Given the decreased rate of morbidity and mortality associated with physical activity, understanding the factors that enhance the efficacy of physical activity interventions is a priority. The present study examined the moderating effect of baseline enjoyment of physical activity on the efficacy of a physical activity intervention. Participants were 238 healthy low-active adults enrolled in Project STRIDE, a randomized, controlled, clinical trial comparing individually tailored print and telephone interventions to a contact control. Results indicated a significant interaction between intervention assignment (telephone or print intervention vs. contact control) and baseline enjoyment on physical activity at 6 months, as measured by the 7-Day Physical Activity Recall (z = 2.44, p < .05). These results indicate that our motivationally tailored physical activity promotion program may be more effective among individuals reporting greater enjoyment of physical activity at baseline, and suggest that attention be paid to designing programs that can be effective for participants who report lower levels of physical activity enjoyment.
The authors are with the Centers for Behavioral and Preventive Medicine, Brown Medical School and the Miriam Hospital, Providence, RI 02903; Lewis is currently with HealthPartners Research Foundation, Minneapolis, MN 55440; and Papandonatos is with the Center for Statistical Sciences, Brown University, Providence, RI 02912.