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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [Pyrenean Wolf] [ In reply to ]
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Why is taking only heelstrikers a problem? The vast majority of all runners strikes with the heel and I imagine that it is really hard to find enough people who are real mid- or forefoot strikers for a study. Moreover, especially a heel striker should profit from maximum cushioned shoes compared to mid- or forefood runners. If that effect cannot be observed with heelstrikers, it will not be observed with forefoot runners either.

Concerning the different drops of the shoes: I do not get why this should make a difference regarding the impact force.

Finally, "citing" anecdotal evidence like "so many runners report that maximum cushioned shoes reduce the risk of getting injured" is not really a strong argument against a peer-reviewed paper published in a scientific journal such as nature.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [sprint_guy] [ In reply to ]
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sprint_guy wrote:
Why is taking only heelstrikers a problem? The vast majority of all runners strikes with the heel and I imagine that it is really hard to find enough people who are real mid- or forefoot strikers for a study. Moreover, especially a heel striker should profit from maximum cushioned shoes compared to mid- or forefood runners. If that effect cannot be observed with heelstrikers, it will not be observed with forefoot runners either.

Concerning the different drops of the shoes: I do not get why this should make a difference regarding the impact force.

Finally, "citing" anecdotal evidence like "so many runners report that maximum cushioned shoes reduce the risk of getting injured" is not really a strong argument against a peer-reviewed paper published in a scientific journal such as nature.

Hello

1) heelstrikers
it is not bad to select heel strikers, but if you select a cohort 100% heel striker, why don't use shoes adapted to heel striker :
10mm drop racing flat : NB 1400, or lower drop flat such Hanzo, ...
vs
10mm cushionned shoe : Vaporfly

Then, you would really compare no-cushion vs cushion

Instead of choosing a cushioned shoe for heel strikers : Ghost, vs a shoe ..... well.... a bad shoe for heel strikers.
Ghost is cushionned for heel strikers. Conquest is... non sense.

Shoe selection make this study mean nothing.

2) drop
is just a consequence of heel cushion vs forefoot cushion (if we assume heigh is cushion, not always true).
When I was heel striking, I loved 10mm drop shoes with good heel cushion and not much front cushion (Ghost for example, is a cushion shoe for heel strikers)
Now mid foot striking, I want forefoot cushion, and not having the heel "scratching" : I love low drop cushioned shoes.

For a 100% heel striker cohort, make coherent choice.

3) anecdotal evidence
was not cited by me

4) This study was "Peer reviewed"
type "fake peer-review article" on Google and have a look. Everybody in scientific community knows hundreds of "peer reviewed" article are just plain bullshit. lot of noise around this last 2 years.

This article is clearly bullshit^4
So either reviewed by peoples not really aware
Or biased
Or...
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [sprint_guy] [ In reply to ]
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sprint_guy wrote:
Why is taking only heelstrikers a problem? The vast majority of all runners strikes with the heel and I imagine that it is really hard to find enough people who are real mid- or forefoot strikers for a study. Moreover, especially a heel striker should profit from maximum cushioned shoes compared to mid- or forefood runners. If that effect cannot be observed with heelstrikers, it will not be observed with forefoot runners either.

Concerning the different drops of the shoes: I do not get why this should make a difference regarding the impact force.

Finally, "citing" anecdotal evidence like "so many runners report that maximum cushioned shoes reduce the risk of getting injured" is not really a strong argument against a peer-reviewed paper published in a scientific journal such as nature.

Did you noticed that at 10km/h, the Conquest reduce the forces very significantly ?
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [Pyrenean Wolf] [ In reply to ]
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Pyrenean Wolf wrote:
sprint_guy wrote:
Why is taking only heelstrikers a problem? The vast majority of all runners strikes with the heel and I imagine that it is really hard to find enough people who are real mid- or forefoot strikers for a study. Moreover, especially a heel striker should profit from maximum cushioned shoes compared to mid- or forefood runners. If that effect cannot be observed with heelstrikers, it will not be observed with forefoot runners either.

Concerning the different drops of the shoes: I do not get why this should make a difference regarding the impact force.

Finally, "citing" anecdotal evidence like "so many runners report that maximum cushioned shoes reduce the risk of getting injured" is not really a strong argument against a peer-reviewed paper published in a scientific journal such as nature.


Did you noticed that at 10km/h, the Conquest reduce the forces very significantly ?

Is it reduced very significantly? It's seems reduced to a similar degree to it is increased at the higher speed but I'm not sure either is very significant. I tried to put the figure in context in an earlier post, someone with a better grasp of the physics could do a better job.

Regarding the study I would of been interested in what is the margin of error in force measurement?

What interests me is that this studies the force on the ground. I'm fairly sure the shoe manufacturers would be making claims about the forces on the body and could care less about the ground. Maybe the study is aimed at engineers maintaining side walks? Isn't the whole point that the cushioning between the ground and the body mitigates some of that force? If the force of impact with the ground is slightly increased (at some speeds) when the cushioning is increased to a higher degree then isn't it entirely possible the net result on the impact to the body is reduced?
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [PTinAZ] [ In reply to ]
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PTinAZ wrote:
Pretty established in the running medicine/rehab world that all the latest shoe company "technology" and "innovation" isn't going to reduce running related injuries and most of their claims aren't true. Runners run, shoes are simply tools. Runners will get injured in all types of shoes.
Totally agree with this.

This study confirms what studies I was reading back in the 90's at university were saying.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [OddSlug] [ In reply to ]
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Hello,

yes, similar in value, but higher in percentage.

But the main issue is (apart cohort selection, shoe selection, speed selection) that force measured mean really nothing.
Because we don't know how this force is produced.
As said in one of my post above, in the real Vaporfly study :
https://link.springer.com/...07/s40279-017-0811-2

they "think" more force can be produced with less muscle impact, due to lower knee angle. Could also happen with different use of the body, when moving from heel strike to mid-foot strike, ...

Saying "more force is more injury" is just .... not proved. For VF article, it seems that more force is produced with to less muscle and tendon impact, because of the cushion.

I remember reading an older study saying : "with more cushion, runner need to produce more leg stiffness. And more leg stiffness is requiring more energy. So cushion leed to less efficiency."
The Vaporfly study show exactly the opposite, and the reason is : leg stiffness can be produced with less energy and impact on muscle and tendon, ... because joint work differently.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [eisforurgent] [ In reply to ]
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If it was as simple as put shoe on and run then everyone would do it! It’s not that simple and likewise we can’t simply blame the shoes. Just like there isn’t one shoe that works for all runners there isn’t one fix for all runners. It really comes down to an N=1.

In my experience working with triathletes and my experience watching hundreds of thousands of runners running every year it comes down to some basics:

1. If there in an imbalance in your structure either skeletal or muscular your run will be compromised. Some like the favorite pro in this forum can. muscle through that imbalance and do quite welll. Most can’t.
2. Running heavy - If you don’t have a running background from high school you probably didn’t learn the basic drills you need to perfect that teach you to be light on your feet. It’s the easiest way I can explain it. When you do your drills imagine your are Eulid Kipchoge.
3. Your body weight - Just read about the 70 year old breaking world records in running. In that article weight is a key statistic for him. It should be for anyone who wants to run injury free too!
4. Shoes - Yes sometimes the shoe is simply a bad match and needs changing out. With the athletes I work one on one with it’s usually about 20% that need to address their shoes. Same in the marathons I watch, roughly 20% need to address their shoes. Sometimes that means simply replace the darn things and a faster rate.
5. Recovery - Listen to the interview Tim Ferriss did with King James. Why is LeBron able to play at such a high level after so long in the League? It’s the recovery practice. We can attribute a large amount of running injury to lack of recovery. Instead of telling you, you are doing too much training I’ll just say your aren’t doing enough recovery.

Dave Jewell
Free Run Speed

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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [PTinAZ] [ In reply to ]
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What I would really like to learn the correlation of highly cushioned shoes and the type of injury trends, ie. is there a correlation between that type of shoe and hip injuries. I am no expert but somehow it seems to me that we are only moving the occurrences up the kinetic chain.....curious, any knowledge there.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [atasic] [ In reply to ]
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atasic wrote:
What I would really like to learn the correlation of highly cushioned shoes and the type of injury trends, ie. is there a correlation between that type of shoe and hip injuries. I am no expert but somehow it seems to me that we are only moving the occurrences up the kinetic chain.....curious, any knowledge there.

Can't think of any particular study that answers your questions. In general what I've seen in evaluating/treating the gamut of running related injuries.

1) Regardless of shoe type, runners get injured.

2) Too much motion control or "pronation control" often does more harm than good (knee/hip injuries)...I didn't say EVERY time, but very common.

3) Training errors ( ie poor recovery, avoiding any sort of ancillary work on their bodies, too much intensity, etc) account for I'm gonna guess 80% of running related injury.

CB
Physical Therapist/Endurance Coach
http://www.cadencept.net
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [PTinAZ] [ In reply to ]
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One thing all of these studies fail to mention, which I find critical in my experience of cushioned vs noncushioned shoes, is WHERE the load occurs.

With cushioned shoes, I find it very quad/hip/knee loaded. If you do steep hillclimbs, your quads will be the ones taking the brunt of the load (and might get sore the next day.) There's relative sparing of the achilles and calf until you get to super steep 18%+ grades. Similar with impact - most of the impact gets cushioned, but with the load sent up the chain to knee/hip (you can really feel it.)

With barefoot or minimalist, your achilles and calf get most of the load, with sparing of the quads/hip/knee. I was really surprised to find how little my quads were used once I was fully converted to minimalist - even on 18%+ climbs, the achilles/calf did most of the work, and the quad just moved things along. Impact here is absorbed mostly by the achilles and calf. Which is why it's so hard for most folks to jump to minimalist without months of acclimating their achilles to this load.

This loading location is really important but not well studied. Most folks get arthritis in their knees and hips, and much less commonly in the ankles (it's like 10x knee/hip vs ankle for occurence.) So one way to extend your running longevity if you have joint arthritis is to use footwear that favors your good joints.

I can't help but wonder if the super common prevalence of knee/hip arthritis today (apparently it's much more common today than decades ago) has something to do with the type of footwear and loading we use, which almost remove the achilles/calf from the run motion.
Last edited by: lightheir: Dec 3, 18 12:54
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [atasic] [ In reply to ]
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There is this study.

Regarding barefoot -
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The descriptive analysis suggests a greater number of calf injuries, but lower number of knee and hip injuries in the barefoot group. Additionally barefoot runners reported less plantar fasciitis than the shod group.

I think it's a reasonable guess to assume the opposite pattern for highly cushioned shoes.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [lightheir] [ In reply to ]
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lightheir wrote:
One thing all of these studies fail to mention, which I find critical in my experience of cushioned vs noncushioned shoes, is WHERE the load occurs.

With cushioned shoes, I find it very quad/hip/knee loaded. If you do steep hillclimbs, your quads will be the ones taking the brunt of the load (and might get sore the next day.) There's relative sparing of the achilles and calf until you get to super steep 18%+ grades. Similar with impact - most of the impact gets cushioned, but with the load sent up the chain to knee/hip (you can really feel it.)

With barefoot or minimalist, your achilles and calf get most of the load, with sparing of the quads/hip/knee. I was really surprised to find how little my quads were used once I was fully converted to minimalist - even on 18%+ climbs, the achilles/calf did most of the work, and the quad just moved things along. Impact here is absorbed mostly by the achilles and calf. Which is why it's so hard for most folks to jump to minimalist without months of acclimating their achilles to this load.

This loading location is really important but not well studied. Most folks get arthritis in their knees and hips, and much less commonly in the ankles (it's like 10x knee/hip vs ankle for occurence.) So one way to extend your running longevity if you have joint arthritis is to use footwear that favors your good joints.

I can't help but wonder if the super common prevalence of knee/hip arthritis today (apparently it's much more common today than decades ago) has something to do with the type of footwear and loading we use, which almost remove the achilles/calf from the run motion.


No evidence that overall injury rates are lower in minimalist shoe folks, and I'm going to wager than the incidence of OA today is due to higher BMI vs shoe wear. And actually there is evidence to support runners have lower incidence of OA vs non-runners.

CB
Physical Therapist/Endurance Coach
http://www.cadencept.net
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [PTinAZ] [ In reply to ]
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The response of 'no injury reduction' is more complex than the studies make it out to be.

Shoed vs unshoed actually get different types of injury. It's definitely not true to say 'they're the same for injuries.' The weightloading from cushioned to noncushioned is pretty dramatic.

It's definitely reasonable that someone who suffers from predominant ankle arthritis but has good knees may do better in a cushioned shoe that relieves the calf/ankle loading, whereas someone with pristine ankles but somewhat limiting knee/hip arthritis might actually benefit from switching to a less cushioned shoe.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [lightheir] [ In reply to ]
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lightheir wrote:
The response of 'no injury reduction' is more complex than the studies make it out to be.

Shoed vs unshoed actually get different types of injury. It's definitely not true to say 'they're the same for injuries.' The weightloading from cushioned to noncushioned is pretty dramatic.

It's definitely reasonable that someone who suffers from predominant ankle arthritis but has good knees may do better in a cushioned shoe that relieves the calf/ankle loading, whereas someone with pristine ankles but somewhat limiting knee/hip arthritis might actually benefit from switching to a less cushioned shoe.

Yes someone with a particular medical history may benefit from a certain type of shoe vs another...agreed.

And yes, types of injuries may vary a bit between types of shoes, but prevalence isn't any different. Folks get injured with any and all types of shoes.

CB
Physical Therapist/Endurance Coach
http://www.cadencept.net
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [eisforurgent] [ In reply to ]
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There are a lot of variables that are not controlled or not mentioned that affect biomechanics of running adaptation, that we simply cannot infer anything about injury prevention... But it's an interesting start.

This is similar to an experiment I did in my graduate program. We had subjects run downhill for 5 minutes comfortably, then stop (no walking flat at all), immediately carted them over to a flat surface with a force plate and kinematic background and had them run. Boy was that hilarious to watch. The GRF numbers showed off the chart impact and heel strike and saw a prancing gait for a solid 20 meters or so. The runners were still in down hill mechanics. The problem with making real world applications with it, as with this article, was that it only shows what happens when you change the environment/ tools we use. It doesn't even show the adaptation to the change. Guaranteed if they had more than a measly 100 meters of running in the new shoes we would have seen a different result, which is what we should be interested in (after which there's a whole additional set of variables)

Basically, If you take a runner and change their mechanics via the shoe or anything in their environment to the opposite of what they're used to they'll have stiffer legs and because the mechanics required to move forward are different. This is called degrees of freedom in motor learning when you attempt to change or learn a new pattern. The more joints involved, the more complex the movement, the more likely you will see "limb stiffness" when a variable is changed. It takes practice to refine and perfect that movement, new or old, when we change a variable.

Its good basic stuff, but more work needs to be done to get any meaningful application to training, injury prevention, or gear development.

Do running drills with whatever shoes you find comfortable and we'll be better off in the meantime.

Matt Leu, M.S. Kinesiology
San Pedro Fit Works, Los Angeles, CA
Endurance Athlete and Coach
Consistency/time=results
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [OddSlug] [ In reply to ]
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Yes, reduced very significantly. The t-test here is the comparison between CON and MAX shoes for a single speed. At 10 km/h (AND for 14.5 km/h), runners in the MAX shoe experience a greater impact peak force. How significant? The t-test says '0.001'. This means that, if the same study were carried out 1000 times, only once would the results be reversed (i.e. the CON providing the greater impact force 1 time in a thousand). This is how science/statistics is done. Typically,a p value of 0.05 or less is considered a 'significant difference' from a statistical POV - i.e. the same result 95 times out of 100. There are statistical models behind this calculation that take into account the mean values, the standard deviations (deviation from the mean values) and the number of observations. Now, does a peak impact force of 2.25 x body weight cause more injuries than 2.01? That is not part of this analysis/study. BUT, according to the t-test value, in this study (i.e. these mean values, these standard deviations, these observation numbers), yup, 2.25 is very significantly different than 2.01. That may not be what you're after (if you're trying to predict injury frequency/intensity from peak impact), but the peak impact forces are different.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [PTinAZ] [ In reply to ]
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PTinAZ wrote:
lightheir wrote:
The response of 'no injury reduction' is more complex than the studies make it out to be.

Shoed vs unshoed actually get different types of injury. It's definitely not true to say 'they're the same for injuries.' The weightloading from cushioned to noncushioned is pretty dramatic.

It's definitely reasonable that someone who suffers from predominant ankle arthritis but has good knees may do better in a cushioned shoe that relieves the calf/ankle loading, whereas someone with pristine ankles but somewhat limiting knee/hip arthritis might actually benefit from switching to a less cushioned shoe.


Yes someone with a particular medical history may benefit from a certain type of shoe vs another...agreed.

And yes, types of injuries may vary a bit between types of shoes, but prevalence isn't any different. Folks get injured with any and all types of shoes.

Wow, I never realized that 37-56% of runners are injured every year. I guess I must be fortunate then b/c I've run for about 33 yrs and have only ever been injured once. I've never run huge amounts but have run up to 50 mi/wk for 6-7 wks at a time. My long-term avg is about 20 mi/wk, low due to lots of swimming (20,000 yd/wk) and some cycling (70 mi/wk). I've never tried to be a pure runner, mostly b/c I just don't enjoy it that much.


"Anyone can be who they want to be IF they have the HUNGER and the DRIVE."
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [eisforurgent] [ In reply to ]
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Saw that! Interesting to say the least.

My +1 is I'm getting old and I'm a little broken. I can run in Hokas much more comfortably than Brooks. I came to Hoka from Brooks. Yes this is completely subjective and not scientific but if it works for me, right?

Edit: Gah! They modeled a mass and spring system. I must stop reading that paper. It is giving me school flashbacks. :p
Last edited by: Dilbert: Dec 3, 18 22:36
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [ericmulk] [ In reply to ]
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ericmulk wrote:
PTinAZ wrote:
lightheir wrote:
The response of 'no injury reduction' is more complex than the studies make it out to be.

Shoed vs unshoed actually get different types of injury. It's definitely not true to say 'they're the same for injuries.' The weightloading from cushioned to noncushioned is pretty dramatic.

It's definitely reasonable that someone who suffers from predominant ankle arthritis but has good knees may do better in a cushioned shoe that relieves the calf/ankle loading, whereas someone with pristine ankles but somewhat limiting knee/hip arthritis might actually benefit from switching to a less cushioned shoe.


Yes someone with a particular medical history may benefit from a certain type of shoe vs another...agreed.

And yes, types of injuries may vary a bit between types of shoes, but prevalence isn't any different. Folks get injured with any and all types of shoes.


Wow, I never realized that 37-56% of runners are injured every year. I guess I must be fortunate then b/c I've run for about 33 yrs and have only ever been injured once. I've never run huge amounts but have run up to 50 mi/wk for 6-7 wks at a time. My long-term avg is about 20 mi/wk, low due to lots of swimming (20,000 yd/wk) and some cycling (70 mi/wk). I've never tried to be a pure runner, mostly b/c I just don't enjoy it that much.
I get PF every few years, and IT band issues that come and go. Mostly gone past few years. Also got ball of foot pain last year that luckily healed. Was not indicated in imaging at all, but was there during exam. This year so far so good. These are never mid-run injuries like a stress fracture or rolled ankle would be. They crop up after usually the morning after.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [giorgitd] [ In reply to ]
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giorgitd wrote:
Yes, reduced very significantly. The t-test here is the comparison between CON and MAX shoes for a single speed. At 10 km/h (AND for 14.5 km/h), runners in the MAX shoe experience a greater impact peak force. How significant? The t-test says '0.001'. This means that, if the same study were carried out 1000 times, only once would the results be reversed (i.e. the CON providing the greater impact force 1 time in a thousand). This is how science/statistics is done. Typically,a p value of 0.05 or less is considered a 'significant difference' from a statistical POV - i.e. the same result 95 times out of 100. There are statistical models behind this calculation that take into account the mean values, the standard deviations (deviation from the mean values) and the number of observations. Now, does a peak impact force of 2.25 x body weight cause more injuries than 2.01? That is not part of this analysis/study. BUT, according to the t-test value, in this study (i.e. these mean values, these standard deviations, these observation numbers), yup, 2.25 is very significantly different than 2.01. That may not be what you're after (if you're trying to predict injury frequency/intensity from peak impact), but the peak impact forces are different.

Thanks for the discussion. You're obviously more familiar with this sort or area than me.

Is 2.25 to 2.01 a ratio you are using for the purposes of discussion or specifically what we are talking about at 10km/h in the Hoka ? If it is not the ratio in that instance then what is the correct ratio.
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Re: Cushioned shoes increase leg stiffness and amplifies impact loading [OddSlug] [ In reply to ]
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Have a look in Table 1, next to last line on the right (14.5 km/h). Running in CON delivers a max force of 2.01 in units of BW, so body weight. Running in MAX has a max force of 2.25 BW. The numbers in parenthesis next to each value are the respective standard deviations - essentially the variability of the results. The most RH column says '0.001***'. That is the t-test result of comparing the CON and MAX max force results and imply that the CON max force would be less than the MAX max force 999 times if the experiment were repeated 1000 times. So, these results indicate high confidence that the MAX max force is bigger than the max CON force. But that does not mean that the difference results in differences in injury rate or injury type or injury location or...anything else. Just a statistical evaluation comparing the max forces.
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