Multimodal sensorimotor assessment of hand and forearm asymmetries: a reliability and correlational study.

Background: Effective rehabilitation of upper limb musculoskeletal disorders requires multimodal assessment to guide clinicians' decision-making. Furthermore, a comprehensive assessment must include reliable tests. Nevertheless, the interrelationship among various upper limb tests remains unclear. This study aimed to evaluate the reliability of easily applicable upper extremity assessments, including absolute values and asymmetries of muscle mechanical properties, pressure pain threshold, active range of motion, maximal isometric strength, and manual dexterity. A secondary aim was to explore correlations between different assessment procedures to determine their interrelationship. Methods: Thirty healthy subjects participated in two experimental sessions with 1 week between sessions. Measurements involved using a digital myotonometer, algometer, inclinometer, dynamometer, and the Nine-Hole Peg test. Intraclass correlation coefficients, standard error of the mean, and minimum detectable change were calculated as reliability indicators. Pearson's correlation was used to assess the interrelationship between tests. Results: For the absolute values of the dominant and nondominant sides, reliability was 'good' to 'excellent' for muscle mechanical properties, pressure pain thresholds, active range of motion, maximal isometric strength, and manual dexterity. Similarly, the reliability for asymmetries ranged from 'moderate' to 'excellent' across the same parameters. Faster performance in the second session was consistently found for the Nine-Hole Peg test. No systematic inter-session errors were identified for the values of the asymmetries. No significant correlations were found between tests, indicating test independence. Conclusion: These findings indicate that the sensorimotor battery of tests is reliable, while monitoring asymmetry changes may offer a more conservative approach to effectively tracking recovery of upper extremity injuries.

Potential of micro-exercise to prevent long-term sickness absence in the general working population: prospective cohort study with register follow-up.

This study assesses the potential of workplace-based micro-exercise (brief and simple exercise bouts) to prevent long-term sickness absence (LTSA) at the population level. In the Work Environment and Health in Denmark Study (2012-2018), we followed 70,130 workers from the general working population, without prior LTSA, for two years in the Danish Register for Evaluation of Marginalisation. We used Cox regression with model-assisted weights and controlled for various confounders. From 2012 to 2018, the percentage of workers in Denmark using workplace-based micro-exercise during and outside of working hours increased from 7.1 to 10.9% and from 0.8 to 1.4%, respectively. The incidence of long-term sickness absence (at least 30 days) was 8.4% during follow-up. The fully adjusted model showed reduced risk of long-term sickness absence from using micro-exercise during working hours, (HR 0.86, 95% CI 0.77-0.96), but not when used outside of working hours. If used by all workers, micro-exercise during working hours could potentially prevent 12.8% of incident long-term sickness absence cases (population attributable fraction). In conclusion, micro-exercise performed during working hours holds certain potential to prevent incident long-term sickness absence in the general working population. Large-scale implementation of workplace-based micro-exercise may represent an unexploited opportunity for public health promotion.

Habitual side-specific loading leads to structural, mechanical, and compositional changes in the patellar tendon of young and senior lifelong male athletes.

Effects of lifelong physical activity on tendon function have been investigated in cross-sectional studies, but these are at risk of "survivorship" bias. Here, we investigate whether lifelong side-specific loading is associated with greater cross-sectional area (CSA), mechanical properties, cell density (DNA content), and collagen cross-link composition of the male human patellar tendon (PT), in vivo. Nine seniors and six young male lifelong elite badminton players and fencers were included. CSA of the PT obtained by 3-tesla MRI and ultrasonography-based bilateral PT mechanics were assessed. Collagen fibril characteristics, enzymatic cross links, nonenzymatic glycation (autofluorescence), collagen, and DNA content were measured biochemically in PT biopsies. The elite athletes had a ≥15% side-to-side difference in maximal knee extensor strength, reflecting chronic unilateral sport-specific loading patterns. The PT CSA was greater on the lead extremity compared with the nonlead extremity (17%, P = 0.0001). Furthermore, greater tendon stiffness (18%, P = 0.0404) together with lower tendon stress (22%, P = 0.0005) and tendon strain (18%, P = 0.0433) were observed on the lead extremity. No effects were demonstrated from side-to-side for glycation, enzymatic cross link, collagen, and DNA content (50%, P = 0.1160). Moreover, tendon fibril density was 87 ± 28 fibrils/µm2 on the lead extremity and 68 ± 26 fibrils/µm2 on the nonlead extremity (28%, P = 0.0544). Tendon fibril diameter was 86 ± 14 nm on the lead extremity and 94 ± 14 nm on the nonlead extremity (-9%, P = 0.1076). These novel data suggest that lifelong side-specific loading in males yields greater patellar tendon size and stiffness possibly with concomitant greater fibril density but without changes of collagen cross-link composition.NEW & NOTEWORTHY The present data demonstrate that lifelong side-specific loading yields greater patellar tendon structure on the lead extremity without affecting glycation that is associated with aging. These novel data suggest that lifelong side-specific habitual loading induce structural alterations that may serve to improve the mechanical properties of the tendon.

Combined ergonomic exposures and development of musculoskeletal pain in the general working population: A prospective cohort study.

OBJECTIVE: This study aimed to investigate the importance of combined ergonomic exposures at work for the development of musculoskeletal pain. METHODS: Through four rounds (2012-2018) of the Work Environment and Health in Denmark Study, 18 905 employees of the general working population replied to a baseline and 2-year follow-up questionnaire. First, a k-means cluster analysis of seven ergonomic factors (back bending, arm above shoulders, lifting etc., from 'never' to 'almost all the time') identified nine naturally occurring clusters. Second, using a weighted survey regression model controlling for age, gender, survey year, education, lifestyle, influence at work, and pain intensity at baseline, we estimated development of pain intensity (0-10) in the neck-shoulder and low-back in these clusters. The largest cluster served as reference to the other clusters and was characterized by low ergonomic exposures. RESULTS: Clusters characterized by multiple combined ergonomic exposures for a relatively high percentage of the working time showed the largest increase in neck-shoulder as well as low-back pain intensity from baseline to follow-up. However, clusters characterized by high exposure to a few specific ergonomic factors also increased pain significantly, eg, standing/walking combined with lifting/carrying or twisted/bent back for the majority of the working time increased low-back pain, whereas repetitive arm movements for the majority of the working time with or without standing/walking increased neck-shoulder pain. CONCLUSION: Combined occupational ergonomic exposures play an important role in the development of musculoskeletal pain. Workplace preventive approaches should consider this in risk assessments and organization of the work.

Barriers and Willingness to Accept Re-Employment among Unemployed Senior Workers: The SeniorWorkingLife Study.

Labor market participation has a positive impact on social inclusion and is linked to financial security. This study identifies barriers and willingness to accept re-employment among unemployed seniors that could highlight opportunities for societal action. From the first wave of SeniorWorkingLife in 2018 combined with the Danish version of the International Standard Classification of Occupations register (ISCO), +50-year-old unemployed senior workers (n = 1682) were stratified into mainly seated work (ISCO 1-4) and mainly physical work (ISCO 5-9), respectively, in their latest employment. We used SurveyFreq and SurveyLogistics of SAS combined with model-assisted weights based on national registers to estimate representative frequencies and odds ratios (OR) for barriers and willingness to accept re-employment. Higher age was perceived as a general barrier for re-employment in both groups. Health was a more pronounced barrier for seniors with mainly physical work compared to seniors with mainly seated work (OR 2.35; CI95 1.31-4.21). Overall, seniors showed a large degree of flexibility and willingness to re-enter the labor market. Different barriers and willingness to accept re-employment exist among currently unemployed seniors. These results highlight the need for different approaches across occupational groups to help unemployed seniors back into the labor market.