Examination of print and telephone channels for physical activity promotion: Rationale, design, and baseline data from Project STRIDE

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Abstract

Background

Project STRIDE is a 4-year randomized controlled trial comparing two computer-based expert system guided intervention delivery channels (phone vs. print) for physical activity adoption and short-term maintenance among previously sedentary adults.

Methods

Sedentary adults (n = 239) were randomized to one of the following (1) telephone-based, individualized motivationally-tailored feedback; (2) print-based, individualized motivationally-tailored feedback; (3) contact-control delayed treatment group (received intervention after 12 months as control). This paper: (1) outlines the study design, rationale, and participant sample; and (2) describes relationships between baseline variables to better understand their influence on the efficacy of the intervention.

Results

Participants averaged 19.8 ± 25.0 min of physical activity/week that was at least of moderate intensity, with no group differences. The average estimated VO2 at 85% of maximum heart rate was 25.6 ml/kg/min. Body fat was 34.1% for women and 23.2% for men and the BMI of the sample averaged 28.5 kg/m2.

Conclusions

Project STRIDE examines non face-to-face approaches for promoting physical activity behavior. It has unique features including a direct comparison of an expert system guided intervention delivered via phone or print. Future analyses will examine the cost-effectiveness of the interventions and this will likely yield important information for policy-makers.

Introduction

The American College of Sports Medicine (ACSM) and the Centers for Disease Control and Prevention (CDC) recommend that healthy individuals with no known cardiovascular disease engage in at least 30 min of moderate intensity physical activity on most, preferably all, days of the week [1]. Only 25% of Americans meet the recommended levels of physical activity participation [2] despite the health benefits of a physically active lifestyle (e.g., reduced risk of cardiovascular disease and non-insulin-dependent diabetes) [3], [4].

In order to reach the large number of sedentary individuals, non face-to-face interventions utilizing different delivery channels such as print and telephone need to be developed and evaluated. To improve the efficacy of these interventions, researchers recommend that such interventions be grounded in psychological theories of behavior change [5]. Both Social Cognitive Theory [6] and the Transtheoretical Model [7] are two frameworks that have been used to guide physical activity interventions in community, workplace, and primary care settings, with promising results (e.g., [8], [9], [10]). The Stages of Motivational Readiness for Change Model posits that individuals move through a series of stages when making a behavior change [7]. These stages include Precontemplation (not intending to make changes), Contemplation (considering a change), Preparation (making small changes), Action (actively engaging in the behavior) and Maintenance (sustaining the change over time). In addition, aspects of Social Cognitive Theory (e.g., self-efficacy, outcome expectations) have been shown to be important factors in predicting physical activity behaviors [11], [12].

Theory-based face-to-face interventions have been found to be efficacious; however, their reach to the broad population of sedentary individuals is limited because there are numerous barriers associated with face-to-face interventions (e.g., work schedules, time, childcare, cost). Consequently, the examination of non face-to-face channels, such as print materials delivered through the mail, for intervention delivery is critical when cost containment and time constraints do not allow for frequent or lengthy in-person contacts. Non face-to-face channels, or mediated interventions, are especially important for reaching individuals who have typically not availed themselves of health promotion programs because of real or perceived barriers of access, cost, or transportation.

In a review of 127 published studies on physical activity interventions from the years 1965–1995, Dishman and Buckworth [13] found larger effect sizes for those interventions that employed non face-to-face interventions (e.g., print mailings, telecommunication) when compared with those that were strictly face-to-face. This review indicates that interventions designed to increase physical activity can be effective, particularly when they are delivered using non face-to-face approaches and emphasize home-based, lifestyle activities.

Individually-tailored, print-based interventions are one example of a low cost, less time intensive channel for facilitating behavior change. Several investigations have demonstrated that print-based interventions are effective for the adoption of physical activity [10], [14]. For example, one study found that participants who received a 6-month individualized motivationally tailored print intervention (Tailored) spent more time exercising per week (151.4 min) and were more likely to achieve CDC/ACSM recommended levels of physical activity (p < 0.01) than participants who received standard print materials (Standard; 97.6 min, p < 0.05) [14]. Interestingly, at 12 months, both groups reported increases in their time spent in physical activity (Tailored: 187 min vs. Standard: 133 min), although these increases were not significant [15]. At month 12, Tailored participants were significantly more likely than the Standard group to meet or exceed the CDC/ACSM criteria for physical activity participation (42% vs. 25%). These results indicate that print-based materials are effective tools for enhancing physical activity adoption, particularly when they are individualized, motivationally tailored, and emphasize key social cognitive concepts such as self-efficacy and outcome expectations.

Theory-based telephone-delivered programs have also been shown to be efficacious for physical activity promotion. For example, one study examining the efficacy of three exercise programs found that initially sedentary participants in the two telephone-delivered home-based programs reported a greater number of exercise minutes (averaging approximately 120–131 min/week) than participants in the group-based program (who averaged approximately 60 min/week) at 1 year [16]. These findings were generally maintained at 2 years [9]. Similarly, in a recently completed study evaluating telephone-based physical activity interventions delivered through either a health educator or a telephone-linked computer system, both telephone-based programs were shown to be able to significantly increase 12-month physical activity levels above the 150 min of moderate or more vigorous activity per week recommended in the 1996 Surgeon General's report [5], [17].

In summary, both print- and telephone-based interventions can be effective for adults who, due to work, family, or social demands, may have difficulty attending face-to-face programs. This is an important area for public health given that print-based interventions are typically less costly and more easily disseminated than telephone-based interventions. The primary aim of this study was to determine the differential effects of intervention delivery channel (phone vs. print vs. contact-control) on physical activity adoption and short-term maintenance among previously sedentary adults. In order to control for content across the intervention delivery channels, we utilized a computer-based expert system to guide the information for both delivery arms. Based on previous research in the field, we hypothesized that individuals randomized to either the telephone or print conditions would exhibit significantly higher levels of physical activity participation at 6 and 12 months than individuals in the delayed treatment condition (contact control). Additionally, we hypothesized that participants randomized to the telephone condition would exhibit significantly higher levels of physical activity participation at 6 and 12 months than those in the print condition. We hypothesized that the telephone intervention would outperform the print intervention because of the potential for increased support and social connectedness between the telephone counselor and participant.

The purpose of this paper is to describe: (1) the study design and rationale; (2) sample of participants; and (3) relationships between baseline variables in order to better understand how these variables may influence the efficacy of the intervention. Because baseline variables may interact with one another to influence the outcome of the intervention, it is important to examine the correlations among these variables at baseline.

Section snippets

Methods

This was a randomized controlled clinical trial comparing three conditions: (1) telephone-based, individualized motivationally-tailored feedback; (2) print-based, individualized motivationally-tailored feedback; (3) contact-control delayed treatment control group (received intervention after 12 months as control). As mentioned previously, both interventions utilized a computer-based expert system platform to guide the delivery of content. The intervention period was for 12 months with a more

Measures

Questionnaires were used to assess physical activity behavior, selected cognitive–behavioral mediators and history variables, intervention preferences, social support, environmental access to physical activity opportunities, and level of depression and anxiety.

Demographics

Table 2 presents baseline characteristics of the participants randomized to the study. The randomization procedure produced equivalent groups. The study population was predominantly Caucasian (90.3), female (82.0%), and middle-aged (mean = 44.5 years). Of the 239 participants, the majority had a college education or above (70.6%) and a total household income above $50,000 (60.8%).

Physical activity behavior and physiologic measurement of exercise capacity

The baseline PAR levels indicate that this sample is sedentary (Table 2). The participants averaged 19.8 ± 25.0 min of

Discussion

This trial is designed to move the field forward by examining non face-to-face approaches for promoting physical activity behavior. In prior studies it has been demonstrated that print-based materials that are individualized, motivationally tailored, and emphasize key social cognitive concepts such as self-efficacy and outcome expectations are effective tools for enhancing physical activity adoption [10], [14]. Prior studies have also shown that telephone-based interventions emphasizing social

Acknowledgments

This research was supported in part through a grant from the National Heart, Lung, and Blood Institute (#HL64342). The authors would like to acknowledge the contributions of Linda Christian, R.N., Robin Cram, M.F.A., Lisa Cronkite, B.S., Santina Ficara, B.S., Maureen Hamel, B.S., Jaime Longval, M.S., Kenny McParlin, Hazel Ouellette, Susan Pinheiro, B.A., Regina Traficante, Ph.D., and Kate Williams, B.S. in the conduct of the study. We also would like to thank Manoj Eapen M.D., Vikas Verma M.D.

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