot for the athlete? Presumably, many people with smaller feet are also shorter and lighter. Isn't this a competitive advantage?
Shouldn't I be able to wear 45 mm foam shoes, legally, to keep it fair?
Without knowing exactly what the regulations specify, I can't say for sure, but it seems like a fair question.
I have wondered if some super shoes work better for runners of a certain build, and pay a little more attention to the shoe choice of faster runners who are taller and weigh closer to 175 than 125. Most of the truly elite guys probably weigh under 150 even if they are pretty tall, but there are some quick guys in the supershoe era who are close to my size.
I am size 13, my Adidas Adios Pro 2's have the stack height listed as 39mm on the side of the shoe.
If you wear size 7 shoes, and they also have the legal stack heigh of under 40mm in the heel, isn't that much more cushion/foam under foot for the athlete? Presumably, many people with smaller feet are also shorter and lighter. Isn't this a competitive advantage?
Shouldn't I be able to wear 45 mm foam shoes, legally, to keep it fair?
I'd say it has more to do with the angle and curvature of the carbon fiber plate (as well as the geometry) and drop of the shoe.
Obviously running form and mechanics (from pronation rate and relative impact forces as well as torque and the "spring" component reaction) greatly influence the effectiveness of any particular shoe design in boosting Running Economy over baseline for an individual.
Generally people with smaller feet (relative to their height) can have better Running Economy and imo people with bigger feet generally have more of an injury risk/liability. They also tend to weigh more in general though.
The ratio of foam compromising the stack height (compared to horizontal volume) is greater for a shorter shoe (smaller size shoe) of course, but I'd say it what matters more is the angle and curvature and shape of the carbon fiber plate and your own running form mechanics.
It can certainly help someone increase their Running Economy by well over 2%...but also maybe 5% or 6% depending on the response and exact design. But I wouldn't say it necessarily means those with smaller shoe sizes are at an advantage because of all these variables involved.
All other things being equal, wouldn't more foam underfoot change the angles in a smaller foot vs. a larger foot? Also, with plenty of data showing that the "super foams" are more responsible for performance gains than mere carbon plates, wouldn't more foam mean faster times?
Thanks for the reply Sage. Best of luck on your recovery and return to elite racing.
The listed stack height for a shoe is for a size 9, or 8.5 I cannot remember for super shoes, but an increase in size will typically have a corresponding increase in stack height. The 'super shoe' rules are based on the 'standard size'. I do not know specifically about the Adios Pro 2, however. So a size 13 runner can exceed the 40 mm stack height and be legal.
I am size 13, my Adidas Adios Pro 2's have the stack height listed as 39mm on the side of the shoe.
If you wear size 7 shoes, and they also have the legal stack heigh of under 40mm in the heel, isn't that much more cushion/foam under foot for the athlete? Presumably, many people with smaller feet are also shorter and lighter. Isn't this a competitive advantage?
Shouldn't I be able to wear 45 mm foam shoes, legally, to keep it fair?
The 40mm limit is for sample size Euro 42 (US men's 8.5). You are allowed more than that for larger than size Euro 42.
World Athletics wrote:
World Athletics acknowledges that an Athletic Shoe above that standard sample size might contain a marginally thicker sole than that of a standard sample size shoe of the same make and model, which marginal increase in sole thickness is only attributable to the larger size of the shoe. Such marginal increases will be disregarded for the purposes of confirming compliance with these Rules.
Kipchoge's original Alphaflys were in fact reported to be 45mm, and that was and is allowed because his shoe size is 10.5.
As others have mentioned, the 40mm rule is for a US 8.5, so it's likely your size 13 already has close to 50mm of stack.
Also, why would increased cushioning benefit a lighter person (who likely doesn't need it) - and who's also not going to load up the plate as much as a heavier person - more ?
Generally people with smaller feet (relative to their height) can have better Running Economy and imo people with bigger feet generally have more of an injury risk/liability. They also tend to weigh more in general though.
I don't know where this comes from. Feet are levers in the system of legs, feet, springy tissues (including Achilles and plantar fascia) and muscles that allow people to run. It's not beneficial to have short, stumpy feet. Think of the carbon prosthestic legs that Pistorius uses. They could have chosen any length carbon feet, or none at all, just carbon stumps, but they have especially long carbon feet.
Kipchoge has size 10.5 feet, even though he's only 167cm tall (a bit under 5'6"). That's very long for his height. I'm sure he has pretty darn good running economy.
Generally people with smaller feet (relative to their height) can have better Running Economy and imo people with bigger feet generally have more of an injury risk/liability. They also tend to weigh more in general though.
I don't know where this comes from. Feet are levers in the system of legs, feet, springy tissues (including Achilles and plantar fascia) and muscles that allow people to run. It's not beneficial to have short, stumpy feet. Think of the carbon prosthestic legs that Pistorius uses. They could have chosen any length carbon feet, or none at all, just carbon stumps, but they have especially long carbon feet.
Kipchoge has size 10.5 feet, even though he's only 167cm tall (a bit under 5'6"). That's very long for his height. I'm sure he has pretty darn good running economy.
Well "injury risk" is obviously also highly dependent on tons of variables (from training habits to genetics to diet etc).
I'd say in general though the "longer the lever" (foot specifically) the more potential for certain increases in injury risk (depends on other mechanics and anatomy of course!). The general trend is that foot size roughly correlates to height (which also correlates to body mass).
I also never set anything about "short stumpy feet".... but just that generally the elites aren't wearing size 14.
Ankle flexion, elasticity of tendons/fascia, rate and degree of pronation, arch type....these things call come into play.
So you citing Kipchoge as an n=1 for a size 10.5 doesn't show a trend for anything (that would be bad science!). I'm sure he has great economy (a lot of that is also influeced by things besides just mechanics fyi).
Also note: the link/images you presented shoe how Pistorius's prosthetics actually have a relatively short and small length for the actual "foot part" that would be in contact with ground....
This supports my argument a lot more than whatever point you are trying to make
Also note: the link/images you presented shoe how Pistorius's prosthetics actually have a relatively short and small length for the actual "foot part" that would be in contact with ground....
This supports my argument a lot more than whatever point you are trying to make
The lever obviously goes all the way to the ankle of the prosthetic. That's the part that has the most flex and therefore stores and returns the most mechanical strain energy when it is flexed. That's the part analogous to the Achilles tendon. The foot part of the prosthetic is also flexing along the entire length, analogous to the flexing in the tendons/ligaments in the arch of a foot.
Yes, I know Kipchoge is n=1. That's the only fast runner whose foot size has been reported in the press that I know of. He's at the extreme end though, and his characteristics should be more representative of an ideal than anyone else. Your statement was n=0 on foot size.
I did a search of studies on foot size and running and saw speculation in discussion sections along the lines of noting the effect of weight on the foot (like shoe weight) and trying to say that means that larger feet=heavier feet and therefore are probably worse for running economy. But those statements in those studies I looked at did not consider mechanical benefits of larger feet at all and did not study it either. There are studies about feet as part of a spring-damper system with feet having aspects that both return and dissipate energy, but that says nothing about how those things would change with proportionally larger/smaller feet on the same height/weight runners. I don't think there are actually any studies that actually test foot size/body height (or weight) ratio and running economy or if there is a prevalence of proportionally small or large feet in elite runners. I browsed through studies for at least an hour, looked at the studies those studies referenced, and am pretty sure that would be something wide open to do a study on.
This post was edited 13 minutes after it was posted.
I am size 13, my Adidas Adios Pro 2's have the stack height listed as 39mm on the side of the shoe.
If you wear size 7 shoes, and they also have the legal stack heigh of under 40mm in the heel, isn't that much more cushion/foam under foot for the athlete? Presumably, many people with smaller feet are also shorter and lighter. Isn't this a competitive advantage?
Shouldn't I be able to wear 45 mm foam shoes, legally, to keep it fair?
This is an interesting study but most runners are not 6 foot 5 or taller. Most of those guys are playing football, basketball, baseball, hockey, and similar sports where height is rewarded. Therefore there is not a great study on people with long feet having a biological advantage. Stack height, cushion, and now "carbon fiber" are other factors that need to fit into any further study, too.
Generally people with smaller feet (relative to their height) can have better Running Economy and imo people with bigger feet generally have more of an injury risk/liability. They also tend to weigh more in general though.
I don't know where this comes from. Feet are levers in the system of legs, feet, springy tissues (including Achilles and plantar fascia) and muscles that allow people to run. It's not beneficial to have short, stumpy feet. Think of the carbon prosthestic legs that Pistorius uses. They could have chosen any length carbon feet, or none at all, just carbon stumps, but they have especially long carbon feet.
Kipchoge has size 10.5 feet, even though he's only 167cm tall (a bit under 5'6"). That's very long for his height. I'm sure he has pretty darn good running economy.
I don't know where this comes from. Feet are levers in the system of legs, feet, springy tissues (including Achilles and plantar fascia) and muscles that allow people to run. It's not beneficial to have short, stumpy feet. Think of the carbon prosthestic legs that Pistorius uses. They could have chosen any length carbon feet, or none at all, just carbon stumps, but they have especially long carbon feet.
Kipchoge has size 10.5 feet, even though he's only 167cm tall (a bit under 5'6"). That's very long for his height. I'm sure he has pretty darn good running economy.
Yes, that's why horses, antelope, cheetahs - and just about any other animal renowned for running - all have massive feet.
Oh wait, no they don't.
Yes, they in fact do. The hock is the equivalent structure to the ankle in humans (both green in the photo below). Hock to tip of the hoof or paw is like ankle to toes in humans. They just keep what would be the heel region way off the ground. The Achilles tendon behaves like a spring off that long lever just like the Achilles tendon in humans behave like a spring off their feet. So, to become fast, they evolved really long "feet" (hock to toes/hooves).
Probably the most famous anatomical demonstration that students of equine anatomy regularly see in the dissecting room — and certainly one of the most spectacular and interesting — is the coordinated opening and closing of th...
I am size 13, my Adidas Adios Pro 2's have the stack height listed as 39mm on the side of the shoe.
If you wear size 7 shoes, and they also have the legal stack heigh of under 40mm in the heel, isn't that much more cushion/foam under foot for the athlete? Presumably, many people with smaller feet are also shorter and lighter. Isn't this a competitive advantage?
Shouldn't I be able to wear 45 mm foam shoes, legally, to keep it fair?
I'd say it has more to do with the angle and curvature of the carbon fiber plate (as well as the geometry) and drop of the shoe.
Obviously running form and mechanics (from pronation rate and relative impact forces as well as torque and the "spring" component reaction) greatly influence the effectiveness of any particular shoe design in boosting Running Economy over baseline for an individual.
Generally people with smaller feet (relative to their height) can have better Running Economy and imo people with bigger feet generally have more of an injury risk/liability. They also tend to weigh more in general though.
The ratio of foam compromising the stack height (compared to horizontal volume) is greater for a shorter shoe (smaller size shoe) of course, but I'd say it what matters more is the angle and curvature and shape of the carbon fiber plate and your own running form mechanics.
It can certainly help someone increase their Running Economy by well over 2%...but also maybe 5% or 6% depending on the response and exact design. But I wouldn't say it necessarily means those with smaller shoe sizes are at an advantage because of all these variables involved.
We may see even more than this 5-6% if we were to put a super responder to carbon plated shoes in a shoe specially designed for their foot. No one has a "stock foot" and we're all just buying shoes that fit closest to what would be best.
Yes, they in fact do. The hock is the equivalent structure to the ankle in humans (both green in the photo below). Hock to tip of the hoof or paw is like ankle to toes in humans. They just keep what would be the heel region way off the ground. The Achilles tendon behaves like a spring off that long lever just like the Achilles tendon in humans behave like a spring off their feet. So, to become fast, they evolved really long "feet" (hock to toes/hooves).
Stack height will be higher for larger sizes, shorter for smaller.
Drops should also be the same however the slopes or angles from heel to toe will be higher for smaller sizes and lower or flatter for larger sizes due to geometry.
Would a carbon fiber plate and bouncy foam work better in a shorter shoe with a higher slope? Possibly. That actually makes sense. The original 4% had a drop of 12 or so for a men's 9, didn't it? That should greatly increase the propulsive effect, especially if someone is more of a heel to toe runner. If someone lands flat or more so on their forefoot, or has a larger shoe size, the propulsive effects of the plate should be mathematically minimized.
Stack height will be higher for larger sizes, shorter for smaller.
This. Everything is proportional in terms of dimensions.
Where I have my doubts that shoe manufactorers cater enough for tall outliers is when it comes to density of the foam and or bounce of the carbon fiber plate. A 6'5" rec runner will weigh around 200 lbs, you can imagine that if the carbon plate has the same characteristics as the one made for 110 lbs Kipchoge, that may not bounce as nicely.
Yes, that's why horses, antelope, cheetahs - and just about any other animal renowned for running - all have massive feet.
Oh wait, no they don't.
Yes, they in fact do. The hock is the equivalent structure to the ankle in humans (both green in the photo below). Hock to tip of the hoof or paw is like ankle to toes in humans. They just keep what would be the heel region way off the ground. The Achilles tendon behaves like a spring off that long lever just like the Achilles tendon in humans behave like a spring off their feet. So, to become fast, they evolved really long "feet" (hock to toes/hooves).
I knew when I wrote the comment that I should've subbed out "feet" for "ground contact point", but I thought "no, that sounds clunky, and anyway, people will understand the point I'm making."
But no, this is the internet, where people willfully ignore a point if they can weasel around the semantics.
In all of those animals, the foot does not behave the same way as it does in humans. You yourself admit that the back half of the foot (the part not touching the ground) behaves like the achilles tendon in humans. Therefore, with a larger human foot, you have all of this additional mass (which bears a large energy cost, as it's positioned at the end of a lever) and a larger contact point, which is necessary for bipedal stability, but ultimately hinders running efficiency.
Therefore, a runner with a smaller foot better mimics the foot and ankle structure of the above-mentioned animals e.g. small mass at the end of a lever, small contact point that attaches to a long vertical(ish) spring.
I knew when I wrote the comment that I should've subbed out "feet" for "ground contact point", but I thought "no, that sounds clunky, and anyway, people will understand the point I'm making."
But no, this is the internet, where people willfully ignore a point if they can weasel around the semantics.
In all of those animals, the foot does not behave the same way as it does in humans. You yourself admit that the back half of the foot (the part not touching the ground) behaves like the achilles tendon in humans. Therefore, with a larger human foot, you have all of this additional mass (which bears a large energy cost, as it's positioned at the end of a lever) and a larger contact point, which is necessary for bipedal stability, but ultimately hinders running efficiency.
Therefore, a runner with a smaller foot better mimics the foot and ankle structure of the above-mentioned animals e.g. small mass at the end of a lever, small contact point that attaches to a long vertical(ish) spring.
The weight being supported, loaded, and has energy returned to by the Achilles is the weight of the rest of the body above the ankle/hock, not the feet. The parts below the ankle or hock behave as a lever (more accurately a series of levers since you have another joint and another lever in the toes or equivalent). It seems you see those levers more as dead weight rather than function parts first.
If you think the weight of a longer foot is a problem - why don't you think the longer cannon bones (=metatarsals in human feet) in horses have no more mass than if they were shorter? By your reasoning horses would be faster if you shrink down everything below the hock to the length of a human foot to save weight. Developmentally (early in the womb), all mammals look the same. Fast mammals evolved those same bones to be bigger than human feet.
Feet go for a ride in the air when running, but a lot of that motion is efficiently controlled by passive tension in muscles/tendons/ligaments. Realistically, a human saving weight at the foot/shoe location (about 1 second per mile per ounce saved is often quoted) is almost nothing. That's tiny compared to animals running 40mph to 80 mph, enabled in large part by "long feet".
