8 ± 1.5 8.7 ± 2.5 2.9 ± 1.2**

46.9 ± 18.5 Plasma osmolality (mosmol/kg H2O) 292.2 ± 2.8 290.6 ± 4.6 -1.7 ± 4.3 -0.6 ± 1.5 Urine urea (mmol/L) 290.5 ± 204.9 463.0 ± 172.5 172.5 ± 246.5 190.6 ± 292.3 IWP-2 mw Urine osmolality (mosmol/kg H2O) 724.3 ± 214.0 716,4 ± 329.1 -7.9 ± 276.5 -1.0 ± 36.6 Urine specific gravity (g/mL) 1.000 ± 0.005 1.001 ± 0.005 0.001 ± 0.005 0.1 ± 0.4 Results are presented as mean ± SD; * = P < 0.05, ** = P < 0.001. Statistical analysis Results are presented as mean ± standard deviation (SD). The Shapiro-Wilk test was applied to check for normal distribution of data. Differences between men and women in parameters of pre-race experience and training, the average race speed and the total number of kilometers were evaluated using paired t-test. The correlations of the changes in parameters during the race were evaluated using Pearson product–moment in male group and Spearman correlation analysis to assess uni-variate associations in female group. Paired t-tests in male group and the Wilcoxon signed rank tests in female group were used to check for significant changes in the anthropometric and laboratory parameters before and after the race. The critical value for rejecting the null hypothesis was set at 0.05. The data was evaluated in the program Statistic 7.0 (StatSoft, Tulsa, U.S.A.). Results Pre-race experience and training parameters Pre-race results of 37 male and 12 female 24-hour Go6983 cell line ultra-MTBers are presented in

Table  1. Male ultra-MTBers displayed a significantly higher body stature and Selleckchem AZD6738 body mass compared to female ultra-MTBers. Additionally, mean training cycling intensity, mean training cycling speed and session duration during pre-race training were higher in men compared to women. On the contrary, no significant differences between sexes were noted in the years spent as an active MTBer, in the number of finished ultra-cycling marathons, in the personal best performance in a 24-hour cycling race, in total hours spent cycling in training, in the total duration (hour) and the distance (km) of a cycling training in the three months before the race. Race performance and changes in body composition Forty-nine ultra-MTBers

(37 men and 12 women) finished the race. Significant differences in the average cycling speed during the race were Adenosine triphosphate observed between male (16.7 ± 2.2 km/h) and female (14.2 ± 1.7 km/h) ultra-MTBers (P < 0.001). Men achieved a mean distance of 282.9 ± 82.9 km during the 24 hours, whereas women achieved 242.4 ± 69.6 km. Despite the differences in the average speed for each sex, men did not achieve a significantly higher number of kilometers during the 24 hours (P > 0.05). In men, the change in body mass was significantly and negatively related to the achieved number of kilometers during the 24 hours (r = -0.41, P < 0.05). Their absolute ranking in the race was significantly and positively related to post-race body mass (r = 0.40, P < 0.05), the change in body mass (r = 0.46, P < 0.