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Cited by 17Muscle metabolism and nutritionSports Performance and TrainingExercise and Physiological Responses

Males and females exhibit similar muscle glycogen recovery with varied recovery food sources

Open access
Flynn, Shannon, Rosales, Alejandro, Hailes, Walter, Ruby, Brent·2020·European Journal of Applied Physiology
DOI 10.1007/s00421-020-04352-2PMC PMC7181447
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Abstract

Purpose: Research has elucidated the impact of post-exercise carbohydrate nutrition and environmental conditions on muscle glycogen re-synthesis. However, research has minimally considered the implications of glycogen recovery in females and has mostly focused on commercial sport nutrition products. The purpose of this study was to determine the effects of varied mixed macronutrient feedings on glycogen recovery and subsequent exercise performance in both sexes. Methods: Males (n = 8) and females (n = 8) participated in a crossover study. Subjects completed a 90-min cycling glycogen depletion trial, then rested for 4 h. Two carbohydrate feedings (1.6 g kg−1) of either sport supplements or potato-based products were delivered at 0 and 2 h post-exercise. Muscle biopsies (glycogen) and blood samples (glucose, insulin) were collected during the recovery. Afterwards, subjects completed a 20 km cycling time trial. Results: There was no difference between sexes or trials for glycogen recovery rates (male: 7.9 ± 2.7, female: 8.2 ± 2.7, potato-based: 8.0 ± 2.5, sport supplement: 8.1 ± 3.1 mM kg wet wt−1 h−1, p > 0.05). Time trial performance was not different between diets (38.3 ± 4.4 and 37.8 ± 3.9 min for potato and sport supplement, respectively, p > 0.05). Conclusions: These results indicate that food items, such as potato-based products, can be as effective as commercially marketed sports supplements when developing glycogen recovery oriented menus and that absolute carbohydrate dose feedings (g kg−1) can be effectively applied to both males and females.

AI snapshot

Written from the paper’s full text.

TL;DR

In a crossover trial, males and females showed similar muscle glycogen recovery rates after glycogen-depleting cycling when fed either potato-based foods or commercial sport supplements at 1.6 g carbohydrate kg−1 per feeding. Subsequent 20 km cycling time trial performance also did not differ between diets.

Key findings

  • Muscle glycogen recovery rates did not differ between sexes (male: 7.9 ± 2.7, female: 8.2 ± 2.7 mM kg wet wt−1 h−1, p > 0.05) or between potato-based and sport supplement diets (potato: 8.0 ± 2.5, sport supplement: 8.1 ± 3.1 mM kg wet wt−1 h−1, p > 0.05).
  • 20 km time trial performance did not differ between diets (potato: 38.3 ± 4.4 min; sport supplement: 37.8 ± 3.9 min, p > 0.05), though males completed time trials faster than females (34.7 ± 1.7 vs 41.0 ± 3.0 min, p < 0.0001).
  • Blood glucose showed a time × trial interaction: at 150 min, glucose was higher during the sport supplement trial than the potato trial (p < 0.01); there were no sex differences in blood glucose at any measured time (p > 0.05).
  • Serum insulin also showed a time × trial interaction: potato led to higher insulin at 120 min (p < 0.05), while sport supplement led to higher insulin at 150 min (p < 0.05); no sex differences were observed (p > 0.05).
  • Potato-based meals were rated more tasty (0.65 ± 0.04 vs 0.43 ± 0.04), satisfying (0.65 ± 0.05 vs 0.45 ± 0.05), and acceptable (0.59 ± 0.04 vs 0.47 ± 0.05) than sport supplements; males reported less stomach discomfort during the potato trial than the supplement trial (0.12 ± 0.04 vs 0.20 ± 0.06).

Methods

  • Sixteen recreationally active subjects (8 males, 8 females) completed a crossover, counter-balanced study with two trials separated by 7 days. Each trial included a 90-min cycling glycogen depletion protocol, a 4-h recovery, and a 20 km cycling time trial.
  • During recovery, subjects consumed either sports supplement products or potato-based foods at 0 and 2 h, each providing approximately 1.6 g carbohydrate kg body weight−1 per feeding with comparable fat and protein. Muscle biopsies from the vastus lateralis were taken at 0 and 4 h; blood samples for glucose and insulin were collected at 0, 30, 120, 150, and 240 min.
  • Glycogen was analyzed by enzymatic spectrophotometric methods, glucose by spectrophotometry, and insulin by ELISA. Statistical analyses used repeated-measures ANOVAs (sex × trial and sex × trial × time), with significance set at p < 0.05. All female subjects were using hormonal contraceptives (oral pill, n = 4; intrauterine device, n = 4), and testing was not controlled for menstrual cycle phase.

Limitations

  • The paper states that it did not consider protein, fat, micronutrient, or specific amino acid needs that may differ between sexes; that the study used a fasted state while athletes often train or compete fed; and that environmental conditions were not modified, with environmental effects on glycogen recovery not yet investigated in women.
  • The paper also notes that because all females used exogenous hormones for birth control, it is difficult to consider a particular menstrual cycle phase.
  • Evident from the text: the sample was small (n = 8 per sex), subjects were recreationally active rather than elite, and gastric emptying was not measured, so mechanisms for subtle glucose/insulin differences between diets remain speculative.

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

Integrity signals

Registry

Crossref · 10.1007/s00421-020-04352-2

Cites

67 of 67 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 60 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Males completed the 20 km time trials significantly faster than females (male: 34.7 ± 1.7, female: 41.0 ± 3.0 min, p < 0.0001).

    “However, there was a main effect for sex, with males completing the time trials significantly faster than females (male: 34.7 ± 1.7, female: 41.0 ± 3.0 min, p < 0.0001).”
    Quote in the paperNot a substantial claim
  • Findingown data

    There was no difference between males and females in the rate of muscle glycogen re-synthesis (male: 7.9 ± 2.7, female: 8.2 ± 2.7 mM kg wet wt−1 h−1, p > 0.05).

    “Correspondingly, there was no difference between males and females in the rate of glycogen re-synthesis (male: 7.9 ± 2.7, female: 8.2 ± 2.7 mM kg wet wt−1 h−1, p > 0.05).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Menstrual cycle phase does not affect muscle glycogen recovery or the comparison between sexes.
    • Rests on an assumption: Hormonal contraceptive use does not affect muscle glycogen recovery or the comparison between sexes.
  • Findingown data

    Time trial performance was not different between the potato-based and sport supplement diets (38.3 ± 4.4 and 37.8 ± 3.9 min, respectively, p > 0.05).

    “Time trial performance was not different between diets (38.3 ± 4.4 and 37.8 ± 3.9 min for potato and sport supplement, respectively, p > 0.05).”
    Quote in the paperSubstantial claim
  • Findingown data

    There was no difference in the rate of muscle glycogen re-synthesis between the sport supplement and potato-based diets (PB: 8.0 ± 2.5, SS: 8.1 ± 3.1 mM kg wet wt−1 h−1, p > 0.05).

    “no difference in the rate of muscle glycogen re-synthesis (PB: 8.0 ± 2.5, SS: 8.1 ± 3.1 mM kg wet wt−1 h−1, p > 0.05).”
    Quote in the paperSubstantial claim
  • Findingown data

    There was no learning effect in time trial performance across the order of trials or practice and experimental trials.

    “This indicates there was no learning effect and no difference between SS and PB.”
    Quote in the paperNot a substantial claim
  • The quote only partly states this claim. 1
  • Classified as probably not a substantial claim. 39
  • May combine two claims. 20

  • The quote only partly states this claim.

    Findingown data

    Muscle glycogen content increased over the 4-h recovery period following the glycogen-depleting exercise.

    “There was a main effect for time, where muscle glycogen content increased over the recovery period (Fig. 4, p < 0.0001).”
    Quote in the paperSubstantial claim

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

    Findingown data

    There was a main effect for trial regarding how tasty, how satisfying, and how acceptable the meals were (p < 0.0001, p < 0.01, p < 0.05, respectively).

    “In reference to meal satisfaction, there was a main effect for trial regarding how tasty (p < 0.0001), how satisfying (p < 0.01), and how acceptable (p < 0.05) the meals were.”
    Quote in the paperNot a substantial claim

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

    Findingown data

    Participants rated hunger higher at 0 h and 2 h of recovery, which was before each meal.

    “Participants rated hunger higher at 0 h and 2 h of recovery, which was before each meal (0 h: 0.62 ± 0.05, 1 h: 0.45 ± 0.04, 2 h: 0.55 ± 0.04, 3 h: 0.32 ± 0.04, 4 h: 0.31 ± 0.04 VAS scores).”
    Quote in the paperNot a substantial claim

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

    Findingown data

    The potato-based meals were rated more satisfying than the sport supplement meals (PB: 0.65 ± 0.05, SS: 0.45 ± 0.05).

    “satisfying (PB: 0.65 ± 0.05, SS: 0.45 ± 0.05)”
    Quote in the paperNot a substantial claim

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

    Findingown data

    There was a trial × sex interaction for stomach discomfort (p < 0.05).

    “There was a trial × sex interaction for stomach discomfort (p < 0.05).”
    Quote in the paperNot a substantial claim

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

    Findingown data

    The potato-based meals were rated more acceptable than the sport supplement meals (PB: 0.59 ± 0.04, SS: 0.47 ± 0.05).

    “and more acceptable (PB: 0.59 ± 0.04, SS: 0.47 ± 0.05) than the SS.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In the current study, there were minimal differences in subsequent exercise performance between males and females and between the two diets.

    “In the current study, males and females resynthesized muscle glycogen at similar rates following glycogen depletion and consumption of two different diets (potato-based food items and common sport supplement products), leading to minimal differences during subsequent exercise performance.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The study had adequate statistical power to detect meaningful differences in glycogen re-synthesis and exercise performance between diets and sexes.
    • Rests on an assumption: Exogenous hormone use by all female participants does not confound the comparison of muscle glycogen recovery between sexes.
    • Rests on an assumption: The fasted state used in the study does not alter the relative effects of different recovery food sources on glycogen recovery compared to a fed state.

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

    Findingown data

    Males rated hunger higher than females across trials (male: 0.53 ± 0.05, female: 0.36 ± 0.05).

    “Males rated hunger higher than females across trials (male: 0.53 ± 0.05, female: 0.36 ± 0.05).”
    Quote in the paperNot a substantial claim

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

    Findingown data

    The potato-based meals were rated more tasty than the sport supplement meals (PB: 0.65 ± 0.04, SS: 0.43 ± 0.04).

    “The PB were rated more tasty (PB: 0.65 ± 0.04, SS: 0.43 ± 0.04)”
    Quote in the paperNot a substantial claim

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

    Findingnone given

    Both PB had higher fiber content than SS.

    “Although the SS and PB at both feedings were matched for fat and protein content, both PB had higher fiber content, while both SS had a higher portion of calories from liquid sources.”
    Quote in the paperNot a substantial claim

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

    Findingreasoning

    Both SS had a higher portion of calories from liquid sources than PB.

    “Although the SS and PB at both feedings were matched for fat and protein content, both PB had higher fiber content, while both SS had a higher portion of calories from liquid sources.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Blood glucose and insulin rose quickly following the 0 and 2-h feedings before returning to baseline in the current study.

    “Similar to other studies using a variety of feeding strategies (Ivy et al. 1988a, b, 2002), blood glucose and insulin rose quickly following the 0 and 2-h feedings before returning to baseline.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ivy et al. 1988a, b, 2002 source

      Not checked in the free run.

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

    Findingcitation

    The current study found no significant difference between men and women in VO2peak when normalized for FFM.

    “Like Tarnopolsky et al. (1997), the current study found no significant difference between men and women in VO2peak when normalized for FFM.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Tarnopolsky et al. (1997) source

      Not checked in the free run.

  • May combine two claims.

    Findingreasoning

    While the 0-h feedings had a similar proportion of carbohydrate calories from simple sugars, the SS meal at 2 h had a higher simple sugar content.

    “While the 0-h feedings had a similar proportion of carbohydrate calories from simple sugars, the SS meal at 2 h had a higher simple sugar content, potentially explaining our results.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Endurance exercise performance and time to exhaustion have historically been linked to initial levels of glycogen storage within the skeletal muscle.

    “Endurance exercise performance and time to exhaustion have historically been linked to initial levels of glycogen storage within the skeletal muscle (Ahlborg et al. 1967; Bergstrom et al. 1967).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Ahlborg et al. 1967 source

      Not checked in the free run.

    • cites Bergstrom et al. 1967 source

      Not checked in the free run.

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

    Premisecitation

    The underlying rates of glycogen re-synthesis are influenced by the extent of glycogen depletion, the timing of ingestion, dose and amount, the composition as either varied carbohydrate source or in combination with amino acid blends or protein, and ambient and skeletal muscle temperature.

    “Collectively, the underlying rates of glycogen re-synthesis are influenced by the extent of glycogen depletion (Price et al. 1994; Zachwieja et al. 1991), the timing of ingestion (Ivy et al. 1988a), dose and amount (Blom et al. 1987; Ivy et al. 1988b; Jentjens et al. 2001; van Loon et al. 2000), the composition as either varied carbohydrate source (Blom et al. 1987; Burke et al. 1993; Ivy et al. 1”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Price et al. 1994 source

      Not checked in the free run.

    • cites Zachwieja et al. 1991 source

      Not checked in the free run.

    • cites Ivy et al. 1988a

      Not checked in the free run.

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

    Study design and conductown data

    Subjects were blinded to time and intensity during the 20 km time trial.

    “Subjects were not provided encouragement or entertainment and were blinded to time and intensity.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    Each trial utilized a different leg in randomized order for muscle biopsies.

    “Each trial utilized a different leg in randomized order.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    Mean intra-assay coefficients of variation for muscle samples, glucose, and insulin using these techniques were less than 5%.

    “Mean intra-assay coefficients of variation for muscle samples, glucose, and insulin using these techniques were less than 5%.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Most of the subtle metabolic differences previously demonstrated between sexes appear associated with circulating levels of endogenous and exogenous estradiol.

    “However, most of the subtle metabolic differences previously demonstrated appear associated with circulating levels of endogenous and exogenous estradiol.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Tarnoposky and Ruby 2001

      Not checked in the free run.

    • cites Tarnoposky 2008

      Not checked in the free run.

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

    Study design and conductnone given

    Females were tested without attempting to control timing across the menstrual cycle.

    “Females were tested without attempting to control timing across the menstrual cycle.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Research provides conflicting results regarding both the impacts of glycogen super-compensation (or pre-loading) and substrate use during endurance exercise when comparing women to men.

    “When comparing women to men, research provides conflicting results regarding both the impacts of glycogen super-compensation (or pre-loading) (James et al. 2001; Paul et al. 2001; Tarnopolsky et al. 2001; Walker et al. 2000) and substrate use during endurance exercise (Devries 2016; Riddell et al. 2003; Roepstorff et al. 2002; Ruby et al. 2002a; Tarnopolsky and Ruby 2001).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites James et al. 2001 source

      Not checked in the free run.

    • cites Paul et al. 2001 source

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    • cites Devries 2016 source

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

    Study design and conductnone given

    The study used a crossover, counter-balanced design with 7 days between trials.

    “Subjects completed two trials in a crossover, counter-balanced design with 7 days between trials.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    There was no difference between males and females for age, body fat percentage, or VO2peak when normalized for fat-free mass.

    “However, there was no difference between males and females for age, body fat percentage, or VO2peak when normalized for FFM.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Chocolate milk and fast food items restore glycogen similarly to common commercial sport nutrition products.

    “Both chocolate milk (Lunn et al. 2012) and fast food items (Cramer et al. 2015) restore glycogen similarly to common commercial sport nutrition products.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Lunn et al. 2012 source

      Not checked in the free run.

    • cites Cramer et al. 2015 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Exogenous provision of adequate substrate in the form of liquid supplements yields comparable glycogen restoration for men and women.

    “Exogenous provision of adequate substrate in the form of liquid supplements yields comparable glycogen restoration for men and women, but subsequent exercise performance has not been previously evaluated following a post-exercise carbohydrate feeding recovery period (Tarnopolsky et al. 1997).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Tarnopolsky et al. 1997 source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    There was a significant difference between men and women for weight, fat-free mass (FFM), and VO2peak (absolute and relative).

    “There was a significant difference between men and women for weight, fat-free mass (FFM), and VO2peak (absolute and relative).”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    The investigation did not consider protein, fat, micronutrient, or specific amino acid needs that may differ between sexes.

    “Nonetheless, there are some limitations. The investigation did not consider protein, fat, micronutrient, or specific amino acid needs that may differ between sexes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Premisecitation

    Current recommendations for refueling after exercise can be misleading, in particular for recreational athletes who are targeted by commercial marketing.

    “Current recommendations for refueling after exercise can be misleading, in particular for recreational athletes who are targeted by commercial marketing (Heneghan et al. 2012; Zytnick et al. 2015).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Heneghan et al. 2012 source

      Not checked in the free run.

    • cites Zytnick et al. 2015 source

      Not checked in the free run.

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

    Premisecitation

    Many athletes, especially females, have a lower overall energy intake and consume less than the recommended amounts of carbohydrate.

    “Evidence shows that many athletes, especially females, have a lower overall energy intake and consume less than the recommended amounts of carbohydrate (Baranauskas et al. 2015; Black et al. 2019; Burke et al. 2001; Masson and Lamarche 2016; Shriver et al. 2013).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Baranauskas et al. 2015 source

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    • cites Black et al. 2019 source

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    • cites Burke et al. 2001 source

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  • Classified as probably not a substantial claim.

    Interpretationreasoning

    When coupled with prior data using fast food items (Cramer et al. 2015), these recent data demonstrate that the exercise recovery carbohydrate oriented feeding recommendations given by health care providers, coaches and trainers can be simplified.

    “When coupled with prior data using fast food items (Cramer et al. 2015), these recent data demonstrate that the exercise recovery carbohydrate oriented feeding recommendations given by health care providers, coaches and trainers can be simplified.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Cramer et al. 2015 source

      Not checked in the free run.

    • Rests on an assumption: The study had adequate statistical power to detect meaningful differences in glycogen re-synthesis and exercise performance between diets and sexes.

  • May combine two claims.

    Premisecitation

    GLUT-4, hexokinase, and glycogen synthase levels and activities are similar between men and women.

    “All of these results are logical when considering that GLUT-4, hexokinase, and glycogen synthase levels and activities are similar between men and women (Lundsgaard and Kiens 2014), which would contribute to limited differences in muscle glucose delivery and storage across sex.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Lundsgaard and Kiens 2014 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    The notion that these recommendations simplify and decrease cost may be particularly important for recreational athletes who may be susceptible to commercial marketing.

    “The uniformity and flexibility of these recommendations simplify and potentially decrease the cost of recovery feeding plans, a notion that may be particularly important for recreational athletes who may be susceptible to commercial marketing.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    The similarities in MPS between males and females occurred despite significantly higher testosterone in males.

    “Moreover, the similarities in MPS between males and females occurred despite significantly higher testosterone in males.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites West et al. (2012) source

      Not checked in the free run.

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

    Premisecitation

    Recovering in room temperature ambient conditions and with warmed muscles will enhance glycogen re-synthesis as demonstrated by prior research on males.

    “Recovering in room temperature ambient conditions (Naperalsky et al. 2010; Slivka et al. 2013) and with warmed muscles (Slivka et al. 2012; Tucker et al. 2012) will enhance glycogen re-synthesis as demonstrated by prior research on males.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Naperalsky et al. 2010 source

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    • cites Slivka et al. 2013 source

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    • cites Slivka et al. 2012 source

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  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    If athletes are encouraged to consume a variety of foods they enjoy, the likelihood of carbohydrate compliance and sustainable dietary design may be enhanced.

    “If athletes are encouraged to consume a variety of foods they enjoy, the likelihood of carbohydrate compliance and sustainable dietary design may be enhanced.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    The effects of endogenous and/or exogenous estradiol reduce the rate of glucose appearance (Ra) and disappearance (Rd) during tightly controlled exercise trials under fasted conditions without altering total carbohydrate oxidation.

    “The effects of endogenous and/or exogenous estradiol has been demonstrated to reduce the rate of glucose appearance (Ra) and disappearance (Rd) during tightly controlled exercise trials under fasted conditions (Zderic et al. 2001; Ruby et al. 2002a, b; Ruby et al. 1997) but without altering total carbohydrate oxidation.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Zderic et al. 2001

      Not checked in the free run.

    • cites Ruby et al. 2002a, b

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    • cites Ruby et al. 1997 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based). May combine two claims.

    Interpretationreasoning

    Variation in recovery food sources may enhance carbohydrate compliance, contributing to sustainable recovery dietary design.

    “Variation in recovery food sources may enhance carbohydrate compliance, contributing to sustainable recovery dietary design.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The study participants are representative of male and female sport and tactical/occupational athletes of various fitness levels.

  • May combine two claims.

    Premisecitation

    Cramer et al. (2015) showed that fast food menu items stimulated glycogen recovery and contributed to subsequent exercise performance as effectively as commercial sports supplement products.

    “Cramer et al. (2015) showed that fast food menu items stimulated glycogen recovery and contributed to subsequent exercise performance as effectively as commercial sports supplement products.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Cramer et al. (2015) source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    The uniformity and flexibility of these recommendations simplify and potentially decrease the cost of recovery feeding plans.

    “The uniformity and flexibility of these recommendations simplify and potentially decrease the cost of recovery feeding plans, a notion that may be particularly important for recreational athletes who may be susceptible to commercial marketing.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The study participants are representative of male and female sport and tactical/occupational athletes of various fitness levels.

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

    Premisecitation

    Exogenous carbohydrate during exercise may alter endogenous depletion of glycogen and rates of subsequent glycogen re-synthesis.

    “It is also important to note that exogenous carbohydrate during exercise may alter endogenous depletion of glycogen (De Bock 2005) and rates of subsequent glycogen re-synthesis (Reinert et al. 2009).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites De Bock 2005 source

      Not checked in the free run.

    • cites Reinert et al. 2009 source

      Not checked in the free run.

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

    Interpretationreasoning

    Directly following exercise, muscle glycogen is most depleted so gastric emptying may have less impact than after the 2-h feeding when glycogen re-synthesis has already commenced.

    “For example, directly following exercise, muscle glycogen is most depleted so gastric emptying may have less impact than after the 2-h feeding when glycogen re-synthesis has already commenced.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Previous research shows that faster gastric emptying can lead to quicker glucose absorption in the small intestine.

    “Although gastric emptying was not measured in the current study, previous research shows that faster emptying can lead to quicker glucose absorption in the small intestine (Macdonald 1996).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Macdonald 1996 source

      Not checked in the free run.

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

    Interpretationreasoning

    The different blood responses could result from differences in the factors impacting gastric emptying between the SS and PB for the 2-h feeding.

    “The different blood responses could result from differences in the factors impacting gastric emptying between the SS and PB for the 2-h feeding.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    The different blood responses might be caused by differences in the content of simple sugars between the SS and PB for the 2-h feeding.

    “Alternately, the different blood responses might be caused by differences in the content of simple sugars between the SS and PB for the 2-h feeding.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    The lack of difference in the glucose and insulin response following the 0-h feeding could indicate that gastric emptying has varying levels of influence based on timing.

    “The lack of difference in the glucose and insulin response following the 0-h feeding could indicate that gastric emptying has varying levels of influence based on timing.”
    Quote in the paperNot a substantial claim

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

    Interpretationown data

    The SS meal at 2 h had a higher simple sugar content, potentially explaining the different blood responses.

    “While the 0-h feedings had a similar proportion of carbohydrate calories from simple sugars, the SS meal at 2 h had a higher simple sugar content, potentially explaining our results.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Some research indicates that substrate use sex differences are eliminated when subjects exercise in a fed as opposed to fasted state.

    “Some research indicates that substrate use sex differences are eliminated when subjects exercise in a fed as opposed to fasted state (Harger-Domitrovich et al. 2007).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Harger-Domitrovich et al. 2007 source

      Not checked in the free run.

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

    Premisecitation

    Gastric emptying is enhanced with decreased fat, fiber, and increased liquids.

    “Other investigations indicate that gastric emptying is enhanced with decreased fat (Frost et al. 2003), fiber (Vincent et al. 1995), and increased liquids (Hellström et al. 2006).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Frost et al. 2003 source

      Not checked in the free run.

    • cites Vincent et al. 1995 source

      Not checked in the free run.

    • cites Hellström et al. 2006 source

      Not checked in the free run.

49 of 49

  • The paper relies on this without support.

    Menstrual cycle phase does not affect muscle glycogen recovery or the comparison between sexes.

    “Females were tested without attempting to control timing across the menstrual cycle.”

  • The paper relies on this without support.

    Hormonal contraceptive use does not affect muscle glycogen recovery or the comparison between sexes.

    “All of the female subjects were currently using supplemental hormone prescriptions (triphasic norethindrone and ethyl estradiol, oral pill, n = 4) or time-release (intrauterine device, n = 4) birth control.”

  • The paper relies on this without support.

    Recommendations for optimal re-synthesis are uniformly applied to both men and women despite a relatively small amount of research including female participants.

    “Recommendations for optimal re-synthesis appear uniformly applied to both men and women despite a relatively small amount of research including female participants.”

  • The paper relies on this without support.

    The study had adequate statistical power to detect meaningful differences in glycogen re-synthesis and exercise performance between diets and sexes.

    “The lack of significant difference between PB and SS feedings for rates of glycogen re-synthesis or exercise performance demonstrates that diverse diets can similarly enhance glycogen recovery.”

  • The paper relies on this without support.

    The study participants are representative of male and female sport and tactical/occupational athletes of various fitness levels.

    “The findings of the current study regarding muscle glycogen re-synthesis and exercise performance can be applied to both male and female sport and tactical or occupational athletes of various fitness levels who require glycogen restoration following extended periods of work or between multiple bouts of work in a single day.”

  • The paper relies on this without support.

    Exogenous hormone use by all female participants does not confound the comparison of muscle glycogen recovery between sexes.

    “Since all of the females were using oral or IUD-derived exogenous hormones for birth control, it is difficult to consider a particular phase of the menstrual cycle.”

  • The paper relies on this without support.

    The fasted state used in the study does not alter the relative effects of different recovery food sources on glycogen recovery compared to a fed state.

    “Our study utilized a fasted state, but athletes often work, train, and compete in a fed state, so additional research using alternate feeding strategies may be warranted.”
7 of 7

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 source of macronutrients for men and women may be diverse and need not be limited to exclusively commercial sport nutrition products as long as an adequate amount of carbohydrates is provided at multiple intervals during post-exercise recovery.

    “Although new bioengineered formulations have been developed and introduced to the market, the source of macronutrients for men and women may be diverse and need not be limited to exclusively commercial sport nutrition products as long as an adequate amount of carbohydrates is provided at multiple intervals during post-exercise recovery [157].”

    From The 4R’s Framework of Nutritional Strategies for Post-Exercise Recovery: A Review with Emphasis on New Generation of Carbohydrates (2020) · cites this paper as [157]

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.

  • Feedings described as matched despite different protein amounts

    Minor

    The text says the diets were matched for fat and protein at both feedings, but the table reports 21.3 g of protein for the potato-based diet over 4 hours versus 32 g for the sports-supplement diet.

  • Feeding details are attributed to the wrong table

    Minor

    The feeding strategy directs readers to Table 2 for menu items and schedules, but Table 2 contains participant characteristics; the feeding protocol is Table 1.

  • Men's fat-free mass conflicts with their reported body-fat percentage

    Minor

    The reported mean weight and fat-free mass imply about 11.3% body fat for men, rather than 14.6%. The reported standard deviations are too small for variation between participants to account for this gap.

3 of 3

Cites

Flagged first, then by citations

1 of the 68 references couldn’t be matched to a known paper.

Cited by

Sorted by citations

Related

Authors
Flynn, S., Rosales, A., Hailes, W., & Ruby, B.
Affiliations
University of Montana (US)
Corresponding author
Ruby, Brent
ORCID
Venue
European Journal of Applied Physiology
Publisher
Springer Science and Business Media LLC
Published
2020-03-25
Volume
120
Issue
5
Pages
1131-1142
ISSN
  • 0020-9376 (ISSN-L)
  • 1439-6319
  • 1439-6327
DOI
10.1007/s00421-020-04352-2
PMC
PMC7181447
OpenAlex
W3013685056
Semantic Scholar
cfcd1daa65a3fffcde14612ac6bf6a3e6f25d7d3
Cited by
17
References
68
Citations by year
2026: 1 · 2024: 2 · 2023: 4 · 2022: 2 · 2021: 5 · 2020: 3
FWCI
1.75
Type
journal article
Language
en
Open access
Licence
Locations
  • European Journal of Applied Physiology (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
Alliance for Potato Research and Education
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Health Sciences › Medicine › Rehabilitation › Exercise and Physiological Responses
Keywords
muscle glycogen resynthesis, sex differences, sports supplements, cycling time trial performance, glycogen depletion, insulin response
MeSH terms
Adult, Bicycling, Blood Glucose, Dietary Carbohydrates, Female, Glycogen, Humans, Insulin, Male, Oxygen Consumption, Exercise, Muscle, Skeletal, Cross-Over Studies, Dietary Supplements

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 2026-10-08.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-08.

Statistics and arithmetic are recomputed, not judged.

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