Relationship Between Visual Analog Scales And Commonly Used Ordinal Scales Of Perceived Thirst And Recovery

Subjective, ordinal scales have been widely used in athlete monitoring and research settings to measure a variety of metrics. Conceptually, subjective assessment tools that employ visual analog scales (VAS) offer an alternative method to capture data with continuous variable properties. PURPOSE: The purpose of this study was to investigate the correlation of two separate VAS to their ordinal counterparts for thirst and recovery in female collegiate-lacrosse athletes. METHODS: Morning measures of thirst and readiness were assessed in a sample of collegiate, female lacrosse athletes (n = 22) over three consecutive days. Each morning, participants reported to the laboratory in a fasted state and were asked to report their current level of thirst and readiness. Thirst and readiness were assessed on a previously validated ordinal scale (thirst 1-9 and recovery 0-10) and the VAS tool. VAS scales asked the participant to mark where they fell on a spectrum line anchored by “not thirsty at all” and “very thirsty” or “not recovered at all” and “full recovered” on a 100 mm line. Spearman’s Rho correlations were used to explore the relationship between VAS and ordinal measures. RESULTS: A total of 66 observations were collected with each participant providing scores over three days. The results of the Spearman’s Rho correlations showed significant, moderately-strong to strong, positive correlations between the measures of thirst [rs(64) = 0.68, p < 0.01] and recovery [rs(64) = 0.96, p < 0.01). VAS scales reported mean ± SD of thirst = 42 ± 20 mm and recovery = 55 ± 20 mm. The median and range for the ordinal measures were, thirst Mdn = 5 (range 1-8) and recovery Mdn = 6 (range 2-10). CONCLUSIONS: The significant relationship between VAS and their commonly used ordinal counterparts provides evidence of criterion validity and supports the use of VAS scales in subjective athlete monitoring and research. VAS provide useful tools for monitoring subjective feelings, minimizing potential participant confusion, while also providing the benefit of recording continuous data that affords researchers the ability to use parametric analyses.