Delivered by Publishing Technology to: University of Nebraska-Lincoln IP: 177.20.247.208 on: Tue, 12 Jan 2016 13:07:00 Copyright (c) PNG Publications. All rights reserved. Am J Health Behav.™ 2008;32(3):305-314 305 Social Cognitive Theory Variables Mediation of Moderate Exercise Brian Hortz PhD, ATC; R. Lingyak Petosa, PhD Brian Hortz, Assistant Professor, Department of Physical Education, Denison University, Granville OH. R. Lingyak Petosa, Associate Pro- fessor, Health Promotion, Exercise Science, The Ohio State University, Columbus, OH. Address correspondence to Dr Hortz, Depart- ment of Physical Education, 200 Livingston Ave, Denison University, Granville OH 43023. E-mail: Hortzb@Denison.edu Objective: To identify the degree to which the social cognitive theory constructs targeted by the Plan- ning to Be Active Program (PBA) were mediators of moderate-inten- sity exercise. Methods: High school students in treatment and com- parison groups received activity- based physical education. The treatment group also received PBA, which develops self-regulation skills to promote leisure-time ex- ercise. Results: PBA increased self- regulation scores, social situation scores, and moderate-intensity ex- ercise. Self-regulation and social situation mediated moderate-inten- sity exercise at posttest. Conclu- sions: As mediators, self-regula- tion and social situation help ex- plain how PBA produces increases in moderate-intensity exercise. Key words : social cognitive theory, intervention, physical ex- ercise Am J Health Behav. 2008;32(3):305-314 T he American Heart Association has identified physical inactivity as one of 5 primary risk factors for cardio- vascular disease. 1 The 1996 Surgeon General’s Report on Physical Activity and Health reported that regular physical ac- tivity reduces the risk of premature mor- tality in general, and coronary heart dis- ease, hypertension, colon cancer, and diabetes mellitus specifically. 2 Maintain- ing a moderately active lifestyle will re- duce the risk of disease among adults. 3-5 Despite this evidence, physical activity begins to decline during adolescence and continues to decline throughout adult- hood. 6,7 The Surgeon General suggests that an important path to disease preven- tion begins by increasing physical activ- ity rates during adolescence. 2 Several school-based interventions to promote physical activity among youth have been evaluated. 8-17 These school interventions demonstrated consistent and modest in- crease in physical activity during physi- cal education classes. 10,13-17 However, school-based studies had no impact on out-of school physical activity. 10,11,13,15 Baranowski et al argue that health behavior interventions should be based on theory. Further they assert that most interventions have yet to demonstrate an improvement in targeted theory variables. This may be an important reason for the limited effectiveness of these interven- tions on physical activity. 18 Although most health interventions claim to be based on theory, few evaluations measure the im- pact of the intervention on the targeted theory variables. As a result, the mecha- nisms by which prevention programs pro- duce changes in health behaviors are poorly understood. It is presumed that theory-based programs produce changes in theoretical variables, which in turn increase the likelihood of the health be- havior. However, these assumptions are rarely tested.