Assessing Need Satisfaction and Frustration in Portuguese Exercise Instructors: scale validity, reliability and invariance between gender

Objective: The aim of the present study was to validate the Basic Psychological Need Satisfaction and Frustration Scale in Exercise for fitness instructors. Methods: Data from 477 exercise professionals (319 males, 158 females) was collected.Results: CFA supported the adapted and validated six-factor model: [χ2(237) = 1096.796, χ2/df= 4.63; B-S p < .001, CFI = .930, TLI = .918, SRMR= .0366, RMSEA = .079 (CI90% = .069, .089)], assessing satisfaction and frustration of basic psychological needs in Portuguese exercise professionals. Moreover, the analysis revealed acceptable composite reliability, and construct validity of the adapted version. Results revealed nomological validity, as well as invariance between male and female. No differences were found across latent means, and magnitude effects were trivial between gender. Conclusion: These results support the use of the adapted scale in exercise professionals, showing measurement invariance between gender. This scale is able to measure how exercise professionals experience satisfaction and frustration of basic needs when prescribing exercise to individuals in fitness context.