Hydration Monitoring In Collegiate Female Lacrosse Athletes During Competition Week

Hydration is relevant to sport performance and safety. However, no studies to date have examined relationships between body weight, urine color (Ucol), and thirst (WUT) with urine specific gravity (USG) in female lacrosse athletes approaching a competitive match. PURPOSE: The purpose of this study was to describe and investigate trends of hydration indices during a competition week in female, collegiate lacrosse athletes. METHODS: A total of 22 female, lacrosse athletes (mean ± SD; age, 20 ± 1 y) participated in this study. After waking, participants collected their first morning void and transported the urine sample to the facility where body mass, thirst, Ucol, and USG (digital refractometer) were assessed over a 3-day period (48-hr prior to Game Day = GD-2, 24-hr prior to Game Day = GD-1, Game Day = GD). USG ≥ 1.0210, body mass loss >1% of highest mass recorded, urine color >5, and thirst level ≥ 5 were used as the thresholds to denote hypohydration. Athletes were categorized as having 0, 1, 2, or 3 WUT indicators. WUT score frequencies were reported, and Spearman’s correlations calculated the relationship between WUT score and USG. Repeated-measures ANOVA was used to explore mean differences between days for USG and body mass. Ucol differences between days were investigated using a Friedman Test, due to the ordinal nature. Pairwise comparisons utilized LSD post-hoc, when warranted (α = 0.05). RESULTS: Group means by day did not differ for body mass (GD-2 = 67.3 ± 10.3 kg, GD-1 = 67.3 ± 10.2 kg, GD = 67.5 ± 10.2 kg; p = 0.36), thirst (GD-2 = 5 ± 2 au, GD-1 = 5 ± 2 au, GD = 5 ± 2 au; p = 0.46), nor USG (GD-2 = 1.0228 ± 0.0059, GD-1 = 1.0228 ± 0.0054, GD = 1.0231 ± 0.0048; p = 0.98). Furthermore, Ucol was not different by day (GD-2 Mdn = 5 au, GD-1 Mdn = 3 au, GD Mdn = 4 au; p = 0.17). Of the 66 observations, WUT score frequencies were as follows: WUT 0, n = 25 (37.9%), WUT 1, n = 36 (54.5%), WUT 2, n = 4 (6.1%), WUT 3, n = 1 (1.5%). Spearman’s correlations revealed a weak, positive relationship between WUT score and USG (r = 0.25, p = 0.04). Critically, 46/66 (70%) of the urine samples presented a USG > 1.0200, including 16/22 (73%) on GD. CONCLUSIONS: A sizable portion of female, collegiate lacrosse athletes in this study provided urine samples that indicated hypohydration. Additionally, this sample’s WUT scores were not strongly related to USG scores.