CHB 2.3.1: We all like Maths!
Mathematical Model to understand the Development of work-related Complaints
When examining the development of MSKd under circumstances prior to COVID-19 confinements, a healthy individual may slowly start noticing the appearance of symptoms/complaints over time, depending on circumstances, i.e. lifestyle and behavioral factors as well as ergonomics of work set-ups. These symptoms may progress over a range of years, from irregular to irregularly regular to regular to consistent to persistent. Prior COVID-19 confinements this time span may have been within a range of 5-20 years, however, as discussed above, COVID-19 confinements such as remote working could act as a catalyst for these conditions, accelerating their persistence in an unknown pace. Though, the development of symptoms depends on individual circumstances, i.e. cofactors that have been shown to be correlated to physical fitness: physical activity and exercise (Patterson et al., 2018; Steele et al., 2017; Vina et al., 2012; Wen et al., 2011; WHO, 2018; Woods et al., 2020), ergonomic work set-up (Moretti et al., 2020), nutrition (Rauber et al., 2018), body composition (Barry et al., 2014), strength and muscle mass (Li et al., 2018), cardiorespiratory fitness (Barry et al., 2014). The less optimal the circumstances, the quicker and more symptoms (e.g. neck and/or back-pain) will show while risks for the developing conditions such as MSK disease increases. As an attempt to better understand the development of these conditions and the impact of cofactors, we have created a simple mathematical model:
Complaints (Occurrence, Severity) = A * t
A (Acceleration Coefficient) = (Sedentariness (Time per day) * Ergonomics (work set-up coefficient) – (Physical Fitness (muscle mass, strength, cardiorespiratory fitness) * Physical Activity (volume*intensity) * Body Composition(BMI; BF%))
t = Duration
ergonomics of work set-up coefficient = Scale 1-10 (10=poor; 1=excellent)
The higher the acceleration coefficient, the less time is needed to develop complaints. Further, complaints may be correlated to morbidity and mortality risks and inversely correlated to health, longevity and life quality. From an economical view, complaints act proportional to (health care) costs for companies, i.e. the more complaints (in occurrence and severity), the higher the costs will be due to worsened productivity as well as more illness and absence.
Sedentary time and the coefficient ergonomics of work-set up may directly increase the acceleration coefficient, whereas countermeasures may decrease the acceleration coefficient in a dose-response manner. On the one hand, it has been suggested that sedentariness as well as poor work set-ups are correlated with developing complaints of MSK disease (Moretti et al., 2020). On the other hand, it is well known that measures of physical fitness as well as levels of PA and body composition are strong indicators for health and longevity (Barry et al., 2014; Patterson et al., 2018; Rauber et al., 2018; Steele et al., 2017; Vina et al., 2012; Wen et al., 2011; WHO, 2018; Woods et al., 2020). Thereafter, the higher the measurement outcomes for the latter, the better individual risk management for developing complaints. It should be noted that those countermeasures are intercorrelated, e.g. body composition and physical fitness is directly affected by physical activity (Barry et al., 2014).
