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This paper presents the psychometric properties of the MoMo-AFB (Bos, Worth, Opper, Oberger & Woll, 2009), a questionnaire designed to measure the physical activity of children and adolescents. The MoMo-AFB consists of 28 items, covering the fields of everyday physical activity, sports within and outside of organised clubs, physical education as well as compliance with physical activity guidelines. A study was conducted with 109 boys and 87 girls aged between 9 and 17 years. The MoMo-AFB was given on two separate occasions to evaluate reliability and was compared with accelerometry data of ActiGraph GT1X to evaluate validity. The overall kappa/weighted kappa coefficient for the one-week testretest reliability was .66 (SD = .19) and the overall intraclass correlation (ICC) .68. Self-reported and accelerometer-measured average weekly time spent performing moderate to vigorous physical activity were significantly correlated (Spearman r = .29). Regarding reliability and validity, the MoMo-AFB is comparable with other international published physical activity questionnaires for adolescents.
Due to the ability of microgels to rapidly contract and expand in response to external stimuli, assemblies of interconnected microgels are promising for actuation applications, e.g., as contracting fibers for artificial muscles. Among the properties determining the suitability of microgel assemblies for actuation are mechanical parameters such as bending stiffness and mobility. Here, we study the properties of linear, one-dimensional chains of poly(N-vinylcaprolactam) microgels dispersed in water. They were fabricated by utilizing wrinkled surfaces as templates and UV-cross-linking the microgels. We image the shapes of the chains on surfaces and in solution using atomic force microscopy (AFM) and fluorescence microscopy, respectively. In solution, the chains are observed to execute translational and rotational diffusive motions. Evaluation of the motions yields translational and rotational diffusion coefficients and, from the translational diffusion coefficient, the chain mobility. The microgel chains show no perceptible bending, which yields a lower limit on their bending stiffness.