External load and the reaction of the musculoskeletal system – A conceptual model of the interaction

Abstract This paper presents a conceptual model of the interaction between the human body and external factors influencing the musculoskeletal system (biomechanical load, vibration and psychosocial factors). The interrelationship of parameters that define each external occupational or non-occupational factor and their combination creates exposure. Exposure influences the human body modelled as a mental system and a musculoskeletal system, and results in responses leading to improved or impaired structures of the musculoskeletal system. The reaction to external factors expressed as a response depends on personal traits. The results of this study are a basis for insights into how external physical and psychosocial risk factors influence the mechanisms responsible for whether body structures improve or are impaired. The model is intended to be filled in with mathematical equations that describe quantitatively phenomena related to processes caused by external load, with consideration of personal traits. This paper discusses ways leading to mathematical formulas, which would explain the phenomena included in the model quantitatively. Relevance to industry The relevance of this study to industry consists in providing, through the use of the proposed model, after a quantitative verification, safety levels that can result in improved work and workers protect against MSDs. By considering both occupational and non-occupational activities, the model can help to protect workers holistically.