Experienced workers may sacrifice peak torso kinematics/kinetics for enhanced balance/stability during repetitive lifting

Abstract

Work-related low back disorders (WRLBDs) are widely recognized problems, and work experience, while often considered important, has an unclear role with respect to modifying WRLBD risks. For example, some studies have shown that peak torso kinematics/kinetics are higher among experienced workers, suggesting a counterintuitive higher risk. To better understand the movement strategies of experienced workers, additional analyses were conducted using data from a prior study, to assess whole body balance and torso movement stability of 6 experienced workers vs. 6 novices during repetitive lifts/lowers. Dynamic balance and torso movement stability were quantified using peak linear/angular momenta and largest Lyapunov exponent (LLE) of torso flexion/extension, respectively. Peak horizontal linear momenta, all angular momenta, and LLEs were lower among experienced workers, suggestive of superior balance maintenance and more stable torso flexion/extension. Thus, experienced workers seem to sacrifice peak torso kinematics/kinetics to obtain better balance maintenance and torso movement stability, whereas the opposite strategies were evident among novices. These findings highlight that movement strategies can be modified by work experience and have potential implications/applications for worker training or work method analyses.