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.

Objective : The purpose was to examine whether a 1-h intervention would help increase fruit consumption in motivated individuals and to study the role of self-regulatory mechanisms in the behaviour change process, with a particular focus on dietary planning and action control. Methods : A randomised controlled trial compared a 1-h online intervention with controls in 791 participants. Dependent variables were fruit intake, planning to consume and dietary action control. Results : Experimental condition by time interactions documented superior treatment effects for the self-regulation group, although all participants benefited from the study. To identify the contribution of the intervention ingredients, multiple mediation analyses were conducted that yielded mediator effects for dietary action control and planning. Conclusions : A very brief self-regulatory nutrition intervention was superior to a control condition. Dietary planning and action control seem to play a major role in the mechanisms that facilitate fruit intake.

Many individuals are not as physically active as recommended or as intended. The aim of the current study was to compare the prevalence of physical activity with official recommendations as well as with individuals' intentions. Moreover, mechanisms were explored further. Therefore, 492 men and women were assessed three times over a time span of approximately 3 and 6.5 weeks, respectively. As expected, behavioral prevalence was lower than recommendations and intentions. Previous behavior, intentions and self-efficacy predicted subsequent behavior. When analyzing non-linear relationships between intentions and behavior, a moderate level of intentions appeared to be best for subsequent performance: Good intentions have to be realistic in order to be translated into behavior. This is especially important for individuals being overweight or obese because particular recommendations exist for them performing physical activities.

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.

OBJECTIVEStage theories of health behavior are popular and of high practical relevance. Tests of the validity of these theories provide limited evidence because of validity and reliability problems. This study provides a bottom-up approach to identify behavioral stages from examining differences in underlying mindsets. We examine the concurrent validity of a latent-class-based approach and a commonly used stage-algorithm based on self-reports about intentions and behavior in order to identify possible strengths and shortcomings of previously used approaches.METHODSSocial-cognitive variables and individuals' stages were assessed in a sample of 2,219 internet users. Latent class analysis (LCA) was used to identify distinct groups with similar patterns of social-cognitive predictors. Convergent validity of the LCA solution and stage algorithms was tested by examining adjusted standardized residuals.RESULTSThe LCA identified four distinct profiles-not intending to change, intending to change (no action), intending to change with action, and maintaining. Convergent validity with a stage algorithm was low, in particular in the nonintending and maintaining stages.CONCLUSIONStages as assigned by the stage-algorithm did not correspond well with the extracted mindsets: This indicates that commonly used stage-algorithms might not be effective in assigning individuals to stages that represent mindsets, undermining the possibility for stage-matched interventions.

Objective: The purpose was to examine whether a one-hour intervention would help increase fruit consumption in motivated individuals and to study the role of self-regulatory mechanisms in the behavior change process, with a particular focus on dietary planning and action control. Methods: A randomized controlled trial compared a one-hour online intervention with controls in 791 participants. Dependent variables were fruit intake, planning to consume, and dietary action control. Results: Experimental condition by time interactions documented superior treatment effects for the self-regulation group, although all participants benefited from the study. To identify the contribution of the intervention ingredients, multiple mediation analyses were conducted that yielded mediator effects for dietary action control and planning. Conclusions: A very brief self-regulatory nutrition intervention was superior to a control condition. Dietary planning and action control seem to play a major role in the mechanisms that facilitate fruit intake.

Zusammenfassung. Bekanntlich sind viele Menschen weniger körperlich aktiv als empfohlen oder als sie es selbst beabsichtigen. Ziel dieser Studie ist es, die Prävalenzen von körperlicher Aktivität einerseits mit den offiziellen Empfehlungen und andererseits mit den Intentionen von Personen zu vergleichen sowie Verhalten längsschnittlich vorherzusagen. Dafür wurden Befragungsdaten von 492 Frauen und Männern zu drei Messzeitpunkten im Abstand von ca. 3 Wochen und 6,5 Wochen untersucht. Wie erwartet lagen die Prävalenzen sowohl unterhalb der Empfehlungen als auch unterhalb der eigenen Intentionen. Früheres Verhalten, Intention und Selbstwirksamkeitserwartung konnten gemeinsam spätere körperliche Aktivität vorhersagen. Bei der Analyse nicht-linearer Zusammenhänge von Intention und berichtetem Verhalten zeigte sich darüber hinaus, dass vor allem ein Mittelmaß an Intention funktional für tatsächliche Verhaltensausübung ist: gute Absichten müssen realistisch sein, um in die Tat umgesetzt werden zu können. Dies gilt insbesondere für Menschen mit Übergewicht, für die spezielle Empfehlungen für die Ausübung von körperlicher Aktivität vorliegen.

Intervention-engagement has received little attention in sports medicine as well as research and promotion of physical exercise. The construct is important, however, in the understanding of why interventions work. This study aimed at shedding more light on the interplay of engagement and the subsequent effectiveness of physical exercise interventions. A three-stage model differentiating among nonintenders, intenders, and actors informed the intervention design in this study. In an Internet-based randomized controlled trial (RCT) with two measurement points, N=326 participants received a stage-matched, stage-mismatched, or control treatment. Assessed variables were goal setting, planning, behavior, and intervention-engagement. It was found that regarding goal setting, nonintenders in the stage-matched intervention and those who engaged highly in the stage-matched intervention improved significantly over time. Regarding planning, intenders in the matched condition as well as all actors increased their levels over time. Regarding behavior, nonintenders and intenders having engaged highly in the intervention improved more than those having engaged little. In order to help nonintenders progress on their way toward goal behavior, it is necessary that they engage highly in a stage-matched intervention. Implications for exercise promotion are that interventions should also aim at increasing participants' intervention-engagement.

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.

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.

Stage-matched interventions can only be more effective than “one-size-fits-all” interventions if they target participants' specific needs. Therefore, individuals must be allocated to a stage that truly reflects their mindsets. Various criteria for stage allocation exist. This study's objective was to demonstrate the impact of different classification criteria on stage allocation, and which criterion yields the best reflection of individuals' mindsets. The sample consists of 569 internet users. Physical activity, intention to change, and four stages of change (Non-Intender, Intender, Maintaining Actor, and Changing Actor) were assessed. Staging was based on two criteria: individual criteria and externally imposed criteria (30 min of physical activity on at least 4 days of the week). Hypotheses were tested by multivariate analyses and validity tests. As predicted, the different criteria affected stage allocation, and staging based on the individual criterion seemed to reflect individuals' intention to change and behavior better than staging based on the external standard.

To change dietary behaviors, people must be motivated to do so. But intentions often do not translate into behavior. Strategic planning (as a mediator) is expected to move people from intention to action. However, individuals who lack perceived self-efficacy might fail to apply their plans when encountering challenging situations. Thus, self-efficacy might operate as a moderator variable when it comes to studying the mediator effects of planning on behaviors. This study examines the interactive role of planning and self-efficacy in the context of dietary changes. A longitudinal sample of 411 employees was surveyed twice in terms of their fruit and vegetable consumption over a 4-week interval. Intentions, planning, and fruit and vegetable consumption were specified as a mediator chain with self-efficacy as a moderator at two stages of the putative change process. Baseline behavior served as a covariate in the model. Intentions were translated into dietary behavior by planning. Self-efficacy moderated this mediation at the second stage, reflected by a planning x self-efficacy interaction on fruit and vegetable consumption. The strength of the mediated effect increased along with levels of self-efficacy. Individuals with very low self-efficacy did not benefit from planning. If a person lacks self-efficacy, planning does not seem to translate intentions into fruit and vegetable consumption.

A first step towards the improvement of daily dietary behaviors is forming an intention to change one's nutrition. However, an intention by itself is not sufficient for successful action. Rather, to translate intentions into behavior, careful planning is recommended. Thus, planning constitutes a mediator between the intention and the behavior. However, if a person lacks self-efficacy, this mediation might fail. Previous research in Costa Rica and South Korea has identified perceived self-efficacy as a moderator of the intention-planning-behavior relationship. To examine further the moderator role of self-efficacy, two additional studies were designed in Thailand and Germany. Study 1 surveyed 1718 Thai university students in terms of a low-fat diet; Study 2 surveyed 1140 German internet users in terms of their fruit and vegetable consumption at two measurement points in time, 6 months apart. Intentions served as predictor, planning as mediator, self-efficacy as moderator, and behaviors as outcomes. First, intentions were translated into nutrition behaviors by planning. Second, self-efficacy moderated this mediation in both studies: The strength of the mediated effect increased along with levels of self-efficacy, even when accounting for baseline behaviors. For planning to mediate the intention-behavior relation, people must not harbor self-doubts. If they lack self-efficacy, intentions are not well translated into nutrition behavior through planning.

The worldwide increasing popularity of health psychology is illustrated by an analysis of data gathered at the International Congress of Psychology (ICP) in Berlin, 2008. The first analysis deals with the topics of interest that participants had stated when registering online for the congress. Out of 26 topics, health psychology obtained rank 9. The second analysis deals with the primary category in which abstracts were classified. Out of 6,252 abstracts, 10.65% were assigned to health psychology as the primary domain of research. These congress-based data may complement previous bibliometric data that attest to the increasing importance of health psychology.