ann. behav. med. DOI 10.1007/s12160-013-9578-3
BRIEF REPORT
Psychosocial Mediators of Two Community-Based Physical Activity Programs Katie Becofsky, M.S. & Meghan Baruth, Ph.D. & Sara Wilcox, Ph.D.
# The Society of Behavioral Medicine 2013
Abstract Background Previous findings are inconclusive regarding the mediators of physical activity behavior change. Purpose To test self-efficacy and social support as mediators of Active Choices, a telephone-delivered physical activity intervention, and Active Living Every Day, a group-based physical activity intervention, implemented with midlife and older adults in community settings. Methods MacKinnon's product of coefficients was used to examine social support and self-efficacy as mediators of change in physical activity. The proportion of the total effect mediated was calculated. Each model controlled for age, gender, race (white vs. non-white), body mass index (BMI), and education (high school graduate or less vs. at least some college). Results Increases in self-efficacy mediated increases in physical activity among Active Choices (n =709) and Active Living Every Day (n =849) participants. For Active Living Every Day, increases in social support also mediated increases in physical activity in single mediator models. Conclusions Increasing self-efficacy and social support may help increase physical activity levels in older adults. K. Becofsky : S. Wilcox (*) Department of Exercise Science, Arnold School of Public Health, University of South Carolina, 921 Assembly Street, Columbia, SC 29208, USA e-mail: [email protected] K. Becofsky e-mail: [email protected] M. Baruth College of Health and Human Services, Saginaw Valley State University, 7400 Bay Rd University Center, Columbia, MI 48710, USA S. Wilcox Prevention Research Center, University of South Carolina, Columbia, SC, USA
Keywords Physical activity . Intervention . Self-efficacy . Social support . Older adults . Behavior change
Introduction Mediation analyses can help explain how physical activity interventions achieve their outcomes [1]. Acquiring this information may provide support for current behavior change theories, or may prompt revision or new theory development. The ultimate goal of mediation analyses is to understand the critical components of successful interventions (or the missing components of unsuccessful ones) to maximize the efficiency and effectiveness of future programs. Physical activity self-efficacy and social support have long been considered key factors for physical activity adoption and maintenance. Physical activity and self-efficacy refers to an individual's confidence in his or her ability to engage in physical activity, even when encountering barriers, whereas social support encompasses various types of encouragement and assistance received for engaging in physical activity. These constructs are consistent with social cognitive theory [2] and the transtheoretical model [3], both of which are commonly used as the theoretical bases for physical activity interventions. Although physical activity self-efficacy and social support are staples of the physical activity behavior change literature, evidence of their ability to mediate intervention effects is conflicting [4, 5]. Even less information is known about their mediating role in interventions targeting older adults. Two review papers have found limited evidence for the role of these behavioral constructs in mediating physical activity interventions, although one excluded studies with adults 65+ [5], and the other included only 1 study with older adults [4]. Cerin et al. suggested that the inconclusive findings regarding the mediators of physical activity behavior change may be
K. Becofsky et al.
due, in part, to the use of statistical methods that are incapable of detecting mediation effects in relatively small samples [6]. The current study sought to test whether self-efficacy for physical activity and social support mediated the effects of two physical activity programs implemented with older adults in community settings. Both programs were theory based [2, 3], and specifically targeted these constructs. Importantly, our study will address two of the limitations Cerin et al. [6] cite as common to physical activity mediation studies: our study has a large sample size and utilizes a powerful analytic approach (MacKinnon [7]).
Methods Active For Life was a 4-year translational initiative that successfully implemented two physical activity programs, Active Choices (a 6-month telephone-based program) and Active Living Every Day (a 20-week group-based program), into community settings with diverse midlife and older adult populations [8]. Both Active Choices [9, 10] and Active Living Every Day [11, 12] were previously tested in rigorous randomized controlled trials. Both led to significant improvements in physical activity when translated to community settings (see Wilcox et al. 2008 [8] for methodology details and other major findings). In the last year of the Active for Life initiative, the Active Living Every Day program was shortened from 20 to 12 weeks at the request of the participating organizations; steps were taken to ensure essential elements were preserved [8]. The current study used a pre– post design, with data collected from 2003 to 2007. Participants All Active for Life participants were ≥50 years of age, not meeting physical activity recommendations (≤2 days/week and
BRIEF REPORT
Psychosocial Mediators of Two Community-Based Physical Activity Programs Katie Becofsky, M.S. & Meghan Baruth, Ph.D. & Sara Wilcox, Ph.D.
# The Society of Behavioral Medicine 2013
Abstract Background Previous findings are inconclusive regarding the mediators of physical activity behavior change. Purpose To test self-efficacy and social support as mediators of Active Choices, a telephone-delivered physical activity intervention, and Active Living Every Day, a group-based physical activity intervention, implemented with midlife and older adults in community settings. Methods MacKinnon's product of coefficients was used to examine social support and self-efficacy as mediators of change in physical activity. The proportion of the total effect mediated was calculated. Each model controlled for age, gender, race (white vs. non-white), body mass index (BMI), and education (high school graduate or less vs. at least some college). Results Increases in self-efficacy mediated increases in physical activity among Active Choices (n =709) and Active Living Every Day (n =849) participants. For Active Living Every Day, increases in social support also mediated increases in physical activity in single mediator models. Conclusions Increasing self-efficacy and social support may help increase physical activity levels in older adults. K. Becofsky : S. Wilcox (*) Department of Exercise Science, Arnold School of Public Health, University of South Carolina, 921 Assembly Street, Columbia, SC 29208, USA e-mail: [email protected] K. Becofsky e-mail: [email protected] M. Baruth College of Health and Human Services, Saginaw Valley State University, 7400 Bay Rd University Center, Columbia, MI 48710, USA S. Wilcox Prevention Research Center, University of South Carolina, Columbia, SC, USA
Keywords Physical activity . Intervention . Self-efficacy . Social support . Older adults . Behavior change
Introduction Mediation analyses can help explain how physical activity interventions achieve their outcomes [1]. Acquiring this information may provide support for current behavior change theories, or may prompt revision or new theory development. The ultimate goal of mediation analyses is to understand the critical components of successful interventions (or the missing components of unsuccessful ones) to maximize the efficiency and effectiveness of future programs. Physical activity self-efficacy and social support have long been considered key factors for physical activity adoption and maintenance. Physical activity and self-efficacy refers to an individual's confidence in his or her ability to engage in physical activity, even when encountering barriers, whereas social support encompasses various types of encouragement and assistance received for engaging in physical activity. These constructs are consistent with social cognitive theory [2] and the transtheoretical model [3], both of which are commonly used as the theoretical bases for physical activity interventions. Although physical activity self-efficacy and social support are staples of the physical activity behavior change literature, evidence of their ability to mediate intervention effects is conflicting [4, 5]. Even less information is known about their mediating role in interventions targeting older adults. Two review papers have found limited evidence for the role of these behavioral constructs in mediating physical activity interventions, although one excluded studies with adults 65+ [5], and the other included only 1 study with older adults [4]. Cerin et al. suggested that the inconclusive findings regarding the mediators of physical activity behavior change may be
K. Becofsky et al.
due, in part, to the use of statistical methods that are incapable of detecting mediation effects in relatively small samples [6]. The current study sought to test whether self-efficacy for physical activity and social support mediated the effects of two physical activity programs implemented with older adults in community settings. Both programs were theory based [2, 3], and specifically targeted these constructs. Importantly, our study will address two of the limitations Cerin et al. [6] cite as common to physical activity mediation studies: our study has a large sample size and utilizes a powerful analytic approach (MacKinnon [7]).
Methods Active For Life was a 4-year translational initiative that successfully implemented two physical activity programs, Active Choices (a 6-month telephone-based program) and Active Living Every Day (a 20-week group-based program), into community settings with diverse midlife and older adult populations [8]. Both Active Choices [9, 10] and Active Living Every Day [11, 12] were previously tested in rigorous randomized controlled trials. Both led to significant improvements in physical activity when translated to community settings (see Wilcox et al. 2008 [8] for methodology details and other major findings). In the last year of the Active for Life initiative, the Active Living Every Day program was shortened from 20 to 12 weeks at the request of the participating organizations; steps were taken to ensure essential elements were preserved [8]. The current study used a pre– post design, with data collected from 2003 to 2007. Participants All Active for Life participants were ≥50 years of age, not meeting physical activity recommendations (≤2 days/week and
