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Effects of Ketone Monoester and Bicarbonate Co-Ingestion on Cycling Performance in WorldTour Cyclists

Domingo Jesús Ramos-Campo, Francisco Javier López-Román, Silvia Pérez-Piñero, Raquel Ortolano, María Salud Abellán-Ruiz, Enrique Molina Pérez de los Cobos, Antonio Jesús Luque-Rubia, Dag Van Elslande, and Vicente Ávila-Gandía

The present randomized study investigated the effect of acute supplementation of 800 mg/kg of ketone monoester ingestion (KE) or placebo (PL) and 210 mg/kg of NaHCO3 co-ingestion on cycling performance of WorldTour cyclists during a road cycling stage simulation. Twenty-eight cyclists participated in the study (27.46 ± 4.32 years; 1.80 ± 0.06 m; 69.74 ± 6.36 kg). Performance, physiological, biochemical, and metabolism outcomes, gut discomfort, and effort perceived were assessed during a road cycling simulation composed of an 8-min time-trial (TT) performance + 30-s TT + 4.5 hr of outdoor cycling + a second 8-min TT + a second 30-s TT. Greater absolute and relative mean power during the first 8-min TT (F = 5.067, p = .033, η p 2 = .163 , F = 5.339, p = .029, η p 2 = .170 , respectively) was observed after KE than after PL (KE: 389 ± 34, PL: 378 ± 44 W, p = .002, d = 0.294 and KE: 5.60 ± 0.42, PL: 5.41 ± 0.44 W/kg, p = .001, d = 0.442). Additionally, greater concentration of β-hydroxybutyrate blood concentration (F = 42.195, p < .001, η p 2 = .619 ) was observed after KE than after PL during the first steps of the stage (e.g., after warm-up KE: 1.223 ± 0.642, PL: 0.044 ± 0.058 mM, p < .001, d = 2.589), although the concentrations returned to near baseline after 4.5 hr of outdoor cycling. Moreover, higher values of anion gap were observed (F = 2.333, p = .026, η p 2 = .080 ) after KE than after PL ingestion, after the warm-up and after the first 8-min and 30-s TT. Additionally, lower concentrations of HCO 3 were reported in the KE condition after warm-up and after the first 8-min and 30-s TT. During the initial phase of the stage simulation, acute supplementation with KE + NaHCO3 co-ingestion enhanced 8-min TT cycling performance (3.1%) in WorldTour cyclists with a concomitant hyperketonaemia.

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The Relationship Between Isometric and Dynamic Strength Following Resistance Training: A Systematic Review, Meta-Analysis, and Level of Agreement

Lachlan P. James, Jonathon Weakley, Paul Comfort, and Minh Huynh

Background: Maximal lower-body strength can be assessed both dynamically and isometrically; however, the relationship between the changes in these 2 forms of strength following resistance training is not well understood. Purpose: To systematically review and analyze the effects of resistance training on changes in maximal dynamic (1-repetition-maximum back squat, deadlift, and power clean) and position-matched isometric strength (isometric midthigh pull and the isometric squat). In addition, individual-level data were used to quantify the agreement and relationship between changes in dynamic and isometric strength. Methods : Databases were systematically searched to identify eligible articles, and meta-analysis procedures were performed on the extracted data. The raw results from 4 studies were acquired, enabling bias and absolute reliability measures to be calculated using Bland–Altman test of agreement. Results: Eleven studies met the inclusion criteria, which resulted in 29 isometric–dynamic change comparisons. The overall pooled effect was 0.13 in favor of dynamic testing; however, the prediction interval ranged from g = −0.49 to 0.75. There was no evidence of bias (P = .825) between isometric and dynamic tests; however, the reliability coefficient was estimated to be 16%, and the coefficient of variation (%) was 109.27. Conclusions: As a range of future effects can be expected when comparing isometric to dynamic strength changes following resistance training, and limited proportionality exists between changes in these 2 strength qualities, there is strong evidence that isometric and dynamic strength represent separate neuromuscular domains. These findings can be used to inform strength-assessment models in athlete populations.

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Erratum. Determinants of 1500-m Front-Crawl Swimming Performance in Triathletes: Influence of Physiological and Biomechanical Variables

International Journal of Sports Physiology and Performance

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Erratum. Swimming With the COSMED AquaTrainer and K5 Wearable Metabolic System in Breath-by-Breath Mode: Accuracy, Precision, and Repeatability

International Journal of Sports Physiology and Performance

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The Fine-Tuning Approach for Training Monitoring

Daniel Boullosa, João Gustavo Claudino, Jaime Fernandez-Fernandez, Daniel Bok, Irineu Loturco, Matthew Stults-Kolehmainen, Juan García-López, and Carl Foster

Purpose: Monitoring is a fundamental part of the training process to guarantee that the programmed training loads are executed by athletes and result in the intended adaptations and enhanced performance. A number of monitoring tools have emerged during the last century in sport. These tools capture different facets (eg, psychophysiological, physical, biomechanical) of acute training bouts and chronic adaptations while presenting specific advantages and limitations. Therefore, there is a need to identify what tools are more efficient in each sport context for better monitoring of training process. Methods and Results: We present and discuss the fine-tuning approach for training monitoring, which consists of identifying and combining the best monitoring tools with experts’ knowledge in different sport settings, designed to improve (1) the control of actual training loads and (2) understanding of athletes’ training adaptations. Instead of using single-tool approaches or merely subjective decision making, the identification of the best combination of monitoring tools to assist experts’ decisions in each specific context (ie, triangulation) is necessary to better understand the link between acute and chronic adaptations and their impact on health and performance. Future studies should elaborate on the identification of the best combination of monitoring tools for each specific sport setting. Conclusion: The fine-tuning monitoring approach requires the simultaneous use of several valid and practical tools, instead of a single tool, to improve the effectiveness of monitoring practices when added to experts’ knowledge.

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Erratum. Competitive Cross-Country Skiers Have Longer Time to Exhaustion Than Recreational Cross-Country Skiers During Intermittent Work Intervals Normalized to Their Maximal Aerobic Power

International Journal of Sports Physiology and Performance

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Erratum. Inconsistent Effect of Psychometric-Scale Familiarization on the Relationship Between Ratings of Perceived Exertion and External Load Measures in Elite Youth Soccer Players

International Journal of Sports Physiology and Performance

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On-Field Methodological Approach to Monitor the Menstrual Cycle and Hormonal Phases in Elite Female Athletes

Marine Dupuit, Alice Meignié, Tom Chassard, Ludivine Blanquet, Julien LeHeran, Thomas Delaunay, Elise Bernardeau, Jean-François Toussaint, Martine Duclos, and Juliana Antero

Objectives: Currently, there are no guidelines for implementing the monitoring of menstrual status, including the natural menstrual cycle (NC) or oral contraception (OC), in a sport setting. We aimed to provide a feasible, on-field methodological approach for monitoring NC and OC in female athletes. Methods: We developed a smartphone app with daily questionnaires to monitor both NC and OC phases in 19 elite female soccer players (23.7 [4.4] y) over 7 months. Adherence and compliance were evaluated. The NC and OC phases were based on calendar data to establish an individual menstrual profile for each athlete. Results: The initial questionnaire revealed that the vast majority of female players (80%) were interested in monitoring their menstrual status. The online monitoring yielded high athlete adherence (87.0% [14.2%]) with a slight decrease over the winter break and at the end of the championship, which necessitated adaptations to promote compliance. Monitoring identified the specific menstrual pattern of each athlete and highlighted large interindividual variability. Conclusion: This study assesses, for the first time, the interest of female players in monitoring their menstrual status. It provides a new methodological approach, as well as guidelines for optimizing on-field monitoring. It also anticipates some obstacles sport staff may encounter when trying to implement such follow-up. It is essential to better understand the menstrual profile of athletes and determine its potential impacts on well-being and performance.

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Performance Science Domains: Contemporary Strategies for Teams Preparing for the Rugby World Cup

Liam P. Kilduff, David B. Pyne, and Christian J. Cook

Purpose: As the start of the 10th Rugby Union World Cup approaches, performance staff will be working on the final elements of their teams’ preparation. Much of this planning and preparation will be underpinned by the latest performance science research. In this invited commentary, we discuss contemporary performance science research in rugby union centered around 4 key performance domains. First, we outline a systematic approach to developing an overall understanding of the game demands and how performance staff can enhance the players’ preparedness for competition. We then move on to outline our understanding of the training science domain, followed by a brief overview of effective recovery strategies at major tournaments. Finally, we outline research in the area of competition-day strategies and how they can positively impact players’ readiness to compete. Conclusions: Evaluating a team’s preparation for the Rugby Union World Cup can be achieved by mapping their performance plan based on the 4 domains outlined above.

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The Physical Preparation of Players for the Rugby World Cup

David B. Pyne, Christian J. Cook, and Liam P. Kilduff