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Defining heel strike and toe-off based on marker velocity/acceleration

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  • Defining heel strike and toe-off based on marker velocity/acceleration

    Hi all,

    I am doing a study in which participants are made to walk overground with their running/leisure shoe at a cadence of 120steps per minute regulated by a metronome. I am not using a force plate for this task. For defining stance and swing phases, I am planning to use heel and toe marker data. I am wondering whether the following methods could be used for this purpose -


    Heel strike - where the heel marker velocity is negative (towards the ground) and there is a maximum in the heel marker acceleration (e.g. maximum slowing effect).

    Toe off - the first time following a heel strike where the toe marker velocity is positive.


    We are thinking about using these definitions to build a MATLAB program. I would appreciate if someone could help me out with this.

    Many thanks,
    Ashok

  • #2
    Re: Defining heel strike and toe-off based on marker velocity/acceleration

    Ashok,

    You are not the first who had this question. Here are a few relevant Biomch-L postings:

    http://biomch-l.isbweb.org/threads/1...act-in-Running
    http://biomch-l.isbweb.org/threads/1...admill-walking
    http://biomch-l.isbweb.org/threads/8...-stride-length

    Biomch-L has a good search engine (search box on top right of the screen). It is a good idea to use it before posting a question. A Google search and literature search is also a good idea. If you report what you have found on your own, and why it did not work for you, it is much more likely that you will get a reply from the experts who have recently worked on this. Other benefits: you make a good impression, and Biomch-L will be more interesting to read.

    Ton van den Bogert
    Biomch-L co-moderator

    Comment


    • #3
      Re: Defining heel strike and toe-off based on marker velocity/acceleration

      Many thanks to you for providing me the relevant links. Please accept my apologies for not using the search engine elaborately before posting my question.

      Kind regards,
      Ashok

      Comment


      • #4
        Re: Defining heel strike and toe-off based on marker velocity/acceleration

        You're welcome. Please post here again if your original question has not been answered yet.

        Ton van den Bogert

        Comment


        • #5
          Re: Defining heel strike and toe-off based on marker velocity/acceleration

          And just a few further references I couldn't find in the above:

          Zeni, J.A., Jr., Richards, J.G., Higginson, J.S., 2008. Two simple methods for determining gait events during treadmill and overground walking using kinematic data. Gait & Posture 27, 710-714.

          Leitch, J., Stebbins, J., Paolini, G., Zavatsky, A.B., 2011. Identifying gait events without a force plate during running: a comparison of methods. Gait & Posture 33, 130-132.

          Peham, C., Scheidl, M., Licka, T., 1999. Limb locomotion--speed distribution analysis as a new method for stance phase detection. Journal of Biomechanics 32, 1119-1124.

          Pantall, A., Gregor, R.J., Prilutsky, B.I., 2012. Stance and swing phase detection during level and slope walking in the cat: Effects of slope, injury, subject and kinematic detection method. Journal of Biomechanics.

          We have tested the Zeni algorithm in horses and found it to be very accurate for horses during walk.....

          Also google scholar search for gait events might help you.

          All the best
          /Emil

          Comment


          • #6
            Re: Defining heel strike and toe-off based on marker velocity/acceleration

            Just a quick note that your proposed toe-off method may not work because the toe marker will begin moving up and maybe forward during the third rocker phase (rolling over ball of foot).

            Comment


            • #7
              Re: Defining heel strike and toe-off based on marker velocity/acceleration

              It is important to consider if your runners are rearfoot strikers or land with their midfoot or forefoot as the method you propose to identify footstrike may not work well in runners whose heels continue to move downward after footstrike.

              If your subjects are rearfoot strikers, then your footstrike method should work well (~25 ms of error compared to forceplate data). You could simply it to just use the change in velocity of the heel marker. I agree that a different method might be better for toe-off, such as using peak knee extension. I refer you to a paper (free in PubMed Central) that compared 5 methods from the literature of identifying stance using kinematic data in rearfoot strikers.

              Fellin RE, Rose WC, Royer TD, Davis IS. Comparison of methods for kinematic identification of footstrike and toe-off during overground and treadmill running. J Sci Med Sport. 2010 Nov;13(6):646-50.

              Comment


              • #8
                Re: Defining heel strike and toe-off based on marker velocity/acceleration

                Originally posted by Ashok View Post
                Hi all,

                I am doing a study in which participants are made to walk overground with their running/leisure shoe at a cadence of 120steps per minute regulated by a metronome. I am not using a force plate for this task. For defining stance and swing phases, I am planning to use heel and toe marker data. I am wondering whether the following methods could be used for this purpose -


                Heel strike - where the heel marker velocity is negative (towards the ground) and there is a maximum in the heel marker acceleration (e.g. maximum slowing effect).

                Toe off - the first time following a heel strike where the toe marker velocity is positive.


                We are thinking about using these definitions to build a MATLAB program. I would appreciate if someone could help me out with this.

                Many thanks,
                Ashok
                Many thanks to all of you for all your valuable suggestions. I am currently working on different methods stated here. Let me see which method works better for my data!

                Comment

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