Validation of a brief German Physical Activity Questionnaire (German-PAQ): Biometric, physiological, strength, and psychological considerations
Authors: Nigg Claudio R. , Kubica Claudia , Ketelhut Sascha 
Published: February 2023

“It is impossible to change things that cannot be measured.” (Nigg et al., 2012, p. 455)
Background
For valid conclusions about physical activity (PA) prevalence, intervention efficacy, dose-response and health outcome, and provide evidence-based recommendations, high-quality measurement is essential (Nigg et al., 2020). PA Questionnaires (PAQs) are a type of self-report allowing both assessment of quantitative and qualitative aspects. An important aspect of a quality measure is its validity – or the degree to which an instrument truly measures the construct it purports to measure. Specifically, criterion validity documents the extent to which an operationalization of a construct, such as a PA (as measured by a PAQ), relates to another representation of the construct.
PA-related indicators include biometric, physiological, strength, and behavioral domains. Although several long German language PAQs exist (e.g., Frey et al., 1999; Jekauc et al., 2013), there is only one brief German PAQ (the IPAQ-short form), however, without criterion validity established. Therefore, this study aimed to validate a brief German PAQ using various criterion validation domains.
Methods
Data from eight different studies (overall N = 155; 31.0% female; mean age = 24.5, SD = 4.8) were combined for this purpose. Six PA items assessed how many days per week and how many minutes per day individuals participated in vigorous, moderate, and mild activity, respectively. To enable PA guideline conclusions moderate to vigorous PA (MVPA) min/wk was calculated (2*vigorous PA min/wk + moderate PA min/wk). Criterion validity measures included biometric indicators: body mass index (BMI, kg/m2), body fat (%), muscle mass (kg), waist circumference (cm), waist-to-height ratio; physiological indicators: resting heart rate (bpm), systolic and diastolic blood pressure (mmHg), maximum oxygen consumption [VO2max, ml/min/kg]); strength indicators: countermovement jump (cm), handgrip strength (kg); and a psychological indicator: PA stage of change.
Results
As expected MVPA min/wk negatively correlated with body fat % (r = -.17, p < .05), and positively with VO2max (r = .36, p < .001), hand grip strength (r = .27, p < .05), and PA stage of change (r = .39, p = .003). Those who met PA guidelines according to the German-PAQ had lower BMI (Cohen’s d [d] = -.20), bodyfat % (d = -.32), waist circumference (d = -.32), waist-to-height ratio (d = -.36), resting heart rate (d = -.31) (all small effects), higher handgrip strength (d = .55; medium effect), VO2max (d = .75, large effect) and PA stage of change (d = 3.46, large effect) versus those who did not. No effects were found for muscle mass, systolic and diastolic blood pressure, and countermovement jump (|d| ≤ .1),
Conclusion
In addition to high face validity, the brief German-PAQ exhibited criterion validity with biometric, physiological, strength, and psychological indicators, similar to other (English language) PAQs. The fact that meeting the guidelines according to the German-PAQ was associated with differences in the indicators adds additional credence to the validity of this measure.
References
Frey, I., Berg, A., Grathwohl, D., & Keul J. (1999). Freiburger Fragebogen zur körperlichen Aktivität-Entwicklung, Prüfung und Anwendung [Freiburg questionnaire on physical activity-development, testing and application]. Sozial und Präventivmedizin, 44, 55–64. https://doi.org/10.1007/BF01667127
Jekauc, D., Wagner, M. O., Kahlert, D. & Woll, A. (2013). Reliabilität und Validität des MoMo-Aktivitätsfragebogens für Jugendliche (MoMo-AFB) [Reliability and validity of the MoMo Activity Questionnaire for Adolescents (MoMo-AFB)]. Diagnostica, 59(2), 100-111. https://doi.org/10.1026/0012-1924/a000083
Nigg, C. R., Fuchs, R., Gerber, M., Jekauc, D., Koch, T., Krell-Roesch, J., Lippke, S., Mnich; C., Novak, B., Ju, Q., Sattler, M., Schmidt, S. C. E., van Poppel, M., Reimers, A. K., Wagner, P., Woods, K., & Woll, A. (2020). Assessing physical activity through questionnaires – A consensus of best practices and future directions. Psychology of Sport and Exercise, 50, Article 101715. https://doi.org/10.1016/j.psychsport.2020.101715
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