Validity and reliability of scales on intrapersonal, interpersonal and environmental factors associated with physical activity in Brazilian secondary students / Validade e fidedignidade de escalas sobre fatores intrapessoais, interpessoais e ambientais associados à atividade física em escolares brasileiros do ensino fundamental

ABSTRACT

Abstract This study aimed to examine the validity and reliability of scales of intrapersonal, interpersonal, and environmental factors associated with physical activity (PA) in secondary students. Two cross-sectional studies were conducted with students in 7th to 9th grades form secondary schools in order to test the validity, internal consistency (n = 1,178, 51.4% were boys), and test–retest reproducibility (n = 194, 56.2% were boys) of the instrument. Factors associated with PA (attitude, self-efficacy, social support of friends, parents and the school’s teachers, as well as the perceived neighborhood environment and perceived school environment) were measured. The confirmatory factor analysis and Spearman correlation between the scales and the weekly time spent in moderateto-vigorous PA (measured by questionnaire) were applied to test the construct validity. For reliability, the Cronbach’s α (internal consistency), composite reliability (CR) and intraclass correlation coefficient (ICC for test–retest reproducibility) were applied. The confirmatory factorial analysis showed five one-dimensional and two two-dimensional (self-efficacy and perceived environment) scales, with factor loadings ranging from 0.46 to 0.85. Significant and positive correlations between almost all scale scores and moderateto-vigorous PA (p<0.05) were found. The Cronbach’s α and CR were greater than 0.70 in almost all scales (except perceived school environment, α and CR of 0.61) and the ICC ranged from 0.62 (parental social support) to 0.70 (self-efficacy). In conclusion, the scales showed acceptable validity and reliability and can be used for measuring of PA correlates in elementary students.

RESUMO

Resumo Este estudo analisou a validade e a fidedignidade de escalas de fatores intrapessoais, interpessoais e ambientais associados à atividade física (AF) em escolares do ensino fundamental. Estudos transversais incluíram escolares dos 7º ao 9º anos para análises de validade e consistência interna (n=1.178, 51,4% meninos), e reprodutibilidade teste-reteste (n=194, 56,2% meninos) do instrumento. Atitude, autoeficácia, apoio social dos amigos, pais e professores da escola, e o ambiente percebido do bairro e da escola relacionados à AF foram avaliados. A análise fatorial confirmatória e a correlação de Spearman entre os escores das escalas e o tempo semanal em AF moderada a vigorosa foram aplicadas para testar a validade de constructo das escalas. Utilizou-se o α de Cronbach e o índice de fidedignidade combinada (IFC) para avaliar a consistência interna, e o coeficiente de correlação intra-classe (CCI) para a reprodutibilidade teste-reteste. A análise fatorial confirmatória indicou cinco escalas unidimensionais e duas bi-dimensionais (autoeficácia e ambiente percebido para AF), com ajustes de modelo adequados e cargas fatoriais de 0.46 a 0.85. Houve correlações significativas entre os escores de quase todas as escalas e AF moderada a vigorosa (p<0,05). O a e o IFC foram maiores de 0.70 em quase todas as escalas (exceto ambiente percebido da escola, a e IFC de 0.61) e o CCI variou de 0.62 (apoio social dos pais para AF) a 0.70 (autoeficácia para AF). Em conclusão, as escalas apresentaram validade e fidedignidade aceitáveis e pode ser utilizado na mensuração de fatores associados à AF em escolares do ensino fundamental.