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William J. Kraemer, Scott E. Gordon, James M. Lynch, Mariana E.M.V. Pop, and Kristine L. Clark

The purpose of this investigation was to determine the effects of a 3.5-day dietary multibuffer supplement (containing predominantly inorganic phosphate, or Pj, along with bicarbonate and carnosine, i.e., PhosFuel™) on repetitive (four trials separated by 2 min rest) Wingate test (WT) performances and whole blood 2,3-diphosphoglycerate (2,3-DPG) concentrations in 10 recreationally trained road cyclists (T) and 10 normally active but untrained (UT) men. A 2-week washout period was utilized between experimental sessions. Venous blood samples were obtained via cannula once before exercise (baseline), immediately post each WT, and 3 min after the final WT (recovery). The data indicate that this supplement does not affect acid-base status with following intense anaerobic exercise and does not improve repetitive WT performance. However, the supplement does enhance post-exercise levels of 2,3-DPG and the 2,3-DPG/Hb ratio in recreationally trained cyclists while improving acute recovery of peak power in these men.

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J.C. Siegler, J. Bell-Wilson, C. Mermier, E. Faria, and R.A. Robergs

The purpose of this study was to profile the effect of active versus passive recovery on acid-base kinetics during multiple bouts of intense exercise. Ten males completed two exercise trials. The trials consisted of three exercise bouts to exhaustion with either a 12 min active (20% workload max) or passive recovery between bouts. Blood pH was lower in the passive (p) recovery compared to active (a) throughout the second and third recovery periods [second recovery: 7.18 ± 0.08 to 7.24 ± 0.09 (p), 7.23 ± 0.07 to 7.32 ± 0.07 (a), P < 0.05; third recovery: 7.17 ± 0.08 to 7.22 ± 0.09 (p), 7.23 ± 0.08 to 7.32 ± 0.08 (a), P < 0.05]. Exercise performance times did not differ between recovery conditions (P = 0.28). No difference was found between conditions for recovery kinetics (slope and half-time to recovery). Subsequent performance during multiple bouts of intense exercise to exhaustion may not be influenced by blood acidosis or mode of recovery.

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Lewis A. Gough, Steven Rimmer, Callum J. Osler, and Matthew F. Higgins

This study evaluated the ingestion of sodium bicarbonate (NaHCO3) on postexercise acid-base balance recovery kinetics and subsequent high-intensity cycling time to exhaustion. In a counterbalanced, crossover design, nine healthy and active males (age: 23 ± 2 years, height: 179 ± 5 cm, body mass: 74 ± 9 kg, peak mean minute power (Wpeak) 256 ± 45 W, peak oxygen uptake (V̇O2peak) 46 ± 8 performed a graded incremental exercise test, two familiarization and two experimental trials. Experimental trials consisted of cycling to volitional exhaustion (TLIM1) at 100% WPEAK on two occasions (TLIM1 and TLIM2) interspersed by a 90 min passive recovery period. Using a double-blind approach, 30 min into a 90 min recovery period participants ingested either 0.3 body mass sodium bicarbonate (NaHCO3) or a placebo (PLA) containing 0.1 body mass sodium chloride (NaCl) mixed with 4 tap water and 1 orange squash. The mean differences between TLIM2 and TLIM1 was larger for PLA compared with NaHCO3 (-53 ± 53 vs. -20 ± 48 s; p = .008, d = 0.7, CI =-0.3, 1.6), indicating superior subsequent exercise time to exhaustion following NaHCO3. Blood lactate [Bla-] was similar between treatments post TLIM1, but greater for NaHCO3 post TLIM2 and 5 min post TLIM2. Ingestion of NaHCO3 induced marked increases (p < .01) in both blood pH (+0.07 ± 0.02, d = 2.6, CI = 1.2, 3.7) and bicarbonate ion concentration [HCO3 -] (+6.8 ± 1.6 mmo.l-1, d = 3.4, CI = 1.8, 4.7) compared with the PLA treatment, before TLIM2. It is likely both the acceleration of recovery, and the marked increases of acid-base after TLIM1 contributed to greater TLIM2 performance compared with the PLA condition.

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Robert Robergs, Keith Hutchinson, Shonn Hendee, Sean Madden, and Jason Siegler

The purpose of this study was to measure the recovery kinetics of pH and lactate for the conditions of pre-exercise acidosis, alkalosis, and placebo states. Twelve trained male cyclists completed 3 exercise trials (110% workload at VO2max), ingesting either 0.3 g/kg of NH4Cl (ACD), 0.2 g/kg of Na+HCO3 - and 0.2 g/kg of sodium citrate (ALK), or a placebo (calcium carbonate) (PLAC). Blood samples (heated dorsal hand vein) were drawn before, during, and after exercise. Exercise-induced acidosis was more severe in the ACD and PLAC trials (7.15 ± 0.06, 7.21 ± 0.07, 7.16 ± 0.06, P < 0.05, for ACD, ALK, PLAC, respectively). Recovery kinetics for blood pH and lactate, as assessed by the monoexponential slope constant, were not different between trials (0.057 ± 0.01, 0.050 ± 0.01, 0.080 ± 0.02, for ACD, ALK, PLAC, respectively). Complete recovery of blood pH from metabolic acidosis can take longer than 45 min. Such a recovery profile is nonlinear, with 50% recovery occurring in approximately 12 min. Complete recovery of blood lactate can take longer than 60 min, with 50% recovery occurring in approximately 30 min. Induced alkalosis decreases metabolic acidosis and improves pH recovery compared to acidodic and placebo conditions. Although blood pH and lactate are highly correlated during recovery from acidosis, they recover at significantly different rates.

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Jennifer Kappenstein, Jaime Fernández-Fernández, Florian Engel, and Alexander Ferrauti

The aim of this study was to compare the effect of active (AR) and passive recovery (PR) after a high-intensive repeated sprint running protocol on physiological parameters in children and adults. Blood lactate (La) and blood pH were obtained during two sets of 5 × 5 s all-out sprints and several times during subsequent 30-min recovery in 16 children and 16 adults. End-exercise La was significantly lower and pH significantly higher in children (La: 5.21 ± 2.73 mmol·L1; pH: 7.37 ± 0.06) compared with adults (La: 10.35 ± 5.76 mmol·L−1; pH: 7.27 ± 0.10) (p > .01). La half-life during postexercise recovery was significantly shorter in children (AR: 436 ± 371 s, PR: 830 ± 349 s) than in adults (AR: 733 ± 371 s, PR: 1361 ± 372 s), as well as in active compared with passive recovery for both age groups (p > .01). The age x recovery interaction for La half-life only approached statistical significance (p = .06). The results suggest a faster lactate disappearance and an earlier return to resting pH after a repeated sprint running protocol in children compared with adults and a less pronounced advantage of active recovery in children.

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Nathan Philip Hilton, Nicholas Keith Leach, Melissa May Craig, S. Andy Sparks, and Lars Robert McNaughton

suggests that delayed-release (DEL) NaHCO 3 , which contained an enteric coating within the shell, minimizes GI symptoms in comparison with an oral solution, while inducing a comparable acid–base balance ( Hilton et al., 2019 ). However, there is speculation as to how the site of disintegration may alter

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Oliver C. Witard, Ina Garthe, and Stuart M. Phillips

. Amino Acid-Based Supplements for High-Quality Weight Loss in Track and Field Athletes Anecdotally, there is significant interest in the role of protein-based supplements during weight loss for improved body composition and performance in athletic populations, including track and field athletes. In this

Open access

In the article by Gough, L.A., Rimmer, S., Osler, C.J., & Higgins, M.F. (2017). Ingestion of sodium bicarbonate (NaHCO3) following a fatiguing bout of exercise accelerates postexercise acid-base balance recovery and improves subsequent high-intensity cycling time to exhaustion, International Journal of Sport Nutrition and Exercise Metabolism, 27(5), 429–438, doi:10.1123/ijsnem.2017-0065, we did not accurately reflect several content and layout corrections which were needed.

These include:

  1. (a)The key for Figure 1 was erroneously included for Figure 3 (and not for Figure 1).
  2. (b)The abbreviation for PRE was missing from the Figure 1 key.
  3. (c)Figure 3 contained two indicators (+) which were not necessary.

The online version of this article has been corrected. We sincerely apologize for these errors.

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Kristen L. Heck, Jeffrey A. Potteiger, Karen L. Nau, and Jan M. Schroeder

We examined the effects of sodium bicarbonate ingestion on the VO2 slow component during constant-load exercise. Twelve physically active males performed two 30-min cycling trials at an intensity above the lactate threshold. Subjects ingested either sodium bicarbonate (BIC) or placebo (PLC) in a randomized. counterbalanced order. Arterialized capillary blood samples were analyzed for pH, bicarbonate concentration ([HCO3 ), and lactate concentration ([La]). Expired gas samples were analyzed for oxygen consumption (VO2). The VO2 slow component was defined as the change in VO2 from Minutes 3 and 4 to Minutes 28 and 29. Values for pH and [HCO3 ] were significantly higher for BIC compared to PLC. There was no significant difference in [La] between conditions. For both conditions there was a significant time effect for VO2 during exercise: however, no significant difference was observed between BIC and PLC. While extracellular acid-base measures were altered during the BIC trial, sodium bicarbonate ingestion did not attenuate the VO2 slow component during constant-load exercise.

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Jeffrey J. Zachwieja, David L. Costill, Glenn C. Beard, Robert A. Robergs, David D. Pascoe, and Dawn E. Anderson

To determine the effect of a carbonated carbohydrate (CHO) drink on gastric function and exercise performance, eight male cyclists completed four 120- min bouts of cycling. Each bout consisted of a 105-min ride at 70% VO2max followed by a 15-min self-paced performance ride. During each trial, one of four test solutions was ingested: carbonated CHO (C-10%), noncarbonated CHO (NC-10%), carbonated non-CHO (C), and noncarbonated non-CHO (NC). Following the performance ride, the subjects had their stomach contents removed by aspiration. There were no significant differences in gastric emptying (GE) except for Trial C-10%, which averaged 13.3% less than NC. However, there was no difference in the perception of gastrointestinal comfort between this trial and any other. Average power output during the performance ride was not significantly different between carbonated and noncarbonated trials, or between CHO-fed and no-CHO trials; however, the subjects worked at a greater intensity when fed CHO. Finally, acid base status did not change when a carbonated drink was ingested. This indicates that adding carbonation to a sport drink does not significantly alter gastric function, the perception of GI comfort, or exercise performance.