Cross-cultural adaptation and validation of the nutrition knowledge questionnaire for ultra-endurance athletes (ULTRA-Q) for Brazil.

Aims: This study aimed to perform a cross-cultural adaptation and validate a questionnaire to assess the nutrition knowledge of Brazilian ultra-endurance athletes.

Methods: This is an observational and cross-sectional study, which adapted and validated the Nutritional Knowledge Questionnaire for Ultra-endurance Athletes (ULTRA-Q). ULTRA-Q was translated into Portuguese, and then the translated version was assessed for semantic, idiomatic, cultural and conceptual equivalence by six specialist nutritionists. In addition to suggesting adaptations to the questionnaire, the experts evaluated the clarity and relevance of the items, calculating the Content Validity Coefficient (CVC). The adapted version was applied to 46 ultra-endurance athletes to evaluate reproducibility and validity. After the test-retest, the instrument was also answered by 54 nutritionists, to evaluate the construct validity of the questionnaire.

Results: The Brazilian version (ULTRA-QBR) of the questionnaire for ultra-endurance athletes had adequate CVC for clarity (0.97) and pertinence (0.95), and presented adequate discriminant validity. The data from the intraclass correlation coefficient indicates good reproducibility of the questionnaire, and the difference observed between athletes and nutritionists reinforces the evidence of the questionnaire's construct validity.

Conclusion: The results demonstrate content, construct and discriminant validity, test-retest reproducibility, and internal consistency of the ULTRA-QBR. We concluded that this questionnaire can be used as an interesting tool in research and clinical practice in ultra-endurance sports.