Mental health and vitality predict spinal pain in healthcare workers.

BACKGROUND: Despite extensive investigation of ergonomic risk factors for spinal pain in healthcare workers, limited knowledge of psychological risk factors exists. AIMS: To assess the prospective association of mental health and vitality with development of spinal pain in healthcare workers. METHODS: A prospective cohort study was carried out involving 1950 healthcare workers from 19 hospitals in Denmark. Assessments were done at baseline and at 1-year follow-up. Mental health and vitality were measured using the Short Form-36 Health Survey, while spinal pain intensity was measured using a 0-10 scale in the low-back, upper-back and neck, respectively. Cumulative logistic regressions adjusted for several confounding factors were applied, reporting risk estimates as odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Using good mental health as reference, moderate (but not poor) mental health at baseline was associated with increased pain intensity in the low-back (OR: 1.41 [95% CI: 1.21-1.77]), upper-back (OR: 1.63 [95% CI: 1.31-2.02]) and neck (OR: 1.31 [95% CI: 1.07-1.61]) at 1-year follow-up. Likewise, using high vitality as reference, both moderate and low vitality at baseline were associated with increased pain intensity in the low-back (OR: 1.54 [95% CI: 1.22-1.94] and OR: 2.34 [95% CI: 1.75-3.12], respectively), upper-back (OR: 1.72 [95% CI: 1.34-2.23] and OR: 2.46 [95% CI: 1.86-3.25], respectively) and neck (OR: 1.66 [95% CI: 1.34-2.06] and OR: 2.06 [95% CI: 1.61-2.63], respectively) at 1-year follow-up. CONCLUSIONS: Compared to healthcare workers with good mental health and high vitality, those with moderate mental health and low/moderate vitality, respectively, were more likely to increase spinal pain intensity at 1-year follow-up. These components should also be considered in the prevention of spinal pain in healthcare workers.

Validity and reliability of elastic resistance bands for measuring shoulder muscle strength.

Valid and reliable measurements of muscle strength are important in sport medicine. This study assesses concurrent validity and intrarater reliability (test-retest reliability) of elastic resistance bands for measuring shoulder muscle strength. Altogether, 50 healthy adults [mean age 36.0 (SD: 11.6), 29 women and 21 men] participated in testing and retesting 1-2 weeks later. The maximal elastic resistance (TheraBand) that each participant could hold for 3 s during standing bilateral shoulder abduction to 90° was converted into torque and validated against gold standard maximal voluntary isometric contraction (MVC) (Vishay force transducer) performed unilaterally while lying supine. The intrarater reliability of both tests were high; for the MVC and elastic band test, respectively, ICC(3,1) was 0.98 (95% CI: 0.97-0.99) and 0.99 (95% CI: 0.98-1.00), and measurement error was 4.8% (95% CI: 3.7-5.9) and 4.7% (95% CI: 3.1-6.2). For concurrent validity, ICC(3,1) was 0.96 (95% CI: 0.95-0.98) and measurement error was 8.1% (95% CI: 6.6-9.6), and the elastic band test explained 93% of the variance in the MVC test. However, the elastic band test produced systematically lower torque values than the MVC [56.5 (SD: 26.8) vs 66.5 (SD: 25.5) Nm, P < 0.01]. In conclusion, the test for shoulder muscle strength using elastic resistance bands has excellent validity and reliability, but produces systematically lower torque values than MVC. The reason for the lower torque values may be that the elastic band test has an initial concentric phase and is performed bilaterally and standing upright.