Sample size of only 15 and heavily skewed - in this case female. This might be true (perhaps for females but not males - yes, there are real differences - or true for neither) but little can be generally concluded based on such a small, heavily skewed, sample size. Quadruple the sample size and even out the female to male ratio, then we might have something to talk about.
If I have recently been diagnosed with flat feet
That can't be cured right away.
I can run in the competition with flat feet 10 km and expect to win considering that one lap I run in 90-92 seconds
too small sample size, let's look at 100, 200 , 1000 . top placers in olympics, world champs, and see who stays healthy and who has success.
It's like saying walking on a carpet is as stressful as walking on a bare floor. The whole western world disagrees.
This amounts to a pilot study that provides just enough evidence to guide further study. It’s sufficient to generate a falsifiable hypothesis that larger, adequately powered randomized trials could evaluate, controlling for variables like footwear, mileage, running speed, runner weight, temperature, etc. No way to blind the studies though, which reduces evidence quality considerably.
This really couldn’t be considered even a pilot study for competitive runners at fast paces, who were unexamined and could conceivably generate different forces on different surfaces. It’s about as useful as Malmo’s anecdote, which is the equivalent of saying “I smoked 77,000 cigarettes and lived to a ripe old age so smoking has no effect on longevity.”
So light up and hit the asphalt!
I run trails because the scenery is pretty and the world is your toilet. Not because of potential injury reduction.
I downloaded the published study and read it. They made two obvious statistical errors, one in interpretation of their results, and one in methodology. This is the type of study that should probably be completely ignored. Unfortunately the internet picked it up and now people are talking about it.
In interpretation, they made the common mistake of concluding that there is no difference on the basis of not finding a statistically significant difference. This is just the wrong way to interpret the results. This error is logically equivalent to not collecting any data at all, being unable to detect a difference, and then concluding that there is no difference. This is a stats 101 error.
In methodology, the paper claims they did a one-way ANOVA, which means that they did not account for differences among runners. If you look at the pictures of the data they provided, there is a large amount of variation among runners in the variables they collected, but they didn't account for this in their statistical analysis.
Some further thoughts:
They measured 6 acceleration variables, and the average on the paved surface was higher than on dirt in all 6 of them. They were higher on paved than on gravel in 5 of the 6, and equal on the other one. Some of the values are 5-10% higher on paved. This seems to me like an amount that could potentially make a difference in injury rates.
The accelerations varied by a factor of 2 among the different people. I'm guessing this has to do with weight.
carmine9 wrote:
Fewer people get hit by cars on the trails
Just today I was jogging home from the park when I got injured and had to walk. The only sign of life on the long block was a black van idling.
Nobody greets anybody on forest trails (except once when I wore a t-shirt saying "Jeep Off Road Adventures").
MyAchilles' wrote:
Sample size of only 15 and heavily skewed - in this case female. This might be true (perhaps for females but not males - yes, there are real differences - or true for neither) but little can be generally concluded based on such a small, heavily skewed, sample size. Quadruple the sample size and even out the female to male ratio, then we might have something to talk about.
These comments go to show how little Letsrunners know about exercise science.
Getting +30 people to participate is nearly impossible for these researchers.
Most runners are female. Heck, most people who work out are female, so that is going to skew the study.
These studies are not useless. As long as the researchers provided specifics on how they made this study, it should be repeatable. It can be redone, and a meta-analysis can be made from it.
coachcommentsnicely wrote:
MyAchilles' wrote:
Sample size of only 15 and heavily skewed - in this case female. This might be true (perhaps for females but not males - yes, there are real differences - or true for neither) but little can be generally concluded based on such a small, heavily skewed, sample size. Quadruple the sample size and even out the female to male ratio, then we might have something to talk about.
These comments go to show how little Letsrunners know about exercise science.
Getting +30 people to participate is nearly impossible for these researchers.
Most runners are female. Heck, most people who work out are female, so that is going to skew the study.
These studies are not useless. As long as the researchers provided specifics on how they made this study, it should be repeatable. It can be redone, and a meta-analysis can be made from it.
Okay Mr. Exercise Science expert. Some of us on here know statistics. Sample size in this study and many physiology studies are way too small to make an accurate assumption of population. Difficulty of sampling does not make a sample accurate. I have stated in my salad days decades ago I worked on Consumer Price Index. I am not going to state the sampling process. A private corporation about 15 years ago attempted to replicate what U.S. Department of Labor, Bureau of Labor Statistics does on C.P.I. and P.P.I. Trust me, sampling is difficult. No one legally has to answer any questions but employees of Department of Labor are expected to obtain compliance. Hundreds of employees interviewing thousands of people every day seven days a week. Just think if C.P.I. or P.P.I. were based on a sample of 15?
teapot willy wrote:
This is the type of study that should probably be completely ignored. Unfortunately the internet picked it up and now people are talking about it.
Unless the difference in hardness of these surfaces is significant compared to the cushiony softness of the running shoes - or even the variation in their cushiony softness - there is nothing for these studies to investigate to begin with. Ignore the entire topic.
If you're a serious princess, start by investigating which soft cushiony mattress best flattens out that pea.
coachcommentsnicely wrote:
These comments go to show how little Letsrunners know about exercise science.
Getting +30 people to participate is nearly impossible for these researchers.
Most runners are female. Heck, most people who work out are female, so that is going to skew the study.
These studies are not useless. As long as the researchers provided specifics on how they made this study, it should be repeatable. It can be redone, and a meta-analysis can be made from it.
"you guys just need to understand that exercise science studies are typically this awful and not apply your higher standards from other fields. This is the best we have. So do what all of us exercise scientists do - remember the study's conclusions, and forget about the limitations that made those conclusions impossible to draw in the first place. Like this: 'A study showed there is no difference in injury risk between running on trails and on paved streets!'"
EZ10Miler wrote:
versatile wrote:
I am amazed how many people here avoid trails altogether because of the potential unevenness!
But then again, I see people running on the street in traffic because they don't feel confident to navigate sidewalks.
It's like gym bros who only worry about aesthetics in the mirror but are not actually strong in a functional sense. What's it like to be trapped on smooth, flat roads? Most here should take a break from focusing on pace every once in a while and have some fun engaging body and mind on an uneven trail! I feel like the typical LRCer is a joyless pace slave and that makes me sad.
You're creating an argument where there is none. Most runners will run on a various surfaces if given the chance, it's just that most find it easier to hit the roads and bike paths because most people don't live close to miles and miles of dirt trails. I mean trails are great but even on the best trails around me to get more than 10M I'd doing a number of loops.
It's best to mix it up, roads, trails, paths, and tracks- even treadmills.
Bro I was reading comments saying how they deliberately avoid trails for one reason or another. I think it's a bummer that people miss out
versatile wrote:
coachcommentsnicely wrote:
These comments go to show how little Letsrunners know about exercise science.
Getting +30 people to participate is nearly impossible for these researchers.
Most runners are female. Heck, most people who work out are female, so that is going to skew the study.
These studies are not useless. As long as the researchers provided specifics on how they made this study, it should be repeatable. It can be redone, and a meta-analysis can be made from it.
"you guys just need to understand that exercise science studies are typically this awful and not apply your higher standards from other fields. This is the best we have. So do what all of us exercise scientists do - remember the study's conclusions, and forget about the limitations that made those conclusions impossible to draw in the first place. Like this: 'A study showed there is no difference in injury risk between running on trails and on paved streets!'"
But it doesn't say this at all.
My unsubstantiated theory is that running on pavement is harder on the knees for runners who haven't put in sufficient volume over sufficiently many years to have strong lower legs, but for anyone who has and is running even moderately fast, pavement is a lot easier and a lot less injury prone. I basically always run on pavement or well-conditioned gravel if it's available.
Also, there's a noticeable difference between running on asphalt and running on concrete or paving tiles. Asphalt is basically the best surface to run on from my point of view.
Cross Country Runner wrote:
It's like saying walking on a carpet is as stressful as walking on a bare floor. The whole western world disagrees.
I much prefer walking on a bare floor, and so does everybody else in the country where I live, where carpet is unheard of.
Carpet is a US thing. Everyone else hates it.
varicela wrote:
My unsubstantiated theory is that running on pavement is harder on the knees for runners who haven't put in sufficient volume over sufficiently many years to have strong lower legs, but for anyone who has and is running even moderately fast, pavement is a lot easier and a lot less injury prone. I basically always run on pavement or well-conditioned gravel if it's available.
Also, there's a noticeable difference between running on asphalt and running on concrete or paving tiles. Asphalt is basically the best surface to run on from my point of view.
To clarify - I've never tripped on a tree root or slipped on sand while running on pavement. For me the risk of twisting an ankle, particularly when running in the dark, outweighs all the other stuff.
It's interesting that people will ding this study as being useless because it is focused on hobby joggers, yet trumpet the Vapor/AlphaFly studies as the gospel, despite them being focused on non-hobby joggers.
The study authors do not say that they measure injury risk. They write that the biomechanical measures they made (loading forces) have been associated with running-related injuries in prior studies. The authors also emphasise the need for further research; in their discussion, they write: "Further research is warranted to understand the importance of non-axial shock attenuation, especially as it relates to RRIs [running-related injuries].".
Therefore...
This study did not examine injury risk. The media article made it about injury risk. The OP inadvertently emphasised the media article's focus on injury risk. Pointless banter followed.
teapot willy wrote:
I downloaded the published study and read it. They made two obvious statistical errors, one in interpretation of their results, and one in methodology. This is the type of study that should probably be completely ignored. Unfortunately the internet picked it up and now people are talking about it.
In interpretation, they made the common mistake of concluding that there is no difference on the basis of not finding a statistically significant difference. This is just the wrong way to interpret the results. This error is logically equivalent to not collecting any data at all, being unable to detect a difference, and then concluding that there is no difference. This is a stats 101 error.
In methodology, the paper claims they did a one-way ANOVA, which means that they did not account for differences among runners. If you look at the pictures of the data they provided, there is a large amount of variation among runners in the variables they collected, but they didn't account for this in their statistical analysis.
Some further thoughts:
They measured 6 acceleration variables, and the average on the paved surface was higher than on dirt in all 6 of them. They were higher on paved than on gravel in 5 of the 6, and equal on the other one. Some of the values are 5-10% higher on paved. This seems to me like an amount that could potentially make a difference in injury rates.
The accelerations varied by a factor of 2 among the different people. I'm guessing this has to do with weight.
Are you able to share the full PDF here? I’d like to read the paper.