Effects of Caffeine Ingestion on Anaerobic Capacity in a Single Supramaximal Cycling Test.

The aim of this study was to verify the effects of caffeine on anaerobic capacity estimated by the sum of the estimated glycolytic [E[La]] and phosphagen [EPCr] metabolism based on blood lactate and excess post-oxygen consumption responses (AC[La-]+EPOCfast). Fourteen male cyclists were submitted to a graded exercise test to determine the maximal oxygen uptake ( V ° O 2 m a x ) and intensity associated with   V ° O 2 m a x (i V ° O 2 m a x ). Subsequently, the participants performed two supramaximal efforts at 115% of i V ° O 2 m a x to determine the AC[La-]+EPOCfast, after previous supplementation with caffeine (6 mg·kg-1) or a placebo (dextrose), in a cross over, randomized, double blind, and placebo-controlled design. The time to exhaustion was higher in the caffeine (186.6 ± 29.8 s) than in the placebo condition (173.3 ± 25.3 s) (p = 0.006) and a significant correlation was found between them (r = 0.86; P = 0.00008). Significant differences were not found between AC[La-]+EPOCfast values from the placebo (4.06 ± 0.83 L and 55.2 ± 5.7 mL·kg-1) and caffeine condition (4.00 ± 0.76 L and 54.6 ± 5.4 mL·kg-1); however, a significant correlation was observed only for AC[La-]+EPOCfast expressed in absolute values (r = 0.74; p < 0.002). The E[La] and EPCr also presented no significant differences and they were significantly correlated (r = 0.82 and r = 0.55, respectively; p < 0.05). We conclude based on the overall comparison of mean values between two treatments that acute caffeine ingestion improves the time to exhaustion but does not affect anaerobic capacity estimation.

The sensitivity of the alternative maximal accumulated oxygen deficit method to discriminate training status.

The purpose of the study was to investigate the sensitivity of an alternative maximal accumulated oxygen deficit (MAODALT) method to discriminate the "anaerobic" capacity while comparing: least trained (LT) participants (n = 12), moderately trained (MT) participants (n = 12), endurance trained (ET) participants (n = 16), and rugby (RG) players (n = 11). Participants underwent a graded exercise test on a treadmill and a supramaximal effort for assessing MAODALT. MAODALT was calculated as the sum of oxygen equivalents from the phosphagen and glycolytic metabolic pathways. MAODALT was significantly higher (P < 0.05) in RG (64.4 ± 12.1 mL · kg-1) than in ET (56.8 ± 5.4 mL · kg-1; effect size [ES] = 0.77; +13.5%), MT (53.8 ± 5.3 mL · kg-1; ES = 1.08; +19.8%), and LT (49.9 ± 4.5 mL · kg-1; ES = 1.50; +36.4%). In addition, the magnitude-based inference analysis revealed that MAODALT was likely (LT vs. MT), very likely (MT vs. RG, and ET vs. RG) and most likely (LT vs. ET, and LT vs. RG) different between all groups, except for MT and ET, which presented an unclear difference. In conclusion, MAODALT was sensitive enough to distinguish the "anaerobic" capacity in individuals with different training status, especially for RG players compared with LT participants and MT participants.

Hyperlactemia induction modes affect the lactate minimum power and physiological responses in cycling.

The aim of this study was to verify the influence of hyperlactemia and blood acidosis induction on lactate minimum intensity (LMI). Twenty recreationally trained males who were experienced in cycling (15 cyclists and 5 triathletes) participated in this study. The athletes underwent 3 lactate minimum tests on an electromagnetic cycle ergometer. The hyperlactemia induction methods used were graded exercise test (GXT), Wingate test (WAnT), and 2 consecutive Wingate tests (2 × WAnTs). The LMI at 2 × WAnTs (200.3 ± 25.8 W) was statistically higher than the LMI at GXT (187.3 ± 31.9 W) and WAnT (189.8 ± 26.0 W), with similar findings for blood lactate, oxygen uptake, and pulmonary ventilation at LMI. The venous pH after 2 × WAnTs was lower (7.04 ± 0.24) than in (p ≤ 0.05) the GXT (7.19 ± 0.05) and WAnT (7.19 ± 0.05), whereas the blood lactate response was higher. In addition, similar findings were observed for bicarbonate concentration [HCO3] (2 × WAnTs lower than WAnT; 15.3 ± 2.6 mmol·L and 18.2 ± 2.7 mmol·L1, respectively) (p ≤ 0.05). However, the maximal aerobic power and total time measured during the incremental phase also did not differ. Therefore, we can conclude that the induction mode significantly affects pH, blood lactate, and [HCO3] and consequently they alter the LMI and physiological parameters at LMI.