Document Type



In ergonomics, lifting tasks can be categorized according to their risk level of suffering work-related low back disorders (WRLBD). The aim of this study was to investigate whether trunk muscles form synergies that stabilize the time profile of selected performance variables that have been used previously to characterize the risk level for developing WRLBD. At the neuromuscular level, the spatiotemporal pattern of motoneuronal activity was quantified by applying matrix factorization algorithm with Varimax rotation. With this procedure, synergies were quantified using the framework of the UCM hypothesis. The results supported the hypothesis that trunk muscles form synergies to stabilize the time profile of variables that are being also used to characterize the risk of injury.