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Predicting Co-contraction with Optimization Methods

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  • Predicting Co-contraction with Optimization Methods

    Hello biomch-L readers:

    I am reviewing optimization methods that have been developed to predict
    muscle forces from either movement data or goal directed forward dynamic
    simulation. In reviewing the static optimization approach (inverse
    dynamic method with iterative solution for force distribution based on an
    optimizing criteria, ie. min. muscle stress, min. muscle force, etc.) and
    dynamic optimization approach (forward dynamic simulation, with optimal
    control based on maximizing a performance goal, ie. min. time, maximum
    jumping height).

    In reviewing the methods, both seem to be unable to accurately predict
    muscle phasic activity of antagonistic muscles durng gait, primarily the
    quadriceps-hamstrings action at the knee and hip around heelstrike. Is
    there any optimization criteria that has been tried out there (yet not
    published) that can predict this activity. Or will it be impossible to
    find an optimizing criteria, since co-contraction is not an optimal
    response but rather a safety measure to increase joint stiffness at times
    of peak loading. These methods at this juncture, would be inadequate to
    predict muscle forces in pathalogical cases, where the presence of
    co-contraction is alot greater throughout.

    The most recent and informative review of the static optimization method
    has been:
    Collins, J.J. (1995) The redundant nature of locomotor optimization
    laws. J. Biomechanics 28, 3, pp.251-267.

    I will post responses.

    Alan R. Morris, M.A.Sc, P.Eng.
    Research Engineer - Gait Laboratory
    The Hugh MacMillan Rehabilitation Centre
    350 Rumsey Road
    Toronto, Ont.
    M4G 1R8

    (416) 425-6220 x508