Influence of body composition and trunk strength in psychosocial variables in chronic low back pain adults

Abstract

Objective: To compare pain, disability, kinesiophobia, body composition, and trunk strength between sexes and age groups in adults with non-specific chronic low back pain (NSCLBP); and to explore the associations of pain, disability, and kinesiophobia with psychosocial variables, body composition and trunk strength in adults with NSCLBP. Design: Cross-sectional study. Settings: University research laboratory. Participants: 43 patients with NSCLBP (33.8 ± 11.8 years; 49% female, pain intensity 5.07/10 points) were recruited by convenience. Interventions: Not applicable. Main Outcome: Isometric and isokinetic trunk strength were performed. Validated questionnaires for pain intensity, disability, and kinesiophobia were administered. Between-group comparisons (sex and age group) were performed using independent-samples t-tests, and associations between psychosocial outcomes and body composition/trunk strength variables were assessed using linear regression. Results: No significant differences were found by sex or age group in any psychosocial variable. (p>0.05). Weak to moderate associations were found between psychosocial measured and trunk strength and body composition. Variance in disability meadured with ODI (Adj. R2 = 0.195, p = 0.005), or RMQD (Adj. R2 = 0.324, p <0.001) and kinesiophobia (Adj. R2 = 0.316; p < 0.001) could be explained through the psychosocial variables, body composition and trunk strength covariates. Conclusion: Kinesiophobia emerged as a key factor associated with disability, regardless of the questionnaire used. Trunk extensor strength was related to disability, whereas trunk flexor strength was associated with kinesiophobia. Lean mass was the only body composition variable predicting both outcomes. These findings highlight the relevance of assessing trunk strength when addressing psychosocial factors in NSCLBP, and suggest that strength-oriented interventions may help reduce disability and kinesiophobia in this population.