Validating device-based physical activity indicators with observation physical activity indicators in Swiss pre-school children
Authors: Schmidli Bianca Celine , Endes Simon , Stoffel Kerr Sonja D. , Nigg Claudio R. 
Published: February 2023

Purpose
Accelometry is a very important tool to measure physical activity (PA) in preschoolers, as it can measure 24-hour PA and detect activity which cannot be captured by other methods. However, accelerometer validation for preschoolers is lacking (Altenburg et al. 2022). Specifically, for the ActiGraph wGT3X-BT and Move 4 (ActiGraph LLC; Move4 activity sensor, movisens GmbH) only a few, respectively no preschooler validation studies, were found. Thus, the purpose was to validate these two accelerometers in Swiss preschoolers with the System for Observing Children’s Activity and Relationships during Play (SOCARP; Ridgers et al., 2010).
Methods and Design
Preschoolers (2-5 years old) from two Swiss Sunday activity programs (MiniMove & Ä Halle wo’s fägt) were randomly selected as part of a larger program evaluation. PA was assessed SOCARP for a duration of 12 minutes per child. During the observation, the children wore both an ActiGraph and a Move4 device taped to their right hip to record steps. Step-counts from the ActiGraph and Move4 were correlated with each other and with moderate-to-vigorous (MV)PA from SOCARP (as SOCARP does not count steps).
Results
Valid PA data was available for 45/58 (77.6%) children (49% girls) for SOCARP and for 47/58 (81%) children (51% girls) for accelometry. Step count correlations between the accelerometers (Actigraph and Move4) and %MVPA (SOCARP) was medium and positive (r(43) = .34, p = .03 and r(43) = .37, p = .02; respectively). There was a strong step count correlation between the two devices (r(45) = .90, p < .001), although ActiGraph measured significantly more steps than Move4 (m = 557.74, SD = 255.77 versus m = 397.81, SD = 164.10); t(46)=8.47, p < .001).
Discussion
PA measurement in preschool children can be challenging. However, the correlation between step counts and observed %MVPA indicates criterion validity for both devices. The step-counts of Actigraph and Move4 validate each other, but there is a difference in the absolute number of measured steps. Due to different outcome parameters, calculation algorithms, and inaccessibility to raw acceleration the comparison of the two devices on movement intensity was not possible. Although promising preliminary indications of validity of device-based measurement of PA in Swiss preschool children, further investigations into the methodological approaches of comparing measurements of movement intensity are warranted.
References
Altenburg, T. M., de Vries, L., op den Buijsch, R., Eyre, E., Dobell, A., Duncan, M., & Chinapaw, M. J. M. (2022). Cross-validation of cut-points in preschool children using different accelerometer placements and data axes. Journal of Sports Sciences, 40(4), 379-385. https://doi.org/10.1080/02640414.2021.1994726
Ridgers, N. D., Stratton, G., & McKenzie, T. L. (2010). Reliability and validity of the system for observing children’s activity and relationships during play (SOCARP). Journal of Physical Activity and Health, 7(1), 17–25. https://doi.org/10.1123/jpah.7.1.17