Modulation of cortical and subcortical brain areas at low and high exercise intensities.

INTRODUCTION: The brain plays a key role in the perceptual regulation of exercise, yet neuroimaging techniques have only demonstrated superficial brain areas responses during exercise, and little is known about the modulation of the deeper brain areas at different intensities. OBJECTIVES/METHODS: Using a specially designed functional MRI (fMRI) cycling ergometer, we have determined the sequence in which the cortical and subcortical brain regions are modulated at low and high ratings perceived exertion (RPE) during an incremental exercise protocol. RESULTS: Additional to the activation of the classical motor control regions (motor, somatosensory, premotor and supplementary motor cortices and cerebellum), we found the activation of the regions associated with autonomic regulation (ie, insular cortex) (ie, positive blood-oxygen-level-dependent (BOLD) signal) during exercise. Also, we showed reduced activation (negative BOLD signal) of cognitive-related areas (prefrontal cortex), an effect that increased during exercise at a higher perceived intensity (RPE 13-17 on Borg Scale). The motor cortex remained active throughout the exercise protocol whereas the cerebellum was activated only at low intensity (RPE 6-12), not at high intensity (RPE 13-17). CONCLUSIONS: These findings describe the sequence in which different brain areas become activated or deactivated during exercise of increasing intensity, including subcortical areas measured with fMRI analysis.

Association between physical activity and walking capacity with cognitive function in peripheral artery disease patients.

OBJECTIVE: To identify the association between objectively measured physical activity and walking capacity with cognitive function in patients with symptomatic peripheral artery disease. METHODS: This was an observational, cross sectional study. One hundred and thirty patients (age 67 ± 8 years) were recruited at a tertiary centre specializing in vascular disease. Cognitive function (global, memory, executive function and attention) was evaluated using the Montreal Cognitive Assessment tool. Physical activity levels (total, light, and moderate-vigorous) were obtained using an accelerometer. A 6 min and 4 m walk test were undertaken to assess walking capacity. Crude and covariate adjusted, linear regression analyses confirmed significant associations between physical activity levels and walking capacity with cognitive function. RESULTS: Positive and significant associations were observed between moderate to vigorous physical activity (p = .039) and walking capacity (p = .030) with memory after adjusting for covariates. No significant association was identified between light physical activity and usual gait speed with any cognitive function outcome. CONCLUSION: Greater memory performance was associated with greater moderate to vigorous physical activity levels and walking capacity in patients with symptomatic peripheral artery disease. Clinical interventions focused on improving moderate to vigorous physical activity levels and walking capacity may provide important therapies to potentially enhance cognitive health in patients with peripheral artery disease.

The mediating role of inhibitory control in the relationship between prefrontal cortex hemodynamics and exercise performance in adults with overweight or obesity.

Physical inactivity has been suggested to impair physical performance, cognitive functions and facilitate weight gain. One hypothesis is that long periods of physical inactivity could impair oxygen delivery to the prefrontal cortex (PFC), impairing one's cognitive ability to inhibit unhealthy automated behaviors and, therefore, reduce exercise tolerance. The present study sought to further understand the relationship among PFC hemodynamics, inhibitory control, and exercise tolerance in individuals with low physical fitness levels who are overweight or obese. Thirty-four participants were asked to perform a series of inhibitory control tests (i.e., Stroop task) in one testing session and complete an incremental cycling exercise test with hemodynamic fluctuations of the PFC measured with functional near-infrared spectroscopy in another session. Our results indicate that exercise performance varied with PFC oxygenation. We also found that inhibitory control played a key role mediating the relationship between PFC oxygenation and exercise performance, suggesting that the cognitive ability to inhibit automated responses has an impact on exercise behavior in adults with overweight and obesity.

Insular cortex activity during food-specific inhibitory control is associated with academic achievement in children.

BACKGROUND/OBJECTIVES: Inhibitory control (IC) is usually poorer in children with overweight and obesity and has been associated with unhealthy eating behaviors and lower academic achievement. Food-specific IC tasks depicting salient unhealthy foods may be more sensitive to predicting fat accumulation and unhealthy behaviors than traditional IC tasks. However, the neural activation patterns in response to food-specific IC remain unclear, especially in developing children`s brains. Here, we investigated brain activity associated with food-specific IC in children with accumulated fat mass. SUBJECTS/METHODS: 36 children with overweight and obesity performed a food-specific Go/No-Go task in an MRI scanner. We assessed the children's body composition with dual-energy x-ray absorptiometry, academic achievement, somatic maturation, and cardiorespiratory fitness. RESULTS: The left insular cortex was significantly activated during successful inhibition of palatable food cues and was associated with higher academic achievement. Also, linear regression showed that academic achievement correlated with insular cortex activation even when controlling for somatic maturation, cognitive performance, and cardiorespiratory fitness. CONCLUSION: Our results indicate that insular cortex activation, an area known for rational and emotional processing, is associated with successful inhibitory control in response to food images in children with overweight and obesity, while academic performance seems to play a role in the magnitude of this activation.

Effects of 12 weeks of high-intensity interval, moderate-intensity continuous and self-selected intensity exercise training protocols on cognitive inhibitory control in overweight/obese adults: A randomized trial.

Growing evidence shows that aerobic exercise improves cognitive function. However, it is unclear how exercising at different exercise intensities affects cognitive inhibitory control in overweight/obese adults. Herein we compared the effects of 12 weeks of high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), and self-selected intensity training (SSIT) on cognitive inhibitory control in overweight/obese adults. A total of 64 adults (59.4% women, 31.3 ± 7.1 years, 29 ± 2.5 kg/m²) were randomized into three walking/running groups: HIIT, MICT and SSIT. All groups performed three exercise sessions per week on an outdoor running track for 12 weeks. Cognitive inhibitory control was assessed at baseline and after the exercising programs using a computerized version of the Stroop Color-Words test. The HIIT and SSIT resulted in a faster Stroop effect (i.e. enhanced performance) when compared to MICT (p=.018; p= .026), however, there were no significant differences between the HIIT and SSIT groups (p> .05). The enhanced Stroop effect was correlated with increases in cardiorespiratory fitness after HIIT (r= -.521, p= .018) and decreases in body fat after MICT (r= .671, p= .001). These findings may suggest that overweight/obese adults performing exercise interventions at higher intensities or self-selected intensity may enhance their cognitive ability to inhibit automated behavioral responses.Highlights HIIT and/or SSIT are more effective than MICT in improving cognitive inhibitory control after 12-weeks in overweight/obese adults.Increases in cardiorespiratory fitness and decreases in body fat after HIIT and MICT were correlated with improvements in cognitive inhibitory control.Our study highlights the possibility of performing different exercise programs in an outdoor environment to improve cognitive function in overweight/obese adults.

Electromyographic activity and rate of muscle fatigue of the quadriceps femoris during cycling exercise in the severe domain.

This study compared the activation pattern and the fatigue rate among the superficial muscles of the quadriceps femoris (QF) during severe cycling exercise. Peak oxygen consumption (VO(2)peak) and maximal accumulated oxygen Deficit (MAOD) were established by 10 well-trained male cyclists (27.5 ± 4.1 years, 71.0 ± 10.3 kg, 173.4 ± 6.6 cm, mean VO(2)peak 56.7 ± 4.4 ml·kg·min(-1), mean MAOD 5.7 ± 1.1 L). Muscle activity (electromyographic [EMG] signals) was obtained during the supramaximal constant workload test (MAOD) and expressed by root mean square (RMS) and median frequency (MF slope). The RMS of the QF, vastus lateralis (VL) and vastus medialis (VM) muscles were significantly higher than at the beginning after 75% of exercise duration, whereas for the rectus femoris (RF), this was observed after 50% of exercise duration (p ≤ 0.05). The slope of the MF was significantly higher in the RF, followed by the VL and VM (-3.13 ± 0.52 vs. -2.61 ± 0.62 vs. -1.81 ±0.56, respectively; p < 0.05). We conclude that RF may play an important role in limiting performance during severe cycling exercise.

The Relative Age Effect on Anthropometry, Body Composition, Biological Maturation and Motor Performance in Young Brazilian Soccer Players.

The present study aimed to investigate the influence of months of birth on anthropometry, body composition, biological maturation, and motor performance in young Brazilian soccer players. Young Brazilian soccer players from the Under-13 (n = 50; 13.6 ± 0.3 years), Under-15 (n = 50; 15.5 ± 0.4 years), and Under-17 categories (n = 46; 17.7 ± 0.3 years) took part in this study. Athletes were divided according to chronological age, 1st tertile (January to April); 2nd tertile (May to August); and 3rd tertile (September to December). Anthropometry, body composition, biological maturation, and motor performance variables were evaluated for all participants. There were no differences between the U-13, U-15, and U-17 categories regarding birth tertiles (p > 0.05). Differences between the ages and birth tertiles were observed for the stature, body mass, and lean body mass (p < 0.05). Moreover, differences were found in maturational status between the ages and birth tertiles (p < 0.05). In general, U-13 players showed lower values compared to U-15 and U-17 players in tests of motor performance. In addition, there was a difference in motor performance between the birth tertiles only for RSA variables. The months of birth influenced the stature, body mass, lean body mass, and repeated sprint ability in the U-13 and U-15 categories. Thus, care should be taken during the process of talent selection, as many young players could be underestimated due to their date of birth.

Phase angle is associated with cardiorespiratory fitness and body composition in children aged between 9 and 11 years.

Phase angle (PhA) is a marker of health and cellular integrity and is used as a tool for predicting nutritional status in children with various health conditions. Even though physical activity and cardiorespiratory fitness have been shown to provide several health benefits, few studies have evaluated the relationship between PhA and health parameters, i.e., cardiorespiratory fitness and body composition. Thus, we aimed to evaluate the association between PhA and cardiorespiratory fitness in children aged between 9 and 11 years. Twenty-three children (52% girls) were tested in a cross-sectional study. The PhA was calculated by bioelectric impedance parameters. Body fat (BF) and fat-free mass (FFM) were measured by dual-energy absorptiometry. Cardiorespiratory fitness (VO2 peak) was performed using the 20-meter shuttle-run test, and allometric scaling were calculated to better control the effect of body weight (VO2 peak BW), BF (VO2 peak BF) and FFM (VO2 peak FFM) on fitness. All analyses were performed separately for each sex group. Pearson's correlation was used to test the association between PhA, cardiorespiratory fitness (relative and absolute), and body composition [BF (kg and%) and FFM]. Linear regression analysis was used to test the determinant effect of cardiorespiratory fitness values on PhA. In girls, the PhA was negatively associated with%BF (r = -0.66), and positively associated with FFM (r = 0.68), VO2 peak BW (r = 0.69), and VO2 peak FFM (r = 0.78). While in boys, the PhA was positively associated with VO2 peak BW (r = 0.71), VO2 peak BF (r = 0.75), and VO2 peak FFM (r = 0.70). Linear regression showed an association of VO2 peak FFM on PhA in girls and boys (ß = 0.781 and ß = 0.703, respectively), and an association of VO2 peak BW and VO2 peak BF on PhA only in boys (ß = 0.705 and ß = 0.746, respectively). We concluded that PhA was negatively associated with %BF and positively associated with FFM in girls. Furthermore, when allometric scaling was used to better control the effect of body weight, body fat and fat-free mass, the PhA was positive associated with VO2 peak BW, VO2 peak FFM (in girls and boys), and VO2 peak BF in boys. These results suggest that the value of phase angle can be an important parameter to investigate health status related to body composition and cardiorespiratory fitness in children.

Systolic blood pressure mediates the association between body mass index and inhibitory control in children.

Here, we examine whether systolic blood pressure (SBP) mediates the relationship between body mass index (BMI) and inhibitory control in children. Twenty children with high blood pressure (HBP) were approximately matched with twenty children with low blood pressure (LBP) by fitness, BMI, somatic maturation, sex and age. Inhibitory control was measured by a cognitive Go/Nogo task, where number of commission errors during Nogo trials and reaction time during Go trials were used as performance. We compared performance between the two groups and conducted a mediation analysis using SBP as mediator of the relationship between BMI and commission errors. Results revealed that HBP children presented higher number of commission errors, compared to LBP children. Moreover, SBP mediated the relation between BMI and number of errors. Thus, early exposure to high levels of SBP can negatively impact inhibitory control and SBP acts as a mediator between BMI and inhibitory functioning in children.

Influence of Judo Experience on Neuroelectric Activity During a Selective Attention Task.

OBJECTIVE: We compared the cognitive performance and neuroelectric responses during a selective attentional task in judo athletes with different levels of expertise. METHODS: Judo black and white belt athletes performed both general and specific fitness tests while simultaneously completing a Stroop color-word test recorded by 64 electroencephalogram channels. RESULTS: Cognitive behavioral performance and event-related spectral perturbation (ERSP) present no differences between groups. However, the topographic analysis found different neural source patterns in each group. Judo black belts compared to judo white belts presented a greater peak amplitude of P300 in the middle frontal gyrus and of N200 in the cuneus, but slower latency of P300 in the precuneus. CONCLUSION: Despite no difference in cognitive behavioral performance, judo expertise causes a difference in the allocation of attentional and conflict detection neural resources.

Fat mass predicts food-specific inhibitory control in children.

BACKGROUND/OBJECTIVES: Impaired inhibitory control has been associated with obesity, high blood pressure and lack of physical fitness. These impairments are thought to be related to decreased cognitive control over excessive food consumption and may start in childhood. However, previous studies in children have examined inhibitory control deficits using general (non-food-specific) tasks and relied on body mass index, which does not distinguish the amount of fat mass. As fat mass, hypertension and physical fitness have been shown to play a role in cognition, the aim of this study was to investigate the relationship between these variables and food specific inhibitory control in children. SUBJECTS/METHODS: Children's (n = 48; Age 10.7 ±â€¯0.6 years) general characteristics, fat mass, cardiorespiratory fitness, blood pressure and performance on a food-specific inhibitory control task (Go/No-go) were measured across two sessions. RESULTS: Fat mass and sex were associated with inhibitory control performance, while no associations were found for cardiorespiratory fitness, blood pressure and other potential confounding variables (i.e. age, pubertal timing, body mass index, waist-to-hip ratio, scholar test performance and heart rate). Linear regression analyses showed that only fat mass predicted poorer food-specific inhibitory control (ß = 0.36; ΔR2 = 0.04; p < .05) and sex predicted inhibitory control for toys (control condition) (ß = 0.42; ΔR2 = 0.11; p < .01). Neither blood pressure nor cardiorespiratory fitness predicted food specific inhibitory control. CONCLUSION: These findings suggest that fat mass is an independent predictor of inhibitory control for food in children.

Improving Cycling Performance: Transcranial Direct Current Stimulation Increases Time to Exhaustion in Cycling.

The central nervous system seems to have an important role in fatigue and exercise tolerance. Novel noninvasive techniques of neuromodulation can provide insights on the relationship between brain function and exercise performance. The purpose of this study was to determine the effects of transcranial direct current stimulation (tDCS) on physical performance and physiological and perceptual variables with regard to fatigue and exercise tolerance. Eleven physically active subjects participated in an incremental test on a cycle simulator to define peak power output. During 3 visits, the subjects experienced 3 stimulation conditions (anodal, cathodal, or sham tDCS-with an interval of at least 48 h between conditions) in a randomized, counterbalanced order to measure the effects of tDCS on time to exhaustion at 80% of peak power. Stimulation was administered before each test over 13 min at a current intensity of 2.0 mA. In each session, the Brunel Mood State questionnaire was given twice: after stimulation and after the time-to-exhaustion test. Further, during the tests, the electromyographic activity of the vastus lateralis and rectus femoris muscles, perceived exertion, and heart rate were recorded. RM-ANOVA showed that the subjects performed better during anodal primary motor cortex stimulation (491 ± 100 s) compared with cathodal stimulation (443 ± 11 s) and sham (407 ± 69 s). No significant difference was observed between the cathodal and sham conditions. The effect sizes confirmed the greater effect of anodal M1 tDCS (anodal x cathodal = 0.47; anodal x sham = 0.77; and cathodal x sham = 0.29). Magnitude-based inference suggested the anodal condition to be positive versus the cathodal and sham conditions. There were no differences among the three stimulation conditions in RPE (p = 0.07) or heart rate (p = 0.73). However, as hypothesized, RM- ANOVA revealed a main effect of time for the two variables (RPE and HR: p < 0.001). EMG activity also did not differ during the test accross the different conditions. We conclude that anodal tDCS increases exercise tolerance in a cycling-based, constant-load exercise test, performed at 80% of peak power. Performance was enhanced in the absence of changes in physiological and perceptual variables.

Performance during a 20-km cycling time-trial after caffeine ingestion.

BACKGROUND: The objective of this study was to analyze the effect of caffeine ingestion on the performance and physiological variables associated with fatigue in 20-km cycling time trials. METHODS: In a double-blind placebo-controlled crossover study, 13 male cyclists (26 ± 10 y, 71 ± 9 kg, 176 ± 6 cm) were randomized into 2 groups and received caffeine (CAF) capsules (6 mg.kg(-1)) or placebo (PLA) 60 min before performing 20-km time trials. Distance, speed, power, rpm, rating of perceived exertion (RPE), electromyography (EMG) of the quadriceps muscles and heart rate (HR) were continuously measured during the tests. In addition, BRUMS questionnaire was applied before and after the tests. RESULTS: Significant interactions were found in power and speed (P = 0.001), which were significantly higher at the end of the test (final 2 km) after CAF condition. A main effect of time (P = 0.001) was observed for RPE and HR, which increased linearly until the end of exercise in both conditions. The time taken to complete the test was similar in both conditions (PLA = 2191 ± 158 s vs. CAF = 2181 ± 194 s, P = 0.61). No significant differences between CAF and PLA conditions were identified for speed, power, rpm, RPE, EMG, HR, and BRUMS (P > 0.05). CONCLUSION: The results suggest that caffeine intake 60 min before 20-km time trials has no effect on the performance or physiological responses of cyclists.

Birth month distribution and anthropometric measures of U-15 national elite soccer players / Distribuição do mês de nascimento e medidas antropométricas de jogadores de futebol de elite nacional sub-15

Abstract The aim of this study was to analyze the birth month distribution and anthropometric measurements of U-15 elite soccer players. The sample consisted of 400 athletes (15.4 ± 0.4 years, 171.0 ± 10.6 cm and 63.0 ± 8.8 kg) participants of the 11th edition of the Brazil U-15 Soccer Cup, who had their birth month information and height and body mass measures obtained from data available on the organization's website. Athletes were separated according to the categorization of chronological age into four-month periods: 1st quarter (1st QDT), athletes born between January and April; 2nd quarter (2nd QDT), those born between May and August, and 3rd quarter (3rd QDT), those born between September and December. The non-parametric chi-square test (X2) was used to analyze the possible differences between observed and expected birth date distributions in the four-month periods. The significance level was P<0.05. The results show that the number of players born in 1st QDT was higher when compared to 2nd QDT and 3rd QDT (P<0.05), and higher when compared to 2nd QDT with 3rd QDT (P<0.05). For variables height and body mass, it was observed that players born in 1st QDT presented values significantly higher than those born in 2nd QDT and 3rd QDT (P<0.05). In the same way, players born in 2nd QDT presented higher values than those born in 3rd QDT (P<0.05). It could be concluded that the relative age effect exerts an influence on the selection of Brazilian U-15 soccer players because it is associated with differences in the anthropometric characteristics of these young players.

Resumo O propósito deste estudo foi analisar a distribuição do mês de nascimento e a influência do efeito relativo da idade (ERI) sobre as medidas antropométricas de jogadores de futebol de elite nacional sub-15. Para tanto, a amostra foi composta por 400 atletas (15,4 ± 0,4 anos; 171.0 ± 10,6 cm e 63,0 ± 8,8 kg) participantes da 11ª edição da Copa Brasil de Futebol Sub-15, e que tiveram suas informações de datas de nascimento e medidas de estatura e massa corporal, obtidas a partir de dados disponíveis no site da organização do evento. Os atletas foram separados de acordo com a categorização de idade cronológica em quadrimestres: 1˚ quadrimestre (1˚ QDT) jovens nascidos entre janeiro e abril; 2˚ quadrimestre (2˚ QDT) os nascidos entre maio e agosto, e o terceiro quadrimestre (3˚ QDT) os nascidos entre setembro e dezembro. Os resultados demonstraram diferença estatisticamente significativas entre as frequências de datas de nascimento dos jogadores nos quadrimestres. Da mesma forma, as variáveis antropométricas estatura e massa corporal, apresentaram diferenças significativas entre os quadrimestres. Pode-se concluir que o ERI exerce influência na seleção de jovens jogadores brasileiros de elite por estar associado à diferenças nas características antropométricas.

Carbohydrate mouth rinse does not improve repeated sprint performance / Enxágue bucal com carboidrato não melhora o desempenho em sprints repetidos

The objective of this study was to evaluate the effect of a carbohydrate mouth rinse on the repeated sprint ability (RSA) of young soccer players. Nine youth soccer players (15.0 ± 1.5 years; 60.7 ± 4.84 kg; 1.72 ± 0.05 m; 20.5 ± 1.25 kg/m²) were selected. The athletes were submitted to an RSA test consisting of six sprints of 40 m (going/ return = 20 m + 20 m), separated by 20 s of passive recovery, under three experimental conditions: carbohydrate mouth rinse (CHO) or placebo (PLA) and control (CON). The mouth rinses containing CHO or PLA were administered 5 min and immediately before the beginning of the test in doses of 100 mL. The best sprint time (RSAbest), mean sprint time (RSAmean), and drop-off in sprint performance (fatigue index) were determined for the different treatments. One-way ANOVA for repeated measures did not identify significant differences (P > 0.05) in RSAbest (CHO = 7.30 ± 0.31 s; PLA = 7.30 ± 0.30 s; CON = 7.26 ± 0.16 s), RSAmean (CHO = 7.71 ± 0.30 s; PLA = 7.71 ± 0.25 s; CON = 7.66 ± 0.24 s), or fatigue index (CHO = 5.58 ± 2.16%; PLA = 5.77 ± 3.04%; CON = 5.55 ± 3.72%). The results suggest that a carbohydrate mouth rinse does not improve the repeated sprint performance of young soccer players.

O objetivo deste trabalho foi analisar os efeitos do enxágue bucal com carboidrato sobre o desempenho, durante sprints repetidos (RSA), de jovens jogadores de futebol. Nove atletas de futebol da categoria infantil (15,0 ± 1,5 anos; 60,7 ± 4,84 kg; 1,72 ± 0,05 m; 20,5 ± 1,25 kg/m²) foram submetidos ao teste de RSA. O teste foi composto por seis sprints de 40 m (ida/volta = 20 m + 20 m), separados por 20 s de recuperação passiva com três condições experimentais: enxágue bucal com carboidrato (CHO) ou placebo (PLA) e controle (CON). O enxágue bucal com CHO ou PLA foi conduzido 5 min antes e imediatamente antes do início dos testes em doses de 100 mL. O tempo do melhor sprint (RSAbest), a média de tempo dos sprints (RSAmean) e o índice de fadiga (IF) foram determinados nas diferentes condições experimentais. ANOVA one-way para medidas repetidas não identificou diferenças significantes (P > 0,05) para RSAbest (CHO = 7,30 ± 0,31 s; PLA = 7,30 ± 0,30 s; CON = 7,26 ± 0,16 s), RSAmean (CHO = 7,71 ± 0,30 s; PLA = 7,71 ± 0,25 s; CON = 7,66 ± 0,24 s) e IF (CHO = 5,58 ± 2,16%; PLA = 5,77 ± 3,04%; CON = 5,55 ± 3,72%). Os resultados sugerem que o enxágue bucal com CHO não parece capaz de melhorar o desempenho, sobre sprints repetidos, de jovens jogadores de futebol.

Efeito da ingestão de cafeína sobre o desempenho físico e estado de humor de ciclistas / Effects of caffeine on performance and mood of cyclists

O objetivo do estudo foi analisar os efeitos da ingestão de cafeína sobre o desempenho físico e estado de humor de ciclistas em teste contrarrelógio de 1 km. Dez ciclistas do sexo masculino realizaram aleatoriamente um teste contrarrelógio de 1 km em duas condições experimentais: ingestão de cafeína (CAF - 6 mg.kg-1) e placebo (PL) 60 min antes do teste. Durante os testes foram obtidas as medidas de tempo total e estado de humor pelo questionário de Brunel (BRUMS). Para comparações dos parâmetros tempo total e estado de humor, foi utilizado o teste t de Student pareado e teste Wilcoxon, respectivamente. Nenhuma diferença estatisticamente significante foi encontrada no tempo total e no estado de humor nas condições CAF e PL (P>0,05). Os resultados sugerem que a cafeína não melhora o desempenho físico e nem altera o estado de humor dos atletas em um teste contrarrelógio de 1 km.

This study analyzed the effects of caffeine ingestion on physical performance and mood state of cyclists in a 1km time trial test. Ten male cyclists performed randomly a 1km time-trial test under two experimental conditions: Caffeine (CAF - 6 mg.kg-1) and placebo (PL) 60 min before the test. During the test were obtained the total time and the mood using the Brunel questionnaire (BRUMS). For comparisons of total time and mood states it was applied the paired Student's t-test and Wilcoxon test, respectively. No significant differences were found in the total time to complete tests and in the mood states between CAF and PL conditions (P>0.05). The results suggested that caffeine does not improve performance or change the mood of cyclists in a 1km time trial test.

Influência da música em variáveis psicofisiológicas durante um exercício submáximo em ciclossimulador / Music influence on psychophysiological variables during submaximal exercise in cycle simulator

O Colégio Americano de Medicina do Esporte (CAME) propõe algumas recomendações para a prática de atividade física na tentativa de aprimorar a saúde ou prevenir problemas crônicos degenerativos ao ser humano, dessa forma algumas estratégias ergogênicas podem auxiliar essa prática, entre elas o uso da música, capaz de possibilitar um melhor desempenho e menor percepção de esforço. Sendo assim, o objetivo deste estudo foi investigar o efeito da música em variáveis psicofisiológicas de adultos durante a prática de atividade física prescrita segundo as recomendações do CAME/AAC, (2007). Participaram deste estudo 10 voluntários saudáveis do sexo masculino (22,3 ± 1,8 anos, 175,0 ± 5,5 cm e 74,8 ± 11,0 Kg) que realizaram duas sessões experimentais de 30 minutos em ciclossimulador com intensidade correspondente a 60% da frequência cardíaca de reserva (FC Limiar de Treino), sobre duas condições: Música (M) e Controle (C). Foram avaliadas as variáveis: potência média (WMED), variabilidade da frequência cardíaca (VFC), percepção subjetiva de esforço (PSE) e o estado de humor (EH) dos participantes. Para as variáveis: PSE, WMED, VFC foi usado o teste de análise de variância (ANOVA ? two-way) para medidas repetidas, seguido do post-hoc de Bonferroni e para a variável EH foi usado o teste de Wilcoxon. O nível de significância estatística adotada nas análises foi de 5%. Nenhuma diferença estatisticamente significante foi encontrada para as variáveis WMED, VFC, PSE e EH dos participantes entre as condições M e C (P > 0,05). Conclui-se que a música não foi capaz de influenciar as medidas psicofisiológicas em esforço submáximo.

The American College of Sports Medicine and the American Heart Association (ACSM and AHA) bring some recommendations for the practice of physical activity with the intention of health increase or prevent diseases like degenerative problems on human, in this way some ergogenics strategies can help this practice, between them, the use of music, capable to enable a better performance and lower the perception of effort (RPE). Thus, the objective of this study was to investigate the effect of music in psychophysiological variables in adults during practice of physical activity following the recommendations of ACSM/AHA. Participated of this study 10 healthy volunteers from masculine genre (22.3 ± 1.8 years, 175.0 ±5.5 cm and 74.8 ± 11.0 Kg) that did two experimental session with 30 minutes in a cyclesimulator with intensity corresponding to 60% of the heart reserve rate (HR training threshold), in two conditions: with music (M) and control (C). Was evaluated the variables: power output (WMED), heart rate variability (HRV), rate perception of effort (RPE) and mood status (MS) of volunteers. For the variables RPE, WMED, HRV was used the variance analyses test (ANOVA ? two way) for repeated measures followed by the post hoc of Bonforreoni and the Wilcoxon?s test was used to compare the ME. The level of statistical significance was 5%. No differences were found in any variables WMED, HRV, RPE e MS of participants between conditions M and C (P > 0.05). Concluded that music don?t was capable to change psychophysiological measures in submaximal effort.

Relação entre variabilidade da frequência cardíaca e aumento no desempenho físico em jogadores de futebol / The correlation between heart rate variability and improvement in soccer player's physical performance

O objetivo deste estudo foi analisar se a variabilidade da frequência cardíaca (VFC) analisada no período inicial da pré-temporada de futebol apresenta relação com a melhora do desempenho físico ao longo deste período. Dez jogadores de futebol fizeram parte da amostra. O desempenho foi analisado através dos seguintes testes: Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1), sprint de 30 m e salto vertical, aplicados antes e após seis semanas da pré-temporada. As medidas de VFC foram realizadas em repouso, na posição supina, durante dez minutos. O teste de Spearman foi usado para investigar as possíveis relações entre VFC e melhora no desempenho e o teste T de Student para verificar as mudanças no desempenho e na VFC. A inferência prática baseada em magnitudes (analise qualitativa) foi aplicada para verificar as chances dos valores encontrados serem positivos, irrelevantes e negativos. Houve melhora significante do desempenho para o Yo-Yo IR1 (P< 0,001) e Sprint de 30 m (P< 0,001). A análise qualitativa revelou que a mudança do desempenho no Yo-Yo IR1 foi "muito provavelmente positiva", para o Sprint de 30 m foi "quase certamente positiva" e para o salto vertical foi "inconclusiva". Houve forte correlação entre um índice parassimpático da VFC e a variação no desempenho [r = 0,85; P = 0,003 (IC95% =0,49 - 0,97)]. Em conclusão, esse estudo mostrou uma correlação forte entre índices parassimpáticos da VFC analisados antes do treinamento, com a melhora do desempenho no Yo-Yo IR1 durante a pré-temporada em atletas de futebol.

The aim of this study was to analyze whether the heart rate variability (HRV), assessed at the beginning of a soccer preseason, reveals a correlation with the improvement of physical performance over this training period. Ten soccer players took part in the study. Their performance was evaluated by the following tests: the Yo-Yo intermittent recovery test, Level 1(Yo-Yo IR1); the 30-m sprint time, and the vertical jump; all were conducted before and after six weeks of pre-season. The HRV measurements were performed at rest in the supine position for ten minutes. The Spearman Rank Correlation test was used to investigate any possible relationship between HRV and improvements in performance, while the Student's t-test verified the changes in both performance and HRV. The Magnitude-Based Inferences approach (qualitative analysis) was applied to verify the possibilities of the observed values being positive, negative or inconclusive. There were significant improvements in Yo-Yo IR1 performance (P< 0.001) and in the 30-m sprint time (P< 0.001). The qualitative analysis revealed that the differences in Yo-Yo IR1 performance were very likely positive, were almost certainly positive for the sprint, but were inconclusive for the vertical jump. There was a strong correlation between one parasympathetic index and the change in performance [r = 0.85 P = 0.003 (IC95% = 0.49 - 0.97)]. In conclusion, this study revealed a strong correlation between parasympathetic indices of HRV (analyzed before the training) with the performance improvement in Yo-Yo IR1 in football athletes during pre-season.

EMG spectral analysis of incremental exercise in cyclists and non-cyclists using Fourier and Wavelet transforms / Análise espectral do sinal emg de exercício incremental em ciclistas e não ciclistas usando as transformadas de Fourier e Wavelet

The aim of this study was to compare the electromyographic indices of fatigue (slope of median frequency) calculated with the fast Fourier transform (FFT) and wavelet transform (WT) in trained and untrained individuals during cycle exercise. A second objective was to compare the variance of the spectral parameters (median frequency - MF) obtained by the FFT and WT during exercise. Twelve cyclists and non-cyclists performed a maximal incremental test to determine the peak power (Wp) and electromyographic activity of the vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF), semitendinous (ST) and tibialis anterior (TA). Mean values of median frequency, determined by the FFT and WT, were used for the spectral analysis of the electromyographic signals of the studied muscles. The analyzed parameters were obtained for each time period corresponding to 0, 25, 50, 75, and 100% of total duration of the maximal incremental test. No statistically significant differences were found in the values of MF and electromyographic indices of fatigue between the two techniques (FT and WT) both in the cyclists and non-cyclists group (P>0.05). Regarding the MF variance, statistically significant differences were found in all analyzed muscles, as well as in different time periods, both in the cyclists and non-cyclists groups when comparing the FFT and WT techniques (P<0.05). The WT seems to be more adequate to dynamic tasks, since it does not require the signal to be quasi-stationary, unlike the limitation imposed upon the use of the FFT.

O objetivo deste estudo foi comparar índices de fadiga eletromiográfica (inclinação da frequência mediana), calculado com a transformada rápida de Fourier (FFT) e transformada de wavelet (WT) em indivíduos treinados e não treinados durante o exercício de ciclismo. Um segundo objetivo foi o de comparar a variância dos parâmetros espectrais (frequência mediana - MF), obtidos por FFT e WT durante o exercício. Doze ciclistas e doze não ciclistas realizaram um teste incremental máximo, para determinar a potência pico (Wp) e atividade eletromiográfica do vasto lateral (VL), reto femoral (RF), bíceps femoral (BF), semitendíneo (ST) e tibial anterior (TA). Os valores médios da frequência mediana determinados pelo FFT e WT, foram utilizados para a análise espectral dos sinais eletromiográficos dos músculos estudados. Os parâmetros avaliados foram obtidos para cada período de tempo correspondente a 0, 25, 50, 75 e 100% da duração total do teste incremental máximo. Nenhuma diferença estatisticamente significativa foi encontrada nos valores da MF e índices eletromiográficos de fadiga entre as duas técnicas utilizadas (FT e WT), em ambos os grupos, ciclistas e não ciclistas (P> 0,05). Quanto à variância da MF, as diferenças estatisticamente significativas foram encontradas em todos os músculos analisados, bem como em diferentes períodos de tempo, tanto nos ciclistas quanto nos não ciclistas, quando se compara as técnicas FFT e WT (P <0,05). A WT parece ser mais adequada para tarefas dinâmicas, uma vez que não requer que o sinal a ser quase estacionário, ao contrário da limitação imposta ao uso da FFT.