Anderson-Bill, Eileen SmithWinett, Richard A.Wojcik, Janet R.Williams, David M.2017-09-182017-09-182011-04-28Eileen Smith Anderson-Bill, Richard A. Winett, Janet R. Wojcik, and David M. Williams, “Aging and the Social Cognitive Determinants of Physical Activity Behavior and Behavior Change: Evidence from the Guide to Health Trial,” Journal of Aging Research, vol. 2011, Article ID 505928, 11 pages, 2011. doi:10.4061/2011/505928http://hdl.handle.net/10919/79020Part one of this study investigated the effect of aging on social-cognitive characteristics related to physical activity (PA) among adults in the baseline phase of a health promotion intervention. Participants' questionnaire responses and activity logs indicated PA levels and self-efficacy declined with age, while social support and the use of self-regulatory behaviors (e.g., goal setting, planning, and keeping track) increased. With age participants were also less likely to expect PA to interfere with their daily routines and social obligations. Part two of the study was among overweight/obese, inactive participants completing the intervention; it examined whether improvements in psychosocial variables might counteract declining PA associated with age. After treatment, participants were more active and decreased body weight regardless of age, and improved self-efficacy, outcome expectations, and self-regulatory behaviors. In a causal model, increases in self-efficacy at 7-months lead to increased PA levels and, albeit marginally, weight loss at 16 months; increased PA was associated with greater weight loss. Aging adults who were more confident exercised more and as a result lost more weight. This longitudinal study suggests interventions that offset the effect of aging on self-efficacy may be more successful in helping older participants become more active and avoid weight gain.application/pdfenCreative Commons Attribution 4.0 InternationalArticle - Refereed2017-09-18Copyright © 2011 Eileen Smith Anderson-Bill et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.https://doi.org/10.4061/2011/505928