This secondary data analyses of a longitudinal study assessed whether self-efficacy for exercise (SEE) mediated online intervention effects on exercise among older adults and whether age (50−64 vs. ≥65 years) moderated the mediation. Data were from an online bone health intervention study. Eight hundred sixty-six older adults (≥50 years) were randomized to three arms: Bone Power (n = 301), Bone Power Plus (n = 302), or Control (n = 263). Parallel process latent growth curve modeling (LGCM) was used to jointly model growths in SEE and in exercise and to assess the mediating effect of SEE on the effect of intervention on exercise. SEE was a significant mediator in 50- to 64-year-old adults (0.061, 95 BCI: 0.011, 0.163) but not in the ≥65 age group (−0.004, 95% BCI: −0.047, 0.025). Promotion of SEE is critical to improve exercise among 50- to 64-year-olds.
Zhu, Nahm, Resnick, and Friedmann are with the University of Maryland School of Nursing, Baltimore, MD. Brown is with the University of Maryland School of Medicine, Baltimore, MD. J. Park is with the National Institutes of Health Clinical Center, Bethesda, MD. Cheon is with the Sungshin Women's University, School of Nursing, Seoul, South Korea. D. Park is with the Department of Statistics, University of Maryland, Baltimore, MD.