Interaction between biomechanical and psychosocial workplace stressors: Implications for biomechanical responses and spinal loading.

摘要

With the majority of the workforce suffering from low back pain (LBP) at sometime in their lifetime, there is a tremendous need to identify the factors that increase the risk of LBP. In order to understand the complex relationship between workplace stressors and low back injuries, the underlying injury mechanisms must be understood. One such pathway is workplace stressors alter trunk motions and kinetics that translate into a muscle coactivity response and ultimately produce the loads on the spinal structures. Traditionally, biomechanical and psychosocial work stressors have been investigated independently.; A laboratory study was conducted to investigate the simultaneous impact of biomechanical and psychosocial workplace stressors on the spinal load injury mechanism. Thirty male and 30 female students volunteered to lift boxes from a conveyor directly in front of them and placed on an asymmetric destination shelf. Five different workplace stressors were evaluated simultaneously: weight lifted—6.8 and 11.4 kg, task asymmetry—clockwise and counter-clockwise, mental concentration—none and number identification task, placement control—general placement and placement within a target, and lift rate—2 lifts/min and 8 lifts/min. Several potential modifying factors (gender, personality, and social environment) were also explored.; Not surprising, the workplace stressor that had the largest impact was box weight. Mental concentration demands had a minor affect on sagittal trunk kinematics and compressive loads but interacted with lift rate to produce more trunk motion and loads when lifting. Controlled placement was particularly detrimental to the individual, producing faster motions and more awkward postures, increased muscle coactivity, and higher spinal loads. Lift rate influenced the trunk kinematics and muscle activity but only moderate increases were found in spinal loads (about 10 to 15%). Modifying factors such as gender and personality had major roles in how individuals reacted to the workplace stressors.; All together, these results provide evidence of the complex relationships that occur between physical and mental aspects of the workplace. Even with the limited exposure levels, the current study suggests the need for future research to account for the interactive nature of the workplace stressors. This study also provides an indication of the relative contribution of the various workplace stressors.