Intervention Engagement Moderates the Dose-Response Relationships in a Dietary Intervention.

Behavioral interventions could lead to changes in behavior through changes in a mediator. This dose-response relationship might only hold true for those participants who are actively engaged in interventions. This Internet study investigated the role of engagement in a planning intervention to promote fruit and vegetable consumption in addition to testing the intervention effect on planning and behavior. A sample of 701 adults (mean = 38.71 years, 81% women) were randomly assigned either to a planning intervention (experimental group) or to one of 2 control conditions (untreated waiting list control group or placebo active control group). Moderated mediation analyses were carried out. Significant changes over time and time × group effects revealed the effectiveness of the intervention. The effect of the intervention (time 1) on changes in behavior (time 3; 1 month after the personal deadline study participants set for themselves to start implementing their plans) was mediated by changes in planning (time 2; 1 week the personal deadline). Effects of planning on behavior were documented only at a moderate level of intervention engagement. This indicates an inverse U-shaped dose-response effect. Thus, examining participants' intervention engagement allows for a more careful evaluation of why some interventions work and others do not.

Self-efficacy, planning, and preparatory behaviours as joint predictors of physical activity: A conditional process analysis.

OBJECTIVE: Planning can bridge the gap between intentions and action, but what bridges the gap between planning and action? This study helps to answer the question by disentangling the interrelationships between self-efficacy, planning and preparatory behaviours in predicting physical activity. Preparatory behaviours are tested as a working mechanism of planning. Moreover, it is tested whether the utility of preparatory behaviours depends on an individual's level of self-efficacy. METHODS: A survey assessed planning, self-efficacy and preparatory behaviours for physical activity. Adults (N = 166) provided data at two measurement points. In a longitudinal model, preparatory behaviours were specified as a mediator between planning and physical activity. Self-efficacy was specified as a possible moderator at two points in the model. RESULTS: Preparatory behaviours mediated the relationship between planning and physical activity. An interaction between self-efficacy and preparatory behaviours on physical activity was found, indicating that individuals with low self-efficacy beliefs were more active if they engaged more frequently in preparatory behaviours. CONCLUSION: Planning seems to stimulate preparatory behaviours, which in turn make future physical activity more likely. Furthermore, as performing preparatory behaviours represent a step forward towards the enactment of behavioural goals, preparatory behaviours may be particular beneficial for individuals afflicted by self-doubts regarding physical activity.

Sources of self-efficacy for physical activity.

OBJECTIVE: The effects of self-efficacy beliefs on physical activity are well documented, but much less is known about the origins of self-efficacy beliefs. This article proposes scales to assess the sources of self-efficacy for physical activity aims and to comparatively test their predictive power for physical activity via self-efficacy over time to detect the principal sources of self-efficacy beliefs for physical activity. METHOD: A study of 1,406 German adults aged 16-90 years was conducted to construct scales to assess the sources of self-efficacy for physical activity (Study 1). In Study 2, the scales' predictive validity for self-efficacy and physical activity was tested in a sample of 310 older German adults. RESULTS: Short, reliable and valid instruments to measure six sources of self-efficacy for physical activity were developed that enable researchers to comparatively test the predictive value of the sources of self-efficacy. CONCLUSION: The results suggest that mastery experience, self-persuasion, and reduction in negative affective states are the most important predictors of self-efficacy for physical activity in community-dwelling older adults.

Positive Exercise Experience Facilitates Behavior Change via Self-Efficacy.

PURPOSE: Motivational processes can be set in motion when positive consequences of physical exercise are experienced. However, relationships between positive exercise experience and determinants of the motivational and the volitional phases of exercise change have attracted only sparse attention in research. METHOD: This research examines direct and indirect associations between positive experience and motivational as well as volitional self-efficacy, intention, action planning, and exercise in two distinct longitudinal samples. The first one originates from an online observational study in the general population with three measurement points in time (N = 350) and the second one from a clinical intervention study in a rehabilitation context with four measurement points (N = 275). RESULTS: Structural equation modeling revealed the following: Positive experience is directly related with motivational self-efficacy as well as intentions in both samples. In the online sample only, positive experience is associated with volitional self-efficacy. In each sample, experience is indirectly associated with action planning via motivational self-efficacy and intentions. Moreover, action planning, in turn, predicts changes in physical exercise levels. CONCLUSIONS: Findings suggest a more prominent role of positive experience in the motivational than in the volitional phase of physical exercise change. Thus, this research contributes to the understanding of how positive experience is involved in the behavior change process.

Physical activity among adults with obesity: testing the Health Action Process Approach.

OBJECTIVE: This study tested the applicability of the Health Action Process Approach (HAPA) in a sample of obese adults in the context of physical activity. METHOD: Physical activity was assessed along with motivational and volitional variables specified in the HAPA (motivational self-efficacy, outcome expectancies, risk perception, intention, maintenance self-efficacy, action planning, coping planning, recovery self-efficacy, social support) in a sample of 484 obese men and women (body mass index ≥ 30 kg/m2). RESULTS: Applying structural equation modeling, the fit of the HAPA model was satisfactory-χ²(191) = 569.93, p < .05, χ²/df = 2.98, comparative fit index = .91, normed-fit index = .87, and root mean square error of approximation = .06 (90% CI = .06, .07)-explaining 30% of the variance in intention and 18% of the variance in physical activity. Motivational self-efficacy, outcome expectancies, and social support were related to intention. An association between maintenance self-efficacy and coping planning was found. Recovery self-efficacy and social support were associated with physical activity. No relationships were found between risk perception and intention and between planning and physical activity. The assumptions derived from the HAPA were partly confirmed and the HAPA may, therefore, constitute a theoretical backdrop for intervention designs to promote physical activity in adults with obesity.

Preparing for physical activity: pedometer acquisition as a self-regulatory strategy.

When people intend and plan to perform higher levels of physical activity, they do not start on impulse without preparing. Thus, preparation is a behavioral construct positioned between planning and target behavior. This may be reflected by the acquisition of sports equipment as well as monitoring devices such as pedometers. The research questions are who takes such preparatory action, whether picking up a complimentary pedometer can be predicted by self-efficacy and outcome expectancies, and whether this kind of preparatory action facilitates subsequent physical activity. A longitudinal physical activity survey was conducted with 143 university students who were offered a complimentary pedometer. Collecting this free gift served as indicator of preparatory behavior. Outcome expectancies and self-efficacy beliefs were specified as predictors of this behavior. Two weeks later, physical activity differences between the groups were determined. Collecting the pedometer was associated with higher levels of physical activity at follow-up. Outcome expectancies failed to predict the pedometer collection, but self-efficacy did. An interaction between these two factors indicated that self-efficacy compensated for low outcome expectancies. Pedometer acquisition signifies a preparatory action that is facilitated by self-efficacy. Positioned between planning and target behavior, they constitute a proximal self-regulatory step towards health behavior change.

Positive experience, self-efficacy, and action control predict physical activity changes: a moderated mediation analysis.

OBJECTIVES: Experiencing positive consequences of one's physical activity is supposed to facilitate further activity. This motivational outcome might be generated by an increase in perceived self-efficacy. In addition to such a mediator effect, we examine whether this applies generally or only under conditions of volitional control. For this purpose, perceived action control was considered as a putative moderator. DESIGN AND METHOD: N = 193 students participated in a study with three measurement points in time. At baseline, positive experience with previous physical activity was measured as a predictor of physical activity. Two weeks later, self-efficacy and action control variables were assessed as putative mediator and moderator, respectively. After another 2 weeks, physical activity was measured as the outcome. A moderated mediation model was specified with baseline physical activity and sex as covariates. RESULTS: Self-efficacy was found to mediate between initial positive experience and later physical activity, and this mediation was moderated by action control. CONCLUSIONS: Participants' perceptions of positive experience were associated with their subsequent self-efficacy fostering physical activity. However, persons with low levels of action control did not translate positive experience into physical activity via self-efficacy. STATEMENT OF CONTRIBUTION: What is already known on this subject? Numerous studies have shown that exercise-specific self-efficacy predicts subsequent physical activity. Prior positive experience with physical activity is suggested to be associated with exercise-specific self-efficacy. Furthermore, action control was found to be beneficial for the maintenance of physical activity. What does this study add? This study unveils the mechanisms between these social-cognitive determinants: our longitudinal results suggest that the mediation of positive experience and subsequent physical activity via self-efficacy is moderated by action control. Persons with low levels of action control did not translate positive experience into physical activity via self-efficacy.

A combined planning and self-efficacy intervention to promote physical activity: a multiple mediation analysis.

Many individuals are motivated to improve their physical activity levels, but often fail to act upon their intention. Interventions fostering volitional strategies, such as action planning, coping planning, and self-efficacy beliefs, can help to translate intentions into behavior. This study examines the effectiveness and the mechanisms of a combined planning and self-efficacy intervention to promote physical activity among motivated individuals. Participants (N = 883) were randomly assigned to the intervention or to a waiting-list control condition. Multivariate analysis of variance revealed that the intervention resulted in significantly more physical activity, higher levels of action planning, coping planning, and volitional self-efficacy beliefs (p < 0.01). In addition, multiple mediation analysis showed that action planning, coping planning, and volitional self-efficacy mediate between the intervention and physical activity. The study shows that the intervention successfully fostered physical activity and unfolds the underlying self-regulatory mechanisms of the intervention's effectiveness.

Synergistic effects of planning and self-efficacy on physical activity.

Many individuals are motivated to improve their physical activity levels but often fail to act on their good intention. This study examines the roles of planning and self-efficacy in the prediction of physical activity. A total of 290 participants (77% women, mean age = 41.9 years) were surveyed three times. Intentions, planning, and physical activity were specified as a mediator chain. Results reveal that intentions were partly translated into physical activity by planning. Self-efficacy moderated this mediation, reflected by a planning × self-efficacy interaction (p < .05) on physical activity accounting for 16% of the variance in behavior. If a person is self-efficacious, planning seems more likely to be translated into physical activity.

Changes in social-cognitive variables are associated with stage transitions in physical activity.

When it comes to the adoption or maintenance of physical activity, individuals can be placed along a continuum or into stages of change. The Health Action Process Approach proposes three such stages: non-intentional, intentional and actional. Intraindividual differences are reflected by stage transitions: either progression or regression. The present study examines social-cognitive factors of stage transitions: outcome expectancies, self-efficacy and planning. In an online study on physical activity, 660 adults completed questionnaires at baseline and approximately 3 weeks later. Social-cognitive factors were converted into standardized residual change scores to account for changes in outcome expectancies, self-efficacy and planning within the observation period. Discriminant function analyses revealed stage-specific patterns: progression out of non-intentional stage was associated with self-efficacy increases. Out of intentional stage, regression was correlated with decreases in planning, whereas progression was linked to increases in self-efficacy and planning. Regression from action stage was associated with decreases in self-efficacy. Physical activity promotion should focus on improving self-efficacy for non-intending, intending and acting individuals, whereas planning interventions are recommended for intending individuals. Interventions may be more effective by considering specific mechanisms instead of providing generic interventions for all individuals at different stages.