Purpose: Insufficient physical activity is a public health concern in Indonesia, but there are no valid Indonesian tools for exploring the influences. Due to cultural and contextual differences, the Indonesian version of the Influence on Physical Activity Instrument (IPAI-I) was developed and tested the psychometric properties in community obese-adults.
Methods: The cross-sectional study enrolled 846 obese-adults in Indonesian community health-centre. The IPAI was translated with culturally appropriate Indonesian. Using Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) assessed the psychometric properties. The scale reliability was tested by Cronbach's α for internal consistency and intra-class correlation coefficient (ICC) for stability.
Results: Through EFA via Principal Axis Factoring with Oblimin rotation, the 21-item IPAI-I exhibited cross-cultural appropriateness, readability with three factors in the individual domain, one factor in the support domain, and two factors in the environment domain. The indices of good fit model for three domains testing by a second-order CFA was achieved at χ2/df=1.5, goodness of fit index = .93, root mean square error of approximation = .039 (p < .001). Furthermore, a high correlation (r = .52; p < .001) was between the support domain and the environment domain, but the two domains had a very low correlation with the individual domain, respectively. The test-retest reliability was by ICC with .73 - .92 and Cronbach's α with .82 - .91 among six-factor, respectively.
Conclusions: The IPAI-I is a valid, reliable instrument to assess in Indonesian context. Enhancing ecological effects are high-priority to increase physical activity for community obese-individual.
Keywords: Culture; Exercise; Factor Analysis; Obesity; Psychometrics; Statistical.
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