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Dietary β-Alanine Intake Assessed by Food Records Does Not Associate With Muscle Carnosine Content in Healthy, Active, Omnivorous Men and Women

Nathalia Saffioti Rezende, Giulia Cazetta Bestetti, Luana Farias de Oliveira, Bruna Caruso Mazzolani, Fabiana Infante Smaira, Alina Dumas, Paul Swinton, Bryan Saunders, and Eimear Dolan

essential processes, including antioxidation ( Boldyrev et al., 2004 , 2010 ), Ca 2+ regulation ( Dutka & Lamb, 2004 ), antiglycation ( Hipkiss & Brownson, 2000 ), and intracellular buffering ( Bate Smith, 1938 ; Dolan, Saunders et al., 2019 ). The latter is one of carnosine’s most studied actions, and

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Topical Sodium Bicarbonate: No Improvement in Blood Buffering Capacity or Exercise Performance

Alannah K.A. McKay, Peter Peeling, Martyn J. Binnie, Paul S.R. Goods, Marc Sim, Rebecca Cross, and Jason Siegler

The ingestion of sodium bicarbonate (NaHCO 3 ) is well accepted as an efficacious ergogenic aid to improve short-duration, high-intensity exercise performance. 1 The exogenous intake of NaHCO 3 acts as an extracellular buffer, raising blood pH and bicarbonate (HCO 3 − ) concentrations and

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A Buffering Effect of Mental Toughness on the Negative Impact of Basic Psychological Need Thwarting on Positive Youth Athlete Functioning

Keita Kinoshita, Eric MacIntosh, and Shintaro Sato

to Gucciardi et al. ( 2017 ), MT has the potential to be a personal resource that would buffer the maladaptive effect of uncontrollable factors (e.g., coaching behaviors) on thriving. The results suggest that MT might be a personally controllable factor to protect youths from the negative effect of

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Hypervolemia and Blood Alkalinity: Effect on Physiological Strain in a Warm Environment

Michael D. Nelson, Lynneth A. Stuart-Hill, and Gordon G. Sleivert

Purpose:

To evaluate the influence of acute hypervolemia, achieved through the ingestion of a sodium citrate-rich beverage, on cardiovascular strain and thermoregulatory function, during moderate-intensity aerobic exercise in a warm environment. Sodium citrate’s ability to increase buffering capacity was also assessed.

Methods:

Twelve endurance-trained athletes completed two blind randomized treatment trials, separated by a minimum of seven days, on a cycle ergometer under heat stress (30.9°C, 64% RH). The subjects ingested 12 mL·kg−1of (1) Gatorade, the control (CNT), or (2) sodium-citrate plus Gatorade (NaCIT: 170 mmol Na+L−1) before cycling at 15% below ventilatory threshold (VT) for 62 minutes. Core and skin temperature, expired gas samples, heart rate, and perceived exertion were measured throughout exercise. Blood samples were taken before drinking each beverage, before commencing exercise, and throughout the exercise bout.

Results:

Plasma volume (PV) was significantly expanded in the NaCIT trial (3.6 ± 5.5%) and remained significantly higher throughout exercise in the NaCIT trial compared with the CNT trial (P ≤ .05). No significant differences were found in heart rate, in core and skin temperature, or in the metabolic data between the treatment groups. NaCIT significantly increased [HCO3 ], base excess, and pH throughout the trial.

Conclusion:

Acute oral ingestion of high-sodium citrate beverages before moderate exercise induces mild levels of hypervolemia and improves blood-buffering capacity in humans; however, mild hypervolemia during 62 minutes of moderate exercise does not reduce physiological strain or improve thermoregulation.

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Warm-Up Intensity Does Not Affect the Ergogenic Effect of Sodium Bicarbonate in Adult Men

Rebecca L. Jones, Trent Stellingwerff, Paul Swinton, Guilherme Giannini Artioli, Bryan Saunders, and Craig Sale

“check-in” time) to finish warm-ups 20–40 min prior to competition, allowing for greater recovery ( Ingham et al., 2013 ). It is unknown if SB supplementation prior to a HI or LI warm-up would be similarly effective due to buffering requirements during the warm-up itself. Although HI athletes will

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Effect of Sodium Bicarbonate and Beta-Alanine on Repeated Sprints During Intermittent Exercise Performed in Hypoxia

Bryan Saunders, Craig Sale, Roger C. Harris, and Caroline Sunderland

Purpose:

To investigate the separate and combined effects of sodium bicarbonate and beta-alanine supplementation on repeated sprints during simulated match play performed in hypoxia.

Methods:

Study A: 20 recreationally active participants performed two trials following acute supplementation with either sodium bicarbonate (0.3 g·kg−1BM) or placebo (maltodextrin). Study B: 16 recreationally active participants were supplemented with either a placebo or beta-alanine for 5 weeks (6.4 g·day−1 for 4 weeks, 3.2 g·day−1 for 1 week), and performed one trial before supplementation (with maltodextrin) and two following supplementation (with sodium bicarbonate and maltodextrin). Trials consisted of 3 sets of 5 × 6 s repeated sprints performed during a football specific intermittent treadmill protocol performed in hypoxia (15.5% O2). Mean (MPO) and peak (PPO) power output were recorded as the performance measures.

Results:

Study A: Overall MPO was lower with sodium bicarbonate than placebo (p = .02, 539.4 ± 84.5 vs. 554.0 ± 84.6 W), although there was no effect across sets (all p > .05). Study B: There was no effect of beta-alanine, or cosupplementation with sodium bicarbonate, on either parameter, although there was a trend toward higher MPO with sodium bicarbonate (p = .07).

Conclusions:

The effect of sodium bicarbonate on repeated sprints was equivocal, although there was no effect of beta-alanine or cosupplementation with sodium bicarbonate. Individual variation may have contributed to differences in results with sodium bicarbonate, although the lack of an effect with beta-alanine suggests this type of exercise may not be influenced by increased buffering capacity.

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Direct and Buffering Effects of Physical Activity on Stress-Related Depression in Mothers of Infants

Melinda Jane Craike, Denis Coleman, and Clare MacMahon

This study examined the role of leisure-time physical activity in reducing the impact of high life stress and time pressure on depression, a buffer effect, for mothers of infants. A direct association between leisure-time physical activity and depression, regardless of both sources of stress, was also tested. A sample of approximately 5,000 mothers of infant children completed questionnaires that measured demographic characteristics, frequency of participation in leisure-time physical activity, life stress, time pressure, and depression (depressive symptoms). Hierarchical multiple regression incorporating an interaction component to represent the buffering effect was used to analyze the data. Frequency of leisure-time physical activity was significantly associated with lower levels of depressive symptoms for both types of stress and acted as a buffer of the association between life stress and depressive symptoms, but did not buffer the influence of time pressure on depressive symptoms. These findings indicated that leisure-time physical activity assists in maintaining the mental health of mothers of infants; however, caution is needed when promoting physical activity for mothers who feel under time pressure.

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Effect of Warm-Up and Sodium Bicarbonate Ingestion on 4-km Cycling Time-Trial Performance

William H. Gurton, Steve H. Faulkner, and Ruth M. James

lactate. 1 Extracellular buffering mechanisms act to remove these H + from the skeletal muscle cell, but once production rates overwhelm neutralization reactions, the excess H + contribute toward decreasing intramuscular pH. 2 Exercise-induced acidosis inhibits glycolytic energy production and

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Oral Bovine Colostrum Supplementation Enhances Buffer Capacity but Not Rowing Performance in Elite Female Rowers

Grant David Brinkworth, Jonathan David Buckley, Pitre Collier Bourdon, Jason Paul Gulbin, and Adrian Zachei David

A randomized, double-blind, placebo controlled design was used in which 13 elite female rowers, all of whom had competed at World Championships, were supplemented with 60 g · day−1 of either bovine colostrum (BC; n = 6) or concentrated whey protein powder (WP; n = 7) during 9 weeks of pre-competition training. All subjects undertook the study as a group and completed the same training program. Prior to, and after 9 weeks of supplementation and training, subjects completed an incremental rowing test (ROW1) on a rowing ergometer consisting of 3 3 4-min submaximal workloads and a 4-min maximal effort (4max), each separated by a 1-min recovery period. The rowing test was repeated after a 15-min period of passive recovery (ROW2). The 4max for ROW1 provided a measure of performance, and the difference between the 4max efforts of ROW1 and ROW2 provided an index of recovery. Blood lactate concentrations and pH measured prior to exercise and at the end of each workload were used to estimate blood buffer capacity (b). Food intake was recorded daily for dietary analysis. There were no differences in macronutrient intakes (p > .56) or training volumes (p > .99) between BC and WP during the study period. Rowing performance (distance rowed and work done) during 4max of ROW2 was less than ROW1 at baseline (p < .05) but not different between groups (p > .05). Performance increased in both rows by Week 9 (p < .001), with no difference between groups (p > .75). However, the increase was greatest in ROW2 (p < .05), such that by Week 9 there was no longer a difference in performance between the two rows in either group (p > .05). b was not different between groups for ROW1 at baseline (BC 38.3 ± 5.0, WP 38.2 ± 7.2 slykes; p > .05) but was higher in BC by Week 9 (BC 40.8 ± 5.9, WP 33.4 ± 5.3 slykes; p < .05). b for ROW2 followed the same pattern of change as for ROW1. We conclude that supplementation with BC improves b, but not performance, in elite female rowers. It was not possible to determine whether b had any effect on recovery.

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Effect of Beta-Alanine Supplementation on 2,000-m Rowing-Ergometer Performance

Kagan J. Ducker, Brian Dawson, and Karen E. Wallman

Beta-alanine supplementation has been shown to improve exercise performance in short-term high-intensity efforts. However, whether supplementation with beta-alanine is ergogenic to actual sporting events remains unclear and should be investigated in field testing or race simulations.

Purpose:

The aim of this study was to assess if beta-alanine supplementation could improve 2,000-m rowing-ergometer performance in well-trained male rowers.

Methods:

Participants (N = 16) completed duplicate trials (2 × before supplementation and 2 × after supplementation) of a 2,000-m rowing-ergometer race separated by 28 days of either beta-alanine (n = 7; 80 mg · kg−1 BM · d−1) or placebo (n = 9; glucose) supplementation.

Results:

Beta-alanine group (pooled) race times improved by 2.9 ± 4.1 s and placebo group slowed by 1.2 ± 2.9 s, but these results were inconclusive for performance enhancement (p = .055, ES = 0.20, smallest worthwhile change = 49% beneficial). Race split times and average power outputs only significantly improved with beta-alanine at the 750-m (time –0.7 s, p = .01, power +3.6%, p = .03) and 1,000-m (time –0.5 s, p = .01, power +2.9%, p = .02) distances. Blood La and pH postrace values were not different between groups before or after supplementation.

Conclusions:

Overall, 28 d of beta-alanine supplementation with 80 mg · kg−1 BM · d−1 (~7 g/d) did not conclusively improve 2,000-m rowing-ergometer performance in well-trained rowers.