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  • Summary of Joint Stiffness

    Biomch-L,

    Following my original question is a summary of replies. I am in the process
    of investigating these avenues. Thank you to all those who replied.

    Original Question:
    > Biomch-L Colleagues,
    >
    > I have a query that relates very closely to a question recently posed by
    > John Finan (University College Dublin) on joint stiffness. Within our
    > research we are modelling the Standing Hybrid III Dummy on a moving floor.
    > The defined joint stiffness of the lower limbs (particularly the knee)
    > consist of little or no stiffness throughout the normal range of motion
    > with a dramatic increase when nearing the end of the joint ROM. This is to
    > simulate the physical end-limits of joint motion.Therefore any upward
    > movement of the floor causes the dummy to crumble. Is there any data or has
    > there been any work done on the stiffness properties of these joints in
    > anticipation of an upward force? For example, the stiffness in the knee
    > before landing from a jump. We are not primarily concerned with any
    > increased stiffness due to increased muscle activation during the impact.
    > We would like some idea of joint stiffness applied by the semi-conscious
    > muscle activation in anticipation of the upward force.
    >
    > Your help would be greatly appreciated and a summary will be posted.
    >
    > Thanks,
    > Justin

    RESPONSE 1:
    Dear Justin,

    In my opinion, (I would say just to be polite) joint stiffness is not a
    parameter which the nervous susystem cares about while controls any
    movement. You can take a look at the article: Feldman AG, Ostry DJ, Levin
    MF, Gribble PL, and Mitnitski AB. Recent tests of the equilibrium-point
    hypothesis (lambda model). Motor control 2: 189-205, 1998 for very clear
    explanations. You can also take a look at the papers of D. Ostry and P.
    Gribble in Biocybern appeared about at the same time. There are the
    examples of simulation of poiting movement. As far as I know, there is no
    publications of the simulation of knee joint approach using the same
    approach (started by Dr Feldman 30 years ago), though I myself performed
    some preliminary simulations but nothing has been published... .

    There is no anticipation of the reaction force (again, in my opinion),
    using the techniques corresponding to the lambda-model, one don't need any
    anticipation. Everything will be the concequence of the control parameters
    specified before the movement (for fast movements).

    If you have any questions about the matter I will be happy to discuss them,
    Arnold

    Arnold B. Mitnitski
    Ecole Polytechnique, Applied Mechanics Dept.

    RESPONSE 2:
    Any increase in joint stiffness in mid-range can come only from muscle
    activation either in anticipation of an upward force or in response to an
    unexpected force. When landing from a jump subjects anticipate landing and
    usually activate muscles before or shortly after contact with the ground,
    thereby stiffening the knee and other lower limb joints. However, the
    stiffness properties are complex as there is high short-range stiffness to
    small changes in knee and lower stiffness after the short-range is
    exceeded. This is a complex issue. Good luck with it.

    Sincerely,
    Warren Darling

    RESPONSE 3:
    Justin,

    You should have done some searching on your own (or let us know that you
    did). Nevertheless, here are some references:

    PASSIVE JOINT STIFFNESS:
    Mansour, JM and Audu, ML (1987) Passive Elastic Moment at the Knee and its
    Influence on Human Gait. Journal of Biomechanics 19: 51-58.
    Yoon, YS and Mansour, JM (1982) Passive Elastic Moment at the Hip. Journal
    of Biomechanics 15: 905-910.
    Weiss, PL, Kearney, RE and Hunter, IW (1986) Position Dependence of ankle
    joint dynamics -- I. passive mechanics. Journal of Biomechanics 19: 727-735.

    OVERALL LEG STIFFNESS:
    Farley, CT, Glasheen, J and McMahon, TA (1993) Running springs: Speed and
    animal size. Journal of Experimental Biology 185: 71-86.
    Farley, CT and Gonzalez, O (1996) leg stiffness and stride frequency in
    human running. Journal of Biomechanics 29: 181-186.
    Ferris, DP and Farley, CT (1997) Interaction of leg stiffness and surfaces
    stiffness during human hopping. Journal of Applied Physiology 82: 15-22;
    discussion 13-4.
    Ferris, DP, Louie, M and Farley, CT (1998) Running in the real world:
    adjusting leg stiffness for different surfaces. Proceedings of the Royal
    Society of London - Series B: Biological Sciences 265: 989-94.
    McMahon, TA and Cheng, GC (1990) The mechanics of Running: How does
    stiffness couple with speed. Journal of Biomechanics 23: 65-78.
    McMahon, TA and Greene, PR (1979) The influence of track compliance on
    running. Journal of Biomechanics 12: 893-904.
    McMahon, TA, Valiant, G and Frederick, EC (1987) Groucho running. Journal
    of Applied Physiology 62: 2326-2337.

    LANDING (AND CATCHING):
    Armand, M, Huissoon, JP and Patla, AE (1998) Stepping over obstacles during
    locomotion: insights from multiobjective optimization on set of input
    parameters. IEEE Transactions on Rehabilitation Engineering 6: 43-52.
    Dyhre-Poulsen, P, Simonsen, E and Voight, M (1991) Dynamic control of
    muscle stiffness and H reflex modulation during hopping and jumping in man.
    Journal of Physiology 437: 287-304.
    Gross, TS and Nelson, RC (1988) The shock attenuation role of the ankle
    during landing from a vertical jump. Medicine and Science in Sports and
    Exercise 20: 506-514.
    Lacquaniti, F, Carrozzo, M and Borghese, NA (1993) Time-varying mechanical
    behavior of multijointed arm in man. Journal of Neurophysiology 69: 1443-1464.
    Lee, DN and Young, DS (1986) Gearing action ot the environment.
    Experimental Brain Research Series 15: 217-230.
    McKinley, P, and Smith, JL (1983) Visual and vestibular contributions to
    prelanding EMG during jump downs in cats. Experimental Brain Research 52:
    439-448.
    McKinley, P, , Smith, JL and Gregor, RJ (1983) Responses of elbow extensors
    to landing forces during jump downs in cats. Experimental Brain Research
    49: 218-228.
    McKinley, P and Pedotti, A (1992) Motor strategies in landing from a jump:
    The role of skill in task execution. Experimental Brain Research 90: 427-440.
    McNitt-Gray, JL (1993) Kinetics of the lower extremities during drop
    landings from three heights. Journal of Biomechanics 26: 1037-1046.
    Melvill Jones, G and Watt, DGD (1971) Muscular control of landing from a
    unexpected falls in man. Journal of Physiology 219: 729-737.
    Wicke, RW and Oman, CM (1982) Visual and graviceptive influences on lower
    leg EMG activity in humans during brief falls. Experimental Brain Research
    46: 324-330.

    J A M E S P A T T O N , P H . D .
    Research Associate,
    Sensory Motor Performance Program
    Rehabilitation Institute of Chicago.

    RESPONSE 4:
    Justin,
    Sounds like pretty challenging and interesting work. I have modelled (in
    Pro/Mechanica) a shoulder and elbow joint in the past and just used a
    different figure for static and dynamic friction coefficients. I don't
    think that helps you much though. I have a few suggestions;
    1. Add MADYMO muscles around the joints (they don't have to be exact) then
    look in the Automotive impact literature (SAE STAPP Conferences,
    International Research Council On the Biomechanics of Impact proceedings -
    IRCOBI, Enhanced Safety of Vehicles Conference - ESV) for data on lower
    limb muscle activity in pre-impact braking and add this to your model.
    2. Look at the knee joint stiffness (Cardan Restraints are used) in the
    Madymo EEVC Legform Impactor and then add these (or similar magnitude -
    check result sensitivity) constraints to your model.
    3. Talk to MADYMO help (they really are very helpful!) about how they would
    recommend solving the problem.

    Hope this helps
    Mike.

    Michael Buckley
    Senior Safety Engineer
    Daewoo Worthing Technical Centre

    RESPONSE 5
    Justin,

    We published:

    DeVita, P. & Skelly, W. (1992). Effect of landing stiffness on joint
    kinetics and energetics in the lower extremity. Medicine and Science in
    Sports and Exercise, 24, 108-115.

    and one section emphasized the anticipatory adjustments made during the 100
    ms prior to contact. We did not assess actual stiffness however but had
    subjects land with relatively soft (much flexion) and stiff (little
    flexion) techniques.

    Paul DeVita


    ----------------------------------------------------------------------------
    ----------------
    Justin Ludcke
    PhD Student
    School of Mechanical, Manufacturing and Medical Engineering
    Queensland University of Technology
    GPO Box 2434
    Brisbane Q 4001
    AUSTRALIA

    Ph: +61 7 3864 2980
    Fax: +61 7 3864 1469
    Email : j.ludcke@qut.edu.au
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