Effect of temperature for cooling leg on intermittent exercise performance during half-time in a hot environment / 体力科学

Intermittent exercise performance in a hot environment is lower than in temperate conditions. Cooling strategies at rest are important; however, the appropriate cooling temperature is not clear. The purpose of this study was to investigate the effect of temperature for cooling leg during half-time (HT) on intermittent exercise performance. Eleven men performed two pre-tests and three experimental trials of a 2 × 30 min intermittent exercise protocol in the heat (33°C; 50% relative humidity). During HT, three experimental conditions were set: no cooling (CON), cooling at the thigh using 12°C ice packs (COOL), and cooling at the thigh using 0°C ice packs (ICE) for 15 min. During the 2nd half, which consisted of 5 s maximal power pedaling every minute separated by 50 s of unloaded pedaling (80 rpm) and rest (5 s), the subjects repeated 2 × 15 sets of the intermittent exercise protocol. The peak power output under the COOL condition (694 ± 80 W) was significantly higher than that of the CON (653 ± 84 W). Thigh skin and deep temperatures showed a significant difference between each condition. In the COOL, thermal sensation was significantly lower, and thermal comfort was significantly higher. In a protocol that simulates intermittent athletic competitions such as soccer in a hot environment, using ice packs at 12°C to cool the thigh during HT lowered thigh skin and deep temperatures and improved heat perception and intermittent exercise performance. This cooling strategy is practical, suggesting that it would be effective for actual competitive situations.

The peak velocity of Carminatti's Test for aerobic-fitness training in male soccer players / O pico de velocidade do Teste de Carminatti para treinamento aeróbio em jogadores de futebol

Abstract Aerobic energy transference is highly required and accounts for more than 90% of total energy consumption during a soccer match. In addition high aerobic fitness contributes to recovery from high-intensity intermittent exercise, specific to performance in soccer. The aim of the present study was to examine whether the peak velocity in the Carminatti's test (PVT-CAR) for prescribing interval-training drills is effective in eliciting aerobic-fitness development intensities in male soccer-players. Fifteen Brazilian male elite soccer-players (U20) were tested for T-CAR and monitored for heart rate (HR) during PVT-CAR prescribed interval-training drills (i.e., 4x4min with 3min passive recovery). Drills were performed with a 1:1 work-to-rest ratio with either straight-line (6/6s) or 180° shuttle running (12/12s). The interval training performed at PVT-CAR elicited HR above 90% of HRmax and lactate above 4m.mol.l-1. In the shuttle-running drills, HR and lactate (93.3±2.1% HRmax; 7.7±1.4 m.mol.l-1) were significantly higher than in the straight line drills (vs 90.3±2.6 %HRmax; 4.5±0.9 m.mol.l-1). The coefficient of variations showed low inter-subject variability in HR (CV 2.3 and 3.0% for 12/12 and 6/6 respectively). The results of this study demonstrated that PVT-CAR can be successfully used to individualize high-intensity interval running training in players with different aerobic profiles, while shuttle-running drills presented higher values at intern load than straight line. The physiological and time-motion profiles resemble the most demanding phases of the match, especially for the fittest players.

Resumo A transferência de energia aeróbia é altamente necessária e representa mais de 90% do consumo total de energia durante um jogo no futebol. Ademais, a alta aptidão aeróbia contribui para a recuperação durante exercício intermitente de alta intensidade, específico do desempenho do futebol. O objetivo deste estudo foi examinar se o pico de velocidade no teste de Carminatti (PVT-CAR) para a prescrição de treino intervalado é funcional na obtenção de desenvolvimento de aptidão aeróbia em jogadores de futebol. Quinze jogadores de futebol brasileiros (Sub-20) foram testados no T-CAR e monitorados por freqüência cardíaca (FC) durante o treinamento intervalado prescrito por PVT-CAR (ou seja, 4x4min com recuperação passiva de 3min). Os treinos foram realizados com uma relação de trabalho e repouso de 1:1 com corrida em linha reta (6/6s) e corrida de 180° com mudança de direção em vai-e-vem (12/12s). O treinamento intervalado prescrito com PVT-CAR induziu respostas de FC acima de 90% de FCmax, lactato superior a 4m.mol.l-1. uOs resultados de FC e lactato no treinamento de corrida com mudança de direção (93,3±2,1% FCmax; 7,7±1,4 m.mol.l-1) foram significativamente maiores que no treino de corrida em linha (vs 90,3±2,6 %FCmax; 4,5±0,9 m.mol.l-1). O coeficiente de variação mostrou baixa variabilidade inter-sujeitos na frequência cardíaca (CV 2,3 e 3,0% para 12/12 e 6/6, respectivamente). Os resultados do estudo mostraram que o PVT-CAR pode ser utilizado com sucesso para individualizar o treinamento de corrida intervalado de alta intensidade em jogadores com diferentes perfis aeróbicos. Os perfis fisiológicos e momentos de demandas se assemelham às fases mais exigentes da partida, especialmente para os jogadores melhor condicionados.

Running economy in elite soccer and futsal players: differences among positions on the field / Economia de corrida em jogadores de futebol e futsal de elite: diferenças entre as posições em campo

OBJECTIVE: To determine running economy in a large sample of elite soccer and futsal players to obtain benchmarks in different positions. METHODS: Running Economy is the energy demand at a submaximal running velocity. Players were divided into 6 subgroups. Soccer: defenders, midfielders, and strikers; futsal: defenders, wingers, and pivots. Elite soccer players (n=129) and elite futsal players n=72 performed an incremental running test starting at 8.4 km.h-1 with increments of 1.2 km.h-1 every two minutes on a treadmill until exhaustion. Running Economy was determined by interpolation between ventilatory thresholds 1 and 2 (VT1 and VT2). RESULTS: Running Economy (measured as mL.kg-1.km-1) was compared between the playing positions in the two team sports. In soccer, running economy was 222.7 (defenders), 227.0 (midfielders), and 219.8 (strikers) mL.kg-1.km-1, respectively. In futsal, the corresponding values were 198.5 (defenders), 196.9 (wingers), and 190.5 (pivots) mL.kg-1.km-1, respectively. We no found significantly differences between the three positions in both sports. The Running Economy of futsal players was 12.5% better than that of soccer players. Running Economy correlated positively with oxygen uptake at VT2 in both sports and in all positions. CONCLUSION: Futsal players exhibited better Running Economy than soccer players; this should be considered as a factor in the athlete's training plan.

OBJETIVO: Determinar a Economia de Corrida numa grande amostra de jogadores de futebol e futsal de elite em diferentes posições do campo. METODOS: Os jogadores foram subdivididos em três subgrupos: futebol (jogadores de defesa, meio-campistas e atacantes) e futsal (jogadores de defesa, alas e pivôs). Foram 129 jogadores de futebol e 72 jogadores de futsal, que competem nas respectivas primeiras divisões do Brasil. Os jogadores foram submetidos a teste de esforço em esteira (8,4 km-1.h+1,2km-1.h a cada dois minutos) até a exaustão. Consumo máximo de oxigênio, limiares ventilatórios e Economia de Corrida foram registrados por análise de troca gasosa respiratória. A Economia de Corrida foi determinada por interpolação utilizando as velocidades dos limiares ventilatórios 1 e 2 e o consume de oxigênio nas duas velocidades. RESULTADOS: Os valores de Economia de Corrida entre as posições nos dois esportes foram os seguintes: Futebol, jogadores de defesa (222,7±16,7mL.kg-1.km-1), meio-campistas (227±19,9mL.kg-1.km-1), e atacantes (219,8±17,2mL.kg-1.km-1). Futsal, jogadores de defesa (198,5±10,8mL.kg-1.km-1), alas (196,9±16,2mL.kg-1.km-1), e pivôs (190,5±11,8mL.kg-1.km-1). Não foram encontradas diferenças significativas entre as três posições em ambos os esportes. A Economia de Corrida dos jogadores de futsal foi 12,5% melhor do que dos jogadores de futebol. Neste estudo, os jogadores da posição pivô no futsal tiveram os melhores valores de Economia de Corrida (custo de oxigênio mais baixo). Embora o consumo máximo de oxigênio (VO2max) e o limiar ventilatório 2 (LV2) fosse maior nos jogadores de futebol, a Economia de Consumo foi pior. Esta correlacionou-se positivamente com o VO2 no LV2 em ambos os esportes e em todas as posições CONCLUSÃO: Futsal tem melhor Economia de Consumo do que futebol. O presente estudo aponta a importância dos índices Economia de Consumo no plano de treinamento físico dos atletas.

The Concepts Change of Exercise Intensity for Obesity

As being obesity is associated with numerous health problems, effective fat loss strategies are required. Although dieting has been the major fat loss method, aerobic exercise programs have been shown to increase cardiorespiratory fitness and preserve fat-free mass. Most aerobic exercise interventions have consisted of moderate-intensity steady-state exercise. Disappointingly, these kinds of exercise programs have resulted in minimal fat loss. In contrast, high-intensity intermittent exercise (HIIE) has been shown to result in greater fat loss. Accumulating evidence suggests that high intensity intermittent exercise (HIIE) has the potential to be an economical and effective exercise protocol for reducing fat of overweight individuals, especially Tabata workout and Crossfit.

Vertical jump fatigue does not affect intersegmental coordination and segmental contribution / Fadiga em salto vertical não afeta a coordenação intersegmental e contribuição segmental / Fatiga salto vertical no afecta a la coordinación entre segmentos y la contribución segmentaria

The aim of this study was to describe the intersegmental coordination and segmental contribution during intermittent vertical jumps performed until fatigue. Seven male visited the laboratory on two occasions: 1) the maximum vertical jump height was determined followed by vertical jumps habituation; 2) participants performed intermittent countermovement jumps until fatigue. Kinematic and kinetic variables were recorded. The overall reduction in vertical jump height was 5,5%, while the movement duration increased 10% during the test. The thigh segment angle at movement reversal significantly increased as the exercise progressed. Non-significant effect of fatigue on movement synergy was found for the intersegmental coordination pattern. More than 90% of the intersegmental coordination was explained by one coordination pattern. Thigh rotation contributed the most to the intersegmental coordination pattern, with the trunk second and the shank the least. Therefore, one intersegmental coordination pattern is followed throughout the vertical jumps until fatigue and thigh rotation contributes the most to jump height...

"Fadiga em salto vertical não afeta a coordenação intersegmental e contribuição segmental." O objetivo deste estudo foi descrever a coordenação entre segmentos e suas contribuições durante saltos verticais intervalados realizados até a fadiga. Sete indivíduos visitaram o laboratório em duas ocasiões: 1) foi determinada a altura máxima do salto vertical e realizada familiarização com saltos verticais; 2) participantes realizaram saltos verticais em contramovimento até a fadiga. Foram coletadas variáveis cinemáticas e cinéticas. A altura do salto vertical reduziu 5,5% e duração do movimento aumentou 10%. O ângulo da coxa no instante de reversão do movimento aumentou durante o exercício. A fadiga na sinergia do movimento não influenciou na coordenação intersegmental. Acima de 90% da coordenação entre segmentos foi explicada por um padrão coordenativo. A rotação da coxa foi o que mais contribuiu com o padrão coordenativo, seguido pelo tronco e perna. Portanto, em saltos verticais realizados até a fadiga, a coordenação intersegmental é mantida e a rotação da coxa tem maior contribuição na altura do salto...

"Fatiga salto vertical no afecta a la coordinación entre segmentos y la contribución segmentaria." El objetivo fue describir la coordinación entre los segmentos y sus contribuciones durante los saltos verticales realizadas hasta la fatiga. Siete sujetos visitaron laboratorio dos ocasiones: 1) determinó la máxima altura en el salto vertical y amistad con los saltos verticales; 2) participantes completaron saltos verticales contramovimento la fatiga. Se recogieron las variables cinemáticas y cinéticas. La altura del salto vertical disminuyó 5,5% y la duración del movimiento se incrementó 10%. El ángulo del muslo en instante de inversión del movimiento aumentó durante ejercicio. No hubo efecto de fatiga en sinergia de movimiento para la coordinación de movimientos. Más del 90% de coordinación entre sectores ha sido explicado por un patrón coordinativo. La rotación del muslo fue mayor contribuyente la coordinación de movimientos, seguido por tronco y piernas. En los saltos verticales realizados hasta la fatiga se mantiene coordinación entre segmentos y rotación del muslo tiene mayor contribución en altura del tacón...

Exercicio Aerobio Intervalado Induz Maior Reducao na Sobrecarga Cardiaca na Recuperacao em Ratos / Aerobic Interval Exercise Training Induces Greater Reduction in Cardiac Workload in the Recovery Period in Rats

Fundamento: O treinamento aeróbio intervalado produz maior benefício na função cardiovascular comparado ao treinamento aeróbio contínuo. Objetivo: O presente estudo teve como objetivo analisar os efeitos de ambas as modalidades nas respostas hemodinâmicas de ratos sadios. Métodos: Ratos machos foram distribuídos aleatoriamente em três grupos: exercício contínuo (EC, n = 10); exercício intervalado (EI, n = 10); e controle (C, n = 10). A sessão do grupo EC consistiu em 30 min à intensidade de 50% da velocidade máxima (Vel Máx). O grupo EI realizou 30 min, incluindo três períodos de 4 min a 60% da Vel Máx intercalados com 4 min de recuperação a 40% da Vel Máx. Frequência Cardíaca (FC), Pressão Arterial (PA) e Duplo Produto (DP) foram medidos antes, durante e após o exercício. Resultados: Os grupos EC e EI apresentaram aumento da PA sistólica e DP durante o exercício em comparação ao repouso. Após o término do exercício, o grupo EC mostrou menor resposta da PA sistólica e do DP em relação ao repouso, enquanto o grupo EI apresentou menor PA sistólica e PA média. No entanto, somente no grupo EI a FC e o DP apresentaram menor resposta na recuperação. Conclusão: Uma sessão de exercício intervalado em ratos sadios induziu respostas hemodinâmicas similares durante o exercício às obtidas em exercício contínuo. Na recuperação, o exercício intervalado promoveu maiores reduções no esforço cardíaco do que em sessões contínuas de exercício. .

Background: Aerobic interval exercise training has greater benefits on cardiovascular function as compared with aerobic continuous exercise training. Objective: The present study aimed at analyzing the effects of both exercise modalities on acute and subacute hemodynamic responses of healthy rats. Methods: Thirty male rats were randomly assigned into three groups as follows: continuous exercise (CE, n = 10); interval exercise (IE, n = 10); and control (C, n = 10). Both IE and CE groups performed a 30-minute exercise session. The IE group session consisted of three successive 4-minute periods at 60% of maximal velocity (Max Vel), with 4-minute recovery intervals at 40% of Max Vel. The CE group ran continuously at 50% of Max Vel. Heart rate (HR), blood pressure(BP), and rate pressure product (RPP) were measured before, during and after the exercise session. Results: The CE and IE groups showed an increase in systolic BP and RPP during exercise as compared with the baseline values. After the end of exercise, the CE group showed a lower response of systolic BP and RPP as compared with the baseline values, while the IE group showed lower systolic BP and mean BP values. However, only the IE group had a lower response of HR and RPP during recovery. Conclusion: In healthy rats, one interval exercise session, as compared with continuous exercise, induced similar hemodynamic responses during exercise. However, during recovery, the interval exercise caused greater reductions in cardiac workload than the continuous exercise. .

Acute effects of resistance exercise and intermittent intense aerobic exercise on blood cell count and oxidative stress in trained middle-aged women

The aim of this study was to compare the effect of an intermittent intense aerobic exercise session and a resistance exercise session on blood cell counts and oxidative stress parameters in middle-aged women. Thirty-four women were selected and divided into three groups: RE group (performing 60 min of resistance exercises, N = 12), spinning group (performing 60 min of spinning, N = 12), and control group (not exercising regularly, N = 10). In both exercise groups, lymphocytes and monocytes decreased after 1-h recuperation (post-exercise) compared to immediately after exercise (P < 0.05). Immediately after exercise, in both exercised groups, a significant increase in TBARS (from 16.5 ± 2 to 25 ± 2 for the spinning group and from 18.6 ± 1 to 28.2 ± 3 nmol MDA/mL serum for the RE group) and protein carbonyl (from 1.0 ± 0.3 to 1.6 ± 0.2 for the spinning group and from 0.9 ± 0.2 to 1.5 ± 0.2 nmol/mg protein for the RE group) was observed (P < 0.05). A decrease in antioxidant activities (non-protein sulfhydryl, superoxide dismutase, catalase) was also demonstrated with a negative correlation between damage markers and antioxidant body defenses (P < 0.05). These results indicate that an acute bout of intermittent or anaerobic exercise induces immune suppression and increases the production of reactive oxygen species, causing oxidative stress in middle-aged and trained women. Furthermore, we demonstrated that trained women show improved antioxidant capacity and lower oxidative damage than sedentary ones, demonstrating the benefits of chronic regular physical activity.

Efeito da recuperação na máxima fase estável de lactato sanguíneo / Effect of recovery on the maximal lactate steady state

O objetivo deste estudo foi comparar a potência correspondente à máxima fase estável de lactato sanguíneo determinada de forma contínua (MLSSC) e intermitente com recuperação ativa (MLSSI). Dez ciclistas treinados do sexo masculino (25 ± 4 anos; 72,5 ± 10,6 kg e 178,5 ± 4,0 cm), realizaram os seguintes testes, em um cicloergômetro: 1) incremental até a exaustão voluntária para a determinação da potência máxima (Pmax); 2) dois a cinco testes submáximos de carga constante para determinar a MLSSC, e; 3) dois a três testes submáximos de carga constante, consistindo de oito repetições de quatro minutos, com dois minutos de recuperação a 50% Pmax para determinar a MLSSI. A MLSSC (273,2 ± 21,4 W) foi significantemente menor do que a MLSSI (300,5 ± 23,9 W). Com base nestes resultados, verifica-se que o modelo de exercício intervalado utilizado permite um aumento de aproximadamente 10% na intensidade correspondente à MLSS.

The objective of this study was to compare the power corresponding to maximal lactate steady state determined through continuous (MLSSC) and intermittent protocol with active recovery (MLSSI). Ten trained male cyclists (25 ± 4 yr., 72.5 ± 10.6 kg, 178.5 ± 4.0 cm), performed the following tests on a cycle ergometer: (1) incremental test until voluntary exhaustion to determine the maximal power (Pmax); (2) two to five constant workload tests to determine MLSSC, and; 3) two to three constant workload tests to determine MLSSI, consisting on eight repetitions of four minutes interspersed by two minutes of recovery at 50% Pmax. The MLSSC (273.2 ± 21.4 W) was significantly lower than MLSSI (300.5 ± 23.9 W). With base on these data, it can be verified that the intermittent exercise mode utilized in this study, allows an increase of 10% approximately, in the exercise intensity corresponding to MLSS.

The influence of intense intermittent versus moderate continuous exercise on postprandial lipemia

INTRODUCTION: Postprandial lipemia is characterized by an increased concentration of circulating lipids after fat intake and is an independent risk factor for cardiovascular disease. Exercise is known to reduce postprandial lipemia and its negative clinical outcomes. OBJECTIVE: This study investigated the effect of intense intermittent versus moderate continuous exercise using the same energy expenditure in postprandial lipemia. MATERIALS AND METHODS: Twenty healthy men (aged 21.5 + 3.5 years) performed a random sequence of either rest or 500 Kcal tests separated by a minimum 48 h interval as follows: (a) no exercise (control), (b) intense intermittent exercise, or (c) moderate continuous exercise. Each test series was completed 30 min before ingestion of a high-fat meal (1 g fat/kg). Venous blood was collected before and at 1, 2, 3 and 4 hours after the high-fat meal. Postprandial lipemia was assessed using the area under the curve approach as well as a kinetic profile of mean lipid variables. Statistical significance was tested at the p<0.05 level. RESULTS: With both statistical approaches, intense intermittent and moderate continuous exercises were both effective in reducing postprandial triglycerides; however, only intense intermittent exercise reduced the levels of postprandial very low density lipoprotein. Intense intermittent and continuous exercise produced lower levels of insulinemia using the area under the curve analysis only. CONCLUSION: Intense intermittent or continuous exercise with an energy expenditure of 500 kcal completed 30 min before ingestion of high-fat meal reduced postprandial lipid levels to different levels in physically active men. Understanding these relevant differences will enable clinicians to provide the best exercise prescription for patients.

Comportamento da frequência cardíaca durante uma sessão de surfe / Heart rate behavior during a surfing session

O objetivo do estudo foi determinar o comportamento da frequência cardíaca durante uma sessão de surfe, a média total, a média dentro de cada fase do padrão de movimento e o porcentual da frequência cardíaca máxima. Fizeram parte da amostra sete homens com respectivas médias de massa corporal, estatura, idade e tempo de prática de 77,57 ± 3,21 (kg), 176,3 ± 8,14 (cm), 24,71 ± 4,82 (anos) e 9,86 ± 3,02 (anos). A frequência cardíaca foi monitorizada com utilização de um frequencímetro marca Polar, modelo S610i em intervalos de cinco segundos durante uma sessão de vinte minutos de surfe, realizada na praia do Rosa – Imbituba (SC), filmada com uma câmera de vídeo marca JVC, modelo GR-SXM289UB. Foram avaliados os porcentuais de tempo e frequência cardíaca média em cada uma das fases do padrão de movimento pré-estabelecido, e média total. A frequência cardíaca média da sessão foi 143,94 ± 13,18 (bpm), e as médias da frequência cardíaca durante as fases de movimento onda, parado, remando e outros movimentos foram, respectivamente de 157,10 ± 14,81, 127,58 ± 8,86, 151,93 ± 10,73 e 141,08 ± 18,34 (bpm). A média da frequência cardíaca da sessão correspondeu a 78,91% da frequência cardíaca máxima dos participantes. A intensidade de uma sessão de surfe pode ser considerada moderada e a fase onda do padrão de movimento no surfe possui a média de frequência cardíaca mais elevada. Palavras chave: surfe, frequência cardíaca e exercício intermitente.

The objective of the study was determine the behavior of the cardiac frequency during a session of surfi ng, on average total, on average inside each phase of the standard of movement and the percentage of the maximum cardiac frequency. They were part of the sample seven men with respective medium of corporal mass, stature, age and time of practice of 77.57 ± 3.21 (kg), 176.3 ± 8.14 (cm), 24.71 ± 4.82 (years) and 9.86 ± 3.02 (years). The cardiac frequency was monitored with utilization of a frequencímetro marks Polar, model S610i in breaks of fi ve seconds during a session of twenty minutes of surfi ng, carried out in the beach of the Rose – Imbituba (SC), it fi lmed with a camera of video marks JVC, model GR-SXM289UB. They were evaluated the percentages of time and medium cardiac frequency in each one of the phases of the standard of movement pre-established, and medium total. The medium cardiac frequency of the session was 143.94 ± 13.18 (bpm), and the medium of the cardiac frequency during the wave movement phases, standstill, rowing and others movements were, respectively of 157.10 ± 14.81, 127.58 ± 8.86, 151.93 ± 10.73 and 141.08 ± 18.34 (bpm). On average of the cardiac frequency of the session corresponded to 78.91% of the cardiac frequency maxim of the participants. The intensity of a session of surfi ng can be considered moderated and the phase wave of the standard of movement in the surfi ng possessed on average of cardiac frequency more elevated.

THE COMPARISON OF POST EXERCISE OXYGEN CONSUMPTION BETWEEN TWO DIFFERENCE SUPRAMAXIMAL EXERCISES / 体力科学

Exercise intensity has been identified as a major determinant of the excess post-exercise oxygen consumption (EPOC). However, no studies have compared the prolonged EPOC after supramaximal intermittent exercise and supramaximal continuous exercise. Six young healthy male [age=26±3 (mean±SD) yr ; stature=175.4±5.7 cm ; body weight=66.8±6.7 kg ; maximal oxygen uptake (VO₂max)=44.1±8.5 ml/kg/min] xercised on separate days on a cycle ergometer at two equated total energy expenditures (intermittent exercise : 7×30-second intervals at 150%VO₂max with intervening 15-seconds rest periods ; continuous exercise : 5 min at 105%VO₂max) and then sat quietly in an armchair for 3h. A control trial without any exercise was also performed in a counterbalanced research design. The VO₂, carbon dioxide output (VCO₂), pulmonary ventilation (VE), respiratory exchange ratio (RER), heart rate (HR) and blood lactate concentration (LA) were measured before exercise, during exercise and during the 3-h recovery period. The mean VO₂ after intermittent trial at 150%VO₂max were higher than these of the control trial and the continuous trials at 105%VO₂max for 3-h recovery periods (p<0.05). The 3-h EPOC value for intermittent exercise trial (10.5±2.4L) was significantly greater than that of continuous exercise trial (4.8±2.7L) (p<0.05). The mean RER values for intermittent exercise trial were significantly lower than those of the control trial during 60-180 min post-exercise (p<0.05). We examined the effect of supramaximal exercise intensity on the magnitude of 3-h EPOC after 12-fasting. In the present study, 3-h EPOC was significantly greater for supramaximal intermittent exercise compared with the supramaximal continuous exercise when the amounts of work output performed are same. Therefore, our results indicate that exercise intensity may be a primary factor of 3-h EPOC even in a supramaximal exercise and that one of mechanisms for the 3-h EPOC would be related to the promoted lipid metabolism.

Effects of Amino Acid Supplementation of Endocrine Responses and Profile of Mood States During Intermittent Exercise for 24 Hours / 体力科学

The purpose of this study was to clarify the effects of amino acid supplementation on mental and physical stress during severe exercise. 20 male college students were assigned to amino acid treated group (group AA) and placebo treated group (group P), each containing 10 subjects, and performed 1600 m-run relay for 24 hours. Each subjects of AA group received 1 g of amino acid powder, containing 34% of branched-chain amino acid (BCAA), after each work bout. The score of rating of perceived exertion (RPE) and category rate of pain scale (CPS) for each work bout were recorded. Scoring of profile of mood states (POMS) was performed and blood samples were drawn at pre-, mid-, and post-session. Total running distance was similar in both groups. In group AA, compared with group P, (1) total score of RPE and CPS through 25 work bouts and plasma cortisol concentration (C) at post- was significantly lower, and (2) molar ratio of plasma free testosterone concentration (FTS) to C (FTS/C) at mid- was significantly greater. In group P alone, plasma BCAA concentration, FTS, FTS/C, and POMS score about ‘tension-anxiety’, ‘anger-hostility’ and ‘vigor’ decreased significantly over time. Our data suggest that BCAA administration during severe exercise may diminish mental or physical stress, inhibit FTS/C decrease and be effective in maintaining aggressive mentality.

The relationship between high power output during intermittent exercise and three energy delivery systems / 体力科学

This study investigated the relationship of high-power work capacity with physiological variables during supramaximal intermittent exercise and individually measured alactic (ATP-CP), lactic (LA), and oxygen (O<SUB>2</SUB>) energy delivery systems. Nineteen university handball players (experiment 1) and 23 university basketball players (experiment 2) performed an intermittent exercise routine consisting of a combination of high-power and low-power exercise. The exercise protocols were a laboratory test consisting of pedaling on a bicycle ergometer (experiment 1) and a field test consisting of a running protocol incorporating changes in direction (experiment 2) . The main results were as follows :<BR>(1) The ATP-CP system was significantly related to power output during the early stage of intermittent exercise and the O<SUB>2</SUB> system was significantly related to power output in the middle and late stages of intermittent exercise. As an indicator of the O2 system, blood lactate concentration during submaximal exercise correlated more closely with power output during intermittent exercise compared with VO<SUB>2</SUB>max/BW. The LA system was not significantly related to power output during intermittent exercise.<BR>(2) Subjects were divided into 2 groups according to energy delivery ability and then power output ability during intermittent exercise was compared. The high ATP-CP system group had a significantly higher power output during the early stage of intermittent exercise compared with the low ATP-CP system group. The high O<SUB>2</SUB> system group had a significantly higher power output in the middle and late stages of intermittent exercise compared with the low O<SUB>2</SUB> system group. Compared to the low O<SUB>2</SUB> system group, the high O<SUB>2</SUB> system group had a higher absolute VO<SUB>2</SUB> during the low intensity active recovery periods of intermittent exercise, as well as a tendency to have lower blood lactate levels. The high LA system group showed lower power output over the course of intermittent exercise compared with the low LA system group.<BR>These results indicate that the O<SUB>2</SUB> system is important for exerting higher power output during supramaximal intermittent exercise.

Metabolic and hormonal responses to prolonged intermittent exercise / 体力科学

The purpose of this study was to compare the influence of prolonged continuous (CON) and intermittent (INT) exercises on metabolic and hormonal responses in 8 male college students (age ; 23.0±0.5 yr, weight; 67.7±1.5 kg, VO<SUB>2</SUB>max ; 2.8±0.1 L/min, mean±SE) . Both trials consisted of two 40 min cycling bouts divided by a 5-min rest period. The intensity of INT was alternated every 4 min at low intensity (25% VO<SUB>2</SUB>max) and high intensity (75% VO<SUB>2</SUB>max), whereas the intensity of CON was maintained at 50% VO<SUB>2</SUB>max. Blood samples were collected before, and after 40 and 80 min of exercise, to determine blood lactate, serum glucose, FFA, insulin, plasma adrenaline and noradre-naline. Perceived exertion (RPE) was assessed at 40 and 80 min of exercise using the Borg scale. Although the changes in the concentration of plasma noradrenaline and serum insulin from basal values were similar in INT and CON, the degree of increase in plasma adrenaline during INT was significantly smaller than that during CON (90.5±16.6 vs. 152.8±27.0 pg/ml, p<0.05, after 80 min of exercise) . There was no difference in the change in the serum glucose level between the two trials. However, serum FFA in INT was significantly smaller than that in CON after 40 min (0.28±0.06 vs. 0.10±0.04 mEq/l, p<0.05) and 80 min (0.54±0.08 vs. 0.33±0.07 mEq/l, p<0.05) of exercise. RPE did not differ between the trials. These data indicate that even if performed total work and exercise duration are the same, metabolic and hormonal responses during prolonged intermittent exercise differ from those during continuous exercise.