Sodium Bicarbonate and Time-to-Exhaustion Cycling Performance: A Retrospective Analysis Exploring the Mediating Role of Expectation.

BACKGROUND: Research has shown that ingesting 0.3 g·kg-1 body mass sodium bicarbonate (NaHCO3) can improve time-to-exhaustion (TTE) cycling performance, but the influence of psychophysiological mechanisms on ergogenic effects is not yet understood. OBJECTIVE: This study retrospectively examined whether changes in TTE cycling performance are mediated by positive expectations of receiving NaHCO3 and/or the decline in blood bicarbonate during exercise. METHODS: In a randomised, crossover, counterbalanced, double-blind, placebo-controlled design, 12 recreationally trained cyclists (maximal oxygen consumption, 54.4 ± 5.7 mL·kg·min-1) performed four TTE cycling tests 90 min after consuming: (1) 0.3 g·kg-1 body mass NaHCO3 in 5 mL·kg-1 body mass solution, (2) 0.03 g·kg-1 body mass sodium chloride in solution (placebo), (3) 0.3 g·kg-1 body mass NaHCO3 in capsules and (4) cornflour in capsules (placebo). Prior to exercise, participants rated on 1-5 Likert type scales how much they expected the treatment they believe had been given would improve performance. Capillary blood samples were measured for acid-base balance at baseline, pre-exercise and post-exercise. RESULTS: Administering NaHCO3 in solution and capsules improved TTE compared with their respective placebos (solution: 27.0 ± 21.9 s, p = 0.001; capsules: 23.0 ± 28.1 s, p = 0.016). Compared to capsules, NaHCO3 administered via solution resulted in a higher expectancy about the benefits on TTE cycling performance (Median: 3.5 vs. 2.5, Z = 2.135, p = 0.033). Decline in blood bicarbonate during exercise was higher for NaHCO3 given in solution compared to capsules (2.7 ± 2.1 mmol·L-1, p = 0.001). Mediation analyses showed that improvements in TTE cycling were indirectly related to expectancy and decline in blood bicarbonate when NaHCO3 was administered in solution but not capsules. CONCLUSIONS: Participants' higher expectations when NaHCO3 is administered in solution could result in them exerting themselves harder during TTE cycling, which subsequently leads to a greater decline in blood bicarbonate and larger improvements in performance. KEY POINTS: Ingesting 0.3 g·kg-1 body mass sodium bicarbonate in solution and capsules improved time-to-exhaustion cycling performance Positive expectancy about the benefits of sodium bicarbonate and decline in blood bicarbonate were higher when sodium bicarbonate was administered in solution compared with capsules Improvements in time-to-exhaustion cycling performance for sodium bicarbonate administered in solution were related to expectancy and the enhanced extracellular buffering response.

Efficacy of sodium bicarbonate ingestion strategies for protecting blinding.

Sodium bicarbonate (NaHCO3) is a widely researched ergogenic aid, but the optimal blinding strategy during randomised placebo-controlled trials is unknown. In this multi-study project, we aimed to determine the most efficacious ingestion strategy for blinding NaHCO3 research. During study one, 16 physically active adults tasted 0.3 g kg-1 body mass NaHCO3 or 0.03 g kg-1 body mass sodium chloride placebo treatments given in different flavour (orange, blackcurrant) and temperature (chilled, room temperature) solutions. They were required to guess which treatment they had received. During study two, 12 recreational athletes performed time-to-exhaustion (TTE) cycling trials (familiarisation, four experimental). Using a randomised, double-blind design, participants consumed 0.3 g kg-1 body mass NaHCO3 or a placebo in 5 mL kg-1 body mass chilled orange squash/water solutions or capsules and indicated what they believed they had received immediately after consumption, pre-TTE and post-TTE. In study one, NaHCO3 prepared in chilled orange squash resulted in the most unsure ratings (44%). In study two, giving NaHCO3 in capsules resulted in more unsure ratings than in solution after consumption (92 vs 33%), pre-TTE (67 vs. 17%) and post-TTE (50 vs. 17%). Administering NaHCO3 in capsules was the most efficacious blinding strategy which provides important implications for researchers conducting randomised placebo-controlled trials.

Reproducibility of 20-min Time-trial Performance on a Virtual Cycling Platform.

This study aimed to analyse the reproducibility of mean power output during 20-min cycling time-trials, in a remote home-based setting, using the virtual-reality cycling software, Zwift. Forty-four cyclists (11 women, 33 men; 37±8 years old, 180±8 cm, 80.1±13.2 kg) performed 3×20-min time-trials on Zwift, using their own setup. Intra-class correlation coefficient (ICC), coefficient of variation (CV) and typical error (TE) were calculated for the overall sample, split into 4 performance groups based on mean relative power output (25% quartiles) and sex. Mean ICC, TE and CV of mean power output between time-trials were 0.97 [0.95-0.98], 9.4 W [8.0-11.3 W], and 3.7% [3.2-4.5], respectively. Women and men had similar outcomes (ICC: 0.96 [0.89-0.99] vs. 0.96 [0.92-0.98]; TE: 8.3 W [6.3-13.1] vs. 9.7 W [8.2-12.2]; CV: 3.8% [2.9-6.1] vs. 3.7% [3.1-4.7], respectively), although cyclists from the first quartile showed a lower CV in comparison to the overall sample (Q1: 2.6% [1.9-4.1] vs. overall: 3.7% [3.2-4.5]). Our results indicate that power output during 20-min cycling time-trials on Zwift are reproducible and provide sports scientists, coaches and athletes, benchmark values for future interventions in a virtual-reality environment.

Training load impact on recovery status in professional volleyball athletes / Impacto da carga de treinamento no estado de recuperação em atletas profissionais de voleibol / Impacto de la carga de entrenamiento en el estado de recuperación de atletas profesionales de vóleibol

ABSTRACT Introduction: The success of training depends on the balance between training load magnitude and recovery. Objective: Verify the effect of training load distribution on recovery status, vigor and fatigue in volleyball players during a season. Methods: Nine male athletes from a professional volleyball team participated in the study. During 19 weeks of the season, quantification of the training load was performed through the session rating of perceived exertion (RPE) method, evaluation of the athletes' recovery status through the Total Quality Recovery (TQR) scale, and evaluation of the profile of mood state through the POMS questionnaire, with research focus for the subscales vigor and fatigue. Results: The average total weekly training load (TWTL) was 3206 ± 685.5 A. Us and the average recovery of the whole season was 15.3 ± 0.57. The mean values of fatigue and vigor were 11 ± 3.05 and 19.4 ± 2.84, respectively. Significant differences were found for the variables RPE, fatigue and Energy Index (Vigor - Fatigue) in the three different periods of the season (Preparatory Period, Competitive Period I and Competitive Period II). Conclusion: It was concluded that the training load and recovery monitoring methods used throughout the season were effective in controlling the variables, with a positive impact of training loads verified on the recovery values presented by the athletes. Level of Evidence III; Diagnostic study.

RESUMO Introdução: O sucesso do treinamento depende do equilíbrio entre a magnitude da carga de treinamento e a recuperação. Objetivo: Verificar o efeito da distribuição das cargas de treinamento no estado de recuperação, vigor e fadiga, em jogadores de voleibol ao longo de uma temporada. Métodos: Participaram do estudo nove atletas do sexo masculino de uma equipe profissional de voleibol. Durante 19 semanas da temporada, realizou-se a quantificação da carga de treinamento através do método da Percepção Subjetiva do Esforço da sessão (PSE), da avaliação do estado de recuperação dos atletas através da escala da Qualidade Total de Recuperação (TQR), além da avaliação do perfil do estado de humor através do questionário POMS, com foco de investigação para as subescalas vigor e fadiga. Resultados: A carga de treinamento semanal total (CTST) média foi de 3206 ± 685,5 U.A. e a recuperação média de toda a temporada foi de 15,3 ± 0,57. Já os valores médios da fadiga e vigor foram 11 ± 3,05 e 19,4 ± 2,84, respectivamente. Diferenças significativas foram encontradas para as variáveis PSE, fadiga e Energy Index (Vigor - Fadiga) nos três diferentes períodos da temporada (Período Preparatório, Período Competitivo I e Período Competitivo II). Conclusão: Conclui-se que os métodos de monitoramento da carga de treinamento e recuperação utilizados ao longo da temporada foram eficazes no controle das variáveis, observando-se um impacto positivo das cargas de treinamento verificado nos valores de recuperação apresentados pelos atletas. Nível de evidência III; Estudo Diagnóstico.

RESUMEN Introducción: El éxito del entrenamiento depende del equilibrio entre la magnitud de la carga de entrenamiento y la recuperación. Objetivo: Verificar el efecto de la distribución de las cargas de entrenamiento en el estado de recuperación, vigor y fatiga, en jugadores de vóleibol a lo largo de una temporada. Métodos: Participaron en el estudio nueve atletas del sexo masculino de un equipo profesional de vóleibol. Durante 19 semanas de la temporada, se realizó la cuantificación de la carga de entrenamiento a través del método de Percepción Subjetiva del Esfuerzo de Sesión (PSE), de la evaluación del estado de recuperación de los atletas a través de la escala de la Calidad Total de Recuperación (TQR), además de la evaluación del perfil del estado de humor a través del cuestionario POMS, con enfoque de investigación para las subescalas vigor y fatiga. Resultados: La carga de entrenamiento semanal total (CEST) promedio fue de 3206 ± 685,5 U.A. y la recuperación promedio de toda la temporada fue de 15,3 ± 0,57. Los valores promedio de fatiga y vigor fueron 11 ± 3,05 y 19,4 ± 2,84, respectivamente. Se encontraron diferencias significativas para las variables PSE, fatiga y Energy Index (Vigor - Fatiga) en los tres diferentes períodos de la temporada (Período Preparatorio, Período Competitivo I y Período Competitivo II). Conclusión: Se concluye que los métodos de monitorización de la carga de entrenamiento y recuperación utilizados a lo largo de la temporada fueron eficaces en el control de las variables, observándose un impacto positivo de las cargas de entrenamiento verificado en los valores de recuperación presentados por los atletas. Nivel de evidencia III; Estudio diagnóstico.

Influence of a slow-start on overall performance and running kinematics during 6-h ultramarathon races.

The aim of this study was to describe the pacing during a 6-h ultramarathon (race 1) and to investigate whether a slow-start affects performance, running kinematic changes, ratings of perceived exertion (RPE) and fatigue (ROF) (race 2). After a critical speed test, participants completed two 6-h ultramarathons. Race 1 (n = 16) was self-paced, whereas in race 2 (n = 10), athletes performed the initial 36 min at speeds 18% below the mean speed of the initial 36 min of race 1. In race 1, participants adopted an inverse sigmoid pacing. Contact times increased after 1 h, and flight times decreased after 30 min (all P ≤ .009); stride length reduced after 1 h 30 min (all P = .022), and stride frequency did not change. Despite the lower speeds during the first 10% of race 2, and higher speeds at 50% and 90%, performance remained unchanged (57.5 ± 10.2 vs. 56.3 ± 8.5 km; P = .298). However, RPE and ROF were lowered for most of race 2 duration (all P < .001). For the comparison of kinematic variables between races, data were normalised by absolute running speed at each time point from 1 h onwards. No differences were found for any of the kinematic variables. In conclusion, decreasing initial speed minimises RPE and ROF, but does not necessarily affect performance. In addition, running kinematic changes do not seem to be affected by pacing manipulation.

Pacing Strategy During 24-Hour Ultramarathon-Distance Running.

PURPOSE: To describe pacing strategy in a 24-h running race and its interaction with sex, age group, athletes' performance group, and race edition. METHODS: Data from 398 male and 103 female participants of 5 editions were obtained based on a minimum 19.2-h effective-running cutoff. Mean running speed from each hour was normalized to the 24-h mean speed for analyses. RESULTS: Mean overall performance was 135.6 ± 33.0 km with a mean effective-running time of 22.4 ± 1.3 h. Overall data showed a reverse J-shaped pacing strategy, with a significant reduction in speed from the second-to-last to the last hour. Two-way mixed ANOVAs showed significant interactions between racing time and both athlete performance group (F = 7.01, P < .001, ηp2 = .04) and race edition (F = 3.01, P < .001, ηp2 = .02) but not between racing time and either sex (F = 1.57, P = .058, ηp 2 < .01) or age group (F = 1.25, P = .053, ηp2 = .01). Pearson product-moment correlations showed an inverse moderate association between performance and normalized mean running speed in the first 2 h (r = -.58, P < .001) but not in the last 2 h (r = .03, P = .480). CONCLUSIONS: While the general behavior represents a rough reverse J-shaped pattern, the fastest runners start at lower relative intensities and display a more even pacing strategy than slower runners. The "herd behavior" seems to interfere with pacing strategy across editions, but not sex or age group of runners.