Physical Workload and Work Capacity Across Occupational Groups

1. Introduction

1.1 Background

Regarding occupational rehabilitation, a balance between workload and individual's work capacity is required for returning to work successfully after an injury or illness. Therefore, it is of great value to evaluate a wide range of physical work requirements and to assess employee's work capacity across occupational groups. Although several approaches have been made in this regard, there are few objective data available so far and no established reference values exist to evaluate, whether, when and how a return to work is possible. One reason could be that objectifying workload and work capacity is methodically challenging because of their multidimensional nature [1, 2].

Physical activity is defined as any bodily movement produced by skeletal muscles resulting in energy expenditure [3]. In classical work physiology, energy expenditure was therefore considered as basis for assessing the amount of workload [4, 5]. However, the energy cost of physical activity may not necessarily be equivalent to body movement [6]. For that reason, modern concepts include also other aspects reflecting the severity of manual work. The 'Dictionary of Occupational Titles' (DOT), developed by the U.S. government, classifies professions into five categories (sedentary, light, medium, heavy, very heavy) based on the amount of energy expended as well as on the intensity and duration of lifting or carrying during work [7]. Though, the DOT classification has not been based on quantitative work-related analyses, but rather on consensus meetings of experts. Furthermore, its validity has not been established.

Work capacity can be assessed using functional capacity evaluations (FCEs), which measure the ability of subjects to perform specific activities [8]. Worldwide, there are various FCE protocols available being job specific [9], pathology specific [10, 11] or of a more general type. Soer et al. applied an evaluation system consisting of 12 work-related tests to establish functional capacity in healthy employees [12]. The assessment included various lifting and energetic exercises as well as coordination tasks. From the test results, normative FCE values were acquired for each DOT-category, which can be compared to patient data in order to make work recommendations.