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Muscle Tuning - Soft Tissue Vibrations

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Asher, Feb 6, 2011.

  1. Asher

    Asher Well-Known Member

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    Hi All

    I am reading Benno Nigg’s new book Biomechanics of Sports Shoes and I’m having trouble understanding the vibrations of soft tissue compartments in regard to the muscle tuning paradigm. Below is my own dumbed-down version within my limited vocabulary. Can you tell me, have I pretty much got this?

    All materials (wine glasses, bones, soft tissues…) can vibrate. The frequency that each material / tissue vibrates at is different to another and this is called its ‘natural frequency’. In the body, it is bad for tissues to vibrate. The force that causes the material / tissue to vibrate is called the input signal.

    The natural frequency of soft tissues is 10-50Hz. For bones it’s 80-100Hz. With heel-toe running, the input signal is around 10-20Hz. So when running, it’s likely that soft tissues are made to vibrate at their natural frequency, a bad thing. This fact is registered by the CNS and the body reacts by tensing the muscles to increase the natural frequency of the muscle tissue. This is called muscle tuning. The aim is that the natural frequency and input signal frequency become more dissimilar and therefore the muscle tissue is not made to vibrate.

    As well as the body doing its own thing by increasing soft tissue natural frequencies, we can modify the frequency of the input signal by changing the hardness / softness of the running surface, shoe sole or orthosis. A hard material will increase the input signal frequency and a soft material will reduce the input signal frequency.

    Light and well trained people have soft tissues that vibrate with a higher natural frequency. Interventions will be aimed at reducing the input signal frequency so that the two are more different. This can be achieved with softer running surfaces / shoes / orthoses. And heavy and untrained people have soft tissues that vibrate with a lower natural frequency. So interventions are aimed at increasing the input signal frequency so that the two are more different ie: harder running surfaces / shoes / orthoses.

    Please feel free to pick this to pieces as that is the point of my post.

  2. Hi Rebecca -

    Sounds ok to me I´m still getting my head around it all as well.

    I´m looking at it this way

    If the impact signal frequency is the same or close to muscle then we will have resonance, this resonance is bad ( the vibrations Nigg) and the CNS muscle will change it´s activation of muscle to dampen the vibrations - this leads to fatigue.

    Fatigue is bad - possible overuse injuries increase and performance goes down.

    I´m at the min. trying to source a whole look of extra reading re Muscle Tuning, PM your email address and I post them to you as I get hold of them.

    I have 1 file that I can´t load up so there can be some reading to you in 5 min if you want.
  3. hamish dow

    hamish dow Active Member

    Isn't one of the problems that the surface under the shoe, ie the floor itself, a constant variable so the only time that one will get the range of vibrations you have posted would be in a lab? The real world and the constant variation of footwear and floor densities will too vary the levels of impact and the efficacy of orthotics if one is hoping for it to be able to attenuate vibration.
  4. Yes, 1 big problem is that the surface - shoe interface keeps changing and this leads to fatigue. The body can damped the vibrations and this is what adds the to fatigue of muscles.

    1st the fast twitch fibers then the slow get used.

    But the interesting this is that if the surface is more constant the body is better able to cope with the vibrations ie running on the road only

    Nigg states that heaver and fitter people should use a harder surface and lighter softer to reduce the resonance effect which is opposite to most peoples thinking. Ie the big guy who wants to start running to get fit maybe better of road running than running at the park on the grass.

    But it´s still earlier days here.
  5. Admin2

    Admin2 Administrator Staff Member

  6. Rebecca:

    Don't assume that just because Benno Nigg said it is true that it is true. After having read his latest book, "Biomechanics of Sports Shoes" while on the plane to and from Spain, I felt he was really trying to push his "muscle tuning theory" without paying much attention to other explanations for research observations. In addition, I felt Benno was really working hard within the book to try and discount the positive effects seen with foot orthoses. This was probably one of his more subjective books ever, lots of opinion without the research to back it up properly.

    I'm not impressed with the soft tissue vibration theories that he has and don't think this is of any significant clinical importance.
  7. davidh

    davidh Podiatry Arena Veteran

    Hi Mike,

    I haven't read the book, but I'll make a couple of comments about the info in your post if you don't mind.

    Big or small, it is easier to ambulate on hard surfaces. This is little to do with soft tissue vibration, and much to do with Newtons Third Law of Motion.

    Now a big guy running to get fit on a hard surface may well experience problems at some stage, because our feet haven't adapted for hard and flat.
    Hopefully he'll be wearing a shoe which allows for a more natural interface (for him) between the ground and his feet. Maybe he'll need orthotics:eek:.

    Maybe he'll run barefoot:eek:.

    I don't doubt that soft tissue vibration is an interesting observation. I agree with K Kirby though, and cannot see any clinical relevance.
  8. Interesting then that metabolic cost seems to be decreased when running on more compliant surfaces.
  9. So what your saying is that without reading a word on Muscle tuning and resonance of bone and muscle you have decided that there is nothing in it :confused::confused:

    David as you have probably not read anything re the following subjects whats you option on them

    preferred motion pathways
    leg stiffness (Kleg) modelling of gait......

    David I´m a big fan of continuing education which means an open mind and to read and discuss new ideas.

    if in the future I decide for myself there is nothing in muscle tuning at least I will have explored the subject.

    Seems odd to me to make your option up from 4 posts, each to there own.

    I also would see any clinical relevance if I had not explored the subject 1st.
  10. davidh

    davidh Podiatry Arena Veteran


    In my post I was very careful to point out "I haven't read the book, but I'll make a couple of comments about the info in your post if you don't mind."

    I made my comments from reading your post, is all.
    Clearly you do mind - I apologise.

    If there is any clinical relevance to Podiatry someone, preferably a clinician, will highlight the fact. I'd like to think they will do so on this forum.

    The concept itself is interesting - that's why I thanked Rebecca for starting the thread.

  11. Sorry David maybe a little harsh but this line......

    Which what I was trying point out how can you decide without reading, but my choice on tone was not the best sorry.

    Also sorry to all reading............
  12. davidh

    davidh Podiatry Arena Veteran

    No problems at this end - thanks for posting.

  13. question: how is leg stiffness (kleg) modulated? That is, there is obviously a neuromotor process from the foot impacting with the ground to the range of motion at the joints being modified: what is this pathway?
  14. Foot surface impact - input signal frequency of surface detected by CNS (my guess this frequency detection occurs from muscle resonance after the 1st impact)- CNS modifies muscle contraction- Joint ROM adjusts- change in leg stiffness.

    Thats what I´m thinking at the min.
  15. efuller

    efuller MVP

    I recall there being a Nigg paper showing that subjects changed the angle of the knee at contact when running with different surface or shoe. The person subconsciously chooses what there knee angle will be at contact.

    This data is appoint against preferred movement pathway. A person will "figure out" how much knee damping they want at contact. This could also explain the energy expenditure you mentioned earlier. When the knee is flexed more, on harder surfaces, the knee moments will be greater and more energy will be needed.

    Another reason that I don't like the preferred motion pathway idea is the observation of reduction of late stance phase pronation seen with the use of orthotics. If we preferred late stance phase pronation, we would keep it even when standing on orthotics.

    Just some thoughts

  16. Eric, thanks for your response. I get the gross modulation of leg stiffness via changes in joint movement; I was interested in the sensory input to muscle activation pathway. So, we strike the ground, we have a number of sensory nerve endings to choose from, then what.... i.e. how does the body, on the basis of the stimulation of sensory nerve endings, decide how much knee flexion is required? Pain avoidance is one option- right? But in the absence of painful stimuli, this must be a learned response. So lets say ground reaction force stimulates a number of Pacinian corpuscles http://en.wikipedia.org/wiki/Pacinian_corpuscle Next....?
  17. I should like to see a study comparing kleg in patients with neuropathy / anaesthetised feet versus non-neuropathic/ anaesthetised individuals. In the meantime, what might we learn from observations of neuropathic gait versus full sensory gait in terms of joint kinematics? Greater knee joint flexion, hip joint flexion, etc. = lower kleg. So on average do neuropathic individuals walk with a similar leg stiffness, a stiffer leg or more compliant leg than the fully sensate? Why is this?

    What about people without vision? How does vision alter Kleg? Any number of potential studies there.
  18. To be fair, in his book Nigg points to data which shows increased rearfoot eversion in some individuals in association with foot orthoses that were designed to create increased external supination. And studies in which centre of pressure some times moved medially and sometimes moved laterally in association with the same wedging condition (varus or valgus) among the subjects within the study. The cited studies we are familiar with, I'm sure. There is no sub-analysis of phasic changes in rearfoot eversion. However.... it is obvious that some people evert more during gait when wearing devices designed to reduce eversion. Why? preferred movement pathway? Injury / pain avoidance? Aren't these the same thing, just with different names?

    If not, how do we explain the observation of increased eversion with devices designed to increase inversion moments? The only other explanation I might give is that of a direct mechanical effect in which, despite the design, the orthoses directly increased external eversion moment. Oh man, I love them vectors.
  19. efuller

    efuller MVP

    I think the differnence is between motion and stress, or potential stress. Preferred movement pathway is motion. Pain or injury avoidance is more related to stress or potential stress. I agree with you in the thread on stores using video analysis and the guy who devleoped blisters and peroneal pain with the anti pronation shoe. Too much supination moment will lead the person to increase peroneal activiation to prevent the potential sprained ankle. The subject has to make the calculation of increased chance of sprained ankle or increased pressure sub 1st met/ peroneal pain. Running is so dangerous, there are so many ways to get hurt ;).

    Research on feet is so diffiult because of the brain attached to the foot.

  20. musmed

    musmed Active Member

    Dear Simon
    There is no neurological imput with heel strike
    that is why we have the fat pad. This allows the foot to adapt to the surface albiet momentarily but long enough for neurological imput from mainly type 3 and 4 mechanoreceptors to be computed.

    There basically is not enough time for imput to got to even the spinal cord to do corrections at heel strike, let enough time to have musle responding.

    Just watch how a poor soul (pun intended) who has lost their fat pad walk. They have a deliberate slow strike that takes enough time for the foot mechanoreceptors to work to make up for this defect.

    Basically heel strike is the only thing you can do that requires no neurological imput.

    paul Conneely
  21. NewsBot

    NewsBot The Admin that posts the news.

    Tissue vibration in prolonged running.
    Friesenbichler B, Stirling LM, Federolf P, Nigg BM.
    J Biomech. 2011 Jan 4;44(1):116-20
  22. NewsBot

    NewsBot The Admin that posts the news.

    Effects of Footwear on Impact Forces and Soft Tissue Vibrations during Drop Jumps and Unanticipated Drop Landings.
    Fu W, Liu Y, Zhang S.
    Int J Sports Med. 2012 Nov 9.
  23. NewsBot

    NewsBot The Admin that posts the news.

    Fatigue and soft tissue vibration during prolonged running
    Arash Khassetarash, Reza Hassannejad, Mir Mohammad Ettefagh, Vahid Sari-Sarraf
    Human Movement Science; Volume 44, December 2015, Pages 157–167

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