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We investigated whether dietary nitrate (NO(3)(-)) supplementation enhances the effect of training in hypoxia on endurance performance at sea level. Twenty-two healthy male volunteers performed high-intensity endurance training on a cycle ergometer (6 weeks, 5×30 min/week at 4-6 mmol/L blood lactate) in normobaric hypoxia (12.5% FiO(2)), while ingesting either beetroot juice [0.07 mmol NO(3)(-) /kg body weight (bw)/day; BR, n = 11] or a control drink (CON, n = 11). During the pretest and the posttest, the subjects performed a 30-min simulated time trial (TT) and an incremental VO(2max) test. Furthermore, a biopsy was taken from m. vastus lateralis before and after the TT. Power output during the training sessions in both groups increased by ∼6% from week 1 to week 6 (P

Purpose: Recent research has shown that chronic dietary [beta]-alanine ([beta]ALA) supplementation increases muscle carnosine content, which is associated with better performance in short (1-2 min) maximal exercise. Success in endurance competitions often depends on a final sprint. However, whether [beta]ALA can be ergogenic in sprint performance at the end of an endurance competition is at present unknown. Therefore, we investigated the effect of 8-wk [beta]ALA administration in moderately to well-trained cyclists on sprint performance at the end of a simulated endurance cycling race. Methods: A double-blind study was performed, which consisted of two experimental test sessions interspersed by an 8-wk [beta]ALA (2-4 g[middle dot]d-1; n = 9) or matched placebo (PL; n = 8) supplementation period. In the pretesting and the posttesting, subjects performed a 10-min time trial and a 30-s isokinetic sprint (100 rpm) after a 110-min simulated cycling race. Capillary blood samples were collected for determination of blood lactate concentration and pH. Results: Mean power output during the time trial was approximately 300 W and was similar between PL and [beta]ALA during either the pretesting or the posttesting. However, compared with PL, during the final sprint after the time trial, [beta]ALA on average increased peak power output by 11.4% (95% confidence interval = +7.8 to +14.9%, P = 0.0001), whereas mean power output increased by 5.0% (95% confidence interval = +2.0 to +8.1%, P = 0.005). Blood lactate and pH values were similar between groups at any time. Conclusion: Oral [beta]ALA supplementation can significantly enhance sprint performance at the end of an exhaustive endurance exercise bout.

In this study, we compared the effect of sprint interval training (SIT) in normoxia versus hypoxia on muscle glycolytic and oxidative capacity, monocarboxylate transporter content, and endurance exercise performance.Healthy male volunteers (18-30 yr) performed 6 wk of SIT on a cycling ergometer (30-s sprints vs 4.5-min rest intervals; 3 d · wk(-1)) in either normobaric hypoxia (HYP, FiO2 = 14.4%, n = 10) or normoxia (NOR, FiO2 = 20.9%, n = 9). The control group did not train (CON, n = 10). Training load was increased from four sprints per session in week 1 to nine sprints in week 6. Before and after SIT, subjects performed a maximal incremental exercise test plus a 10-min simulated time trial on a cycle ergometer in both normoxia (MAX nor and TT nor) and hypoxia (MAX hyp and TT hyp). A needle biopsy was taken from musculus vastus lateralis at rest 5-6 d after the last exercise session.SIT increased muscle phosphofructokinase activity more in HYP (+59%, P0.05) than that in NOR (+17%), whereas citrate synthase activity was similar between groups. Compared with the pretest, power outputs corresponding to 4 mmol blood lactate in HYP during MAX nor (+7%) and MAX hyp (+9%) were slightly increased (P0.05), whereas values were constant in NOR. V·O 2max in MAX nor and TT performance in TT nor and TT hyp were increased by ≈ 6%-8% (P0.05) in either group. The training elevated monocarboxylate transporter 1 protein content by ≈ 70% (P0.05). In CON, all measurements were constant throughout the study.SIT in hypoxia up-regulated muscle phosphofructokinase activity and the anaerobic threshold more than SIT in normoxia but did not enhance endurance exercise performance.