A biomechanical analysis of industrial manual materials handlers

Resultant forces and torques on the joints of 11 females were studied as the subjects performed two manual materials handling tasks in their industrial environment. The subject's activities were recorded by high speed (102 frames per second) 16mm cinematography and the data analysed by a static and dynamic biomechanical model.

Statistically significant differences were found between the results of the static and dynamic analyses. Slower filming rates were simulated and were found to show fewer significant differences between the static and dynamic analysis as the data sampling rate decreased. A kinematic analysis of the experienced and inexperienced lifters revealed a great deal of intra-subject variability as well as inter-subject variability indicating that the subjects varied their motion patterns as they lifted or lowered several 14 kg loads. For submaximal tasks such a variation in lifting patterns would allow the subjects to develop muscular load sharing which would help reduce localized muscle fatigue associated with repetitive lifting activities.