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Muscle function during gait info

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Ryan McCallum, Sep 28, 2010.

  1. Ryan McCallum

    Ryan McCallum Active Member

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    I was hoping someone could point me in the right direction to any literature regarding lower limb muscle function during the gait cycle or more specifically the activation phases of the muscles.

    In the back of my memory, I recall seeing a diagrammatic representation of this somewhere in my undergraduate notes but have no idea where it came from but getting a hold of something like this would be great. I know there is a small chart somewhere in Valmassy but I was hoping for a bit more.

    I would be very appreciative of any pointers.

    Many thanks,
  2. Hi Ryan depends on what you want.

    Basic stuff try: Gait analysis an indroduction Michael Whittle Gives a good overview of lots of good stuff.

    More complex stuff will be harder to come by as muscles will be under load at different times from person to person, due to lots of different reasons. Alot of the time with questions such as is the muscle a pronator or supinator when is it active in creating moments etc etc the answer will be depends on.........

    Hope that helps some.
  3. Griff

    Griff Moderator

    Hey Ryan,

    I've attached something I put together ages ago - not sure where I scanned it on from - Root, Orien & Weed perhaps? Think it's the kind of diagram you referred to. Not sure of any journal articles off the top of my head but will have a scan through my library tomorrow and post up any I may find.


    Attached Files:

  4. Ryan McCallum

    Ryan McCallum Active Member

    Thanks guys. You are right Michael, any pictures have been hard to come by!

    Ian, this is very similar to what I was thinking of. I had actually thought the picture I was thinking of was from Root, Orien and Weed but couldnt find a copy to check.

    The only thing missing is peroneus brevis. The picture is needed for a slide in a presentation where I need to compare peroneus brevis and flexor digitorum longus activity.

    Thanks a million for the attachment, greatly appreciated!
  5. Dananberg

    Dananberg Active Member

    I believe you are looking for Inman's text, "Human Walking". There are a series
    of diagrams which show when muscles are active in what stage of the gait cycle.

    The part of this which I found most interesting, is that Inman writes that there is a discrepency between when peak thrust is achieved and when peak muscle action occurs. If I recall correctly, this was a 6% difference....which in gait terms, is rather huge. It became one of the reasons why I have come to understand gait as pulling via the swing limb vs. muscle action of the lower extremity pushing.

  6. Which reminds me, I found this a while ago and thought of you, Howard. I've been meaning to post it up here for a while.

    Attached Files:

  7. Dananberg

    Dananberg Active Member

    Hi Simon,

    Fascinating paper and thanks for posting it. I would comment as follows.

    Kuo describes the simplist walking model and points to toe-off as the time of peak propulsion. I would agree that, it this knee-less model, that would be 100% true.

    But when a knee joint is added, it breaks the rigid link between the foot end and the COM, and herein lies the issue. If push-off were to drive the COM forward as Kuo describes, when a knee joint is present, it must flex at the time the hip flexes (know motion during terminal double support). How then, can pushoff at the foot end drive the COM when the knee flexes? To my thinking, this is simply impossible. Interested in hearing your thoughts.


  8. Howard:

    As we have discussed many times before, the loss in distance from hip joint center to plantar metatarsal heads with knee flexion can be easily made up by an increase in distance from hip joint center to plantar metatarsal heads with ankle jiont plantarflexion. Nice to see that Kuo's research confirms the fact that the foot does indeed push off during propulsin.
  9. Dananberg

    Dananberg Active Member


    It is not the distance...but rather the linkage. If there is a push which occurs at toeoff, please explain to me how this is tranferred to the CoM when the knee joint is rapidly flexing as preswing to swing phase occurs at this time. I can understand how this can drive the leg into swing phase (and I am quite sure it does), but with both the knee and hip rapidly flexing forward, how can there be an efficient transfer to the COM when the two joints between the foot and pelvis are collapsing into flexion. In the reference that Simon provided (Kuo) to prove there is propulsion from the foot, the model they used has no knee or ankle. How can this possibly be the same as a step when there is a hinged knee joint?

  10. efuller

    efuller MVP

    Law of inertia: The body will continue on at constant velocity until acted upon by an external force. Once constant walking speed is achieved the only slowing force is heel contact and then climbing up over the stance limb. Once the body is over the top it falls forward so the loss from the upward climb is regained. The point being that there is very little energy input needed to "power" gait.

    The ankle push can be transmitted to the center of mass depending on the moments acting at the hip and knee. If you think of the hip and knee as a spring some of the ankle push goes into compressing the spring and some goes into pushing the top of the spring. You can't compress a spring if there is no push from the other side. (equal and opposite reaction) So, if the hip and knee musculature are pushing back at the same time they are flexing, it is possible for ankle push to move the center of mass forward.

    The hip and knee will not always act as spring. There are different muscle activations that can occur and will occur depending on the needs of the person. But it is possible for a push to be transmitted through flexing joints.

  11. Dananberg

    Dananberg Active Member


    Your response is hypothetical, and it really not relevant to the phasic events of preswing phase. When the knee and hip are flexing in preswing phase, the quads and hamstrings are OFF! Quads and hamstrings fire AFTER once toeoff. It is therefore impossible to be acting spring like during the initial phase of preswing. This is not to say that it can't, but simply to say, at this phase of the step, IT DOESN'T.

    Further, if subjects were to use the limb as you suggest, they likely would be exhausted after only a few steps! You have described a highly inefficient method of limb use, and in normal level ground walking, would be very counterproductive.

  12. efuller

    efuller MVP

    I think we had this conversation before. There is a time delay between the time the emg signal decreases and the time force reduction decreases. So, you need to take take this into account when making conclusions about the EMG data. Also, the amount of force required to make the leg act as spring is going to quite small compared to the support of body weight. We are talking about pushing the leg forward, not up. The forces in the hip and knee will be lower than the amount of ankle push because of the "collapse." These muscle forces may be low enough so that they may not rise above the baseline amount. So, this would not significantly add to fatigue. The forces involved would probably be smaller than the forces you use to hold your head erect while sitting for hours in front of a computer.

    Yes, it is theoretical, but it should not be dismissed out of hand because of EMG data.

    Now, back around the other stump. Of course, if the above explanation didn't work, Winter's power calculations do show that energy added to the swing leg by ankle push can be returned to the body at the end of swing as the swing leg is slowed down before heel contact. If the trunk pulls the swing leg forward then this would slow the forward progression of the center of mass. Ankle push does not do this. The swing leg has to get the energy (Kinetic) from somewhere, so that it can pass the body and become the leading leg. The energy has to come from something that touches it. Choices: trunk, ground. Ankle push, hip pull.


  13. Dananberg

    Dananberg Active Member


    Funny, you like to use EMG data to support you position...until it doesn't. Can't have it both ways.

    I know that there is energy being added to the CoM "AT THE END OF SWING", but of course, this is not what we were discussing. We were specifically talking about push off, and the DIRECT effect this has on the CoM. But thank you for providing additional information as to how the swing limb pulls the body forward. As you know....I have been saying this for 25+ years.

    As single support reaches its conclusion, the trailing limb has reached its maximally extended position. Once contralateral heel contact occurs, extension of the trailing side immediately changes to flexion, with the knee and hip giving way while the ankle is forcibly plantarflexing. The limb is propelled into into swing phase, and at its final 1/3 (or so) of swing, "pulling" the CoM forward. This is very different than push off causing propulsion directly. If it did, the reactive longitudinal thrust curves would be rising through the end of single support phase, but as we both know, they are falling rapidly during this period of the step.

    Inman's comment in "Human Walking" is very telling. He was unable to correlate max EMG with max thrust...and found this perplexing. If there was a direct push off...he wouldn't have been puzzled. Because the system is far more elegant than that, the data didn't add up. As Stephen Jay Gould said in his text "The Panda's Thumb", the exception must prove the rule.

  14. efuller

    efuller MVP

    When did I use EMG data in this discussion? What is wrong with my criticism of the use of EMG data to reach the conclusions that the swing leg can't act as a stiff spring?

    We are in a agreement that at the end of swing, the swing leg pulls the body forward.

    The key is what propels the leg into swing. If the trunk pulls the leg forward, the leg pulls the trunk backward (Newton's third law). Just because the amount of posterior to anterior force from the ground acting on the trailing leg is decreasing, it is still adding energy. It is impossible for the force to be continually increasing, or even staying constant, as weight is transferred to the leading leg. There needs to be a certain amount of friction between the foot and the ground to create the posterior to anterior push from the ground acting onthe leg. Even as the force decreases, it is still adding energy to the swing leg and evetually to the whole body. (Newton's 2nd law. Net force is equal to mass x acceleration and the acceleration is in the direction of the force.) So, when the force is in the direction of pushing the leg forward it is still pushing the leg forward even if the magnitude of the force is decreasing.

    Why is it important to distinguish between directly and indirectly adding energy to the center of mass?

    Even though Howard and I keep having this academic debate on how the foot and leg works, I still believe what he does works, but for a different reason than he claims.

  15. I want to hear Howard's views on the bipedal spring mass model of human walking presented by Hartmut Geyer because I think if anyone will see the significance of this to sagittal plane facilitation theory, he will. Any interest, Howard? It could be time consuming, but I think this is the key to your theories.
  16. Dananberg

    Dananberg Active Member


    I think that by your asking about why it is important when/how power is input gets to the
    crux of the issues involving my overall philosphy of gait and orthotic management.

    If the power to allow humans to walk was intrinsically developed on the weight bearing limb,
    (ie, direct muscle firing causing movement) then either functional issues or even pain responses could alter the input.

    On the other hand, if the power were being provided extrinsically to the weight bearing limb, ie, from the opposite swing side, then the power input would either be used, stored or dissipated.

    If it is used at the time it is created, then gait is efficient. Storage and/or dissipation
    is inefficient. Late phase pronation is the visible event when dissipation is required.

  17. Dananberg

    Dananberg Active Member


    If you can post a pdf of this paper, I would likely read this over the our long weekend and get back to you (eventually). :)

  18. Howard, I'll start it as new thread and link the work, one is his PhD thesis, the other a research paper. I think his observation that the duration of double limb support are key factors links nicely with your observations. I also think that the compensation you've outlined are direct responses of the body attempting to modulate leg stiffness. Thank you for giving this your time and consideration.
  19. Dananberg

    Dananberg Active Member


    Modulating leg stiffness sounds "spot on". I will look forward to reading this, and get back to you when time permits.

  20. BAMBLE1976

    BAMBLE1976 Active Member


    If i may ad my tuppence worth in, when looking at the magnitude of the 'propulsive' vector at toe off, it is so low that it must mearly assist in the swing phase of that limb and not actually have any effect on the CoM due to its low magnitude?

  21. efuller

    efuller MVP

    I missed this one earlier.

    Howard, I'm not understanding your point. Power input is a different issue than power loss. You could have late stance phase pronation that will loose energy to heat (energy cannot be created or destroyed) whenever the energy is created.

  22. efuller

    efuller MVP

    Three points:

    A push is a push, no matter how small.

    To maintain constant velocity, you don't need a whole lot of push. You need just enough push to overcome the anterior to posterior force that occurs at heel contact.

    The swing leg is a part of the center of mass. If you push the swing leg forward it will push the center of mass forward.

    If you want to treat the swing leg as not part of the center of mass:
    At some point in gait, something has to accelerate the trailing leg so that it can catch up and pass the trunk. The options are ground reaction force or a pull from the hip. If the trunk pulls the leg forward, the leg pulls the trunk backward. If ankle plantar flexion causes some push from the foot against the ground, the equal and opposite reaction from the ground pushes the leg forward.

    Both hip pull and ankle push will add energy to the swing leg that will pull the trunk forward at the end of swing. However, ankle push does not pull the trunk backward at the beginning of swing and that is why the ankle push style of gait is more efficient. Ankle push does happen.

  23. David Smith

    David Smith Well-Known Member

    As Eric points out an unbalanced external force applied to a mass changes its velocity i.e. speed and direction and its acceleration in that direction unless the force is applied perpendicularly to the direction of the motion. f=ma so a = f/m lets say the horizontal posterior - anterior force in the same direction of CoM motion is 300N for a 80kg subject then the acceleration is almost 4m/s/s. The critical thing here is time of force application, if the force were applied for 1 minute then the velocity of the mass of 80kg = v= at then terminal velocity would be 240m/s, which is 864 kph quite fast I would say with such a small force applied. Is that surprising to you?

    Of course the force applied to the CoM by the push off leg is only for a short time say 400ms for example and it is not a constant force. It is a constantly increasing force from zero to 300N (E.G.). This then becomes a differential calculus equation that returns a terminal velocity of approx 0.6m/s, which is equal to 2.16k/h about half the velocity of average walking speed.

    So if the heel strike and joint stiffness during stance phase potentially slows the CoM velocity to zero then the input from the push off will return 50% velocity and keep the forward motion going.

    So with respect to Howards argument, regardless of the muscle activity there is a propulsive force acting on the CoM that is significant in terms of its forward progression.

    With regard to the OP, I like Gait Analysis, normal and pathological, Jacqueline Perry, Slack Inc. NJ. ISBN 1-555642 -192-3

    Regards Dave
  24. David Smith

    David Smith Well-Known Member

    Here's a clue to the answer to both Howards and Kevin apparently different perspective to the problem of forward progression in terms of stance leg propulsion.

    Extract from;
    Journal of Biomechanics 40 (2007) 1824–1831
    Mechanical energetic contributions from individual muscles and elastic
    prosthetic feet during symmetric unilateral transtibial amputee walking:
    A theoretical study
    Robert J. Zmitrewicz, Richard R. Neptune, Kotaro Sasaki
    Department of Mechanical Engineering, University of Texas at Austin, 1 University Station C2200, Austin, TX 78712, USA
    Accepted 24 July 2006

    Page 2 (1825) 2nd paragraph NB Acronym - ESAR = energy storage and return

    Recent modeling and simulation analyses have shown
    that the uniarticular soleus and biarticular gastrocnemius
    have distinctly different biomechanical functions during
    stance (e.g., Neptune et al., 2001; Zajac et al., 2003).
    During mid single leg stance, the soleus and gastrocnemius
    act isometrically to provide trunk support by transferring
    power between the trunk and leg, but in opposite
    directions. The soleus decelerates the leg while accelerating
    the trunk forward and the gastrocnemius decelerates the
    trunk while accelerating the leg forward. During late stance
    and pre-swing, both the soleus and gastrocnemius undergo
    concentric activity, with energy from the soleus being
    primarily delivered to the trunk to provide forward
    propulsion and energy from the gastrocnemius being
    primarily delivered to the leg to accelerate it into swing.
    It is unclear to what extent an ESAR prosthesis is able to
    provide these different biomechanical functions, and the
    extent other muscles must compensate to restore normal
    walking mechanics.

    Regards Dave

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