Danijela Kuna, Jasenka Gajdoš Kljusurić, Vesna Bosanac
Beverage consumption practices before, during, and after training are relevant to physical performance and health. However, less is known about whether these self-reported practices remain stable or change over relatively short periods. The primary aim of this study was to determine whether the frequency of self-reported exercise-related beverage consumption changed over a 30-day period in physically active university students. A secondary aim was to characterize individual-level temporal agreement in selected beverage consumption frequency items across the two assessments. A total of 34 participants (18 males and 16 females; age 20.8 ± 0.5 years) completed a 28-item questionnaire on two occasions separated by 30 days. Paired Wilcoxon signed-rank tests were used to examine group-level changes in ordinal beverage-consumption frequency, while weighted Cohen's kappa coefficients (κw) with 95% confidence intervals, exact agreement, and adjacent-category agreement were used to characterize individual-level temporal agreement. No statistically significant group-level differences were detected between assessments for the analyzed beverage-consumption frequency items (all p > 0.05). Across the analyzed items, exact agreement ranged from 73.5% to 100.0%, adjacent-category agreement from 94.1% to 100.0%, and κw values ranged from 0.329 to 1.000. Water was the most frequently reported beverage before, during, and after training. Overall, no systematic group-level changes in exercise-related beverage consumption frequency were detected over the 30-day period, while individual-level temporal agreement varied across beverage categories and exercise-related time points.