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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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Robert A. Robergs

During the initial hours of recovery from prolonged exhaustive lower body exercise, muscle glycogen synthesis occurs at rates approximating 1-2 mmol·kg−1 wet wt·hr1 if no carbohydrate is consumed. When carbohydrate is consumed during the recovery, the maximal rate of glycogen synthesis approximates 7-10 mmol·kg−1 wet wt·hr1. The rate of postexercise glycogen synthesis is lower if the magnitude of glycogen degradation is small, if less than 0.7 gm glucose·kg−1 body wt·hr1 is ingested, when the recovery is active, and when the carbohydrate feeding is delayed. The rate of postexercise glycogen synthesis is not reduced during the initial hours (< 4) after eccentric exercise. For studies evaluating muscle glycogen synthesis in excess of 12 hours of recovery, average rates of glycogen synthesis are balow 4 mmo1·kg−1 wet wt·hr1. Glycogen synthesis is known to be impaired for time periods in excess of 24 hours following exercise causing eccentric muscle damage. Following intense exercise resulting in high concentrations of muscle lactate, muscle glycogen synthesis occurs at between 15-25 mmol·kg−1 wet wt·hr1. These synthesis rates occur without ingested carbohydrate during the recovery period and are maintained when a low intensity active recovery is performed.

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Adam B. Schroer, Michael J. Saunders, Daniel A. Baur, Christopher J. Womack and Nicholas D. Luden

Previous studies reported that adding protein (PRO) to carbohydrate (CHO) solutions enhances endurance performance. The ergogenic effect may be a function of additional protein/amino acid calories, but this has not been examined. In addition, although supplemental L-alanine (ALA) is readily oxidized during exercise, the subsequent impact on metabolism and prolonged endurance performance is unknown. The purpose of this investigation was to independently gauge the impact of whey PRO hydrolysate and ALA supplementation on performance and various physiological parameters. Eight cyclists (age: 22.3 ± 5.6 yr, weight: 70.0 ± 8.0 kg, VO2max: 59.4 ± 4.9 ml·kg−1·min−1) performed 120 min of constant-load cycling (55% of peak power) followed by a 30-km time trial (TT) under placebo (PLA), PRO, and ALA conditions. Magnitude-based qualitative inferences were applied to evaluate treatment differences and data are presented as percent difference between treatments ± 90% confidence limit. Both ALA (–2.1 ± 2.7%) and PRO intake (–2.1 ± 2.2%) possibly harmed performance compared with PLA. Of interest, heart rate was possibly lower with ALA than PLA at 20– (–2.7 ± 3.4%) and 120-min (–1.7 ± 2.9%) of constant-load cycling and the serum interleukin-6 (IL-6) response to 120 min of cycling was likely attenuated with PRO compared with PLA (PLA, 6.6 ± 3.7 fold vs. PRO, 2.9 ± 1.8 fold). In addition, blood glucose levels were lower with PRO than PLA at 20– (–8.8 ± 2.3%; very likely) and 120-min (–4.9 ± 4.6%; likely) of constant-load cycling. Although ALA intake appears to lower HR and PRO ingestion dampens the IL-6 response to exercise, the ingestion of PRO (without CHO) or ALA does not enhance, and may actually impair, performance following prolonged cycling.

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Louise M. Burke, Bronwen Lundy, Ida L. Fahrenholtz and Anna K. Melin

Sports Nutrition and Exercise Metabolism, 13 ( 2 ), 152 – 165 . doi:10.1123/ijsnem.13.2.152 10.1123/ijsnem.13.2.152 Braun , H. , von Andrian-Werburg , J. , Schänzer , W. , & Thevis , M. ( 2018 ). Nutrition status of young elite female German football players . Pediatric Exercise Science

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The International Journal of Sport Nutrition and Exercise Metabolism 27(3), http://journals.humankinetics.com/toc/ijsnem/27/3, was incorrectly paginated. The correct page range for this issue is 197–292. The online versions of these articles have been corrected.

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In the article by Muggeridge DJ, Howe C CF, Spendiff O, Pedlar C, James PE, Easton C, “The effects of a single dose of concentrated beetroot juice on performance in trained flatwater kayakers,” in the International Journal of Sport Nutrition and Exercise Metabolism 23(5), Figures 2 and 3 were incorrectly labeled due to an error in the production process. The online version of the article had been corrected. We apologize for the error.

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In this article by Kilduff LP, Georgiades E, James N, et al., “The Effects of Creatine Supplementation on Cardiovascular, Metabolic, and Thermoregulatory Responses During Exercise in the Heat in Endurance-Trained Humans,” in the International Journal of Sport Nutrition and Exercise Metabolism, 14(4), https://doi.org/10.1123/ijsnem.14.4.443, an author’s name was misspelled as Hadjicharlambous. It should read Hadjicharalambous. We apologize for the error. The online version of this article has been corrected.

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Lanae M. Joubert and Melinda M. Manore

Homocysteine is an independent cardiovascular disease (CVD) risk factor modi-fable by nutrition and possibly exercise. While individuals participating in regular physical activity can modify CVD risk factors, such as total blood cholesterol levels, the impact physical activity has on blood homocysteine concentrations is unclear. This review examines the influence of nutrition and exercise on blood homocysteine levels, the mechanisms of how physical activity may alter homocys-teine levels, the role of homocysteine in CVD, evidence to support homocysteine as an independent risk factor for CVD, mechanisms of how homocysteine increases CVD risk, and cut-off values for homocysteinemia. Research examining the impact of physical activity on blood homocysteine levels is equivocal, which is partially due to a lack of control for confounding variables that impact homocysteine. Duration, intensity, and mode of exercise appear to impact blood homocysteine levels differently, and may be dependent on individual fitness levels.

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Constance Georgiou, Nancy Betts, Terri Hoos and Marty Glenn

Health experts recommend merging a healthy diet and adequate physical activity into one behavior. This study compared attitudes about foods, recent dietary changes, and food choices of 319 18- to 24-year-olds, who defined themselves as exercisers or nonexercisers. Subjects were recruited by telephone and were mailed questionnaires that asked about factors influencing food selection and changes in intake of high-fat foods. Exercisers considered it more important to eat nutritious foods; ate more nutrient-dense, low-fat foods; and more frequently met the Food Guide Pyramid recommended grain and fruit intakes than nonexercisers. Female exercisers more often perceived foods high in calcium to be fattening and not healthful, and they reported decreasing their intake of high-fat foods more than did female nonexercisers. Some merging of healthy diet and exercise behavior is evident among the young adult exercisers in this study. Nutrition and exercise messages targeted to young women should emphasize low-calorie calcium sources.