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Erratum. CYP1A2 Genotype Polymorphism Influences the Effect of Caffeine on Anaerobic Performance in Trained Males

International Journal of Sport Nutrition & Exercise Metabolism

trained males. International Journal of Sport Nutrition and Exercise Metabolism, 32 (1), 16–21. Authors Mohammad Rahman Rahimi and Hemn Mohammadi were omitted from the original author list. The article was corrected July 07, 2023. The authors apologize for the

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Erratum. The Postprandial Plasma Amino Acid Response Does Not Differ Following the Ingestion of a Solid Versus a Liquid Milk Protein Product in Healthy Adult Females

International Journal of Sport Nutrition and Exercise Metabolism

solid versus a liquid milk protein product in healthy adult females. International Journal of Sport Nutrition and Exercise Metabolism . Advance online publication. The Y-axis in Figure 2b was incorrect. The article was corrected July 13, 2023.

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Erratum. Ergogenic Effects of Very Low to Moderate Doses of Caffeine on Vertical Jump Performance

International Journal of Sport Nutrition and Exercise Metabolism

moderate doses of caffeine on vertical jump performance. International Journal of Sport Nutrition and Exercise Metabolism . Advance online publication. There was an error in the equation for vertical jump velocity ( V ) on page 2. The article was corrected July

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Erratum. Effect of Moderate Versus Vigorous Exercise Intensity on Body Composition in Young Untrained Adults: The Activating Brown Adipose Tissue Through Exercise (ACTIBATE) Randomized Controlled Trial

International Journal of Sport Nutrition and Exercise Metabolism

body composition in young untrained adults: The Activating Brown Adipose Tissue Through Exercise (ACTIBATE) randomized controlled trial. International Journal of Sport Nutrition and Exercise Metabolism . Advance online publication. Author Juan M.A. Alcantara

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Erratum: Fensham et al. (2021)

Exercise Metabolism, Advanced online publication, , an error was introduced in the fourth sentence of the abstract. The sentence should read “Each trial involved two, submaximal 90-min rowing ergometer sessions, 2.5 hr apart, with venous blood sampled at baseline

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Ringing the Changes in Sport Nutrition and Exercise Metabolism

Professor James A. Betts

As we enter a new decade with our first issue of 2020, this short editorial serves to announce a number of important developments at International Journal of Sport Nutrition and Exercise Metabolism (IJSNEM). I should start by noting that you are not presently reading the words of Professor Ronald

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Application of Stable Isotope Tracers in the Study of Exercise Metabolism in Children: A Primer

Anthony D. Mahon and Brian W. Timmons

Exercise metabolism in children has traditionally been assessed using the respiratory exchange ratio (RER) to determine the contributions of fat and carbohydrate to the exercise energy demands. Although easily measured, RER measurements have limitations. Other methods to assess metabolism such as the obtainment of a muscle biopsy and the use of nuclear magnetic resonance spectroscopy carry ethical and feasibility concerns, respectively, which limit their use in studies involving children. Stable isotopes, used routinely in studies involving adults, can also be applied in studies involving children in an ethical and feasible manner. Two common stable isotopes used in metabolic studies involving children include carbon-13 (13C) and nitrogen-15 (15N). 13C-glucose can be used to study carbohydrate metabolism and 15N-glycine can be used to assess protein metabolism. This article reviews the use of 13C-glucose and 15N-glycine to study exercise metabolism in children, considers some of the associated ethical aspects, explains the general methodology involved in administering these isotopes and the resources required, and describes studies involving children utilizing these methods. Finally, suggestions for future research are provided to encourage further use of these techniques.

Cover International Journal of Sport Nutrition and Exercise Metabolism

International Journal of Sport Nutrition and Exercise Metabolism

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High-Fat Diet versus Habitual Diet Prior to Carbohydrate Loading: Effects on Exercise Metabolism and Cycling Performance

Estelle V. Lambert, Julia H. Goedecke, Charl van Zyl, Kim Murphy, John A. Hawley, Steven C. Dennis, and Timothy D. Noakes

We examined the effects of a high-fat diet (HFD-CHO) versus a habitual diet, prior to carbohydrate (CHO)-loading on fuel metabolism and cycling time-trial (TT) performance. Five endurance-trained cyclists participated in two 14-day randomized cross-over trials during which subjects consumed either a HFD (>65% MJ from fat) or their habitual diet (CTL) (30 ± 5% MJ from fat) for 10 day, before ingesting a high-CHO diet (CHO-loading, CHO > 70% MJ) for 3 days. Trials consisted of a 150-min cycle at 70% of peak oxygen uptake (V̇O2peak), followed immediately by a 20-km TT. One hour before each trial, cyclists ingested 400 ml of a 3.44% medium-chain triacylglycerol (MCT) solution, and during the trial, ingested 600 ml/hour of a 10% 14C-glucose + 3.44% MCT solution. The dietary treatments did not alter the subjects’ weight, body fat, or lipid profile. There were also no changes in circulating glucose, lactate, free fatty acid (FFA), and β-hydroxybutyrate concentrations during exercise. However, mean serum glycerol concentrations were significantly higher (p < .01) in the HFD-CHO trial. The HFD-CHO diet increased total fat oxidation and reduced total CHO oxidation but did not alter plasma glucose oxidation during exercise. By contrast, the estimated rates of muscle glycogen and lactate oxidation were lower after the HFD-CHO diet. The HFD-CHO treatment was also associated with improved TT times (29.5 ± 2.9 min vs. 30.9 ± 3.4 min for HFD-CHO and CTL-CHO, p < .05). High-fat feeding for 10 days prior to CHO-loading was associated with an increased reliance on fat, a decreased reliance on muscle glycogen, and improved time trial performance after prolonged exercise.

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Running to Maintain Cardiovascular Fitness Is Not Limited by Short-Term Fasting or Enhanced by Carbohydrate Supplementation

Jason A. Schisler and C. David Ianuzzo


This study determined if recreational type of endurance exercise is limited by a short-term fast, such as an overnight fast or benefited by a carbohydrate supplement prior to and during endurance exercise.


Six individuals ran at 70% VO2max for 90 min under three dietary conditions (fed, fasted for 16 to 18 h, fasted plus CHO).


RPE, RER, BG (blood glucose), and La (lactate) were similar between conditions throughout 90 min of exercise. FFA was higher (P ≤ 0.05) only in the fed and fasted groups after exercise.


The psychosomatic sensation, physiologic, and metabolic data all indicated that endurance exercise for up to 90 min for fit individuals is not limited by a short-term fast or enhanced by carbohydrate supplementation. These findings are of interest to persons who exercise to maintain and enhance health and are not concerned with elite performance.