U. Raschke et al., DISTRIBUTED MOMENT HISTOGRAM - A NEUROPHYSIOLOGY BASED METHOD OF AGONIST AND ANTAGONIST TRUNK MUSCLE-ACTIVITY PREDICTION, Journal of biomechanics, 29(12), 1996, pp. 1587-1596
A neurocortical-based technique of muscle recruitment is presented to
solve the muscle indeterminacy problem for lumbar torso modeling. Cort
ical recordings from behaving primates have established motor cortex c
ells that respond to a wide range of task directions, bur are tuned to
a preferred direction. A characteristic activity pattern of these neu
rons seems to be associated with effort direction. It was hypothesized
that a model which recruits muscles based on a similar distribution w
ould predict antagonistic muscle activity with greater realism than a
widely referenced optimization formulation. The predictions of the Dis
tributed Moment Histogram (DMH) method were evaluated under common spe
ed (< 30 degrees s(-1)) sagittal plane lifting conditions using five s
ubjects. The predicted forces showed high correspondence with agonist
and antagonist myoelectric patterns. The mean coefficient of determina
tion for the erector spinae was r(2) = 0.91, and 0.41 for the latissim
us. For the antagonistic muscles, the rectus abdominus was found to be
electrically silent (< 3% MVC) and no activity was predicted by the m
ethod. The external oblique muscle was observed to be minimally active
(< 16% MVC), and the DMH method predicted its mostly constant activit
y with a mean standard error of 1.6% MVC. The realistic antagonistic p
redictions supported the hypothesis and justify this cortical based te
chnique as an alternative for muscle tension estimation in biomechanic
al torso modeling. A primary advantage of this method is its computati
onal simplicity and direct physiologic analogy. Copyright (C) 1996 Els
evier Science Ltd.