Simultaneous assessment of upper limb usage and sedentary behavior time among white- and blue-collar workers using wrist-worn accelerometers

In the present study, wrist-worn accelerometers were employed to estimate inten- sity and symmetry of use of upper limbs (UL) and characterize sedentary behavior during 4 hours of shift in 22 full-time workers assigned to tasks of different physical engagement (i.e., machine tool operators and administrative staff). In particular, the raw accelerations were processed to calculate minutes of use of each limb and vector magnitude counts (as overall measures of limb activity) magnitude ratio and use ratio as symmetry parameters. The same data also allowed to calculate the time spent in sitting position. The results identified the existence of significant asymmetries in the machine tool workers in terms of both duration of UL use and activity intensity, while administrative staff exhibit a marked sedentary activity but no asymmetries in UL use. Such findings suggest that accelerometer-based data allow discriminating among important features of different tasks, highlighting potentially harmful conditions.