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Multi-response optimization and empirical modeling of cardiopulmonary responses during manual lifting tasks



An experimental study involving five independent lifting variables (namely weight, lift frequency, horizontal distance from the object, operator, and vertical distance) and their interactions was conducted using the Taguchi L27 design. Two responses—heart rate and oxygen uptake—were measured during each trial. To optimize both responses simultaneously, the signal-to-noise ratio was normalized to obtain a multi-response signal-to-noise (MRSN) ratio for each trial. The MRSN ratio was analyzed using analysis of variance to identify the optimal condition in which both responses were optimized at the same time. Lift frequency was found to be the most significant factor, and operator and horizontal distance were found to be least significant. The empirical modeling equation was developed and can be used to predict the response values during experimental trials involving similar work conditions. © 2010 Wiley Periodicals, Inc.