A manual materials handling (MMH) task has traditionally been thought of as a continuous type of activity, or according to systems approach, as a unit step function. In fact, a MMH task is a pulse function of 2 to 3 sec duration. The gross assumption of a continuous MMH activity does not reflect the metabolic and cardiorespiratory peaks obtained right at the moment when the physical pulse loading is applied to the human system. Therefore, the peak obtained at the end of the MMH stimulus is underestimated. Possible overexertion occurs because of this underestimation. The authors have developed a first-order theoretical model for any physiologic response to the pulse loading associated with MMH tasks. Based on an experimental evaluation, the model could not describe accurately the dynamics of the cardiovascular system for lowering tasks. Instead, the experimental evaluation suggests that the cardiovascular system behaves as a nonlinear system in response to the pulse loading of lowering tasks.
|Title of host publication||Unknown Host Publication Title|
|Place of Publication||New York, NY, USA|
|Number of pages||4|
|State||Published - Dec 1 1985|
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