A randomized controlled trial evaluated the effectiveness of a 4-wk extended theory of planned behavior (TPB) intervention to promote regular physical activity and healthy eating among older adults diagnosed with Type 2 diabetes or cardiovascular disease (N = 183). Participants completed TPB measures of attitude, subjective norm, perceived behavioral control, and intention, as well as planning and behavior, at preintervention and 1 wk and 6 wk postintervention for each behavior. No significant time-by-condition effects emerged for healthy eating. For physical activity, significant time-by-condition effects were found for behavior, intention, planning, perceived behavioral control, and subjective norm. In particular, compared with control participants, the intervention group showed short-term improvements in physical activity and planning, with further analyses indicating that the effect of the intervention on behavior was mediated by planning. The results indicate that TPB-based interventions including planning strategies may encourage physical activity among older people with diabetes and cardiovascular disease.
White is with the School of Psychology and Counselling, Queensland University of Technology, Brisbane, Australia. Terry, Troup, and Kenardy are with the School of Psychology, University of Queensland, St. Lucia, Brisbane, Australia. Rempel is with the Dept. of Nursing, Brock University, St. Catharines, ON, Canada. Norman is with the Dept. of Psychology, University of Sheffield, Sheffield, UK. Mummery is with the Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Canada. Riley is with Dairy Australia, Level 5 IBM Centre, Victoria, Australia. Posner is with the School of Health Sciences, University of Birmingham, Edgbaston, Birmingham, UK.