Inertial measurements units for assessment of the pattern of forward bending among blue-collar workers from the DPhacto cohort

Background.
New developments in electronics have enabled the use of Inertial Measurement Units (IMUs) to record physical activity in a minimally obstructive manner over several days. Individual, physical and psychosocial risk factors are known to play a role in the development of work-related musculoskeletal disorders. This presentation focuses on the results obtained from diurnal assessments of forward bending among blue-collar workers in Denmark.
Methods.
In total, 681 blue-collar workers were monitored diurnally for four days and nights, on average. The duration and pattern of forward bending of the trunk were extracted from all-day IMU recordings, both at work and during leisure time. Exposure variation analysis was applied on forward bending during both work and leisure time.Low-back pain intensity was measured on a 0–10 scale and divided into low and high pain. Individual factors (age, gender, smoking) as well as psychosocial factors (social support) were adjusted for.Results. The duration of forward bending was not significantly associated with the intensity of pain, but was modified by the level of social support during all day, work and leisure time (p<0.05). A more variable pattern of forward bending was found during leisure compared to work (p<0.05). Further, the pattern of forward bending was modified by individual factors like age and gender (p<0.05).
Discussion.
The findings underline the complex interactions between individual, physical and psychosocial risk factors leading to low-back pain among blue-collar workers.