The Association Between Number of Homework Assignments Completed during a Lifestyle Physical Activity Intervention and Scores on Transtheoretical Measures

An assumption of theory-based physical activity interventions is that active participation positively affects the theoretical constructs upon which the intervention is based. This assumption is rarely tested. This study assessed whether participation, defined as completion of homework, in a lifestyle physical activity intervention was associated with changes over 6 months in constructs the homework addressed: the behavioral and cognitive processes of change, self-efficacy, and decisional balance (the pros and cons). Participants were 244 sedentary adults aged 25 to 75 years. They completed an average of 12 of 20 homework assignments. Those completing at least two-thirds of the homework (n = 113) had greater changes in the theoretical constructs from pretest to posttest than those completing less (n = 90). Post-hoc analyses suggest that completing theory-based homework may impact the processes of change and self-efficacy in lifestyle physical activity interventions and, therefore, are warranted in future interventions.

Acknowledgments

This research was supported in part by National Cancer Institute Grant R25 CA57712. Project PRIME was supported by the National Heart, Lung, and Blood Institute Grant HL58608. A.L. Dunn receives royalties on Active Learning Every Day (Blair et al., 2001), which was written based on work completed for The Cooper Institute's Project Active. The authors have no other commercial, financial, or proprietary interest in the subject matter or materials presented in this paper. We give special thanks to the Project PRIME participants, who provided the data used in our analyses and to the PRIME staff for their work in collecting the data. The authors would also like to acknowledge Susan R. Tortolero for her critical review of the manuscript.

Notes

^aDue to missing data, n = 70 for PRIME G; n = 82 for PRIME C.

* p ≤ .05.

** p ≤ .01.