Florian Lammer

Background: The Global Physical Activity Questionnaire (GPAQ) is applied internationally as a tool to assess the level of physical activity. The GPAQ was designed as an interview, including the use of show cards, which visualise activities of moderate and intensive physical activity and support the distinction between these intensities. The self-administered version of the GPAQ is used in the application-oriented research for reasons of economy and practicality. However, the use of show cards often remains unknown. The aim of the present study was to examine differences in validity between two self-administered versions of the GPAQ with and without show cards. Methods: In this crossover study, two groups (n = 54; 57.4% female; 28.3 ± 12.2 years) received the GPAQ with or without show cards after 7 days and the respective other version after additional 7 days. For validation, all participants wore an accelerometer (ActiGraph GT3X+) on all 14 days. Differences between GPAQ versions and accelerometer data were compared by Wilcoxon signed rank test. Additionally, Spearman analyses and Bland-Altman plots were calculated. Results: No statistically significant difference between the GPAQ versions could be found in regard to the accuracy of physical activity assessment (p > 0.05). Both GPAQ versions show similar correlation coefficients for vigorous physical activity (rho = 0.31–0.42) and sedentary behaviour (rho = 0.29–0.32). No statistically significant correlation was found for physical activity of moderate intensity. The Bland-Altman plots support these results, as both GPAQ versions have the same trends in terms of overestimation and underestimation of physical activity. Conclusion: The use of show cards had no significant impact on questionnaire validity. Therefore, both GPAQ versions can be applied interchangeably. Nevertheless the exact description of application of the GPAQ is desirable in terms of reproducibility and transparent scientific research.

The methodology of intervention studies on physical activity (PA) promotion is of great importance regarding evidence development in complex interventions. The aim of this review was to provide an overview of the methodological quality of those studies which reported statistically significant effects of interventions promoting PA. PUBMED was searched for reviews on PA promotion to identify studies reporting effective interventions with participants of working age (16–67 years). Selected reviews were screened and data from primary studies with effective interventions were extracted to assess methodological quality. Forty-six reviews with 600 primary studies were identified, of which 33 met the inclusion criteria. Twenty-one studies were conducted as randomized controlled trials, 13 included an intervention control group, 25 measured PA by questionnaire, and 13 included objective measurements. Information on used statistics was often scarce, and long-term follow-up measurements were frequently missing. The overall methodological quality was moderate for randomized studies and low for non-randomized studies; information on methods and results was often lacking. To overcome these methodological issues, standardized guidelines for reporting study results should be considered, not only when publishing results but also when designing studies. This review provides a solid foundation for the development of practical advice for planning application-oriented studies in PA promotion.