Fidedignidade e validade de uma escala de avaliação do apoio social para prática de atividade física para adolescentes - Escala ASAFA Reliability and validity of a physical activity social support assessment scale in adolescents - ASAFA Scale

AbstRAct: Objective: To analyze the reliability and validity of a scale used to measure social support for physical activity in adolescents – ASAFA Scale. Methods: This study included 2,755 adolescents (57.6% girls, 16.5 ± 1.2 years of age), from Joao Pessoa, Paraiba, Brazil. Initially, the scale was consisted of 12 items (6 for social support from parents and 6 from friends). The reliability of the scale was estimated by Cronbach’s alpha coefficient (α), by the Composite Reliability (CR), and by the model with two factors and factorial invariance by Confirmatory Factor Analysis (CFA) adequacy. Results: The CFA results confirmed that the social support scale contained two factors (factor 1: social support from parents; factor 2: social support from friends) with five items each (one item was excluded from each scale), all with high factor loadings (> 0.65) and acceptable adjustment indexes (RMR = 0.050; RMSEA = 0.063; 90%CI: 0.060 – 0.067); AGFI = 0.903; GFI = 0.940; CFI = 0.934, NNFI = 0.932). The internal consistency was satisfactory (parents: α ≥ 0.77 and CR ≥ 0.83; friends: α ≥ 0.87 and CR ≥ 0.91). The scale`s factorial invariance was confirmed (p > 0.05; ∆