Comparison of rest allowance models for static muscular work

Static muscular work associated with awkward postures with or without the application of force to an external object results in fatigue, discomfort, and musculoskeletal disorders. To prevent the effects of fatigue, sufficient and well-spaced rest periods are recommended. This paper presents an approach to determining rest periods for static muscular work in manufacturing workstations and compares the recommendations from four rest allowances models. The approach was applied to seven workstations in three industrial sectors: four workstations in the printing industry, one in the automotive industry and two in plant nurseries. The rest allowances proposed by the four models were compared with an estimation of rest allowances using the EN1005-3 standard. Results showed substantial differences in the recommendations from the different rest allowances models. Shoulder fatigue was the determining factor in the rest allowance for most workstations assessed. Caution should be exercised when using EN1005-3 to estimate rest allowances. Relevance to industry: Static and intermittent static muscular work are known risk factors for work-related musculoskeletal disorders (WMSD). Determining appropriate work-rest regimens for static muscular work in industrial settings may be an efficient way to reduce this risk, but information to guide the selection of the most appropriate rest allowance model is lacking. (C) 2008 Elsevier B.V. All rights reserved.