Factors associated with high physical exertion during manual lifting: Cross-sectional study among 200 blue-collar...

High physical exertion during work is a risk factor for back pain and long-term sickness absence.

To investigate which factors are associated with physical exertion during manual lifting.

From 14 workplaces across Denmark, 200 blue-collar workers reported perceived physical exertion (Borg-CR10) during manual lifting from floor to table height of 5, 10, 20 and 30 kg at the beginning and end of the working day. The workers also responded to a questionnaire and went through testing of isometric back muscle strength. Associations were modelled using logistic regression analysis controlled for various confounders. The outcome was dichotomized into low (0-4) and high (5-10) physical exertion.

Gender (OR 8.57 [95% CI 4.46-16.46] for women), load (OR 4.22 [95% CI 3.58-4.97] for each 5-kg increase), back muscle strength (OR 0.43 [95% CI 0.23-0.83] for high), and back pain intensity (OR 2.80 [95% CI 1.43-5.48] for high) were associated with high perceived physical exertion. Age, smoking, Body Mass Index (BMI), and time of the day were not associated with physical exertion.

Gender, load, back muscle strength and back pain influence physical exertion during manual lifting in blue-collar workers. These factors should be considered when planning work with manual lifting for individual workers.