Handling loads with a non-neutral posture induces overloading of the joint structures. Adopting incorrect postures during work can generate injuries. Ten healthy subjects were examined during lifting and repositioning different loads, while instrumented with a system of eight wearable Inertial Measurements Units. The tasks were performed in two conditions, safe and unsafe, when a load was lifted and then released. To detect differences between the two postures, kinematic parameters such as range of motion of joints and relative displacement between trunk and pelvis were estimated through a biomechanical model. Results demonstrated significant differences between the two postures for all kinematic parameters (p<;0.05), except for medio-lateral component of the trunk-pelvis displacement. Only for the hip joints, a dependency on the increase in weight of the loads was found. Our results demonstrate feasibility of a solution for automatically detect incorrect and risky postures in load handling of workers.