Im vorliegenden Beitrag wird der neu entwickelte „Bewegungs- und Sportaktivität Fragebogen” (kurz: BSA-Fragebogen oder BSA-F) vorgestellt und hinsichtlich seiner Validität überprüft. Methode: Als Validierungskriterium dienten fahrradergometrische Parameter der Ausdauerleistungsfähigkeit (u. a. Leistung an der Individuellen Anaeroben Schwelle p [IAS] und errechnete VO₂max), die im Rahmen einer randomisiert kontrollierten Interventionsstudie (N = 118) erhoben wurden. Ergebnisse: Der Index zur Gesamtaktivität korrelierte mit r = .32 bzw. r =.34 signifikant mit den Leistungsparametern VO₂max bzw. p [IAS] (konkurrente Validität); der Index zur Sportaktivität trug signifikant (p < .01) zur Vorhersage der 12 Wochen später gemessenen Ausdauerleistungsfähigkeit bei (prognostische Validität); und die Interventionsstudie zeigte, dass die mit dem Modifikationsprogramm provozierten Verhaltensänderungen mit dem BSA-F sensitiv abgebildet werden konnten (Konstruktvalidität). Diskussion: Die Resultate unterstützen–zusammen mit den Ergebnissen früherer Studien–die Annahme, dass mit dem BSA-Fragebogen eine hinreichend valide Messung der Bewegungs- und Sportaktivität möglich ist. Das Instrument empfiehlt sich auch wegen seiner Ökonomie (zeit- und platzsparend) und klaren Struktur (leicht verständlich, einfach ausfüllbar) zum Einsatz in der gesundheits- und sportwissenschaftlichen Forschung.

Objective: To investigate how the effects of a group-based intervention program (MoVo-LISA) on exercise behaviour were mediated by cognitive variables. Different causal models mapping the short-term (adoption) and long-term (maintenance) intervention effects were tested using path analyses. Design: N = 220 in-patients of a rehabilitation clinic were assigned to an usual care or intervention group (quasi-experimental design). Questionnaire-based assessment was conducted at baseline; discharge; and at six weeks, six months and 12 months post discharge. Measures: The potential mediator variables were outcome expectations, self-efficacy, strength of goal intention (intention strength), self-concordance, action planning and barrier management. Results: Observed intervention effects on exercise behaviour (p < 0.05) were mediated by intention strength at the adoption and maintenance stages, by action planning only at the adoption, and by barrier management only at the maintenance stage. Self-efficacy and outcome expectations were only indirectly involved in these mediations by affecting intention strength and self-concordance. Conclusion: This is the first study to track the cognitive mediation processes of intervention effects on exercise behaviour over a long time-period by differentiating the adoption and maintenance stages of behaviour change. The findings emphasise the importance of deconstructing intervention effects (modifiability vs. predictive power of a mediator) to develop more effective interventions.

Background: The high proportion of people with overweight and obesity has become a worldwide problem in recent decades, mainly due to health consequences, such as cardiovascular diseases, neoplasia, and type 2 diabetes mellitus. Regarding effective countermeasures, the digitization of health services offers numerous potentials, which, however, have not yet been sufficiently evaluated. Web-based health programs are becoming increasingly interactive and can provide individuals with effective long-term weight management support. Objective: The purpose of this randomized controlled clinical trial was to evaluate the effectiveness of an interactive web-based weight loss program on anthropometric, cardiometabolic, and behavioral variables and to compare it with a noninteractive web-based weight loss program. Methods: The randomized controlled trial included people who were aged between 18 and 65 years (mean 48.92, SD 11.17 years) and had a BMI of 27.5 to 34.9 kg/m2 (mean 30.71, SD 2.13 kg/m2). Participants (n=153) were assigned to either (1) an interactive and fully automated web-based health program (intervention) or (2) a noninteractive web-based health program (control). The intervention program focused on dietary energy density and allowed for dietary documentation with appropriate feedback on energy density and nutrients. The control group only received information on weight loss and energy density, but the website did not contain interactive content. Examinations were performed at baseline (t0), at the end of the 12-week intervention (t1), and at 6 months (t2) and 12 months (t3) thereafter. The primary outcome was body weight. The secondary outcomes were cardiometabolic variables as well as dietary and physical activity behaviors. Robust linear mixed models were used to evaluate the primary and secondary outcomes. Results: The intervention group showed significant improvements in anthropometric variables, such as body weight (P=.004), waist circumference (P=.002), and fat mass (P=.02), compared with the control group over the course of the study. The mean weight loss after the 12-month follow-up was 4.18 kg (4.7%) in the intervention group versus 1.29 kg (1.5%) in the control group compared with the initial weight. The results of the nutritional analysis showed that the energy density concept was significantly better implemented in the intervention group. Significant differences in cardiometabolic variables were not detected between the 2 groups. Conclusions: The interactive web-based health program was effective in reducing body weight and improving body composition in adults with overweight and obesity. However, these improvements were not associated with relevant changes in cardiometabolic variables, although it should be noted that the study population was predominantly metabolically healthy. Trial Registration: German Clinical Trials Register DRKS00020249; https://drks.de/search/en/trial/DRKS00020249 International Registered Report Identifier (IRRID): RR2-10.3390/ijerph19031393