Use of bilateral wrist-worn accelerometers to characterize upper limb activity time, intensity and asymmetry of use in physically demanding and sedentary working task

In the present study, we employed wearable accelerometers to characterize the patterns of mono- and bilateral activity of upper limbs (UL) in 46 individuals of a metalworking company (machine tool, fabrication and administrative departments) who were monitored for 4 h of their shift. UL accelerations were processed to calculate minutes of use and vector magnitude counts for both limbs plus several parameters (i.e. magnitude ratio, mono- and bilateral-arm use index) useful for characterizing the existence of asymmetries. The results show that machine tool operators exhibited marked asymmetry of use in favor of their dominant limb and were characterized by the lowest values of mono- and bilateral-arm use index, which indicate a superior use of the dominant limb in movements involving the use of a single or both limbs. Such evidences suggest that the use of wrist-worn accelerometers may provide essential information for assessing the risk of work-related UL disorders.