Lifting low-lying loads in the sagittal plane

A simple geometrical model was employed to investigate various elementary techniques during static, sagittal plane lifts. Relationships between the various joint reaction forces were deduced. In particular, it was found that it is possible to simultaneously increase (or decrease) both knee and low back forces. In terms of the total force on the low back, hip, knee, and ankle joints, vertical back lifting is generally not recommended. This is especially true when lifting low-lying objects from the ground. However, minimization of loads is not the only factor to consider when analysing the optimal technique of a certain lifting task. Several other cost functions have been previously proposed. Comparisons derived from minimizing various cost functions suggest that the minimization of the maximum necessary muscle intensity may be the most appropriate in deducing optimal load lifting configurations.