spencersh wrote:
Malmo,
That's the thing with the impact transient. It's regardless of speed. Even if matched for the same exact speed when measuring, some runners have greater impact transients than others even if the peak GRF is the exact same.
You seem engaged in a real discussion. Do you have any examples impact graphs at varying speeds, and more germane to this thread, impact graphs of elite runners at varying speeds?
"You're the one with the stash of dirty pictures!"
Early lead for post of the year!
For the record, real foot biomechanics experts see a much higher injury correlation with frontal plane deformities than with rearfoot vs. forefoot running style. (And no, I won't provide references, I'm busy treating injured patients. Obamacare has me behind the 8-ball)
malmo wrote:
OK, Lieberman has said that many times.
"one hypothesis is that heel striking contributes to some of these injuries."
He goes on to say. "We emphasize though, that no study has shown that heel striking contributes more to injury than forefoot striking.”
Is there any reason why the discipline of biomechanics has a whole injury theory in running like this, when there are no studies that support it? I understand that scientific discovery has to start somewhere ... but it seems to me you guys are putting the cart before the horse.
spencersh, do you see what I mean by horse before the cart?
Most theories are born out of an observation, like a rash of injuries among heelstrikers that can't be explained. You then look for empirical evidence that might explain the observation of a rash of injuries, and come to a conclusion and have others review your work. Some researcher might look at that impact spike and say, "hmmmm, that might be it." then take further steps to codify and prove the theory.
The problem here is that you people (maybe not you specifically, but we know who you people are. We have files.) have an injury theory that is not based on any linkable observation, nor do you have any studies to support the theory. In this case, the researcher who observed that impact spike is fabricating a seminal observation (rash of injuries that doesn't exist) as the grounds for a theory. I'm sorry, but there's nothing scientific about this process. This is the kind of shit drunk people say at bars, why does it pass as an academic exercise in your field?
please consider wrote:Knowing full well that running more means de facto increasing the risk of all types of injury for the most basic of statistical reaons?
Fact or opinion?
please consider wrote:How long do we need to endure your hate for the fact that your dreams did not come true ?
Sport can be cruel. Good coaching should be dedicated to understading this reality to help athletes deal with it.
I'd be willing to bet that I achieved far more in running that you ever did or will.
spencersh wrote:THere's a reason he focused on the initial peak or the impact transient.
You seem focused on the total GRF which is normal for those outside the field of biomechanics to focus on. It's a common mistake.
However, if you are familiar with biomechanics research for the past 20+years you'd realize that EVERYONE focuses on the initial impact transient.
Why? Because if you look at correlation studies, prospective studies, or retrospective studies on injuries and running, they almost all show that peak GRF doesn't increase injury risk. It doesn't matter whether it is stress fractures of the foot, shin, etc. or runner's knee or any other running injury. Peak GRF rarely correlates with injury.
What does correlate is the impact transient. It's been shown in a variety of studies from stress fractures to a variety of other injuries that runners with higher impact transients have a much higher injury risk than those who don't.
That is why Lieberman (and everyone else) focuses on the impact transient. There's a whole injury theory in running biomechanics that that initial peak (which is present in heel striking and not in forefoot) is a major cause of a variety of injuries.
Again, this is not new. We've known this and focused on it for a while.
It's not some crazy conspiracy of Lieberman using selective data to get his results. He focuses on impact transient because that is what everyone focuses on when lookng at GRF.
Please provide a credible study that shows this, not a paper citing a book by another minimal cutlist.
spencersh wrote:As for evidence, there was a large meta-analysis that just came out recently on GRF and stress fractures:
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T59-511KB89-3&_user=10&_coverDate=01%2F31%2F2011&_rdoc=4&_fmt=high&_orig=browse&_origin=browse&_zone=rslt_list_item&_srch=doc-info%28%23toc%234997%232011%23999739998%232841761%23FLA%23display%23Volume%29&_cdi=4997&_sort=d&_docanchor=&_ct=18&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=aed1405d5bc69e3cca8b14e3e31a41b1&searchtype=aWhat does it say in brief:
When you compare stress fracture and non-stress fracture runners. The peak GRF is NOT different between each group. The loading rate and impact transient IS different between each group. (the loading rate, average and instantanous is what Lieberman measured and found different in his study on footstrike...)
This is a paper citing some other studies. Please provide the links to the relevant STUDIES that prove your point so that we can take a look at them.
spencersh wrote:1.Heel striking causes an initial peak GRF/higher impact transient than forefoot running, regardless of speed.
2. The impact transient increases injury risk.
But we know #1 ans #2 to be correct.
Proof?
Hey doc, don't point fingers at me. You're the one with the stash of dirty pictures!
That's the first intentionally funny thing on this thread that has made me laugh out loud.
Its probably been said many times, but the quoting method on this forum has to be one of the most confusing things ever, often its hard to work out who is saying what.
I feel pretty safe saying that increasing how much you do any activity which has risks associated with it, will increase the possibility of negative outcomes. For running, more miles, more lifts, more strikes, more contractions, more rubbing, more use, more wear, more tear. You disagree? You looking to be eternal?
As far as achievement, I'll be glad to compare notes anytime. I think it will be hard to establish who is happier at the end of the day. And my pursuit of happyness is a pretty big achievement for me. Anyway, thanks for the encouragement. People who can run faster, jump higher or longer, or throw further, have always been a source of inspiration for me.
Just like people who know more, communicate better, have travelled more, have faced more hardship, have done more for others than I do or have done.
Btw, sorry I confused you with Malmo about calling bs. But you guys are playing tag team so I lost track for a minute.
"ELITE RUNNERS DO NOT HEELSTRIKE, END OF STORY" ???
Tell that to these Division 1 track and field runners running at sub 4:00 pace for men(!) and 4:40 pace for women:
http://www.jssm.org/vol9/n1/21/v9n1-21pdf.pdf
"During the initial data collection, 16 out of 20 runners (10 females and 6 males) exhibited a heel strike at the given speeds (Female subjects ran at 4:40 minute per mile pace (5.7 m·s-1), and the males at 3:59 minute per mile pace (6.7 m·s-1), speeds needed to qualify automatically for the 2007 NCAA Division I Indoor Track National Championships meet). Consequently, four additional males who were heel strikers were recruited and tested, giving a total of 20 runners. "
Looks like they did not have to look to hard to find elite heel strikers running sub 4:00 pace, did they?
Just out of curiosity ... did I miss anything important in the last 13 pages of ending the debate "...RIGHT NOW."?
Malmo,
I happily acknowledge, as per your post, you not meaning to hate. It sure looked that way for a while.
Maybe you have a very complex mind yourself as your shareable sense of humor indicates.
Cruel Shoes is an unusual title for something that talks about a pair of spikes working favorably to get world caliber PRs which you witnessed right up close. Unless it is clever product placement, and in that case the more to you.
Just relax and dont jump people. Your criticisms would be heard regardless. And I would not be surprised if they contribute to positive developments.
i was away wrote:
Just out of curiosity ... did I miss anything important in the last 13 pages of ending the debate "...RIGHT NOW."?
ABSTRACT:
Yes, two scientific studies that showed there were many elite heelstrikers, and one of the cultists completely fabricated a statement that one of the grounded debaters didn't make. A couple more cultists went on tilt. The number of elite heelstrikers continues to rise. The cultists are acting like 3rd rate lawyers and objecting to including any of them into the jury pool.
Other than that - same old shit.
malmo wrote:
Here is your scientific evidence.
http://www.ncbi.nlm.nih.gov/pubmed/17685722
re. thread talking about heel strike and study about rearfoot strike. Does this need clarifying? Intuitively they do not seem the same.
please consider wrote:
Cruel Shoes is an unusual title for something
Pop culture 101.
question2 wrote:
re. thread talking about heel strike and study about rearfoot strike. Does this need clarifying? Intuitively they do not seem the same.
Huh? Put me out of my misery.
HHH- Look up the studies your self off the meta-analysis. I don't care enough to look them up for you. They're all there. A meta-analysis looks at the studies done on the subject. Each is cited in the journal article and the majority say what I've been saying. I should know, I've published on the subject of GRF and injury risk.
Malmo- You said "
This is not true, otherwise heelstrikers would have higher injury rates than FFstrikers."
We have no idea whether heel striking causes more injuries or not because it has NEVER been studied. That doesn't mean it does or not. It has been studied that an impact transient leads to increased injury risk. So the statement is true. We don't know whether we can connect that to heel striking yet.
The reason it never has been studied is because a bunch of scientist 30yrs ago decided that (despite a few studies to the contrary) that heel striking was how EVERYONE should run.
So if you read studies on biomechanics, GRF, or whatever from the 80s through early 2000's most have a clause in the methods that say "All non heel strikers were eliminated from this study."
So no one has studied injury rates of heel vs. other foot strike.
What has been studied is injury risk of those with an impact transient and those without a large one. And that's shown that those with increase impact transient are at an increased risk.
We HAVE studied peak GRF (what you say occurs at 100ms). It's been studied a ton because initially people thought exactly what you did that it must relate to injuries. Well all the research shows it really doesn't.
The theory on the initial impact peak has NOTHING do with footstrike.
Researchers noted that all these studies showed that those who had a high impact transient were at a higher risk for getting injured. ALl these shoe innovations were designed to decrease that transient.
It just so happens that foot strike changes it. That's when people started wondering if foot strike could reduce injury risk.
That's where we are now. No one has done a comparitive study.
We don't know for sure if footstrike effects injuries. We have theory saying that it probably does. But it hasn't been studied.
We don't know the answer because a bunch of people ASSUMED that heel striking is correct and never tested that hypothesis to be true. Similar to what many people are doing in this thread.
Keep an open mind.
Also- why could the first 50ms/the initial peak be so important? Probably because of where the impact force is transmitted.
Look at where the body is when you reach the true peak at around 100ms. You are directly vertical. The peak forces are transmitted straight up basically.
During the initial touching of the ground, the foot is in front of the center of gravity and in a heel strike vs. a forefoot strike the direction of the force is different. Perhaps this plays a big role. We're trying to figure that out.
How the lower leg absorbs the force is important.
question2 wrote:
re. thread talking about heel strike and study about rearfoot strike. Does this need clarifying? Intuitively they do not seem the same.
Should I smack my forehead or my frontal bone when reading this comment?
spencersh wrote:
It has been studied that an impact transient leads to increased injury risk. So the statement is true. .
MAY lead. All that meta-analysis, with many limitations, found was a correlation between velocity of impact and stress fractures. Correlation is of course not causation. It is indeed interesting to note, this relationship between "impact transient", heel striking, and one type of injury. But again, this does not show beyond reasonable doubt that higher impact transient leads to more running injuries.
indeed. and i suppose you put a tunafish sandwich under each arm, one or two behind the ears and dont smell like any other guy! And it's economical too...