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1.
Physiol Behav ; 274: 114428, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38065422

RESUMO

Mental fatigue reduces exercise performance through an impaired psychological response such as increased perceived exertion. Carbohydrate (CHO) mouth rinses improve exercise performance and perceived exertion likely due to an improved activation in cerebral reward areas, then we investigated if the CHO mouth rinse-improved exercise performance in mentally fatigued individuals was associated with ameliorated reward-related psychological responses. We hypothesised that CHO mouth rinse would be beneficial for mentally fatigued cyclists mainly in high-metabolic disturbance intensities. After familiarization and baseline sessions, well trained cyclists (n = 20) performed a maximal incremental test (MIT) after mental fatigue induction. They completed the MIT either without mouth rinse (MF) or rinsing their mouth with CHO (MF+CHO) or placebo (FM+PLA) solutions at every 25 % of the MIT. Psychological responses such as ratings of perceived exertion (RPE), affective valence, emotional arousal, and motivation were assessed throughout the MIT, while performance was assessed as peak power output and time of exercise. Mental fatigue reduced MIT performance (P < 0.05), but CHO mouth rinse was effective to counteract this deleterious mental fatigue effect (P < 0.05). However, we found null effects of CHO mouth rinses in psychological responses above the VT2 (P > 0.05) such as RPE, affective valence, emotional arousal, and motivation. Correlational analysis showed a significant, but moderate negative correlation between motivation and time of exercise above the VT2 when participants used CHO mouth rinse. In conclusion, the ergogenic CHO mouth rinse effects on MIT performance of mentally fatigued cyclists were irrespective of ameliorated psychological responses to exercise.


Assuntos
Desempenho Atlético , Antissépticos Bucais , Humanos , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Carboidratos , Carboidratos da Dieta , Teste de Esforço , Fadiga Mental , Boca , Antissépticos Bucais/uso terapêutico
2.
Med Sci Sports Exerc ; 56(2): 315-327, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37796168

RESUMO

PURPOSE: Narrative reviews have suggested that postactivation induced by warm-up routines is effective to increase endurance exercise performance in real-world scenarios. However, systematic reviews with meta-analysis rather than narrative ones are required to provide an up-to-date summary of the evidence and provide directions for practical decisions. Therefore, we systematically reviewed peer-reviewed and gray literature to determine the certainty of evidence and the relative effects of postactivation performance enhancement (PAPE) in endurance exercises. METHODS: The effects of PAPE on endurance performance were meta-analyzed as a standardized mean difference (SMD) from control conditions within a random-effects model considering polled data and subgroups (PAPE strategies, endurance test modalities, and V̇O 2max -based endurance level). RESULTS: Eligible studies ( n = 35) showed a high risk of bias due to methodological flaws in randomization and blinding procedures. A meta-analysis including 57 comparisons (432 participants) revealed a significant but very small PAPE effect on endurance performance ( Z = 2.49, SMD = 0.15-very small, 95% confidence interval = 0.03 to 0.28) due to exceptional effect sizes reported by two studies (SMD of 2.85 and 2.14). We also observed that neither PAPE strategies nor endurance test modalities or V̇O 2max -based endurance levels influenced the PAPE effects on endurance performance. Meta-regression showed that PAPE effects were correlated neither with the time interval between conditioning routines and endurance exercise nor with endurance exercise duration. We found a very low certainty of evidence that PAPE potentiates endurance performance. CONCLUSIONS: Based on the analyses of bias and certainty of evidence, we found no support to recommend PAPE strategies to improve endurance exercise performance. Significant but very small PAPE effects on endurance performance were due to two exceptional effect sizes.


Assuntos
Tolerância ao Exercício , Exercício de Aquecimento , Humanos , Viés
3.
Appl Psychophysiol Biofeedback ; 48(2): 171-178, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36564611

RESUMO

Interoception refers to the competence in perceiving and interpreting internal sensations emerging from the body. The most common approach to assess interoception is through cardiac interoceptive tests like the heartbeat tracking task (HTT), which measures the accuracy on perceive and counting heartbeats during a period. However, the literature is scarce in providing adequate reliability evidence for this measure so that the interoception assessment may be threaten. In addition to HTT accuracy, it is possible to determine sensibility (self-reported confidence) and interoceptive awareness (correspondence between accuracy and sensibility). Thus, we measured the test-retest reliability of HTT and also investigated the behavior of HTT outcomes along the task. Therefore, 31 healthy adults (16 males) with 27.8 (9.4) years old performed two consecutive HTT interspersed by one day. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable difference (MD) analyzes showed 'Good' relative reliability for interoceptive accuracy (ICC = 0.880; SEM = 0.263; MD = 0.728; p < 0.001) and 'Moderate' for sensibility (ICC = 0.617; SEM = 0.648; MD = 1.797; p < 0.001) and awareness (ICC = 0.593; SEM = 0.227; MD = 0.628; p < 0.001). The absolute reliability shows low threshold values for observing true effects in HTT outcomes. The results also showed that reducing the number of HTT blocks did not impact the outcomes. The HTT showed to be reliable in determine the interoceptive competences in healthy adults.


Assuntos
Interocepção , Adulto , Masculino , Humanos , Criança , Frequência Cardíaca , Reprodutibilidade dos Testes , Autorrelato
4.
Res Q Exerc Sport ; 94(4): 1126-1132, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36121708

RESUMO

Purpose: Local cooling with ice massage is a practical and inexpensive technique to decrease perceptual stress and improve motor performance in hot environments. However, it is unknown whether local cooling with ice massage reduces perceptual responses to exercise and improves performance in a normothermic environment. Thus, we investigated whether ice massage on the calf muscles before a 4 km running time trial (TT4km) reduced the ratings of perceived exertion (RPE) and perceived muscle pain, thereby improving exercise performance in a normothermic environment. Methods: After familiarizations, fourteen recreationally endurance-trained men (age = 21.3 ± 1.2 years; body weight = 67.5 ± 9.2 kg; height = 173.0 ± 5.0 cm) underwent two TT4km on a 400 m track in normothermic conditions with or without ice massage before the trial. The time of running, RPE, and pain perception were recorded every 400 m throughout the TT4km. Results: The local cooling with ice massage increased the mean speed (~ 5.2%, p = 0.03) and decreased the time to complete the TT4km (~ 5.5%, p = 0.03). Accordingly, ice massage also reduced the exercise-derived pain perception (p = 0.028), although no effect has been found in the RPE during the TT4km (p = 0.32). Conclusion: Together, these results showed that local cooling with ice massage before the exercise reduced the exercise-derived pain perception, enabling runners to increase the speed for a comparable RPE during exercise, thereby improving the TT4km performance in a normothermic environment.


Assuntos
Gelo , Corrida , Humanos , Masculino , Adulto Jovem , Exercício Físico , Frequência Cardíaca/fisiologia , Perna (Membro) , Massagem/métodos , Corrida/fisiologia
5.
Eur J Appl Physiol ; 122(11): 2321-2329, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36006479

RESUMO

Different from the most popular thinking, the placebo effect is not a purely psychological phenomenon. A body of knowledge from multidisciplinary fields has shown that the expectation of a potential benefit when receiving a treatment induces a cascade of neurochemical-electrophysiological alterations in brain reward areas, including motor-related ones. Alterations in the dopamine, opioid, and glutamate metabolism are the neural representation converting reward-derived declarative forms into an attractive and wanted behavior, thereby changing the activation in reward subcortical and cortical structures involved in motor planning, motor execution, and emotional-cognitive attributes of decision-making. We propose that the expectation of receiving a treatment that is beneficial to motor performance triggers a cascade of activations in brain reward areas that travels from motor planning and motor command areas, passing through corticospinal pathways until driving the skeletal muscles, therefore facilitating the motor performance. Although alternative explanations cannot be totally ruled out, this mechanistic route is robust in explaining the results of placebo-induced effects on motor performance and could lead to novel insights and applications in the exercise sciences. Factors such as sex differences in reward-related mechanisms and aversion-induced nocebo effects should also be addressed.


Assuntos
Analgésicos Opioides , Dopamina , Dopamina/metabolismo , Feminino , Glutamatos , Humanos , Masculino , Efeito Placebo , Recompensa
6.
SAGE Open Med ; 10: 20503121221098120, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35615525

RESUMO

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.

7.
Artigo em Inglês | MEDLINE | ID: mdl-35270686

RESUMO

Low-intensity aerobic training combined with blood flow restriction (LI + BFR) has resulted in increases in aerobic and neuromuscular capacities in untrained individuals. This strategy may help cyclists incapable of training with high intensity bouts or during a rehabilitation program. However, there is a lack of evidence about the use of LI + BFR in injured trained cyclists. Thus, we investigated the effects of LI + BFR on aerobic capacity, maximal isometric strength, cross-sectional area of vastus lateralis (CSAVL), time to exhaustion test (TTE), and 20 km cycling time-trial performance (TT20 km) in a male cyclist with knee osteoarthritis (OA). After a 4-week control period, a 9-week (2 days/week) intervention period started. Pre- and post-intervention TT20 km, peak oxygen consumption (VO2peak), power output of the 1st and 2nd ventilatory thresholds (1st WVT and 2nd WVT), maximum power output (Wmax), TTE, muscle strength and CSAVL of both legs were measured. Training intensity was fixed at 30% of Wmax while the duration was progressively increased from 12 min to 24 min. There was a reduction in time to complete TT20 km (-1%) with increases in TT20 km mean power output (3.9%), VO2peak (11.4%), 2nd WVT (8.3%), Wmax (3.8%), TTE (15.5%), right and left legs maximal strength (1.3% and 8.5%, respectively) and CSAVL (3.3% and 3.7%, respectively). There was no alteration in 1st WVT. Based on the results, we suggest that LI + BFR may be a promising training strategy to improve the performance of knee-injured cyclists with knee OA.


Assuntos
Ciclismo , Força Muscular , Ciclismo/fisiologia , Humanos , Perna (Membro) , Masculino , Força Muscular/fisiologia , Músculo Quadríceps/fisiologia , Fluxo Sanguíneo Regional/fisiologia
8.
J Aging Phys Act ; 30(3): 434-444, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34510027

RESUMO

The purpose of the study was to investigate the effects of passive recovery with self-selected time on affect, ratings of perceived exertion, and heart rate in self-selected interval exercises (SSIE). Fifteen older women (68.1 ± 3.8 years), weekly practitioners of functional activities participated in three SSIE with self-selected recovery time (SSRT) and one self-selected continuous exercise session, all at 24 min approximately. The SSIE had the following configurations: 1'/SSRT, 1.5'/SSRT, and 2'/SSRT. The results showed that at the beginning of stimulus heart rate in 1.5'/SSRT (107.9 ± 16.5) and 2'/SSRT (114.6 ± 17.1) were significantly greater (p < .05) compared with self-selected continuous exercise (102.8 ± 14.5). The ratings of perceived exertion in self-selected continuous exercise (2.4 ± 0.4; p < .05) were higher compared with SSIE in recovery. No significant differences were found in affect. The SSIE provided similar responses based on recoveries manipulations.


Assuntos
Teste de Esforço , Exercício Físico , Idoso , Exercício Físico/fisiologia , Terapia por Exercício , Feminino , Frequência Cardíaca/fisiologia , Humanos , Consumo de Oxigênio/fisiologia , Esforço Físico/fisiologia
9.
Arq. bras. cardiol ; 117(4): 648-654, Oct. 2021. tab
Artigo em Português | LILACS | ID: biblio-1345225

RESUMO

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<0,05. Os dados foram expressos como média ± desvio padrão e intervalo de confiança. O software R foi utilizado para análise dos dados. O tamanho do efeito foi calculado com a fórmula de Cohen. Resultados O grupo pré-hipertensão apresentou aumento da entropia de Shannon e diminuição da variância total. Além disso, no modelo de regressão logística, os adolescentes deste grupo tiveram 1,03 mais chances de ter a entropia de Shannon afetada quando a PAS foi ajustada ao gênero, maturação sexual, tempo escolar, idade, circunferência da cintura e qualidade do sono. Conclusão Nossos dados mostram que a modulação autonômica pode desempenhar um papel importante no desenvolvimento da pressão arterial elevada em adolescentes ao controlar fatores como tempo escolar e qualidade do sono.


Abstract Background The interest regarding hypertension among children and adolescents has increased since the blood pressure rating system was updated to be compared with the adult rating system, changing the terminology from "normal high" to "prehypertension". Objective This study aimed to analyze the association between cardiac autonomic modulation and pressure levels of adolescents. Methods 203 adolescents were grouped according to systolic blood pressure (SBP) and diastolic blood pressure (DBP). One group was characterized as prehypertension, and the other as normotensive. Anthropometric, cardiovascular and sleep quality characteristics were collected. Initially, the data were submitted to the Kolmogorov-Smirnov normality test. Continuous quantitative variables were analyzed using the unpaired Student t-test. For the analysis of categorical variables, a chi-square test was used. A logistic regression model was performed. The level of significance was set at p<0.05. The data were expressed as mean ± standard deviation and confidence interval. The R software was used for data analysis. The effect size was calculated using the Cohen's formula. Results The prehypertension group showed an increase in Shannon entropy and a decrease in total variance. Also, in the logistic regression model, adolescents in this group were 1.03 times more likely to have Shannon entropy's affected when SBP was adjusted for gender, sexual maturation, school time, age, waist circumference, and sleep quality. Conclusion Our data show that autonomic modulation may play an important role in the development of elevated blood pressure in adolescents, when controlling for other factors, such as school time and sleep quality.


Assuntos
Humanos , Criança , Adolescente , Pré-Hipertensão , Hipertensão , Pressão Sanguínea , Estudos Transversais , Fatores de Risco , Circunferência da Cintura
10.
Arq Bras Cardiol ; 117(4): 648-654, 2021 10.
Artigo em Inglês, Português | MEDLINE | ID: mdl-34709291

RESUMO

BACKGROUND: The interest regarding hypertension among children and adolescents has increased since the blood pressure rating system was updated to be compared with the adult rating system, changing the terminology from "normal high" to "prehypertension". OBJECTIVE: This study aimed to analyze the association between cardiac autonomic modulation and pressure levels of adolescents. METHODS: 203 adolescents were grouped according to systolic blood pressure (SBP) and diastolic blood pressure (DBP). One group was characterized as prehypertension, and the other as normotensive. Anthropometric, cardiovascular and sleep quality characteristics were collected. Initially, the data were submitted to the Kolmogorov-Smirnov normality test. Continuous quantitative variables were analyzed using the unpaired Student t-test. For the analysis of categorical variables, a chi-square test was used. A logistic regression model was performed. The level of significance was set at p<0.05. The data were expressed as mean ± standard deviation and confidence interval. The R software was used for data analysis. The effect size was calculated using the Cohen's formula. RESULTS: The prehypertension group showed an increase in Shannon entropy and a decrease in total variance. Also, in the logistic regression model, adolescents in this group were 1.03 times more likely to have Shannon entropy's affected when SBP was adjusted for gender, sexual maturation, school time, age, waist circumference, and sleep quality. CONCLUSION: Our data show that autonomic modulation may play an important role in the development of elevated blood pressure in adolescents, when controlling for other factors, such as school time and sleep quality.


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<0,05. Os dados foram expressos como média ± desvio padrão e intervalo de confiança. O software R foi utilizado para análise dos dados. O tamanho do efeito foi calculado com a fórmula de Cohen. RESULTADOS: O grupo pré-hipertensão apresentou aumento da entropia de Shannon e diminuição da variância total. Além disso, no modelo de regressão logística, os adolescentes deste grupo tiveram 1,03 mais chances de ter a entropia de Shannon afetada quando a PAS foi ajustada ao gênero, maturação sexual, tempo escolar, idade, circunferência da cintura e qualidade do sono. CONCLUSÃO: Nossos dados mostram que a modulação autonômica pode desempenhar um papel importante no desenvolvimento da pressão arterial elevada em adolescentes ao controlar fatores como tempo escolar e qualidade do sono.


Assuntos
Hipertensão , Pré-Hipertensão , Adolescente , Pressão Sanguínea , Criança , Estudos Transversais , Humanos , Fatores de Risco , Circunferência da Cintura
11.
Artigo em Inglês | MEDLINE | ID: mdl-34574457

RESUMO

This study provided a proof-of-concept and test-retest reliability of measures frequently used to assess a mental fatigue paradigm. After familiarization, 28 healthy men performed (40-min) the Rapid Visual Information Processing (RVP) test in a test-retest design, having mental fatigue sensation, motivation, emotional arousal, total mood disturbance, and electroencephalography (EEG) in the prefrontal cortex measured before and after the test. EEG was recorded during a 3-min rest so that the power spectral density of theta (3-7 Hz) and alpha (8-13 Hz) bands was calculated. Pre-to-post RVP test changes in psychological and physiological domains were compared (paired-T tests), and absolute (standard error of measurement (SEM) and minimal difference (MD)) and relative reliability (intraclass correlation coefficient (ICC)) were calculated. The RVP test induced an increase (p < 0.05) in mental fatigue sensation (120.9% (109.4; 132.4)) and total mood disturbance (3.5% (-6.3; 13.3)), and a decrease in motivation (-7.1% (-9.2; -5.1)) and emotional arousal (-16.2% (-19.1; -13.2)). Likewise, EEG theta (59.1% (33.2; 85.0); p < 0.05), but not alpha band, increased due to RVP test. All psychophysiological responses showed poor-to-moderate relative reliability. Changes in mental fatigue sensation and motivation were higher than SEM and MD, but changes in EEG theta band were higher only than SEM. Mental fatigue sensation, motivation, and EEG theta band were sensitive to distinguish a mental fatigue paradigm despite true mental fatigue effects on theta activity may be trivial.


Assuntos
Eletroencefalografia , Fadiga Mental , Humanos , Masculino , Motivação , Reprodutibilidade dos Testes , Descanso
13.
Psychophysiology ; 58(6): e13810, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33713484

RESUMO

Pain arising from exercise potentiates fatigue and impairs the performance of endurance exercise. We assessed neurophysiological and perceptual responses to endurance exercise performed under experimentally induced muscle pain by a model that separates muscle pain from muscle fatigue. After a series of pilot studies investigating different hypertonic saline volumes, 17 healthy males performed a preliminary VO2PEAK test before performing a familiarization of the cycling time-to-exhaustion exercise (80% of the peak power output in the VO2PEAK test). Participants, performed a baseline exercise session before the sessions with hypertonic and isotonic saline injections in the vastus lateralis of both legs, in a crossover and counterbalanced design. Neurophysiological and perceptual responses such as electroencephalography (EEG) in frontal, prefrontal, parietal, and motor cortex, electromyography (EMG) of the vastus lateralis and biceps femoris muscles, ratings of perceived exertion (RPE), pain sensation, and affective valence were measured at rest and during exercise. The hypertonic injection reduced the resting EEG alpha-beta ratio in the frontal and prefrontal cortex. When compared to exercise performed after the isotonic injection (430.5 ± 152.6 s), hypertonic injection shortened the time-to-exhaustion (357.5 ± 173.0 s), reduced the EMG of the assessed muscles, and increased the muscle co-contraction during exercise. The hypertonic injection also reduced the EEG alpha-beta ratio in the prefrontal and parietal cortex, increased RPE and pain sensation, and reduced affective valence during exercise. This proof-of-concept study showed that hypertonic injection-induced muscle pain reduced endurance performance, promoting centrally mediated alterations in motor command and cortical activation, as well as an interplay of perceptual responses.


Assuntos
Eletroencefalografia , Eletromiografia , Mialgia/induzido quimicamente , Resistência Física/fisiologia , Esforço Físico/fisiologia , Adulto , Ciclismo/fisiologia , Humanos , Masculino , Córtex Motor , Fadiga Muscular/fisiologia , Córtex Pré-Frontal , Músculo Quadríceps , Solução Salina Hipertônica
14.
PLoS One ; 16(1): e0246014, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33481947

RESUMO

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

15.
Physiol Behav ; 232: 113290, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33333131

RESUMO

Psychological responses such as affect, mood, motivation, anxiety are important considerations for exercise adherence. A large body of evidence indicates that exercise intensity is a controllable variable capable of increasing positive feelings. Investigations thus far, however, have not considered that the higher incidence of negative psychological responses in women could be due to physiological particularities of the menstrual cycle (MC). This project investigates the effect of MC phases and exercise intensity on psychophysiological responses in fourteen healthy, eumenorrheic and physically active women. Measuring psychophysiological responses before, during and after exercise, participants completed two exercise bouts of 15 min above and below the anaerobic threshold in the follicular phase (FP) and the luteal phase (LP) of the MC. Lower levels of depression and hostility and higher levels of vigor, affect and motivation were observed during exercise in the FP. Exercise at moderate intensity elicited more positive psychological responses compared to high-intensity exercise, highlighted by findings that affect and rating of perceived exertion were worse in the LP without changes in physiological responses. These findings suggest no effect of MC on physiological responses, but psychological responses are impaired in the LP, worsening particularly during exercise at high intensity.


Assuntos
Fase Folicular , Ciclo Menstrual , Limiar Anaeróbio , Exercício Físico , Feminino , Humanos , Fase Luteal
16.
Brain Sci ; 10(8)2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32751162

RESUMO

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.

20.
Nutrients ; 11(10)2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31618910

RESUMO

The central and peripheral effects of caffeine remain debatable. We verified whether increases in endurance performance after caffeine ingestion occurred together with changes in primary motor cortex (MC) and prefrontal cortex (PFC) activation, neuromuscular efficiency (NME), and electroencephalography-electromyography coherence (EEG-EMG coherence). Twelve participants performed a time-to-task failure isometric contraction at 70% of the maximal voluntary contraction after ingesting 5 mg/kg of caffeine (CAF) or placebo (PLA), in a crossover and counterbalanced design. MC (Cz) and PFC (Fp1) EEG alpha wave and vastus lateralis (VL) muscle EMG were recorded throughout the exercise. EEG-EMG coherence was calculated through the magnitude squared coherence analysis in MC EEG gamma-wave (CI > 0.0058). Moreover, NME was obtained as the force-VL EMG ratio. When compared to PLA, CAF improved the time to task failure (p = 0.003, d = 0.75), but reduced activation in MC and PFC throughout the exercise (p = 0.027, d = 1.01 and p = 0.045, d = 0.95, respectively). Neither NME (p = 0.802, d = 0.34) nor EEG-EMG coherence (p = 0.628, d = 0.21) was different between CAF and PLA. The results suggest that CAF improved muscular performance through a modified central nervous system (CNS) response rather than through alterations in peripheral muscle or central-peripheral coupling.


Assuntos
Ritmo alfa/efeitos dos fármacos , Cafeína/administração & dosagem , Córtex Motor/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Substâncias para Melhoria do Desempenho/administração & dosagem , Resistência Física/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Músculo Quadríceps/inervação , Adulto , Ciclismo , Cafeína/efeitos adversos , Estudos Cross-Over , Método Duplo-Cego , Eletromiografia , Humanos , Córtex Motor/fisiologia , Fadiga Muscular , Força Muscular/efeitos dos fármacos , Substâncias para Melhoria do Desempenho/efeitos adversos , Córtex Pré-Frontal/fisiologia , Fatores de Tempo
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