Lower extremity joint moments during symmetric lifting: squat vs stoop

In this study, we analyzed joint moments during the symmetrical lifting in two different postures, using the three-dimensional motion analysis. Boxes weighing 5, 10 and 15kg were lifted by both squat and stoop techniques. The ankle moment in stoop was always larger than that in squat and the support moment was the largest at the end of the lifting in both techniques. The knee flexion moment played an important role in stoop lifting to support the lower limbs. In the end stage of the lifting, the hip joint showed less contributions on the support moment in both lifting techniques. However, the maximum hip extension moment in stoop lifting was larger than that in squat. In addition, the maximum waist moment in squat was larger than in stoop. Therefore, these results could support the previous research that the squat lifting was not the best strategy with no harm to the waist. It is expected that these results could provide a basic information to analyze and propose an efficient lifting strategy.