Social cognitive theory mediators of physical activity in a lifestyle program for cancer survivors and carers: findings from the ENRICH randomized controlled trial

Abstract

BackgroundDespite increasing numbers of cancer survivors and evidence that diet and physical activity improves the health of cancer survivors, most do not meet guidelines. Some social cognitive theory (SCT)-based interventions have increased physical activity behavior, however few have used objective physical activity measures. The Exercise and Nutrition Routine Improving Cancer Health (ENRICH) randomized controlled trial reported a significant intervention effect for the primary outcome of pedometer-assessed step counts at post-test (8-weeks) and follow-up (20-weeks). The aim of this study was to test whether the SCT constructs operationalized in the ENRICH intervention were mediators of physical activity behavior change.MethodsRandomized controlled trial with 174 cancer survivors and carers assessed at baseline, post-test (8-weeks), and follow-up (20-weeks). Participants were randomized to the ENRICH six session face-to-face healthy lifestyle program, or to a wait-list control. Hypothesized SCT mediators of physical activity behavior change (self-efficacy, behavioral goal, outcome expectations, impediments, and social expectations) were assessed using valid and reliable scales. Mediation was assessed using the Preacher and Hayes SPSS INDIRECT macro.ResultsAt eight weeks, there was a significant intervention effect on behavioral goal (A = 9.12, p = 0.031) and outcome expectations (A = 0.25, p = 0.042). At 20 weeks, the intervention had a significant effect on self-efficacy (A = 0.31, p = 0.049) and behavioral goal (A = 13.15, p = 0.011). Only changes in social support were significantly associated with changes in step counts at eight weeks (B = 633.81, p = 0.023). Behavioral goal was the only SCT construct that had a significant mediating effect on step counts, and explained 22 % of the intervention effect at 20 weeks (AB = 397.9, 95 % CI 81.5–1025.5).ConclusionsSCT constructs had limited impact on objectively-assessed step counts in a multiple health behavior change intervention for cancer survivors and their carers. Behavioral goal measured post-intervention was a significant mediator of pedometer-assessed step counts at 3-months after intervention completion, and explained 22 % of the intervention effect. Future research should examine the separate impact of goals and planning, as well as examining mediators of behavior maintenance in physical activity interventions targeting cancer survivors.Trial registrationAustralian and New Zealand Clinical Trials registry ANZCTRN1260901086257.

Correlates of light physical activity among cancer survivors

“…Based on research examining correlates of MVPA, perceived social support was expected to be positively associated with LPA and higher unsupportive partner response to cancer was expected to be negatively associated with LPA. Instead, results revealed no significant association of perceived social support and LPA.…”

Persuasive system features in computer-mediated lifestyle modification interventions for physical activity

“…Additionally, social motivation should be provided in behaviour change interventions. Goal-setting can be self-set, assigned or collaborative (32,33). Therefore, including goal-setting, having an attainable goal, conducting self-monitoring and providing feedback have been recognised as requirements for behaviour change support (34).…”

Psychosocial Mediators of a Group-based Physical Activity Intervention in Older Adults

“…Many theoretical constructs have been tested as mediators of change and results are not consistent. Self-efficacy, [10,16,20] Social support, [10] goal setting, [16,19] and behavioral processes [15,21] have been found to mediate change in physical activity behavior in some studies, although other studies have not found support for some of these constructs [12,13,16,19]. It is important to note that the samples included in these studies are quite diverse (i.e., older adults, pregnant women, cancer survivors, healthy populations).…”

“…Although significant progress has been made in understanding how physical activity interventions exert their effects, [10][11][12][13][14][15][16][17][18][19][20][21] much work remains. Many theoretical constructs have been tested as mediators of change and results are not consistent.…”