Effects of a workplace exercise program on physical capacity and lower back symptoms in hospital nursing assistants: a randomized controlled trial

Purpose Considering the relevance of muscle strength for sustaining good musculoskeletal health among workers who perform physically demanding work, the aim of this study was to evaluate the effectiveness of a therapeutic exercise program on muscle strength and low back symptoms among hospital nursing assistants. Methods One hundred and twenty-nine nursing assistants filled out a questionnaire on personal, occupational information and health status, which allowed the identification of workers able to exercise. Ninety participants were randomly allocated to an intervention and a reference group. The therapeutic exercise program (TEP) lasted 12 weeks and included warm-up, strengthening and stretching exercises. Muscle strength of trunk flexors and trunk extensors, hamstring flexibility, and low back symptoms were evaluated before and after the intervention period by two blinded assessors. The comparison between groups was carried out using Mann-Whitney and chi(2)tests at a significance level of 0.05. Results The average participation in the exercise program was 17.5 sessions. Results showed increased trunk flexors muscle strength (p = 0.002; effect size: 0.77), improved pressure pain threshold for dorsal longissimus (p = 0.001; effect size > 0.8), and reduced low back symptoms (p = 0.002; OR = 6.25). No differences between groups were identified for back extensor muscle strength or flexibility. Conclusion The exercise program applied is a feasible intervention which resulted clinically relevant results for nursing assistants' musculoskeletal health expressed through trunk flexors muscle strength improvement and low back symptoms control among nursing assistants. This RCT brings contribution to the Occupational Health field as the exercise program applied resulted in clinically relevant results for nursing assistants' musculoskeletal health. This study brings contribution especially for low-income and middle-income countries where low back pain and disability can be considered more severe as adequate resources to address the problem are scarce. Thus, we must highlight the importance of low-cost preventive strategies, like exercise programs carried out in hospital settings to avoid the progress of disability among active nursing personnel.