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Cited by 15Sports Performance and TrainingCardiovascular and exercise physiologyMuscle metabolism and nutrition

Neither beetroot juice supplementation nor increased carbohydrate oxidation enhance economy of prolonged exercise in elite race walkers

Open access
Burke, Louise M., Hall, Rebecca, Heikura, Ida A., Ross, Megan L., Tee, Nicolin, Kent, Georgina L., Whitfield, Jamie, Forbes, Sara F. +9 more·2021·Nutrients
DOI 10.3390/nu13082767PMC PMC8398364
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Abstract

Given the importance of exercise economy to endurance performance, we implemented two strategies purported to reduce the oxygen cost of exercise within a 4 week training camp in 21 elite male race walkers. Fourteen athletes undertook a crossover investigation with beetroot juice (BRJ) or placebo (PLA) [2 d preload, 2 h pre-exercise + 35 min during exercise] during a 26 km race walking at speeds simulating competitive events. Separately, 19 athletes undertook a parallel group investigation of a multi-pronged strategy (MAX; n = 9) involving chronic (2 w high carbohydrate [CHO] diet + gut training) and acute (CHO loading + 90 g/h CHO during exercise) strategies to promote endogenous and exogenous CHO availability, compared with strategies reflecting lower ranges of current guidelines (CON; n = 10). There were no differences between BRJ and PLA trials for rates of CHO (p = 0.203) or fat (p = 0.818) oxidation or oxygen consumption (p = 0.090). Compared with CON, MAX was associated with higher rates of CHO oxidation during exercise, with increased exogenous CHO use (CON; peak = ~0.45 g/min; MAX: peak = ~1.45 g/min, p < 0.001). High rates of exogenous CHO use were achieved prior to gut training, without further improvement, suggesting that elite athletes already optimise intestinal CHO absorption via habitual practices. No differences in exercise economy were detected despite small differences in substrate use. Future studies should investigate the impact of these strategies on sub-elite athletes’ economy as well as the performance effects in elite groups.

AI snapshot

Written from the paper’s full text.

TL;DR

In elite male race walkers, neither beetroot juice (BRJ) supplementation nor a multi-pronged Carb Max strategy improved exercise economy during a 26 km race-walking protocol. Carb Max increased total and exogenous carbohydrate oxidation, but this did not translate into detectable changes in oxygen cost.

Key findings

  • In Study 1 (BRJ vs placebo, n = 14), there were no differences in oxygen uptake (p = 0.090), CHO oxidation (p = 0.203), fat oxidation (p = 0.818), RER (p = 0.795), lactate (p = 0.052), heart rate (p = 0.095), or RPE (p = 0.633). BRJ raised fasting plasma NO3− (p < 0.001) and plasma NO2− at pre-exercise and 7 km (p = 0.013), but nitrite elevation was not sustained for the second half of exercise.
  • In Study 2 (CON n = 10 vs MAX n = 9), MAX increased exogenous CHO oxidation: CON peak ~0.45 g/min vs MAX peak ~1.45 g/min (p < 0.001); maximal rates were 1.47 ± 0.25 g/min and 1.40 ± 0.32 g/min for MAX Trials A and C. Total CHO oxidation was higher from 13 km onward in MAX Trials A and C vs Trial B (p = 0.026).
  • Despite higher CHO oxidation, there were no differences in V̇O2 between trials (p = 0.915) or diets (p = 0.442). Gut training did not further increase exogenous CHO oxidation (CON Trial B vs C, p = 0.654; MAX Trial A vs C, p = 0.995), with pre-intervention peak exogenous CHO use already high (~1.47 g/min; oxidation index >90%).
  • Across the 4-week camp, V̇O2peak increased (p = 0.018) and body mass decreased ~1.0 kg (p < 0.001), with no differences between diet groups.

Methods

  • Two investigations were embedded in ~4-week training camps at the Australian Institute of Sport in 21 elite male race walkers: Study 1 was a crossover BRJ vs placebo trial (n = 14); Study 2 was a parallel-group CON vs MAX trial (n = 19).
  • The 26 km race-walking protocol was a hybrid laboratory/field test at ~75% V̇O2peak, with the final kilometre increased by 1.3 km/h. Respiratory gases were collected via Douglas bags and analysed by indirect calorimetry; blood nitrate/nitrite and 13C glucose/fructose tracer methods assessed exogenous CHO oxidation.
  • Diets were strictly controlled. CON reflected lower CHO guidelines (~30 g/h during exercise; 6.5 g/kg/day training diet), while MAX combined chronic high CHO (~10 g/kg/day), acute CHO loading (~12 g/kg), 90 g/h during exercise, and gut-training strategies including sucralose. Linear mixed models were used.

Limitations

  • The paper states that exercise economy is a proxy/contributor to performance, not a performance measure; the study may not detect minor changes important in elite sport, and real changes <2% require repeated measures or larger samples. The BRJ trial was not fully blinded because the placebo condition used a capsule, though the authors note the economy focus was unlikely to be influenced by belief effects.
  • The paper states that multiple treatments in Carb Max prevent identifying the specific contribution of any single element, and no muscle biopsies were taken to confirm glycogen storage. Future studies should investigate sub-elite athletes and performance effects in elite groups.
  • Evident from the text: the sample was small, elite, and male race walkers only, limiting generalisability; no performance outcome was measured; and 13C exogenous CHO calculations may underestimate values in the first hour, so those data were excluded from statistical analyses.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/nu13082767

Cites

78 of 78 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 56 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Compared with CON, MAX was associated with higher rates of CHO oxidation during exercise.

    “Compared with CON, MAX was associated with higher rates of CHO oxidation during exercise, with increased exogenous CHO use (CON; peak = ~0.45 g/min; MAX: peak = ~1.45 g/min, p < 0.001).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: V̇O2 and V̇CO2 accurately reflect tissue O2 consumption and CO2 production.
    • The authors state this as an assumption: Indirect calorimetry is a valid method for quantifying rates of substrate oxidation in well-trained athletes during strenuous exercise of up to 85% of V̇O2peak.
  • Findingown data

    Compared with CON, MAX was associated with increased exogenous CHO use (peak ~1.45 vs ~0.45 g/min, p < 0.001).

    “Compared with CON, MAX was associated with higher rates of CHO oxidation during exercise, with increased exogenous CHO use (CON; peak = ~0.45 g/min; MAX: peak = ~1.45 g/min, p < 0.001).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: V̇O2 and V̇CO2 accurately reflect tissue O2 consumption and CO2 production.
    • The authors state this as an assumption: Indirect calorimetry is a valid method for quantifying rates of substrate oxidation in well-trained athletes during strenuous exercise of up to 85% of V̇O2peak.
  • Findingown data
    § Neither Beetroot Juice Supplementation nor Increased Carbohydrate Oxidation Enhance Economy of Prolonged Exercise in Elite Race Walkers

    Increased carbohydrate oxidation does not enhance exercise economy during prolonged race walking in elite male race walkers.

    “Neither Beetroot Juice Supplementation nor Increased Carbohydrate Oxidation Enhance Economy of Prolonged Exercise in Elite Race Walkers”
    • Also stated in: § Abstract · plain
      “No differences in exercise economy were detected despite small differences in substrate use.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The 26 km race walking protocol at the chosen speeds simulates competitive race walking events.
  • Findingown data

    There were no differences between BRJ and PLA trials for oxygen consumption.

    “There were no differences between BRJ and PLA trials for rates of CHO (p = 0.203) or fat (p = 0.818) oxidation or oxygen consumption (p = 0.090).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: V̇O2 and V̇CO2 accurately reflect tissue O2 consumption and CO2 production.
    • The authors state this as an assumption: Indirect calorimetry is a valid method for quantifying rates of substrate oxidation in well-trained athletes during strenuous exercise of up to 85% of V̇O2peak.
  • Findingown data
    § Neither Beetroot Juice Supplementation nor Increased Carbohydrate Oxidation Enhance Economy of Prolonged Exercise in Elite Race Walkers

    Beetroot juice supplementation does not enhance exercise economy during prolonged race walking in elite male race walkers.

    “Neither Beetroot Juice Supplementation nor Increased Carbohydrate Oxidation Enhance Economy of Prolonged Exercise in Elite Race Walkers”
    • Also stated in: § Abstract · plain
      “No differences in exercise economy were detected despite small differences in substrate use.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The 26 km race walking protocol at the chosen speeds simulates competitive race walking events.
  • May combine two claims. 33
  • Classified as probably not a substantial claim. 46

  • May combine two claims.

    Findingown data

    High rates of exogenous CHO use were achieved prior to gut training, without further improvement.

    “High rates of exogenous CHO use were achieved prior to gut training, without further improvement, suggesting that elite athletes already optimise intestinal CHO absorption via habitual practices.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: V̇O2 and V̇CO2 accurately reflect tissue O2 consumption and CO2 production.
    • The authors state this as an assumption: Indirect calorimetry is a valid method for quantifying rates of substrate oxidation in well-trained athletes during strenuous exercise of up to 85% of V̇O2peak.

  • May combine two claims.

    Findingown data

    No differences in exercise economy were detected despite small differences in substrate use.

    “No differences in exercise economy were detected despite small differences in substrate use.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The 26 km race walking protocol at the chosen speeds simulates competitive race walking events.

  • May combine two claims.

    Findingown data

    Relative VO2 remained similar across the steady state component of the 26 km race walk protocol (1-25 km), with a ~15% increase in VO2 evident during the final kilometre at the higher speed.

    “Relative V˙O2 (mL/kg/min) remained similar across the steady state component of the 26 km race walk protocol (1–25 km), with a ~15% increase in V˙O2 evident during the final kilometre at the higher speed (p < 0.001).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    The intake of BRJ before and during the exercise protocol was well-tolerated.

    “The intake of BRJ before and during the exercise protocol was well-tolerated.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Within the CON group, rates of exogenous CHO oxidation were 0.44 ± 0.10 g/min at the beginning of the second hour of exercise (13 km) and insignificantly increased to 0.46 ± 0.07 g/min during the final (26th) kilometre.

    “Within the CON group, rates of exogenous CHO oxidation (Figure 3C) were 0.44 ± 0.10 g/min at the beginning of the second hour of exercise (13 km) during which values are generally recognised as valid. There was insignificant (p = 0.992) increase to 0.46 ± 0.07 g/min during the final (26th) kilometre at the higher speed.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    There were no differences in the rate of total CHO oxidation or fat oxidation between Trials B and C.

    “However, there were no differences in the rate of total CHO oxidation (p = 0.781) or fat oxidation (p = 0.909) between Trials B and C.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    There were no differences in VO2 between trials or diets.

    “There were no differences in V˙O2 between trials (p = 0.915) or diets (p = 0.442).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Blood glucose concentrations increased at the 7 km mark and remained elevated throughout exercise; however, no differences between trials or diets were observed.

    “Blood glucose concentrations increased at the 7 km mark and remained elevated throughout exercise (p = 0.001); however, no differences between trials (p = 0.416) or diets (p = 0.913) were observed.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    During the 14-day intervention phase, energy intake was slightly but significantly higher in the MAX group than the CON group.

    “Energy intake (kJ/kg/d) was slightly but significantly higher in the MAX group than CON during this phase (p < 0.05).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    A decrease in absolute RMR and RMR expressed relative to FFM occurred during Post Testing, with no differences between diets.

    “A decrease in absolute RMR (p = 0.034) and RMR expressed relative to FFM (p = 0.025) occurred during Post Testing, with no differences between diets (p > 0.05).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    A decrease in body mass occurred over the 4 weeks (~1.0 kg), with no differences between dietary groups.

    “A decrease in BM occurred (~1.0 kg; p < 0.001), however there were no differences between dietary groups (p = 0.817).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    No differences between dietary conditions (MAX vs. CON) were evident for any variable (VO2, blood glucose, RPE, lactate, HR).

    “No differences between dietary conditions (MAX vs. CON) were evident for any variable (p > 0.05).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    A decrease in endogenous CHO oxidation over 13-25 km contributed to a net reduction in rates of total CHO oxidation over the session, and the increase in total CHO oxidation with the increase in speed at 26 km was attributable to an increase in endogenous CHO use.

    “A decrease in endogenous CHO oxidation (Figure 3A) over 13–25 km contributed to a net reduction in rates of total CHO oxidation over the session (p < 0.001, Figure 3E) and the increase in total CHO oxidation with the increase in speed at 26 km was attributable to an increase in endogenous CHO use.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    HR was generally lower during Trial C compared to Trial B.

    “HR was generally lower during Trial C compared to Trial B (p < 0.001).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    No differences in fat free mass were evident over time or between diets.

    “No differences in fat free mass (FFM) were evident over time (p = 0.826) or between diets (p = 0.991).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Increases in VO2peak over the 4 weeks of training camp were evident and were similar between diet groups.

    “Increases in V˙O2peak over the 4 weeks were evident (p = 0.018) and were similar between diet groups (p = 0.795).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    RPE, blood lactate concentrations and HR gradually increased throughout the exercise sessions.

    “RPE, blood lactate concentrations and HR gradually increased throughout the exercise sessions (all p < 0.001).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    The change in fat mass in the MAX group was significant (−1.4 kg) but failed to reach significance in the CON group (−0.7 kg).

    “The change in fat mass in the MAX group was significant (−1.4 kg; p < 0.001) but failed to reach significance in the CON group (−0.7 kg; p = 0.068).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    The Carb Max dietary treatment was well-tolerated and allowed the acute increase in CHO targets to be met without gastro-intestinal discomfort.

    “Unique features of this well-tolerated dietary treatment included a focus on a high intake of potatoes as a CHO source, rather than the usual focus on grains or sugar-rich foods. Furthermore, a reduction in the fibre/residue content of the CHO-loading diet allowed the acute increase in CHO targets to be met without gastro-intestinal discomfort.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Despite differences in CHO oxidation, there were no differences in the oxygen cost of exercise between trials or over the course of exercise, apart from the increased oxygen utilisation at 26 km associated with the higher speed.

    “Despite these differences in CHO oxidation, there were no differences in the oxygen cost of exercise between trials or over the course of exercise, apart from the increased oxygen utilisation at 26 km associated with the higher speed.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Even if the acute CHO loading protocol alone achieved greater muscle glycogen storage prior to each of the MAX Trials A and C, this was not associated with a greater contribution of endogenous CHO stores to total CHO oxidation, at least during the second hour of the exercise protocol.

    “Nevertheless, even if the acute CHO loading protocol alone achieved greater muscle glycogen storage prior to each of the MAX Trials A and C, this was not associated with a greater contribution of endogenous CHO stores to total CHO oxidation, at least during the second hour of the exercise protocol in which tracer methodology provides more credible data.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Our results suggest that neither BRJ supplementation nor increases in the contribution of CHO achieve a measurable change in oxygen utilisation during prolonged race walking which simulated important characteristics of competition.

    “while our results suggest that neither BRJ supplementation nor increases in the contribution of CHO achieve a measurable change in oxygen utilisation during prolonged race walking which simulated important characteristics of competition”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    A "Carb Max" intervention combining chronic and acute strategies to increase endogenous and exogenous CHO availability failed to alter oxygen utilisation during the exercise protocol despite increasing the contribution of CHO oxidation to muscle energy needs.

    “a “Carb Max” intervention combining chronic and acute strategies to increase endogenous and exogenous CHO availability also failed to alter oxygen utilisation during the exercise protocol despite increasing the contribution of CHO oxidation, a more economical muscle fuel source, to muscle energy needs.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Carbohydrate utilisation during prolonged endurance exercise is influenced by numerous factors, including the intensity and duration of the exercise, environmental conditions and the availability of endogenous and exogenous CHO.

    “Carbohydrate utilisation during prolonged endurance exercise is influenced by numerous factors, including the intensity and duration of the exercise, environmental conditions and the availability of endogenous and exogenous CHO (for reviews, see [34,35]).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [34] Jeukendrup, 2003, Modulation of carbohydrate and fat utilization by diet, exercise and environment, Biochem. Soc. Trans. source

      Not checked in the free run.

    • cites [35] Hargreaves, 2015, Exercise, muscle, and CHO metabolism, Scand. J. Med. Sci. Sports source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Nitrate supplementation is thought to reduce the oxygen cost of exercise via enhanced calcium handling and contractile efficiency.

    “nitrate supplementation is thought to reduce the oxygen cost of exercise via enhanced calcium handling and contractile efficiency [19]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [19] Jones, 2018, Dietary Nitrate and Physical Performance, Annu. Rev. Nutr. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Dietary nitrate can be serially reduced to nitric oxide (NO), providing a complementary pathway to the nitric oxide synthase (NOS)-supported conversion of arginine to NO.

    “Dietary nitrate can be serially reduced to nitric oxide (NO), providing a complementary pathway to the nitric oxide synthase (NOS-)supported conversion of arginine to NO [19].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [19] Jones, 2018, Dietary Nitrate and Physical Performance, Annu. Rev. Nutr. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Nitrate supplementation can reduce the oxygen cost of submaximal cycling and running.

    “early observations of a reduction in the oxygen cost of submaximal cycling [16,17] and running [18] following nitrate supplementation.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [16] Larsen, 2007, Effects of dietary nitrate on oxygen cost during exercise, Acta Physiol. source

      Not checked in the free run.

    • cites [17] Bailey, 2009, Dietary nitrate supplementation reduces the O2cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans, J. Appl. Physiol. source

      Not checked in the free run.

    • cites [18] Lansley, 2011, Dietary nitrate supplementation reduces the O2cost of walking and running: A placebo-controlled study, J. Appl. Physiol. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    The substantial increase in muscle fat oxidation achieved by adaptation to a ketogenic low-carbohydrate, high-fat diet is associated with an increase in the oxygen cost of exercise at speeds relevant to the race performance of elite endurance athletes.

    “consistent findings from studies from our group [24,25,26,27] and others [28] that the substantial increase in muscle fat oxidation achieved by adaptation to a ketogenic low-carbohydrate (CHO), high-fat diet is associated with an increase in the oxygen cost of exercise at speeds which are relevant to the race performance of elite endurance athletes [29].”
    Quote in the paperSubstantial claim0 of 6 sources checked
    • cites [24] Burke, L.M., Sharma, A.P., Heikura, I., Forbes, S.F., Holloway, M., McKay, A.K.A., Bone, J.L., Leckey, J.J., Welvaert, M., and Ross, M.L. (2020). Crisis of confidence averted: Impairment of exercise economy and performance in elite race walkers by ketogenic low carbohydrate, high fat (LCHF) diet is reproducible. PLoS ONE, 15. source

      Not checked in the free run.

    • cites [25] Burke, 2021, Adaptation to a low carbohydrate high fat diet is rapid but impairs endurance exercise metabolism and performance despite enhanced glycogen availability, J. Physiol. source

      Not checked in the free run.

    • cites [26] Burke, 2017, Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers, J. Physiol. source

      Not checked in the free run.

    • cites [27] Whitfield, 2021, Acute Ketogenic Diet and Ketone Ester Supplementation Impairs Race Walk Performance, Med. Sci. Sports Exerc. source

      Not checked in the free run.

    • cites [28] Shaw, 2019, Effect of a Ketogenic Diet on Submaximal Exercise Capacity and Efficiency in Runners, Med. Sci. Sports Exerc. source

      Not checked in the free run.

    • cites [29] Burke, 2021, Ketogenic low-CHO, high-fat diet: The future of elite endurance sport?, J. Physiol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Muscle glycogen stores can be supercompensated by diet and training protocols to increase their contribution to muscle substrate use.

    “While muscle glycogen stores can be supercompensated by diet and training protocols to increase their contribution to muscle substrate use [36]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [36] Burke, 2017, Postexercise muscle glycogen resynthesis in humans, J. Appl. Physiol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Nitrate supplementation is more likely to benefit higher-intensity events.

    “Although nitrate supplementation is more likely to benefit higher-intensity events [19]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [19] Jones, 2018, Dietary Nitrate and Physical Performance, Annu. Rev. Nutr. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    The rate of oxidation of exogenous CHO from sources consumed prior to and during exercise is affected by the type and amount of CHO intake, and by prior adaptation of the gut via repeated exposure to enhance tolerance and intestinal absorption.

    “the rate of oxidation of exogenous CHO from sources consumed prior to and during exercise is affected by the type and amount of CHO intake, and by prior adaptation of the gut via repeated exposure to enhance tolerance and intestinal absorption [37,38,39].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [37] Stellingwerff, 2014, Systematic review: Carbohydrate supplementation on exercise performance or capacity of varying durations, Appl. Physiol. Nutr. Metab. source

      Not checked in the free run.

    • cites [38] Costa, 2017, Gut-training: The impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance, Appl. Physiol. Nutr. Metab. source

      Not checked in the free run.

    • cites [39] Jeukendrup, 2017, Training the Gut for Athletes, Sports Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The CON strategies represent the low end of the range of guidelines for CHO intake for endurance athletes for training, and fuelling targets before and during a long distance race.

    “These strategies represent the low end of the range of guidelines for CHO intake for endurance athletes for training, and fuelling targets before and during a long distance race [42].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] Thomas, 2016, American college of sports medicine joint position statement. nutrition and athletic performance, Med. Sci. Sports Exerc.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Fructose absorption via GLUT5 is known to upregulate rapidly following CHO exposure.

    “fructose absorption via GLUT5 is also known to upregulate rapidly following CHO exposure [39].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [39] Jeukendrup, 2017, Training the Gut for Athletes, Sports Med. source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    During the 72-h standardised protocol before the high CHO availability trials (MAX Trials A and C), there was an increase in CHO content and a reduction in fat, protein and fibre intake compared with the moderate CHO availability trials.

    “During the 72-h standardised protocol before the high CHO availability trials (MAX Trials A and C) there was an increase in CHO content (p< 0.05), and a reduction in fat, protein and fibre intake (all p < 0.05) compared with the moderate CHO availability trials.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Each group met dietary intake targets for the 48 h prior to each trial.

    “Each group met dietary intake targets for the 48 h prior to each trial (data not shown).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    The MAX dietary treatment was successfully implemented, and all athletes complied with their assigned dietary treatment and met the targeted energy and macronutrient intakes of each phase.

    “The MAX dietary treatment was successfully implemented, and all athletes complied with their assigned dietary treatment and met the targeted energy and macronutrient intakes of each phase.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    The nitrate supplementation trials were not fully blinded, but the focus on exercise economy rather than performance was unlikely to be influenced by belief effects.

    “Although this meant that the nitrate supplementation trials were not fully blinded, participants were told that the capsule provided an alternative form of NO3−. Furthermore, we note that the focus of the investigation was exercise economy rather than performance, an outcome that was unlikely to be influenced by belief effects.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    The apparent lack of effect of nitrate supplementation in elite endurance athletes may be a function of their athletic status (e.g., superior background NO production or reduced number of Type II muscle fibres) as well as an interaction with the conditions of use.

    “The apparent lack of effect in elite endurance athletes may be a function of their athletic status (e.g., due to a superior background NO production or reduced number of Type II muscle fibres in which nitrate supplementation might be most suited to targeting conditions of hypoxia or acidosis [19,56,61,62]) as well as an interaction with the conditions of use.”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [19] Jones, 2018, Dietary Nitrate and Physical Performance, Annu. Rev. Nutr. source

      Not checked in the free run.

    • cites [56] Jones, 2021, Dietary Nitrate and Nitric Oxide Metabolism: Mouth, Circulation, Skeletal Muscle, and Exercise Performance, Med. Sci. Sports Exerc. source

      Not checked in the free run.

    • cites [61] Jonvik, 2015, Can elite athletes benefit from dietary nitrate supplementation?, J. Appl. Physiol. source

      Not checked in the free run.

    • cites [62] Jonvik, 2015, Last Word on Viewpoint: Can elite athletes benefit from dietary nitrate supplementation?, J. Appl. Physiol. source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    During the 14-day intervention phase, CHO intake was higher in the MAX group than the CON group, while fat intake was lower, and protein and fibre intakes were similar.

    “During the 14 d intervention phase, as directed, CHO intake was higher in the MAX group than the CON group (p < 0.05), while fat intakes were lower, and protein and fibre intakes were similar.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Evidence for the gut training effect has only been investigated using glucose, demonstrating upregulation of its transport protein SGLT1.

    “Although evidence for this ‘training’ effect has only been investigated using glucose (demonstrating upregulation of its transport protein, SGLT1)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [39] Jeukendrup, 2017, Training the Gut for Athletes, Sports Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Dietary allocations in Study Two were made with consideration to athlete preference while matching groups for age, V̇O2peak and personal best race times.

    “Dietary allocations were made with consideration to the athlete’s preference, while also matching for key characteristics including age, V˙O2peak and personal best race times (Table 1).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Ingestion of artificial sweeteners such as sucralose can increase SGLT1 content in animal models via a cascade initiated by sweet taste receptors in the mouth and small intestine.

    “the ingestion of artificial sweeteners such as sucralose can also increase SGLT1 content in animal models [40] via a cascade initiated by sweet taste receptors in the mouth and small intestine.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [40] Margolskee, 2007, T1R3 and gustducin in gut sense sugars to regulate expression of Na+-glucose cotransporter 1, Proc. Natl. Acad. Sci. USA source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    The lack of drift in oxygen uptake over exercise and the failure to see any improvement in economy in association with nitrate supplementation may be related to the calibre and training status of the athletes and the relative intensity of the protocol.

    “The lack of the drift in oxygen uptake over exercise and the failure to see any improvement in economy in association with nitrate supplementation may be related to the calibre and training status of the athletes and the relative intensity of the protocol.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A previous study providing acute exposure to sucralose (1 mM) just prior to exercise failed to find an effect on the oxidation of CHO subsequently consumed throughout the protocol.

    “Although a previous study providing acute exposure to sucralose (1 mM) just prior to exercise failed to find an effect on the oxidation of CHO subsequently consumed throughout the protocol, it was suggested that further studies investigate higher doses and repeated/chronic use [73].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [73] Stellingwerff, 2013, Effects of pre-exercise sucralose ingestion on carbohydrate oxidation during exercise, Int. J. Sport Nutr. Exerc. Metab. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    There is an enhanced effect of gut training when applied to the specific type of CHO and exercise that have been practiced.

    “there seems to be an enhanced effect when applied to the specific type of CHO and exercise that have been practice [38].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [38] Costa, 2017, Gut-training: The impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance, Appl. Physiol. Nutr. Metab. source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    A CHO feeding regimen providing 90 g/h of a glucose:fructose mixture during the 2 h race walking session was compared with the control protocol of 30 g/h CHO intake, with the latter representing the lower end of the range recommended in current sports nutrition guidelines for endurance events.

    “A CHO feeding regimen providing 90 g/h of a glucose:fructose mixture during the 2 h race walking session was compared with the control protocol of 30 g/h CHO intake, with the latter representing the lower end of the range recommended in current sports nutrition guidelines for endurance events [42].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [42] Thomas, 2016, American college of sports medicine joint position statement. nutrition and athletic performance, Med. Sci. Sports Exerc.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The increase in intestinal absorption and oxidation of exogenous CHO from gut training is attributed to upregulated expression of the intestinal glucose transport protein SGLT1 and potentially a similar effect on the fructose transporter GLUT5.

    “This has been attributed to an upregulated expression of the intestinal glucose transport protein, SGLT1, and potentially, a similar effect on the fructose transporter, GLUT5 [39].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [39] Jeukendrup, 2017, Training the Gut for Athletes, Sports Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    A random intercept for athlete and camp were included to adjust for baseline values and differences between camp.

    “A random intercept for athlete and camp were included to adjust for baseline values and differences between camp.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    Calculations of exogenous CHO oxidation may be underestimated at 1 km and 7 km, so these data points were not included in the statistical analyses.

    “Therefore, the calculations of exogenous CHO oxidation may be underestimated at 1 km and 7 km. These data points are presented for completeness but have not been included in the statistical analyses undertaken in the study.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    The chronic intervention associated with Carb Max, which increased total dietary CHO within daily energy intake, was likely associated with better restoration of daily muscle glycogen stores throughout the intensified training block.

    “The chronic intervention associated with Carb Max, which increased total dietary CHO within daily energy intake, was likely associated with better restoration of daily muscle glycogen stores throughout the intensified training block [67].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [67] Simonsen, 1991, Dietary carbohydrate, muscle glycogen, and power output during rowing training, J. Appl. Physiol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    In Study Two, values for exogenous and endogenous CHO oxidation for the first hour of the exercise protocol were not included in statistical analyses due to the likely methodological under-estimation of true values.

    “In Study Two, values for exogenous and endogenous CHO oxidation for the first hour of the exercise protocol were not included in statistical analyses due to the likely methodological under-estimation of true values.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    In Study Two, temperature and humidity were included within the model to account for different environmental conditions between trials.

    “Furthermore, in Study Two, temperature and humidity were included within the model to account for different environmental conditions between trials.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The use of multiple transportable CHOs represents a solution to the gut bottleneck and has been associated with high rates of exogenous CHO oxidation during laboratory exercise.

    “The use of “multiple transportable CHOs” (combinations of CHO sources with non-competing intestinal absorption mechanisms) represents a solution to this gut bottleneck and has been associated with high rates of exogenous CHO oxidation during laboratory exercise (for review, see [68,69])”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [68] Baur, 2021, Carbohydrate supplementation: A critical review of recent innovations, Eur. J. Appl. Physiol. source

      Not checked in the free run.

    • cites [69] Jeukendrup, 2010, Carbohydrate and exercise performance: The role of multiple transportable carbohydrates, Curr. Opin. Clin. Nutr. Metab. Care source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The use of multiple transportable CHOs has been associated with successful performance in endurance events in real-world sports.

    “as well as successful performance in endurance events in real-world sports [70,71].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [70] Fordyce, T. (2021, August 01). Chris Froome: Team Sky’s Unprecedented Release of Data Reveals How British Rider Won Giro d’Italia. Available online: https://www.bbc.com/sport/cycling/44694122.

      Not checked in the free run.

    • cites [71] Pfeiffer, 2012, Nutritional Intake and Gastrointestinal Problems during Competitive Endurance Events, Med. Sci. Sports Exerc. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    No correction was made for background 13C because the pilot protocol found this to be negligible.

    “No correction was made for background 13C since the pilot protocol found this to be negligible.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The rate of intake of CHO during exercise is a key factor in determining exogenous CHO oxidation, with the intestinal absorption of CHO being the limiting factor in gut delivery and subsequent utilisation in the muscle.

    “The rate of intake of CHO during exercise is a key factor in determining exogenous CHO oxidation, with the intestinal absorption of CHO being the limiting factor in gut delivery and subsequent utilisation in the muscle.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [68] Baur, 2021, Carbohydrate supplementation: A critical review of recent innovations, Eur. J. Appl. Physiol. source

      Not checked in the free run.

    • cites [69] Jeukendrup, 2010, Carbohydrate and exercise performance: The role of multiple transportable carbohydrates, Curr. Opin. Clin. Nutr. Metab. Care source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Previous studies in well-trained athletes have identified higher muscle CHO storage when CHO intake was increased for several days from ~10 g/kg/d to 12 g/kg/d within the same energy content.

    “previous studies in well-trained athletes have identified higher muscle CHO storage when CHO intake was increased for several days from ~10 g/kg/d to 12 g/kg/d within the same energy content [66].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [66] Coyle, 2001, Low-fat diet alters intramuscular substrates and reduces lipolysis and fat oxidation during exercise, Am. J. Physiol. Metab.

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Gut training via repeated exposure to CHO consumption during exercise sessions increases the intestinal absorption and oxidation of exogenous CHO as an exercise substrate.

    ““Gut training” via repeated exposure to CHO consumption during exercise sessions has been shown to increase the intestinal absorption and oxidation of exogenous CHO as an exercise substrate (for review, see [39]).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [39] Jeukendrup, 2017, Training the Gut for Athletes, Sports Med. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Enhanced CHO utilisation has been observed following gut training for CHO in general.

    “although the functional outcomes of enhanced CHO utilisation have been observed following gut training for CHO in general [38,72]”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [38] Costa, 2017, Gut-training: The impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance, Appl. Physiol. Nutr. Metab. source

      Not checked in the free run.

    • cites [72] Cox, 2010, Daily training with high carbohydrate availability increases exogenous carbohydrate oxidation during endurance cycling, J. Appl. Physiol. source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Daily variability of exercise metrics within athletes may be reduced and margins between winning and losing are incredibly small in elite sport.

    “where daily variability of exercise metrics within athletes may be reduced and margins between winning and losing are incredibly small [77].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [77] Hopkins, 1999, Design and analysis of research on sport performance enhancement, Med. Sci. Sports Exerc. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The methodology used in this study involved a bespoke system constructed specially for the Australian Institute of Sport to suit the logistics of testing groups of athletes and to maximise the reliability and validity of measurements of pulmonary gas-exchange data.

    “The methodology used in this study involved a bespoke system, constructed specially for the Australian Institute of Sport to suit the logistics of testing groups of athletes as well as to maximise the reliability and validity of measurements of pulmonary gas-exchange data.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductcitation

    The typical error of measurement associated with this system and its best practice protocols is ~2.4%, which is half of the values previously reported for criterion Douglas Bag methods or the most accurate commercial metabolic cart systems.

    “The typical error of measurement associated with this system and its best practice protocols of use is ~2.4% [48], which is half of the values previously reported for criterion Douglas Bag methods or the most accurate commercial metabolic cart systems [76].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [48] Saunders, 2004, Improved running economy in elite runners after 20 days of simulated moderate-altitude exposure, J. Appl. Physiol. source

      Not checked in the free run.

    • cites [76] Crouter, 2006, Accuracy and reliability of the ParvoMedics TrueOne 2400 and MedGraphics VO2000 metabolic systems, Eur. J. Appl. Physiol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The economy metric is reliant on the measurement of steady state oxygen consumption using various types of manual or automated gas-analysis systems.

    “this metric is reliant on the measurement of steady state oxygen consumption using various types of manual (i.e., Douglas bag method) or automated (i.e., commercial breath-by-breath analysers) gas-analysis systems [75].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [75] Barnes, 2015, Running economy: Measurement, norms, and determining factors, Sports Med. Open source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationnone given

    The economy of race walking represents a proxy measure or contributor to performance, rather than being a performance measure per se.

    “the primary outcome variable of this study, the economy of race walking, represents a proxy measure or contributor to performance, rather than being a performance measure per se.”
    Quote in the paperSubstantial claim
64 of 64

  • The authors state this as an assumption.

    V̇O2 and V̇CO2 accurately reflect tissue O2 consumption and CO2 production.

    “These equations are based on the premise that V˙O2 and V˙CO2 accurately reflect tissue O2 consumption and CO2 production”

  • The authors state this as an assumption.

    Indirect calorimetry is a valid method for quantifying rates of substrate oxidation in well-trained athletes during strenuous exercise of up to 85% of V̇O2peak.

    “indirect calorimetry is a valid method for quantifying rates of substrate oxidation in well-trained athletes during strenuous exercise of up to 85% of V˙O2peak [51].”

  • The paper relies on this without support.

    Sucralose ingestion increases intestinal glucose uptake in humans.

    “implementation of 5 mg/kg BM/d of sucralose provided in a 2 mM solution and ingested three times per day between meals in an attempt to increase intestinal glucose uptake.”

  • The paper relies on this without support.

    The 26 km race walking protocol at the chosen speeds simulates competitive race walking events.

    “during a 26 km race walking at speeds simulating competitive events”

  • The paper relies on this without support.

    Elite male race walkers are representative of elite endurance athletes for intestinal CHO absorption.

    “suggesting that elite athletes already optimise intestinal CHO absorption via habitual practices”

  • The authors state this as an assumption.

    During exercise at the intensities used in this study, there is negligible loss of CO2 to the bicarbonate pool once steady state is reached after ~60 min.

    “Calculations were made assuming that during exercise at the intensities used in this study there is negligible loss of CO2 to the bicarbonate pool [53] once steady state is reached after ~60 min [54].”

  • The paper relies on this without support.

    Exercise economy is important in the performance of endurance exercise events.

    “Given the important of exercise economy in the performance of endurance exercise events”

  • The paper relies on this without support.

    Both BRJ supplementation and strategies to enhance CHO oxidation can enhance sports performance via mechanisms other than changes to exercise economy.

    “since both strategies can enhance sports performance via mechanisms other than changes to exercise economy”
    “since these interventions may enhance performance through mechanisms unrelated to exercise economy.”

  • The paper relies on this without support.

    Similar investigations in race walking which calculate the translation of changes in economy to changes in expected race speeds are currently lacking.

    “Similar investigations in race walking which calculate the translation of changes in economy to changes in expected race speeds are currently lacking.”
9 of 9

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The specificity of research principle requires objective features to define targeted individuals/groups.

    “For example, the basic principle of the specificity of research, which states that the results of a study should be applied only to populations and/or scenarios which are similar to those involved in the research design, 5 requires objective features to define the targeted individuals/groups.”

    From Defining Training and Performance Caliber: A Participant Classification Framework (2022) · cites this paper as [5]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Background 13C is both included in the calculation and said not to be corrected

    Minor

    The stated exogenous-oxidation formula subtracts background 13C enrichment from both parts of its ratio, but the next paragraph says no background correction was made.

1 of 1

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Authors
Burke, L. M., Hall, R., Heikura, I. A., Ross, M. L., Tee, N., Kent, G. L., Whitfield, J., Forbes, S. F., Sharma, A. P., Jones, A. M., Peeling, P., Blackwell, J. R., Mujika, I., Mackay, K., Kozior, M., Vallance, B., & McKay, A. K. A.
Affiliations
  • Australian Catholic University (AU)
  • Australian Institute of Sport, Bruce, Canberra, ACT 2616, Australia
  • University of South Australia (AU)
  • University of Exeter (GB)
  • The University of Western Australia (AU)
  • University of the Basque Country (ES)
  • Queensland University of Technology (AU)
  • University of Limerick (IE)
Corresponding author
Burke, Louise M.
ORCID
Venue
Nutrients
Publisher
MDPI AG
Published
2021-08-12
Volume
13
Issue
8
Pages
2767
ISSN
2072-6643 (ISSN-L)
DOI
10.3390/nu13082767
PMC
PMC8398364
OpenAlex
W3190258547
Cited by
15
References
78
Citations by year
2026: 1 · 2025: 4 · 2024: 3 · 2023: 4 · 2022: 2 · 2021: 1
FWCI
2.46
Type
journal article
Language
en
Open access
Licence
Locations
  • Nutrients (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • UWA Profiles and Research Repository (UWA) (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • UniSA Research Outputs Repository (University of South Australia) (acceptedVersion, other-oa)
  • University of Limerick Institutional Repository (University of Limerick) (acceptedVersion, other-oa)
  • QUT ePrints (Queensland University of Technology) (submittedVersion, cc-by)
  • Arrow@dit (Dublin Institute of Technology) (submittedVersion, cc-by-nc-sa)
  • Adelaide Research & Scholarship (AR&S) (University of Adelaide) (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • Figshare (submittedVersion, cc-by-nc-sa)
  • UWA Profiles and Research Repository (University of Western Australia) (submittedVersion, cc-by)
Funders
  • Australian Catholic University (ACURF 2017000034)
  • Association of Potato Research and Education (Grant to Louise Burke)
Topics
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
Keywords
beetroot juice, carbohydrate oxidation, exercise economy, race walking, endurance performance, carbohydrate loading, oxygen consumption, substrate utilization, carbohydrate supplementation, elite athletes
MeSH terms
Fruit and Vegetable Juices, Adult, Dietary Carbohydrates, Humans, Male, Oxidation-Reduction, Oxygen Consumption, Walking, Dietary Supplements, Beta vulgaris, Athletes

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

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