The development and validation of a football-specific nutrition knowledge questionnaire for use within adolescent...

Elite adolescent footballers experience periods of rapid growth and maturation alongside their intense training programs. Therefore, their nutritional habits should reflect this and be tailored to support healthy growth and recovery [1]. Research has shown that U12/13 and U15 footballers within Category One Academy require approximately 2859 ± 265 kcal.d (range 2275-3903 kcal.d) and 3029 ± 262 kcal.d (range 2738-3726 kcal.d), respectively, to fuel their training programs [2]. Food choices can be influenced by a range of physiological, psychological, and social factors, with nutrition knowledge being recognized as an important determinant of nutritional adherence among elite adolescent footballers. However, an ongoing limitation regarding assessing nutrition knowledge is the availability of high-quality, valid procedures, as well as a lack of specificity for certain sports and cohorts. Therefore, the aim of this study was to develop and validate a nutrition knowledge tool, which is based on the most recent football/youth nutrition guidelines, for use with English football academies.

Recruitment of participants involved three different cohorts: (1) an expert panel for the initial item development of the questionnaire via modifying a previously validated tool, the A-NSKQ, (2) an adolescent football player cohort in which much of the analysis would be conducted, and (3) a university student cohort to provide a construct validity comparison. A robust methodology was followed, incorporating content and face validity and item analysis with techniques from classical test theory (CTT). Content validity involved recruiting experts from the industry (nutrition/sport science/academia) to review the initial items and provide objective feedback via a content validity index (CVI) score. Once this was complete, a sample of the adolescent cohort the tool was intended for was recruited to complete the questionnaire and provide live feedback on readability (face validity). Finally, both the full adolescent cohorts completed the questionnaire (n = 66), alongside a cohort of university-educated students (n = 109), to prove the construct validity of the tool.

The resulting tool has 32 items, split across two subsections: general nutrition knowledge (GNK) and sport nutrition knowledge (SNK), and takes around eight minutes to complete. Content and face validity were confirmed by field experts and a sample of participants from whom the tool was intended, respectively. Modifications to the items were made due to the findings of the difficulty index, distractor utility and discrimination index. Evidence of construct validity was examined for the tool by comparing the results from nutrition-educated participants (63 ± 10%) vs non-nutrition-educated participants (52 ± 11%) (p = < 0.001). The test-retest reliability of the tool was confirmed, with a strong correlation (r = 0.77, p = < 0.001) between the individual scores of the adolescent footballers on the two attempts of the test, approximately three weeks apart.

The final version of the tool presents a valid and reliable tool, specific to the sport of football, that practitioners can use to measure the effectiveness of nutrition curriculums within English football academies.