The Validity of Ultrasound Technology in Providing an Indirect Estimate of Muscle Glycogen Concentrations Is Equivocal

Bone, Julia L.; Ross, Megan L.; Tomcik, Kristyen; Jeacocke, Nikki A.; McKay, Alannah K A; Burke, Louise M.

doi:10.3390/nu13072371

Cited by 9 publications

(12 citation statements)

References 54 publications

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“…While some studies have questioned the validity and utility of using skeletal muscle ultrasound to estimate muscle glycogen content (45,46), we successfully detected expected decreases in muscle "fuel" using the MuscleSound ® session fuel percentile score. Although our analyses did not achieve statistical significance, we observed strong directional results suggesting reduced muscle fuel following the ketogenic diet as well as following the time trial across all conditions.…”

Section: Discussionmentioning

confidence: 85%

“…This method has been shown to correlate highly with glycogen content measured by muscle biopsy (29,44). However, some studies have questioned the validity and utility of this technique (45,46). In the present study, we investigated whether the MuscleSound ® system was able to detect assumed changes in muscle glycogen content resulting from dietary interventions and a 30-km time trial.…”

Section: Muscle Ultrasoundmentioning

confidence: 97%

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Ketogenic and High-Carbohydrate Diets in Cyclists and Triathletes

Kreutzer

Graybeal

Rack

et al. 2022

Commun in Kinesiology

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Endurance athletes frequently employ nutritional strategies to enhance performance. While professional organizations recommend high carbohydrate (HC) diets to maximize performance, many athletes, and researchers have recently shown renewed interest in the ketogenic diet (KD) in hopes to promote “fat adaptation”, which would allow athletes to make use of the essentially unlimited energy resources from stored body fat. This would circumvent one fatigue mechanism, the depletion of muscle glycogen stores, that has been considered central to performance outcomes in endurance events. The present study investigated the effects of participants’ habitual diet (HD), HC, and KD on endurance performance in a 30-km simulated cycling time trial (TT), physiological responses during the TT, and muscle session fuel percentile (SFP) before and after the TT using ultrasonic imaging. Due to the COVID-19 pandemic, data collection ceased after only six recreational cyclists and triathletes (f = 4, m = 6; age: 37.2 ± 12.2; VO2max: 46.8 ± 6.8 ml/kg/min; weekly cycling distance: 225.3 ± 64.2 km). Due to the small sample size, we do not report inferential statistics for our primary outcome measure, cycling performance. Participants completed the KD at the lowest power output. Oxygen consumption (V̇O2), heart rate (HR), and perceived exertion (RPE) during the TT were similar in all conditions. FATox rates were highest in the KD condition and lowest in the HC condition. SFP was lower during KD compared with HD and lower following the TT compared with fasted resting values across all conditions. We discuss methodological considerations into the use of exercise equipment, nutritional interventions, and statistical analysis strategies for study designs like the present. Further research is needed to assess the impact of HC and KD on TT performance in this population. ClinicalTrials.gov Identifier: NCT04097171; OSF preregistration: https://osf.io/ujx6e/

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Section: Discussionmentioning

confidence: 85%

Section: Muscle Ultrasoundmentioning

confidence: 97%

Ketogenic and High-Carbohydrate Diets in Cyclists and Triathletes

Kreutzer

Graybeal

Rack

et al. 2022

Commun in Kinesiology

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“…Besides making predictions on total energy turnover during exercise, it is useful to establish the rate of glycogen breakdown, as very high-intensity efforts can substantially reduce muscle glycogen content without very high energy turnover rates [34,176], especially as low glycogen availability can negatively affect performance [30]. Attempts have been made to find ways to non-invasively and cost-effectively measure muscle glycogen concentrations (e.g., using ultrasound); however, to date no independently performed validation has been successful in showing that this method of muscle glycogen quantification provides valid results [177]. Currently, the best solution is to draw on previous studies investigating glycogen breakdown by muscle biopsy in different sports disciplines, such as weightlifting [178], athletics [179], rugby [180], men's football [181], women's football [182] and Australian Rules football [183].…”

Section: Personalizing Carbohydrate Intakementioning

confidence: 99%

New Horizons in Carbohydrate Research and Application for Endurance Athletes

Podlogar

Wallis

2022

Sports Med

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The importance of carbohydrate as a fuel source for exercise and athletic performance is well established. Equally well developed are dietary carbohydrate intake guidelines for endurance athletes seeking to optimize their performance. This narrative review provides a contemporary perspective on research into the role of, and application of, carbohydrate in the diet of endurance athletes. The review discusses how recommendations could become increasingly refined and what future research would further our understanding of how to optimize dietary carbohydrate intake to positively impact endurance performance. High carbohydrate availability for prolonged intense exercise and competition performance remains a priority. Recent advances have been made on the recommended type and quantity of carbohydrates to be ingested before, during and after intense exercise bouts. Whilst reducing carbohydrate availability around selected exercise bouts to augment metabolic adaptations to training is now widely recommended, a contemporary view of the so-called train-low approach based on the totality of the current evidence suggests limited utility for enhancing performance benefits from training. Nonetheless, such studies have focused importance on periodizing carbohydrate intake based on, among other factors, the goal and demand of training or competition. This calls for a much more personalized approach to carbohydrate recommendations that could be further supported through future research and technological innovation (e.g., continuous glucose monitoring). Despite more than a century of investigations into carbohydrate nutrition, exercise metabolism and endurance performance, there are numerous new important discoveries, both from an applied and mechanistic perspective, on the horizon.

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“…For this Special Issue, research leaders in sports nutrition were approached and invited to submit current reviews in their areas of expertise [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. The topics are novel and wide-ranging, and include updates and insights on protein [ 11 , 12 ], dietary patterns and nutritional interventions to support sleep, older athletes, and sports performance [ 13 , 14 , 15 ], pre-exercise nutrition [ 16 ], supplementation with betaine, iron, and creatine [ 17 , 18 , 19 ], and sports nutrition research methodologies for body composition and muscle glycogen analysis [ 20 , 21 ]. A major emphasis in all of the papers was a focus on strengths and weaknesses for various sports nutrition strategies, and insights for future research.…”

mentioning

confidence: 99%

“…This research group concluded that properly conducted skinfold measurements provide useful data and may be preferred over other methods because it is simple, low-cost, least affected by lifestyle confounders, and good for the long-term tracking of athletes. The measurement of muscle glycogen is important in sports nutrition studies, and Bone et al [ 21 ] cautioned that high-frequency ultrasound technology for estimating muscle glycogen content needs further development.…”

mentioning

confidence: 99%