Validation of a sports nutrition knowledge questionnaire for Sri Lankan track and field athletes.

Background: While several validated sports nutrition knowledge questionnaires exist, none are specifically designed to assess the sports nutrition knowledge (SNK) of Sri Lankan track and field athletes. This study aims to validate the Sri Lankan Sports Nutrition Knowledge Questionnaire (SLn-SNKQ), tailored for this athlete group, to provide more accurate and meaningful insights for research and practice. This will enable health professionals and coaches to confidently assess athletes' nutrition knowledge, which directly influences their food choices.

Methods: The validity of the questionnaire was established through a multi-step approach. Content validity was achieved via ratings from nutrition experts, all of whom had specialized training in human nutrition and experience of working with athletes. Face validity was evaluated through in-depth telephone interviews with elite or highly trained athletes, using a retrospective think-out-loud protocol to gather feedback on the clarity and relevance of the questions. Construct validity involved nutrition-trained doctors (NTG), non-nutrition-trained professionals (NNTG), and elite-level athletes' groups (AG). Internal consistency was assessed using Cronbach's alpha, and test-retest reliability was evaluated.

Results: The final tool comprised 123 individual statements or prompts (items) that were organized into 32 broader questions, spanning 12 sub-sections. Content validity was confirmed by fully integrating 49 out of 70 comments and partially integrating four comments received from nutrition experts for each sub-section. Face validity was established by fully integrating 33 out of 40 comments received from 16 elite and highly trained athletes. Construct validity was confirmed, indicating significant differences in the total scores achieved as a percentage of the SLn-SNKQ among the NTG (462.5, 92.5%), NNTG (223.5, 44.7%), and AG (235, 47.0%; p < 0.001). Reproducibility was established by strong test-retest reliability between individuals' scores on two test attempts, three weeks apart (spearman's correlation; ρ = 0.99, p < 0.05). Internal reliability for each sub-section met psychometric reliability requirements (Cronbach's α > 0.7).

Conclusions: The SLn-SNKQ has been validated and demonstrates robust psychometric properties, offering a reliable tool for assessing SNK among Sri Lankan track and field athletes.