Blood and tissue assays Blood lactate concentration was assessed by an electrochemical technique (Lactate Analyzer – Yellow Springs Instruments 2300 Stat Plus) after stabilization in sodium fluoride (4.7 mM). Glycogen determination followed a previously described protocol [19]. Fifteen animals from the same group of rats from which experimental groups were selected were used for

baseline glycogen determinations. Statistical analysis Results are presented as average ± SD. A Proc Mixed Model (SAS®) was performed for blood lactate concentration and glycogen contents [20]. Whenever a significant F-value was obtained, a post-hoc test with a selleck chemicals Tukey adjustment was performed for multiple comparison purposes. Correlation between variables was assessed by a Pearson’s correlation coefficient Significance level was set at p < 0.05. Results Experiment 1 Number of bouts to exhaustion A significant difference was observed between groups for the number of bouts to exhaustion. Group CR performed a significantly Smad inhibitor higher (p = 0.035) number of intermittent high intensity swimming bouts than Pl group (10.80 ± 1.67 and 8.42 ± 1.83 respectively) (Figure 1). Figure 1 Effects of creatine supplementation on the number of intermittent high intensity swimming bouts completed until fatigue. Pl – placebo group; CR – creatine

group; * indicates p < 0.05 when compared to Pl group Experiment 2 Body weight Body weight was increased in CR (229.14 ± 4.38 g) when compared to Pl group after the supplementation period (221.71 ± 4.25 g). Additionally, only CR group showed increased body weight when compared to pre supplementation period (217.55 ± 3.54 g). Blood lactate Blood lactate analysis did not show any differences between groups at rest, after ten-minute unloaded warm-up and after bout 1 of supra anaerobic threshold swimming exercise. However, significantly lower lactate concentrations were observed for CR group in bouts 2, 3, 4, 5 and 6. Figure 2 illustrates blood lactate concentration throughout the experimental protocol. Figure 2 Effects of creatine supplementation on blood lactate concentrations throughout the

experimental protocol (Experiment 2). Pl – placebo group; CR – creatine Nitroxoline group; * indicates p < 0.05 between groups at the same bout Glycogen content Pl and CR groups (0.14 ± 0.03 and 0.17 ± 0.01 mg/100 mg wet tissue, respectively) presented decreased soleus glycogen content compared to baseline (0.19 ± 0.03 mg/100 mg wet tissue). No differences were found between groups (Figure 3). Figure 3 Effects of creatine supplementation on soleus glycogen content. Pl – placebo group; CR – creatine group; * indicates p < 0.05 when compared to baseline A significant interaction was found for gastrocnemius glycogen. CR group showed significant higher glycogen content compared to Pl (33.59%; 0.17 ± 0.01 vs. 0.13 ± 0.02 mg/100 mg wet tissue for CR and Pl groups, respectively). Moreover, only Pl group presented a significant decline (39.