Influence of box type and heights on movement strategies of thoracolumbar region and knee in load handling activities
Keywords:: lower extremity; posture; spine; workers.
Introduction: Handling activities which includes tasks like lifting, loading, pushing and pulling heavy loads have still been used by workers, in general, this activities are characterized for theirs no corporal limits respect; where the overload in the movements herewith theirs duration and intensity may lead to musculoskeletal diseases, which mainly affect the knee joint and thoracolumbar region of the trunk. Objective: This study intends to evaluate the movement strategies of the spine and knee joint of healthy subjects during a load manual handling course verifying the frequency of these strategies and by what they are influenced (handling high and kind of box). Methods: 42 healthy subjects participated in this study, which had to perform a manual box handling task and unload it in three highs: on the level of the floor, on trochanter’s measured level and shoulder’s measured level. There were utilized four kinds of boxes with variations in: size, material, and presence or not of handles. The conditions (kind of the box and high) were randomized for the subjects. The analysis was made using the unload of the boxes as a reference. Results: the results showed that the characteristics of the boxes (size, material and kind of box, with or without handles) made little influence on the strategies of knee and spine. The principal influence on the posture changes was the difference between the removals and unloads highs. Conclusions: it seems the strategies adopted by the subjects were independent of the characteristics of the load, but dependent of the task demands (i.e., handling high).