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Step Frequency, Clinical estimate of leg stiffness left/right differences

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Griff, Aug 3, 2010.

  1. Griff

    Griff Moderator

    Members do not see these Ads. Sign Up.
    Moved these from the Barefoot thread as requested by Ian and Simon, I hope I got it all, Mike ( helping a snowed under Admin.)

    I've currently got a Spooner-inspired n=1 study going on with a pretty decent runner I saw at the start of the week. Long story short -> history of non specific soft tissue problems at knee level (all diagnostic imaging clear) and doesn't like the idea of orthoses (you know the type of athlete I mean). His physio and trainer are both present at the assessment. Of note was a rather long stride for his height, and a fair bit of CoM vertical excursion as a result.

    So thinking experimentally: long stride = decreased leg stiffness = potential decrease in performance and increase in soft tissue injury. Recommended they try and conciously shorten their stride length and lets see how things are in a couple of weeks. I could like like a total hero... or maybe just a worthless tosser that is from London...

    If you are going to see a potential nightmare of a patient like this it may as well be after spending a weekend watching Spooner on a pogo stick or running around a conference room with his tummy banana sticking out...
    Last edited by a moderator: Aug 10, 2010
  2. Re: Barefoot Running Debate

    No, that was an artificial cock banana- rugby player- remember? I'll be interested to hear of your results.
  3. Dana Roueche

    Dana Roueche Well-Known Member

    Re: Barefoot Running Debate

    Ian, do you know what his stride rate is? It should be pushing 180 per minute.

    "Exercise physiologists Jack Daniels, PhD monitored the stride rate, stride lengths of the athletes in the 1984 Olympic track and field competitions. It was found that competitors in the shorter distances had longer stride lengths. Female stride lengths varied form 4 feet 10 inches in the marathon to 6 feet 8 inches for the 800 metres. Male stride length was 6 feet 2 inches during the 10 kilometre race to just over 7 feet 9 inches in the 800 metres.

    In contrast, the stride rate did not vary significantly. Stride rates for all events, for both men and women, fell between 185 and 200 steps per minute.
    Reference: Hoffman, K (1971). Stature, leg length and stride frequency. Track Technique, 46: 1463-69.
    Reference: Rompottie, K (1972). A study of stride length in running. International Track and Field. (pp.249-56)

    Other studies have shown that elite marathoners have a very consistent stride rate of 180 per minute. Given a constant stride rate, their speed is regulated by stride length.

    The simplest way to work on shortening stride length is to increase stride rate.

    My own stride rate is very consistent at 176 per minute. It doesn't matter what my speed is, whether I'm on an incline, decline or flat. But.... that is when wearing traditional running shoes. When I wear Vibrams, my stride rate is consistently at 180 per minute. I'm willing to guess that my body wants to make sure that my stride length is short enough to stay clear of landing on my heels.

  4. Re: Barefoot Running Debate

    It's not the stride rate, but rather the stride length that is significant in leg stiffness, but if you want to maintain a constant velocity then if you shorten stride length, step frequency needs to increase.
  5. Griff

    Griff Moderator

    Re: Barefoot Running Debate

    Hey Dana - no I do not know what his stride rate is I'm afraid. But I'd hazard a guess that it fell quite a bit short of 180. Is there a reference/rationale for this figure at all or is it just commonly accepted practice?

    Thanks for these references do you have a copy of them you could share at all? I have done a fair bit of reading on stride frequency and length - some attached below for interest.

    I agree - the two are fundamentally linked. By asking him to conciously shorten his length he will obviously increase his rate. I may get some figures off of him when I see him in a few weeks.

    Attached Files:

  6. Dana Roueche

    Dana Roueche Well-Known Member

    Re: Barefoot Running Debate

    The magical stride rate of 180 is the number that has been most connected with Jack Daniels himself who is the Head Distance Coach at the Center for High Altitude Training Center in Flagstaff, AZ. He published a book, Daniels Running Formula which goes into great length about stride rate and 180. I don't know if he references studies to prove the 180.

    As a lay person, I really don't have a list of references I can quickly access. I wish I could remember the study I recently read that used video to capture the stride rate of many elite marathoners and demonstrated how consistent they were around the 180. If I find it I will post it.

    From my own experience, I have found the easiest way to increase my stride rate was to focus on spending as little time as possible with my feet on the ground. In order to do that, you can't afford the time it takes to first land on your heels, roll to your toes and push off. You need to land on your midfoot at most and try to push off almost immediately. That naturally forces you to shorten your stride length.

    If you do a search on the internet on stride rate, you will find a ton of articles that reference a stride rate of 180. I'm sure there are as many debates about whether that is really the optimal number. What is important is that if your client has a stride rate in the 160's or lower, no one will argue that it is too low, therefore stride length is too long.

    Thank you for the references you attached, I'll enjoy reading them.

  7. Griff

    Griff Moderator

    Re: Barefoot Running Debate

    Thanks Dana - appreciate your comments. I'd say his stride rate was closer to 160 than it was 180 now I think about it. I will do a bit of reading around optimum stride rates (as I'm guessing it will be a range, dependant on factors such as height, amongst other things). Probably worthy of its own thread, although bears some relevance on the barefoot running debate I'd say.
  8. Dana Roueche

    Dana Roueche Well-Known Member

    Re: Barefoot Running Debate

    WOW, the first reference I opened up talks about "Many studies have demonstrated that contact time is a key factor affecting both the energetics and mechanics of running. The purpose of the present study was to further explore the relationships between contact time (tc), step frequency (f) and leg stiffness (kleg) in human running."

    This is the first line in the abstract from the JB Morin et al. study.

  9. Dana Roueche

    Dana Roueche Well-Known Member

    Re: Barefoot Running Debate

    Ian, I'm not sure height has much to do with it. I'm 6' 4" and as I mentioned my stride rate is 176 with conventional shoes, 180 with Vibrams.

    It yet another study that I read but can't remember where, stride rate had more to do with the level of experience the runner has. For example, novice runners where in the 160 range and with experience moved towards 180. I think the theory was that as you adapt, you become more efficient and your rate increases because it is more efficient.

  10. Griff

    Griff Moderator

    Re: Barefoot Running Debate

    It was my understanding that most runners tend to adopt an optimum stride length/rate almost randomly, but I will have to do some more reading around it, as most of my previous reading has ben in relation to leg stiffness. I will delve into the research over the next few days if I get the chance.

    Cheers Dana
  11. Dana Roueche

    Dana Roueche Well-Known Member

    Re: Barefoot Running Debate

    Ian, I thought that as well but I started reading about this and found an article by Ed Eyestone who used to be an accomplished US marathoner. He explained that when he was in his prime, his stride rate was 184. When he measured recently, it had dropped into the 160's so he worked on improving it.

    Over the past few years after I stopped ultramarathoning, I noticed I felt like I weighed 300 pounds when I was running. It used to feel like I was gliding along and I couldn't figure out why I felt like a slug. A running friend asked me to measure my stride rate. I found it to be 162! The next day I focused on contact time and it instantly popped back to 176! I didn't even have to work on it, it was almost instantaneous. Since everything fell in place so quickly, I would think that you do want to adopt an optimum stride length/rate. The problem is that sometimes that might not happen.

    I think the reason mine dropped so low in the first place was that I spent years running at a pace of 10 or 11 minutes per mile. The point was to learn to run that slow to be able to run 100 miles at a crack. 10 min pace for 100 miles is actually very fast. Being tall, my stride length is going to be long so my guess is that for 10 min pace, my rate had to drop to accommodate long legs.

    Once my stride rate popped back to 176, my pace shot up and the wonderful thing is my HR stayed flat suggesting that I almost automatically had an increase in efficiency.

  12. Re: Barefoot Running Debate

    I think that you have already answered yourself - leg stiffness is affected by stride length. So if the CNS is functioning well and no outside influence ie the thinking brain, one way for the body to tune leg stiffness will be thru stride length changes.

    But thie big problem is the Brain, and once again the random number of 180 will be good for some bad for others dependent on the persons original Kleg.
  13. Re: Barefoot Running Debate

    It will take a few reads about to print it out.

    Great stuff, one question who wrote it ? I could see it anywhere.
  14. Re: Barefoot Running Debate

    Don't know.
  15. Re: Barefoot Running Debate

    Ian, can you pull a full-text of this please?
    Preferred and optimal stride frequency, stiffness and economy ...
    by I Hunter - 2007 - Cited by 9 - Related articles
    Preferred and optimal stride frequency, stiffness and economy: changes with fatigue during a 1-h high-intensity run. Iain Hunter Æ Gerald A. Smith ...

    They are talking about optimal stride frequency in the order of 1.45 hz. As we know hertz (hz) is then number of cycles per second so 1.45 x 60 = 87 strides per minute. Now, I think that Dana is talking about steps rather than strides, two steps per stride, which would give us (1.45 x 2) x 60 = 174 steps per minute. But we need the paper to see how they defined stride frequency.
  16. Griff

    Griff Moderator

    Re: Barefoot Running Debate


    Attached Files:

  17. Re: Barefoot Running Debate

    I just clicked on the PDF button and the full text comes up ;)
  18. Griff

    Griff Moderator

    Re: Barefoot Running Debate

    That's wierd - didn't do that for me initially - but just went back and tested it and it did?!? I figured it might be as I had a copy on my machine... ah well - we've all got a copy now!
  19. Re: Barefoot Running Debate

    Of interest:
    http://www.cchs.clay.k12.ky.us/Science/Mhawkins/Weyand - Faster Top Speeds.pdf
    From the first link: "Of the three mechanisms available to reach faster
    top speeds expressed in Eq. 5, we found that runners
    utilize stride frequency to a limited extent, support
    forces predominantly, and contact lengths essentially
    not at all."
  20. Re: Barefoot Running Debate

    Been finking, what the authors are basically saying here is that faster running is associated with higher ground reaction forces. Am I missing something? This is just Newtons 2nd law: f=mv So.................? Yeah? And? So? What?
  21. Dana Roueche

    Dana Roueche Well-Known Member

    Re: Barefoot Running Debate

    Simon, Ian, Mike, yes when I said I run at 176 strides, I meant steps in this case. I find the two are interchanged quite a bit. Not that confusing though as long as a number is associated with it. Whether I see 87 or 174, it's obvious which is being discussed. In reality, when I measure myself, I count how many times one foot hits the ground in 30 seconds then multiply by 4. Kind of crude but close enough for my purposes. I try for 45 which translates to 180 but it is usually 44 or 176. For all I know, it could be somewhere in between.

    I find the Hunter, Smith study really helpful. I have read a lot of debates on optimal stride rate or step frequency. This is the first time I've seen O2 uptake compared to stride frequency.

    What we have to be careful with is that even though the study found Optimal Stride Frequency to be 87 strides or 174 steps, it is a MEAN and the subjects used to measure this were athletic but not close to being elite athletes based on their average VO2 max of 59.1. Elite athletes have a VO2 Max or 75 to 85 for males and less for females with people like Lance Armstrong in the 90's.

    It is possible that a different optimal stride frequency for elite athletes might be found such as 180 or above.

  22. Re: Barefoot Running Debate

    I agree, step frequency will vary between individuals. The interesting thing from the Weyland study http://www.cchs.clay.k12.ky.us/Scien...p Speeds.pdf is:

    At top speed during level running, the regression
    equation for our 33 subjects indicated that stride frequency
    was 1.16 times greater for a runner with a top
    speed of 11.1 vs. 6.2 m/s. The relatively weak relationship
    between top speed and maximal stride frequency
    was the result of runners with different top speeds
    repositioning their swing legs in similar periods of
    time. Because the swing period comprises threefourths
    of the total stride time at top speed, similarities
    in minimum swing times greatly minimized the extent
    of possible variation in maximal stride frequencies.
    Minimum swing times from our regression relationship
    (Fig. 3) were only 8% or three-hundredths of a
    second shorter for a runner with a top speed of 11.1 vs.
    6.2 m/s. As an illustration of this result, our slowest
    subject, with a top speed of only 6.2 m/s, was able to
    reposition her leg for her next step nearly as rapidly as
    the fastest 100-m sprinter in the world (0.344 vs. 0.320
    s) although she could only run half as fast. Despite the
    widespread belief to the contrary (11, 14, 15, 17, 30), a
    more rapid repositioning of limbs contributes little to
    the faster top speeds of swifter runners.

    Which relates to a step frequency of 174.5ish for our mortal with a 187.5 ish for the fastest man alive at the time of this study. Interesting that the authors didn't see this as significant. So if we compare 174.5 steps per minute over ten seconds with 187.5 steps per minute over 10 seconds and an average stride length of X, which one crosses the finish line of the hundred metre final first? This fag packet calculation doesn't take into account contact times, but as the authors said- swing times account for 3/4 of the stride time. All other factors being equal etc.... Instead, they think that the force applied to the ground is the key to running faster because it gives a better correlation- cause and effect... No brainer. Hint: if they'd have included shear forces they might have got a perfect 1 in their correlation, so long as Newton was right. Hint No.2 its called a law for a reason.
  23. Re: Barefoot Running Debate

    P.S. take a step frequency of 174 per minute then multiply it by 1.16. You get a step frequency of 201.84 per minute. Divide by 6, that gives you the number of steps in 10 seconds. Multiple by step length, that gives you the distance travelled in 10 seconds time... Hundred metre sprint finals last roughly 10 seconds. Metabolic cost over this kind of distance and time don't really count. Y'all see.

    I need to read the Weyland et al. paper again because after a couple of reads, I think their conclusions are completely hatstand.

    That said, if your man Jack Daniels is right and all the elites were all functioning about 180 bpm in 1984 then something else sets the athletes apart, otherwise the 10,000 metre runners would have been running at 100m pace. I couldn't find any scientific papers published by Jack. But they have to be taking much shorter strides in the longer distances, which equals stiffer legs, which might reduce muscular work, which might improve metabolic cost. Is it just me or is the human machine ace?

    Out of interest, when rave and dance music became pervasive, the records tended to have around 120 BPM, just an observation. Is this the optimal frequency for the human machine when dancing? What about walking?
  24. Re: Barefoot Running Debate

    Without becoming too anal, it's not obvious to anyone trying to read and interpret your writing. Steps are not the same as strides. And a stride rate of 87 and 174 are clearly very different. Moreover, without a known time period numbers such as 87 are quite meaningless. Since the hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon, viz. gait, we should probably all be talking in terms of cycles per second, i.e. strides per second- hertz. Lets all try to be clear and accurate in our descriptions. I'm as guilty as the rest, but lets try and put it right.

    I should like to thank Prof. Kirby for his influence upon the tightness of my anal sphincter :D;):drinks
  25. Re: Barefoot Running Debate

    Which gets thrown all out of wake by Drum ´n´base 4/4 with the off beat.

    Give a shout out to the Plymouth massive.....

    I digress.......
  26. Re: Barefoot Running Debate

    I don't want to become Peter the prolific poster, but... leg stiffness is supposed to increase with velocity, but the velocity decreases as the race distance increases... my brain just turned to jam (again) = someone wrong, somewhere.

    Goodnight though...
    So long
    Well there's a lady that knows
    All that glitters is not gold, she said
    "Don't play that awful song
    Don't play that awful song, cos then we'll know
    that the party has gone on too long."
    I said, "This stairway ain't to heaven
    This one's to oblivion"
    She said "You get too drunk, you get too high
    Oh tell me why?
    Sod this, I'm going home on my own."
    So long

    The Wonderstuff. Tune.

    "Swedish possie- this is your shout out."
  27. Re: Barefoot Running Debate

    I've said it before, and I'll say it again: anything with 'n' in the middle is cool in my book.

    Fish 'n' chips
    Rock 'n' roll

    etc, etc...
  28. Re: Barefoot Running Debate

    One more before bed... One of you night owls do me a favour: Watch a video of Bolt breaking the hundred world record at the World Champs. Count his number of strides in 9.58 seconds. Then tell us his average stride frequency in Hz.....

    So long.
  29. Re: Barefoot Running Debate

    An external source says - "he took 41 steps in the race which equates to 4.28 steps per second, and an average step length of 2.44m"

    I'm not sure if they mean steps or strides though:bash: 4.28 x 60 would equal 256.8 steps per minute. Chipping. Either way, it don't add to 180 steps per minute, not even close. I guess it depends on whether you are "one of those runners that goes round and round and round" Blur- park life. Or, if you are the fastest man on the planet Earth.. I know which excites me more.
    Best wishes,
  30. Re: Barefoot Running Debate

    Ive been thinking about this - say you look at an event 10 000 m track, in general it´s like the people have come from the same mold- same body types, similar height, similar stride length probably similar Kleg.

    Then we look at the 100m- 200m very different body types to the 10 000m people but again similar with the rest of the 100m - 200m guys and probably similar kleg.

    so like fitness Kleg will be specific which we I guess already new, but then you get the mold breakers.

    Bolt and Michael Johnson could not be more different in running tech, body type stride length etc - But fast over 200m , would have been a great race

    same thing for the 10 000 Haile G little dude who sometimes looks 30cm shorther than the rest of the field, leaves them running for 2nd.

    Not sure it means anything buts thats what I was thinking about on the way to work this morning

    so I guess there is no normal but like everything else zones and optimal.
    and each distance will have a hertz measurement for the average.
  31. Re: Barefoot Running Debate

    Of course because stride frequency changes with speed.
  32. Griff

    Griff Moderator

    Re: Barefoot Running Debate

    Dude, when was the last time you watched a mens track 10,000m?? It's all about Kenenisa Bekele now - hasn't been beaten over 10k for the last 7 years!
  33. Re: Barefoot Running Debate

    Trying make a body type example Michael Johnson has not run a 200 0r 400 m in a long time as well.
  34. Re: Barefoot Running Debate

    Out of interest at Beijing, Bolt took 41 steps to run the race; everyone else took 44 steps. This means they had higher step frequencies, yet they were slower because his stride length is huuuuuuuuge.

    10,000m? Is that the one where they go round and round and round and round, so you can pop out for a fag, make a brew then come back and watch them go round and round and round again, pop out to the shops, come back and then watch someone finish, have read of the paper and then watch the rest finish?
  35. Griff

    Griff Moderator

    Re: Barefoot Running Debate

    I wouldn't class 10,000m in under 27 minutes as round and round and round but compared to Bolt I take your point. However, just watch the last 2 laps of a 10k and I dare you not to be impressed. When the bell goes Bekele finds something in his locker that no-one else has, and looks like a man fresh out the changing rooms. It's incredible. I think I'm right in saying that his time for the second half of his 10k in Beijing was faster than any British athelte has ever run a stand alone 5k in. Still not impressed? Ah I give up...

    If I get some time today I may look into Bekele's stride stats.

    Of interest? http://speedendurance.com/2009/09/16/who-wins-kenenisa-bekele-vs-usain-bolt-at-600-meters/
  36. Re: Barefoot Running Debate

    If I'd have known I had that long, I'd have added a shower to my list of activities you can do during a 10000m race ;-)
    Been looking already, couldn't see them.

    Did find this:

    and this:
  37. Re: Barefoot Running Debate

    Ian as an aside do you take holidays during the olympics ?

    Had a mate who did and thougth that Guinness would be beverage to go with the 2 weeks- His a big man to begin with, he put on 18 kgs or something like that.

    When the next Olympics came around he suggested to his wife he may take a couple of weeks off again.... well lets just he went to work.
  38. Griff

    Griff Moderator

  39. Griff

    Griff Moderator

    Re: Barefoot Running Debate

    I don't take a few weeks off, but I make sure I'm never working for events that are must see - i.e. most of the track finals. Very nearly went to Beijing but it didn't work out at the last hour - hope to be able to get close to the action in 2012. The office I'm sitting in at the moment is a 12 minute tube journey away so I'd be a bit miffed if I missed out!

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