The predictive value of the Theory of Planned Behavior (TPB) on intention and physical activity (PA) over time was examined. Data from the Aging Well and Healthily intervention program (targeting perceived behavioral control and attitude, not subjective norm) were analyzed, including pretest (T0), posttest (T1, except subjective norm) and 4–6 months follow-up (T2, PA outcomes only) (N = 387, M age 72 years). Structural equation modeling was used to test a TPB model. PA was measured subjectively using the Voorrips sports subscale (T0 and T2), items measured perceived increase in PA (T1), and adherence to exercises (T1 and T2). Model fit was good. The TPB explained variation in intention well (R2 .54–.60) and some PA behavior (R2 .13–.16). The intervention successfully got participants to exercise independent of the measured TPB concepts. More TPB studies in the context of interventions are needed.
Stolte and van Tilburg are with the Department of Sociology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands. Hopman-Rock is with the Department of Lifestyle Leiden, TNO Netherlands Organization for Applied Scientific Research, Leiden, The Netherlands; and Department of Public and Occupational Health, EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands. Aartsen is with Norwegian Social Research, Oslo and Akershus University College, Oslo, Norway. Chorus is with the Department of Lifestyle Leiden, TNO Netherlands Organization for Applied Scientific Research, Leiden, The Netherlands; and Sector Health Care, Innovation Health Care Professions & Education, National Health Care Institute, Diemen, The Netherlands.