manuscript: Anthony Critical revisions of the manuscript, approval its final version, and accountable for all aspects of the work: All authors. Funding Sources : This research was supported by a University of Wollongong, Faculty of Science, Medicine and Health internal research start-up grant (all funds
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Omega-3 Status Evaluation in Australian Female Rugby League Athletes: Ad Libitum Fish Oil Provision Results in a Varied Omega-3 Index
Ryan Anthony, Nicola Jaffrey, Caitlin Byron, Gregory E. Peoples, and Michael J. Macartney
The Use of Continuous Glucose Monitors in Sport: Possible Applications and Considerations
Amy-Lee M. Bowler, Jamie Whitfield, Lachlan Marshall, Vernon G. Coffey, Louise M. Burke, and Gregory R. Cox
’s Faculty of Health Sciences and Medicine, Australian Catholic University, and Queensland Academy of Sport’s Sport Performance Innovation and Knowledge Excellence Programme. Author Contributions: Data curation, conceptualization, investigation, project administration, visualization, writing—original draft
Addition of Fructose to a Carbohydrate-Rich Breakfast Improves Cycling Endurance Capacity in Trained Cyclists
Tim Podlogar, Simon Cirnski, Špela Bokal, Nina Verdel, and Javier T. Gonzalez
paid consultancy for The Dairy Council, PepsiCo, Tour Racing Ltd., and SVGC. This study was funded by Faculty of Health sciences, University of Primorska, Slovenia. References Alghannam , A.F. , Gonzalez , J. , & Betts , J.A. ( 2018 ). Restoration of muscle glycogen and functional capacity: Role
Short-Term Creatine Supplementation and Repeated Sprint Ability—A Systematic Review and Meta-Analysis
Mark Glaister and Lauren Rhodes
The aim of this study was to conduct a systematic review and meta-analysis of the effects of short-term creatine supplementation on repeated sprint ability. Fourteen studies met the inclusion criteria of adopting double-blind randomized placebo-controlled designs in which participants (age: 18–60 years) completed a repeated sprint test (number of sprints: 4 < n ≤ 20; sprint duration: ≤10 s; recovery duration: ≤90 s) before and after supplementing with creatine or placebo for 3–7 days in a dose of ∼20 g/day. No exclusion restrictions were placed on the mode of exercise. Meta-analyses were completed using random-effects models, with effects on measures of peak power output, mean power output, and fatigue (performance decline) during each repeated sprint test presented as standardized mean difference (δ), and with effects on body mass and posttest blood lactate concentration presented as raw mean difference (D). Relative to placebo, creatine resulted in a significant increase in body mass (D = 0.79 kg; p < .00001) and mean power output (δ = 0.61; p = .002). However, there was no effect of creatine on measures of peak power (δ = 0.41; p = .10), fatigue (δ = 0.08; p = .61), or posttest blood lactate concentration (D = 0.22 L/min; p = .60). In conclusion, creatine supplementation may increase mean power output during repeated sprint tests, although the absence of corresponding effects on peak power and fatigue means that more research, with measurements of intramuscular creatine content, is necessary to confirm.
Effects of Changes in Body Fat Mass as a Result of Regular Exercise on Hemoglobin A1c in Patients With Type 2 Diabetes Mellitus: A Meta-Analysis
Yutaka Igarashi, Nobuhiko Akazawa, and Seiji Maeda
An increase in visceral fat is associated with an increase in insulin resistance, so reducing body fat mass through exercise may help alleviate type 2 diabetes mellitus (T2DM). The current meta-analysis evaluated the effect of changes in body fat via an intervention of regular exercise on hemoglobin A1c (HbA1c) in patients with T2DM. The inclusion criteria were randomized controlled trials involving adults with T2DM, intervention involving exercise alone, an overall duration of intervention ≥12 weeks, and reporting HbA1c and body fat mass. The mean differences (MDs) were defined as the MD between the exercise group and the control group, and the MDs in HbA1c (in percentage) and body fat mass (in kilograms) were calculated. All MDs in HbA1c were pooled as overall effects. A meta-regression analysis was performed to evaluate the relationship between the MD in the body fat mass (in kilograms) and the MD in HbA1c. Twenty studies (1,134 subjects) were analyzed. The pooled MD in HbA1c (in percentage) decreased significantly (−0.4; 95% confidence interval [−0.5, −0.3]) but contained significant heterogeneity (Q = 52.7, p < .01; I 2 = 41.6%). A meta-regression analysis showed that a decrease in the MD in body fat mass was significantly associated with a decrease in the MD in HbA1c (R 2 = 80.0%) and heterogeneity decreased (Q = 27.3, p = .61; I 2 = 11.9%), and a reduction in body fat mass of 1 kg was estimated to decrease the HbA1c (%) by approximately 0.2. The current study suggested that a decrease in HbA1c due to regular exercise depends on a reduction in body fat mass in patients with T2DM.
Menthol Mouth Rinsing Improves Cycling Performance in Trained Adolescent Males Under Heat Stress
Kierstyn V. Hawke, Erica H. Gavel, David J. Bentley, and Heather M. Logan-Sprenger
Purpose: This study investigated the effect of menthol (MEN) mouth rinsing (MR) on cycling performance during a modified variable cycle test (M-VCT) in adolescent athletes under hot conditions (31.4 ± 0.9 °C, 23.4 ± 3.7% relative humidity). Methods: Trained adolescent male cyclists (n = 11, 16.7 ± 1.3 years, height 176.6 ± 8.8 cm, body mass 65.8 ± 11.6 kg, maximal oxygen uptake 62.97 ± 7.47 ml·kg−1·min−1) voluntarily completed three trials (familiarization and two experimental) of a 30-min M-VCT, which included five 6-min laps consisting of three 6-s accelerations and three 10-s sprints throughout each lap. In a randomized crossover design, MEN (0.01%) or placebo (PLA) (crystal-light), was swilled for 5 s before the start of each lap (total of 6 MR). Power output, distance (in kilometers), core temperature, heart rate, perceptual exertion, thermal stimulation (thermal comfort and thermal sensation), and blood lactate concentration were recorded. Results: MEN MR significantly improved M-VCT mean power output by 1.81 ± 1.57% compared to PLA (MEN, 177.8 ± 31.4 W; PLA, 174.7 ± 30.5 W, p < .001, 95% confidence interval [1.73, 4.46], d = 1.53). For maximal intermittent sprints, 6- and 10-s mean power output was significantly higher with MEN than PLA (6 s, p = .041, 95% confidence interval [0.73, 27.19], d = 0.71; 10 s, p = .002, 95% confidence interval [11.08, 35.22], d = 1.29). There was no significant difference in core temperature, heart rate, blood lactate concentration, or any perceptual measure between trials (p > .05) despite significantly higher work with MEN. Conclusion: 64% of athletes (7/11) improved M-VCT performance with MEN. The results of this investigation suggest that a MEN MR may improve power output during a sport-specific stochastic cycling task in elite adolescent male cyclists.
No Effect of Calanus Oil on Maximal Oxygen Uptake in Healthy Participants: A Randomized Controlled Study
Lucas Tauschek, Ragnhild E.N. Røsbjørgen, Håvard Dalen, Terje Larsen, and Trine Karlsen
in the study. Data were collected in the core-facility NeXt Move at the Norwegian University of Science and Technology, NTNU, Trondheim, Norway. NeXt Move is funded by the Faculty of Medicine at NTNU and Central Norway Regional Health Authority. Randomization was performed by a web
Warm-Up Intensity Does Not Affect the Ergogenic Effect of Sodium Bicarbonate in Adult Men
Rebecca L. Jones, Trent Stellingwerff, Paul Swinton, Guilherme Giannini Artioli, Bryan Saunders, and Craig Sale
, and final version approval were undertaken by all authors. B. Saunders (2016/50438-0) and G.G. Artioli (2014/11948-8 and 2019/25032-9) have been financially supported by Fundação de Amparo à Pesquisa do Estado de São Paulo. B. Saunders has a current scholarship from the Faculty of Medicine of the
A Comparison of Sodium Citrate and Sodium Bicarbonate Ingestion: Blood Alkalosis and Gastrointestinal Symptoms
Charles S. Urwin, Rodney J. Snow, Dominique Condo, Rhiannon M.J. Snipe, Glenn D. Wadley, Lilia Convit, and Amelia J. Carr
This study compared the recommended dose of sodium citrate (SC, 500 mg/kg body mass) and sodium bicarbonate (SB, 300 mg/kg body mass) for blood alkalosis (blood [HCO3 −]) and gastrointestinal symptoms (GIS; number and severity). Sixteen healthy individuals ingested the supplements in a randomized, crossover design. Gelatin capsules were ingested over 15 min alongside a carbohydrate-rich meal, after which participants remained seated for forearm venous blood sample collection and completion of GIS questionnaires every 30 min for 300 min. Time-course and session value (i.e., peak and time to peak) comparisons of SC and SB supplementation were performed using linear mixed models. Peak blood [HCO3 −] was similar for SC (mean 34.2, 95% confidence intervals [33.4, 35.0] mmol/L) and SB (mean 33.6, 95% confidence intervals [32.8, 34.5] mmol/L, p = .308), as was delta blood [HCO3 −] (SC = 7.9 mmol/L; SB = 7.3 mmol/L, p = .478). Blood [HCO3 −] was ≥6 mmol/L above baseline from 180 to 240 min postingestion for SC, significantly later than for SB (120–180 min; p < .001). GIS were mostly minor, and peaked 80–90 min postingestion for SC, and 35–50 min postingestion for SB. There were no significant differences for the number or severity of GIS reported (p > .05 for all parameters). In summary, the recommended doses of SC and SB induce similar blood alkalosis and GIS, but with a different time course.
Ergogenic Effects of Very Low to Moderate Doses of Caffeine on Vertical Jump Performance
Teppei Matsumura, Yuki Takamura, Kazushi Fukuzawa, Kazuya Nakagawa, Shunya Nonoyama, Keigo Tomoo, Hayato Tsukamoto, Yasushi Shinohara, Motoyuki Iemitsu, Akinori Nagano, Tadao Isaka, and Takeshi Hashimoto
Although the ergogenic effects of 3–6 mg/kg caffeine are widely accepted, the efficacy of low doses of caffeine has been discussed. However, it is unclear whether the ergogenic effects of caffeine on jump performance are dose responsive in a wide range of doses. This study aimed to examine the effect of very low (1 mg/kg) to moderate doses of caffeine, including commonly utilized ergogenic doses (i.e., 3 and 6 mg/kg), on vertical jump performance. A total of 32 well-trained collegiate sprinters and jumpers performed countermovement jumps and squat jumps three times each in a double-blind, counterbalanced, randomized, crossover design. Participants ingested a placebo or 1, 3, or 6 mg/kg caffeine 60 min before jumping. Compared with the placebo, 6 mg/kg caffeine significantly enhanced countermovement jump (p < .001) and squat jump (p = .012) heights; furthermore, 1 and 3 mg/kg of caffeine also significantly increased countermovement jump height (1 mg/kg: p = .002, 3 mg/kg: p < .001) but not squat jump height (1 mg/kg: p = .436, 3 mg/kg: p = .054). There were no significant differences among all caffeine doses in both jumps (all p > .05). In conclusion, even at a dose as low as 1 mg/kg, caffeine improved vertical jump performance in a dose-independent manner. This study provides new insight into the applicability and feasibility of 1 mg/kg caffeine as a safe and effective ergogenic strategy for jump performance.
