The effects of age and musculoskeletal pain on force variability among manual workers

Association of perceived work pace and physical work demands with occupational accidents: a cross-sectional study of ageing male construction workers in Denmark

BACKGROUND

Occupational accidents continue to be a significant public health challenge worldwide. Construction workers in particular are at high risk of occupational accidents, and thus it is of major importance to identify possible predictors of occupational accidents among construction workers. We aimed to investigate the association between self-reported work pace and physical work demands and occupational accidents among ageing male construction workers in Denmark.

METHODS

Data on perceived work pace, physical work demands, and occupational accidents was acquired from questionnaires sent to ageing construction workers in Denmark in 2016 as part of the ALFA project (ALdring og Fysisk Arbejde; Ageing and Physical Work). A sample of 1270 Danish male construction workers above 50 years of age was included in the present study. Multiple logistic regression models were applied, with adjustments for age, smoking, body mass index, musculoskeletal disorders, occupation, work experience, and support at work.

RESULTS

Of 1270 construction workers, 166 (13.1%) reported an occupational accident within the last 12 months. There was no significant association between perceived work pace and occupational accidents, but physical work demands were associated with higher odds for occupational accidents, with an odds ratio of 2.27 (95% confidence interval 1.26-4.10) for medium physical work demands and 2.62 (95% confidence interval 1.50-4.57) for high physical work demands.

CONCLUSIONS

Ageing male construction workers with high physical work demands had statistically significant higher odds of having an occupational accident. By contrast, perceived work pace was not associated with occupational accidents in this large cross-sectional study.

Normative reference values of the handgrip strength for the Portuguese workers

Introduction

The active workforce is increasingly aging. However workload, as well as working time and intensity, sometimes remains unchanged. This can be an even more critical situation in older people, since occupational exposure associated with aging, will further reduce the muscle's ability to generate energy, which in turn facilitates the development of these age-related syndromes. This study aims to identify the normative values of handgrip strength for Portuguese workers in the automotive industry.

Methods

About 1225 employees were invited to participate in the study. The final sample consisted of 656 employees in the assembly area. The handgrip strength was measured in kilograms (kg) using the Jamar digital dynamometer. Sex-specific profiles of handgrip strength were designed by the Ordinary Least Square regression (OLS) analysis, where height, age, age squared, and height squared are entered into the models as determining factors of the maximum grip strength in both female and male groups.

Results

The peak mean values of handgrip strength in the group of women was 34 kg in the age group of 35–39 years, and in the group of men the peak mean was 52 kg in the age group of 25–34 years. The most pronounced decline in the female group appears in the age of 30–34 years of about 4 kg and the male group the decline occurs at 2kg below the peak force, in the age group of 40–57 year-olds. This study used a cut-off at 2 SD below by the sex-specific peak mean.

Conclusion

Normative values can help delineate the career path of workers because they portray risk values according to age, height, and gender. The normative values assist health and engineering professionals and ergonomists in adjusting task demands to the morphological and strength characteristics of the workers.

Physical performances show conflicting associations in aged manual workers

Ageing is associated with a decrease in physical performance implying that aged manual workers may be unable to match the physical requirements of their jobs. In this cross-sectional study, 96 male manual workers aged 51–72 years were recruited. Outcomes included handgrip strength (HGS), fat-free mass (FFM), fat percentage, cardiorespiratory fitness (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{{\rm{V}}}$$\end{document}V˙O₂max), forced vital capacity (FVC), forced expiratory volume after 1 s (FEV₁), spinal flexibility, sit-to-stand test performance and static balance. Covariates included height, smoking habits, leisure-time physical activity and systemic inflammation from blood samples. Outcomes were also compared with general populations. Age was negatively related to FFM and FEV₁, whereas static balance (velocity of displacement) was positively associated with age. Greater HGS, but poorer \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{{\rm{V}}}$$\end{document}V˙O₂max and FEV₁/FEV ratio were found compared with general populations. Age was negatively related with physical performances although a large part of the variance in performance could be explained by factors other than age such as smoking and systemic inflammation. The manual workers had greater muscle strength but had poorer cardiorespiratory fitness and lung function when compared with general populations. Specific health interventions targeting specifically cardiorespiratory fitness, lung function, and balance may be needed to maintain physical performances among manual workers.

On the role of ageing and musculoskeletal pain on dynamic balance in manual workers

The purpose of this study was to explore the interacting effects of age and musculoskeletal pain on balance in manual workers. Ninety male manual workers aged 51-72 yr were recruited and stratified according to lower extremity musculoskeletal pain intensity (pain/no pain) and work status (working/retired). The five-repetition sit-to-stand (STS) test was used to assess lower extremity function including completion time, stand time, sit time and dynamic rate of force development both in the upwards (RFD_up) and downwards moving phase (RFD_down). Dynamic balance was expressed as the range, velocity, standard deviation (SD), maximum Lyapunov Exponent and sample entropy of centre of pressure displacement in the anterior-posterior and medial-lateral direction, as well as free moment during the STS test. Except for higher age, no marked differences were seen between working and retired participants. Both age and musculoskeletal pain were negatively associated with motor function. Age × pain interactions showed that completion time, stand time, RFD_up and RFD_down were negatively associated with age for participants without pain, but positively for those with pain. Similar findings were seen for dynamic balance. These findings indicate that the effects of lower extremity musculoskeletal pain on lower extremity function and dynamic balance are age dependent.

Aging and eye tracking: in the quest for objective biomarkers

Recent applications of eye tracking for diagnosis, prognosis and follow-up of therapy in age-related neurological or psychological deficits have been reviewed. The review is focused on active aging, neurodegeneration and cognitive impairments. The potential impacts and current limitations of using characterizing features of eye movements and pupillary responses (oculometrics) as objective biomarkers in the context of aging are discussed. A closer look into the findings, especially with respect to cognitive impairments, suggests that eye tracking is an invaluable technique to study hidden aspects of aging that have not been revealed using any other noninvasive tool. Future research should involve a wider variety of oculometrics, in addition to saccadic metrics and pupillary responses, including nonlinear and combinatorial features as well as blink- and fixation-related metrics to develop biomarkers to trace age-related irregularities associated with cognitive and neural deficits.