The mediating role of self-perceived health and fitness in the relationship between physical activity and quality of life among individuals with physical disabilities: the moderating effect of self-esteem.

BACKGROUND: This study sought to investigate the psychological mechanisms that connect physical activity (PA) to quality of life (QoL) in individuals with physical disabilities (IWPDs). Three hypotheses were tested: (1) self-perceived health and self-perceived fitness mediate distinct indirect associations involving PA, self-perceptions, and QoL; (2) self-esteem moderates the indirect association between PA and QoL through self-perceived fitness; and (3) an integrated model, including PA level, self-perceptions, and self-esteem, explains a significant variance in QoL. METHODS: A cross-sectional study was performed involving 230 individuals with physical disabilities. Measures comprised PA level (Arabic version of the Physical Activity Scale for Individuals with Physical Disabilities), self-perceived fitness and health, self-esteem (Rosenberg Self-Esteem Scale), QoL (World Health Organization Quality of Life-Disabilities module), and demographic covariates. Mediation and moderated mediation analyses were conducted using the mediation package in R, employing 1,000 bias-corrected bootstrap resamples. Hypothesis 3 was evaluated through hierarchical regression and structural equation modeling using the lavaan package. All tests were checked for validity and reliability among all participants before analyses. RESULTS: Self-perceived health significantly mediated the relationship between self-perceived fitness and QoL (average causal mediation effect = 0.123, 95% CI [0.071, 0.179], p < 0.001), representing 42.3% of the total effect. Self-perceived fitness served as a partial mediator in the relationship between PA level and QoL (average causal mediation effect = 0.004, 95% CI [0.002, 0.007], p < 0.001). Additionally, this mediation effect was moderated by self-esteem, with the influence increasing from low to high self-esteem groups. In the integrated model, self-perceived health (β = 0.431) and fitness (β = 0.203) emerged as the only significant predictors: PA level and self-esteem showed small, statistically non-significant direct associations with QoL. CONCLUSION: The findings endorse the perceptual pathways model, indicating that cognitive appraisals, specifically self-perceived fitness and self-perceived health, are involved in distinct indirect associations between PA and QoL, with self-esteem serving as a moderating factor. Interventions should focus on improving self-perceptions while also encouraging PA, as subjective evaluations showed stronger statistical associations with QoL than the reported PA level in IWPDs.