Search

Introduction: Surfers’ performances are subjectively ranked by 5 judges. Low reliability and validity in judgment may lead to preventable errors and unfair scores. Objective: The aims of the present study is to describe the judgment error for each wave surfed in world surf league (WSL) championship tour of 2021, establish between-judge reliability, and establish judgment validity comparing each judge score with the final control score of the wave. Methodology: To describe the judgment error, we analyzed the available WSL data related to the 2021 Men’s Championship Tour (4,095 waves; 20,475 scores). Results: We found an inverted ‘U’-shaped pattern for the judgment error score vs. control score, explained by a quadratic regression model (R = 0.52; SEE = 0.10). The reliability produced an excellent intraclass correlation coefficient (CI95% = 0.97, 1.00), with a between judge (typical) error of 0.15. Validity analyses indicated a minimal real difference of 0.49 in the sum of two waves between the surfers for having 95% certainty for the heat winner. Conclusion: We recommend WSL incorporate intrinsic judgment errors to increase fairness and trust in the WSL championship tour.

Previous systematic reviews have confirmed that carbohydrate (CHO) mouth rinse may boost physical exercise performance, despite some methodological aspects likely affecting its ergogenic effect. In this review, we discussed if the exercise mode, pre-exercise fasting status, CHO solutions concentration, CHO solutions temperature, mouth rinse duration, and CHO placebo effects may potentially reduce the CHO mouth rinse ergogenic effect, suggesting possible solutions to manage these potential confounders. The effectiveness of CHO mouth rinse as a performance booster is apparently related to the origin of the exercise-induced neuromuscular fatigue, as CHO mouth rinse unequivocally potentiates endurance rather than sprint and strength exercises performance. Furthermore, ergogenic effects have been greater in fasting than fed state, somehow explaining the varied magnitude of the CHO mouth rinse effects in exercise performance. In this regard, the CHO solution concentration and temperature, as well as the mouth rinse duration, may have increased the variability observed in CHO mouth rinse effects in fasting and fed state. Finally, placebo effects have challenged the potential of the CHO mouth rinse as an ergogenic aid. Therefore, we suggest that future studies should consider methodological controls such as sample size and sample homogeneity, proper familiarization with experimental procedures, and the use of alternative placebo designs to provide unbiased evidence regarding the potential of the CHO mouth rinse as an ergogenic aid.

[This corrects the article DOI: 10.1371/journal.pone.0236592.].

Introdução: Placebo é considerado uma substância ou um procedimento inerte que pode proporcionar um efeito positivo ou negativo dependendo da condição em que é aplicado. É bem documentado que o placebo promove resultados positivos em condições patológicas e em condições de desempenho físico. Objetivo: Sendo assim, objetivo desse estudo é revisar em duas sessões, trabalhos que tenham abordado: 1) o efeito placebo e nocebo aplicado à clínica no tratamento da doença de Parkinson, depressão e dor, e 2) o uso do placebo como recurso ergogênico no desempenho físico. Metodologia: Para tal, uma busca foi realizada na base de dados “Pubmed” e “Web of Science”. Resultados e discussão: Nesta revisão narrativa, discutimos como o efeito placebo atua em diversas condições como a dor, depressão, doença de Parkinson, e no desempenho físico, além disso, foram abordados possíveis mecanismos que possam atuar neste fenômeno. Conclusão: Podemos concluir que em condição clínica e de desempenho físico, o placebo compartilha regiões cerebrais semelhantes, que geram respostas positivas ao tratamento.

Objective: The present study aimed to investigate the effects of a 6-month multicomponent exercise program on blood pressure, heart rate, and double product of uncontrolled and controlled normotensive and hypertensive older patients. Methods: The study included 183 subjects, 97 normotensives, of which 53 were controlled normotensives (CNS), and 44 uncontrolled normotensives (UNS), as well as 86 hypertensives, of which 43 were controlled hypertensives (CHS), and 43 uncontrolled hypertensives (UHS). Volunteers were recruited and blood pressure and heart rate measurements were made before and after a 6-month multicomponent exercise program. The program of physical exercise was performed twice a week for 26 weeks. The physical exercises program was based on functional and walking exercises. Exercise sessions were performed at moderate intensity. Results: The results indicated that UHS showed a marked decrease in systolic (−8.0 mmHg), diastolic (−11.1 mmHg), mean (−10.1 mmHg), and pulse pressures, heart rate (−6.8 bpm), and double product (−1640 bpm mmHg), when compared to baseline. Similarly, diastolic (−5.5 mmHg) and mean arterial (−4.8 mmHg) pressures were significantly decreased in UNS. Concomitantly, significant changes could be observed in the body mass index (−0.9 kg/m2; −1.5 kg/m2) and waist circumference (−3.3 cm; only UHS) of UNS and UHS, which may be associated with the changes observed in blood pressure. Conclusions: In conclusion, the data of the present study indicate that a 6-month multicomponent exercise program may lead to significant reductions in blood pressure, heart rate, and double product of normotensive and hypertensive patients with high blood pressure values. Resumen: Objetivo: El presente estudio tuvo como objetivo investigar los efectos de un programa de ejercicios multicomponente de 6 meses sobre la presión arterial, la frecuencia cardíaca y el doble producto de pacientes mayores hipertensos y normotensos (incontrolados y controlados). Método: 183 sujetos, 97 normotensos - 53 normotensos controlados (SNC) y 44 normotensos no controlados (SNU) - y 86 hipertensos - 43 hipertensos controlados (CHS) y 43 hipertensos no controlados (UHS) -, fueron reclutados y sometidos a evaluaciones (presión arterial y frecuencia cardíaca) antes y después de un programa de ejercicios multicomponente de 6 meses. El programa de ejercicio se realizó dos veces por semana durante 26 semanas. El programa de ejercicios físicos se basó en ejercicios funcionales y de caminar. Las sesiones de ejercicio se realizaron a intensidad moderada. Resultados: Los resultados indicaron que UHS presentó una marcada disminución en presión sistólica (−8.0 mmHg), diastólica (−11.1 mmHg), media (−10.1 mmHg) y de pulso, frecuencia cardíaca (−6.8 lpm) y doble producto (−1640 lpm mmHg) cuando se compara con la línea base. De manera similar, las presiones diastólica (−5.5 mmHg) y arterial media (−4.8 mmHg) se redujeron significativamente en los SNU. Concomitantemente, fue posible observar alteraciones significativas en el índice de masa corporal (−0.9 kg/m2; −1.5 kg/m2) y circunferencia de cintura (−3.3 cm, solo UHS) de UNS y UHS, lo que puede estar asociado con los cambios observados en la presión arterial. Conclusiones: En conclusión, los datos del presente estudio indican que un programa de ejercicio multicomponente de 6 meses puede provocar reducciones significativas en la presión arterial, frecuencia cardíaca y doble producto de pacientes normotensos e hipertensos con valores de presión arterial alta. Keywords: Physical exercise, Hypertension, Older people, Obesity, Brazil, Palabras clave: Ejercicio físico, Hipertensión, Personas mayores, Obesidad, Brasil

Caffeine improves cycling time trial performance through enhanced motor output and muscle recruitment. However, it is unknown if caffeine further increases power output entropy. To investigate the effects of caffeine effects on cycling time trial performance and motor output entropy (MOEn), nine cyclists (VO2MAX of 55 ± 6.1 mL.kg.-1min-1) performed a 4 km cycling time trial (TT4km) after caffeine and placebo ingestion in a counterbalanced order. Power output data were sampled at a 2 Hz frequency, thereafter entropy was estimated on a sliding-window fashion to generate a power output time series. A number of mixed models compared performance and motor output entropy between caffeine and placebo every 25% of the total TT4km distance. Caffeine ingestion improved power output by 8% (p = 0.003) and increased MOEn by 7% (p = 0.018). Cyclists adopted a U-shaped pacing strategy after caffeine ingestion. MOEn mirrored power output responses as an inverted U-shape MOEn during the time trial. Accordingly, a strong inverse correlation was observed between MOEn and power output responses over the last 25% of the TT4km (p < 0.001), regardless of the ingestion, likely reflecting the end spurt during this period (p = 0.016). Caffeine ingestion improved TT4km performance and motor output responses likely due to a greater power output entropy.

Detrimental mental fatigue effects on exercise performance have been documented in constant workload and time trial exercises, but effects on a maximal incremental test (MIT) remain poorly investigated. Mental fatigue-reduced exercise performance is related to an increased effort sensation, likely due to a reduced prefrontal cortex (PFC) activation and inhibited spontaneous behavior. Interestingly, only a few studies verified if centrally active compounds may mitigate such effects. For example, carbohydrate (CHO) mouth rinse potentiates exercise performance and reduces effort sensation, likely through its effects on PFC activation. However, it is unknown if this centrally mediated effect of CHO mouth rinse may mitigate mental fatigue-reduced exercise performance. After a proof-of-principle study, showing a mental fatigue-reduced MIT performance, we observed that CHO mouth rinse mitigated MIT performance reductions in mentally fatigued cyclists, regardless of PFC alterations. When compared to placebo, mentally fatigued cyclists improved MIT performance by 2.24–2.33% when rinsing their mouth with CHO during MIT. However, PFC and motor cortex activation during MIT in both CHO and placebo mouth rinses were greater than in mental fatigue. Results showed that CHO mouth rinse mitigated the mental fatigue-reduced MIT performance, but challenged the role of CHO mouth rinse on PFC and motor cortex activation.

Previous studies investigating the effects of high intensity interval training (HIIT) and moderate intensity continuous training (MICT) showed controversial results. The aim of the present study was to systematically review the literature on the effects of HIIT and MICT on affective and enjoyment responses. The PRISMA Statement and the Cochrane recommendation were used to perform this systematic review and the database search was performed using PubMed, Scopus, ISI Web of Knowledge, PsycINFO, and SPORTDiscus. Eight studies investigating the acute affective and enjoyment responses on HIIT and MICT were included in the present systematic review. The standardized mean difference (SMD) was calculated for Feeling Scale (FS), Physical Activity Enjoyment Scale (PACES) and Exercise Enjoyment Scale (EES). The MICT was used as the reference condition. The overall results showed similar beneficial effects of HIIT on PACES and EES responses compared to MICT with SMDs classified as small (PACES-SMD = 0.49, I2 = 69.3%, p = 0.001; EES-SMD = 0.48, I2 = 24.1%, p = 0.245) while for FS, the overall result showed a trivial effect (FS-SMD = 0.19, I2 = 78.9%, p

A etiologia da fadiga tem sido objeto de estudo em pesquisas relacionadas ao desempenho esportivo em função da necessidade de esclarecer os mecanismos que reduzem a capacidade de manutenção do desempenho em intensidades elevadas de esforço. A concepção tradicional de fadiga assume que os mecanismos possam ser desencadeados em sítios de ação central ou periférica. A fadiga periférica é compreendida como uma oferta inadequada de oxigênio tecidual acelerando a acidose muscular. A fadiga central, por sua vez, oriunda do sistema nervoso central (SNC), apresenta alterações nos neurotransmissores, podendo alterar o perfil metabólico e temperatura do SNC. Desta forma, a presente revisão tem como intuito abordar os mecanismos de fadiga central e periférica, norteando futuras interpretações sobre o fenômeno.

A percepção subjetiva de esforço (PSE) foi sugerida, originalmente, como uma marcadora da intensidade do exercício, pois ela responderia às alterações nos sistemas cardiopulmonar e metabólico, principalmente às alterações da FC e concentrações de lactato sanguíneo durante o exercício. Entretanto, esta interpretação não se alinha às respostas fisiológicas observadas em diferentes intensidades de exercícios, pois a PSE aumenta de forma linear, mesmo em intensidades em que ocorre um estado de equilíbrio fisiológico. No presente artigo de revisão, discutimos que este desalinhamento entre teoria e resultados experimentais poderáestar ligado aos mecanismos de geração e modulação da PSE durante o exercício. Neste caso, o mecanismo de geração da PSE pelo sistema nervoso central poderá responder basicamente à intensidade do exercício, enquanto as respostas fisiológicas periféricas poderão modular a PSE ao longo do exercício, indicando as condições fisiológicas quando da realização do exercício. Desta forma, a PSE poderia ser marcadora da duração tolerável do exercício executado numa determinada intensidade.

Little is known about heart rate (HR) kinetics during exercise in the very heavy (VH) and severe (SE) intensity domains. The objective of this study was to describe mathematically the HR kinetics during exercise performed in these intensity domains and to compare the parameters derived from these models between situations of high (HCHO), low (LCHO) and control (C) carbohydrate availability. Twelve men performed three trials to exhaustion in the VH or SE domains after diet manipulation with HCHO, LCHO and C. The VH intensity was ΔLW75% (75% of the difference between VO2max and LL2) and SE was 115% of VO2max identified in a previous incremental test (20 W/3 min). HR responses were mathematically fitted by mono- and biexponential functions. In the VH domain, the residual sum of squares (RSS) obtained with the biexponential model was significantly lower than that obtained with the monoexponential model (P < 0.05). In the SE domain, no significant difference in RSS was observed between the mathematical models (P > 0.05). In the VH domain, there were no significant differences in biexponential parameters between the HCHO, LCHO and C conditions. In the SE domain, there were no significant differences in monoexponential parameters between the HCHO, LCHO and C conditions, although the time constant of the monoexponential model was significantly reduced in LCHO when compared to HCHO (51.5 ± 26.4 vs 65.4 ± 34.1 s; P < 0.05). The bi- and monoexponential mathematical models seem to be the best description of HR responses during exercise performed in the HV and SE intensity domains, respectively. In addition, carbohydrate availability only seems to affect HR kinetics during exercise performed at SE intensity.

Little is known about heart rate (HR) kinetics during exercise in the very heavy (VH) and severe (SE) intensity domains. The objective of this study was to describe mathematically the HR kinetics during exercise performed in these intensity domains and to compare the parameters derived from these models between situations of high (HCHO), low (LCHO) and control (C) carbohydrate availability. Twelve men performed three trials to exhaustion in the VH or SE domains after diet manipulation with HCHO, LCHO and C. The VH intensity was ΔLW75% (75% of the difference between VO2max and LL2) and SE was 115% of VO2max identified in a previous incremental test (20 W/3 min). HR responses were mathematically fitted by mono- and biexponential functions. In the VH domain, the residual sum of squares (RSS) obtained with the biexponential model was significantly lower than that obtained with the monoexponential model (P < 0.05). In the SE domain, no significant difference in RSS was observed between the mathematical models (P > 0.05). In the VH domain, there were no significant differences in biexponential parameters between the HCHO, LCHO and C conditions. In the SE domain, there were no significant differences in monoexponential parameters between the HCHO, LCHO and C conditions, although the time constant of the monoexponential model was significantly reduced in LCHO when compared to HCHO (51.5 ± 26.4 vs 65.4 ± 34.1 s; P < 0.05). The bi- and monoexponential mathematical models seem to be the best description of HR responses during exercise performed in the HV and SE intensity domains, respectively. In addition, carbohydrate availability only seems to affect HR kinetics during exercise performed at SE intensity.

O consumo de oxigênio pós-esforço (EPOC) vem sendo amplamente estudado na literatura, entretanto os mecanismos fisiológicos envolvidos na determinação da magnitude e duração do EPOC não estão totalmente esclarecidos. Na presente revisão são discutidos as principais evidências relacionadas aos mecanismos fisiológicos determinantes do EPOC e o efeito da intensidade e do tempo de exercício sobre a sua magnitude e duração. O EPOC rápido parece ser decorrente da ressíntese de ATP-CP, da remoção do lactato sanguíneo, do aumento da temperatura corporal e do metabolismo lipídico. Muitas dessas alterações ocorrem com cinética diferente das encontradas para o EPOC. O EPOC lento parece decorrer principalmente do ciclo dos triglicerídeos/ácidos graxos. A magnitude e duração do EPOC parecem ser relacionadas linearmente com o tempo e exponencialmente com a intensidade de esforço. Devido a essa relação, a magnitude e duração do EPOC podem interferir em programas de redução da massa corporal.

Resumo Provas cíclicas de longa duração exigem que atletas tomem decisões acerca do uso de energia durante a prova. Visto isso, diferentes estratégias de ritmo (pacing strategy) foram diagnosticadas a fim de promover uma economia de energia durante o esforço. Portanto, o objetivo desta revisão é apresentar os principais mecanismos da estratégia de ritmo, baseados nos modelos de tomada de decisão sustentados por informações aferentes ou contextuais/intuitivas, que são usadas para calcular e reduzir um possível risco de fadiga prematura durante uma tarefa de endurance.

Abstract Aim: The aim of the study was to analyze the impact of a based-team sports physical education class on inhibitory control of elementary school children. Methods: Were selected 29 elementary school students (13 boys and 16 girls; 10.7 ± 0.7 years old; 43.2 ± 8.2 kg weight; 147 ± 5 cm height). Participants were submitted to a 50-minute sports-based physical education class performed at moderate intensity. Inhibitory control was measured before and immediately after the end of the physical education class by the Stroop Test. Results: Results indicate that the variables derived from Stroop Test performance overall reaction time were significantly reduced after the physical education class (p < 0.05). Conclusion: These results suggest that a 50-minute sports-based physical education class performed at moderate intensity elicited a significant improvement on the inhibitory control elementary school students.

Dr Robergs suggested that the central governor model (CGM) is not a well-worded theory, as it deviated from the tenant of falsification criteria. According to his view of science, exercise researches with the intent to prove rather than disprove the theory contribute little to new knowledge and condemn the theory to the label of pseudoscience. However, exercise scientists should be aware of limitations of the falsification criteria. First, the number of potential falsifiers for a given hypothesis is always infinite so that there is no mean to ensure asymmetric comparison between theories. Thus, assuming a competition between CGM and dichotomised central versus peripheral fatigue theories, scientists guided by the falsification principle should know, a priori, all possible falsifiers between these two theories in order to choose the finest one, thereby leading to an oversimplification of the theories. Second, the failure to formulate refutable hypothesis may be a simple consequence of the lack of instruments to make crucial measurements. The use of refutation principles to test the CGM theory requires capable technology for online feedback and feedforward measures integrated in the central nervous system, in a real-time exercise. Consequently, falsification principle is currently impracticable to test CGM theory. The falsification principle must be applied with equilibrium, as we should do with positive induction process, otherwise Popperian philosophy will be incompatible with the actual practice in science. Rather than driving the scientific debate on a biased single view of science, researchers in the field of exercise sciences may benefit more from different views of science.

The objective of this study was to analyze the heart rate (HR) profile plotted against incremental workloads (IWL) during a treadmill test using three mathematical models [linear, linear with 2 segments (Lin2), and sigmoidal], and to determine the best model for the identification of the HR threshold that could be used as a predictor of ventilatory thresholds (VT1 and VT2). Twenty-two men underwent a treadmill incremental test (retest group: n=12) at an initial speed of 5.5 km.h-1, with increments of 0.5 km.h-1 at 1-min intervals until exhaustion. HR and gas exchange were continuously measured and subsequently converted to 5-s and 20-s averages, respectively. The best model was chosen based on residual sum of squares and mean square error. The HR/IWL ratio was better fitted with the Lin2 model in the test and retest groups (p0.05). During a treadmill incremental test, the HR/IWL ratio seems to be better fitted with a Lin2 model, which permits to determine the HR threshold that coincides with VT1.

Resumo Fundamento O interesse pela hipertensão em crianças e adolescentes aumentou desde a atualização do sistema de classificação da pressão arterial para comparar com o sistema de classificação dos adultos, alterando a terminologia de “normal alta” para “pré-hipertensão”. Objetivo O objetivo deste estudo foi analisar a associação da modulação autonômica cardíaca com os níveis pressóricos dos adolescentes. Métodos 203 adolescentes foram agrupados de acordo com a pressão arterial sistólica (PAS) e a pressão arterial diastólica (PAD). Um grupo foi caracterizado como pré-hipertensão, e o outro como normotenso. Foram coletadas características antropométricas, cardiovasculares e de qualidade do sono. Inicialmente, os dados foram submetidos ao teste de normalidade Kolmogorov-Smirnov . As variáveis quantitativas contínuas foram analisadas por meio do teste T de Student não pareado. Para análise das variáveis categóricas, foi utilizado o teste qui-quadrado. Um modelo de regressão logística foi realizado. O nível de significância estabelecido foi p