INTERVAL TRAINING FOR SPRINT RUNNING: EFFECTS OF THE DURATION OF THE PAUSE ON RUNNING KINEMATICS AND BLOOD LACTATE

INTRODUCTION: The use of interval training for improving exercise performance reduces fatigue and enhances the muscular work done. That is why it has been recommended for sprint training. When studying high intensity, short term exercises of about 10 s, there were found to be decreases in performance and increases in lactate concentrations, specially when the recovery time was short (30 to 60s). Biomechanical changes due to fatigue have been studied mostly in long-distance running. The present work was designed to verify the possibility of identifying changes in running kinematics and blood lactate during sprint running with different recovery times during interval type training. METHODS AND PROCEDURES: Six individuals executed 3 series of 5 x 50m sprints at maximum velocity, with pauses of 30, 60 and 120 s respectively. For each individual there were collected: a) video images of the first, third and fifth sprint, using the panning technic through the complete course, with reference targets each 5 m. Velocity, stride lenght and rate were calculated for each 5 m section; b) blood samples for lactate analysis after the first, third, fifth sprint and at 1, 3, 5, 7 and 10 minutes of recovery. RESULTS AND DISCUSSION: With 30s pauses, there were decreases in velocity and stride rate and increases in stride lenght through the 5 repetitions, while during the 120 s pauses these differences were attenuated. There were no significant differences between the lactate concentrations at the different pause systems. The stride rate was found to be the most sensible variable for experimental conditions among those studied. The increases observed in stride lenght were sufficient to compensate the decreases in stride rate, thus maintaining the velocity, only when fatigue was not severe. At the 5th sprint, with 30s pause, stride lenght returned to values observed at the 1st sprint, thus reducing velocity to a greater extent. CONCLUSIONS: The fact that we could not identify significant changes in blood lactate concentrations between the different series of sprints may suggest that lactate concentration measurements are not efficient indicators of fatigue in this kind of exercise, as they are for others. Therefore, stride rate could be usefull for identifying fatigue when there are no significant decreases in velocity or changes in blood lactate concentrations

Critical velocity as a predictor of anaerobic threshold in swimming

Dentre as técnicas não invasivas de determinação do limiar anaeróbio (LAn) o método da velocidade crítica (Vcrit) tem merecido grande atenção. O presente estudo teve como objetivos verificar na natação se a Vcrit: a) corresponde ao LAn determinado pelo lactato sangüíneo e à intensidade do equilíbrio dinâmico máximo do lactato e b) é sensível ao treinamento. Um total de 48 nadadores de ambos os sexos foram sujeitos em três protocolos experimentais. No primeiro foi determinado LAn (3 x 200 m progressivos, lactato= 4mM) e a Vcrit resolvendo-se a equação: distância= a + b Vcrit, para tiros de 100 a 800 m. No segundo protocolo, foram coletadas amostras de sangue ao longo de 5 x 400 m a intensidades de 100, 102 e 104% da Vcrit. No terceiro protocolo a Vcrit foi determinada em duas fases distintas do treinamento. Os principais resultados foram: a) a correlação entre o LAn e a Vcrit foi de r = 0,890 (p < 0,05); b) a 100% da Vcrit o lactato permaneceu estável, tendo aumentado em 102 e 104% e c) o LAn e a Vcrit aumentaram significativamente com o treinamento. Esses resultados indicam que o método da Vcrit é um excelente estimador do LAnThe critical velocity (Vcrit) has been proposed to be an accurate method to estimate the anaerobic threshold (AT). The present study was designed in order to test in swimming: a) the correlation between the Vcrit and AT; b) whether the swimming at the Vcrit lead to maximal blood lactate steady-state and c) the sensibility of the Vcrit to a ordinal training program. Swimmers, who were trained for at least two years were submitted to the following tests: a) determination of Vcrit (maximal 100, 200, 400 and 800 m times) and AT (velocity at 4 mM blood lactate in 3 x 200 m progressive load); b) blood lactate concentrations BLa during 5 x 400 m at 100, 102 and 104% Vcrit; c) the Vcrit and AT were also determined before competitive period and after the tapering. There was a significant correlation between the Vcrit and AT (r = 0.890, p < 0.05) and both parameters increased after training period (Vcrit from 1.226 ± 0.096 to 1.321 ± 0.103 m.s'1 and AT form 1.225 ± 0.103 to 1.312 + 0.108 m.s’1). BLa did not increase in 5 x 400 m 100% Vcrit trial (2.21 ± 0.86 mM at the 1st and 2.68 ± 1.05 mM last) but increased from 2.90 ± 0.61 mM to 4.10 ± 0.71 mM at 102% Vcrit. These results showed that the Vcrit is a good predictor of the AT in swimmin

Relações entre a intensidade e duração das atividades em partida de basquetebol com as capacidades aeróbica e anaeróbica: estudo pelo lactato sangüíneo

Os esportes com bola se caracterizam pela alternância de períodos de atividades de curta duração e alta intensidade intercalados com períodos de recuperação. Neste tipo de exercício, o metabolismo anaeróbico é considerado predominante, porém, o seu grau de solicitação depende da distribuição dessas atividades ao longo da partida. Com o propósito de caracterizar o perfil da atividade e a relação com o metabolismo predominante em partida, jogadores de uma equipe de basquetebol foram submetidos a teste de campo para avaliação do condicionamento anaeróbico (5 x 30 m em velocidade máxima com 1 minuto de pausa) e aeróbico (limiar de lactato, 4 mM em 3 x 1200 m progressivos). Em três partidas foram determinados o lactato sangüíneo, e através de videotape, a distribuição da duração de atividades de alta e baixa intensidade. Durante as partidas o lactato sangüíneo atingiu valores de 2,68 — 1,30 mM, e foi significativamente correlacionado (p < 0,05) com a duração das atividades de baixa intensidade e longa duração (superior a 3") (63,4 — 3,5 %, r = -0,451), alta intensidade e curta duração (inferior a 3”) (11,2 - 1,4 %, r = 0,477) e alta intensidade e longa duração (10,4 —1,1 %, r = 0,900). Houve correlação significativa também entre o lactato médio em partida com o tempo médio (4,28 — 0,24 s, r = -0,758) e lactato (5,15 - 1,42 mM, r = 0,645) nos tiros de 30 m. Esses resultados indicam que durante a partida de basquetebol há predominância do metabolismo anaeróbico alático e que nos períodos de interrupção do jogo, há possibilidade de remoção do lactato circulanteThe ball games represent intermittent work with frequent interchange of short bursts of physcial effort interspaced with pauses. For this reason they are generally considered anaerobic type activities. However, the extent of anaerobic yield is highly correlated with the effort:relief ratio pattern. The present study was designed in order to investigate the metabolic profile of basketball game, particullary the extent of the anaerobic metabolism, and its relation with the intensity of the activities during a game and the aerobic and anaerobic condition of the player. Basketball players (n =14) were evaluated in a set of field test consisted with: a) anaerobic capacity, 5 x 30 m at maximal running speed, with 1 min rest and b) aerobic capacity expressed as a anaerobic threshold (blood lactate = 4 mM 3 x 1200 m graded field test). Three games were videotaped and the duration of high and low intensity activities were determined. Additionally blood samples were obtained at the end of the game for lactate analysis (YSL 2300, Yellow Spring Co, USA). The blood lactate during the games (2.68 — 1.30 mM) was significantly correlated with the duration of the long term (more than 3 s) low intensity activities (63.4 - 3.5 %, r = - 0.451), the short term (less than 3 s) high intensity activities (11.2 — 1.4 %, r = 0.477) and long term high intensity activities (10.4 — 1.1 %, r = 0.900). Significant correlations were also found between the game blood lactate and the mean running time (4.28 -1 0.24 s, r = - 0.758) and blood lactate (5.15 — 1.42 mM, r = 0.645) in the 30 m dashes. These findings showed that the anaerobic alatacid metabolism is the main energy source for the basketball game. Additionally, the blood lactate are removed during the light activities which interspace the high intensity bursts of effort

Brazilian soccer players and no-players adolescents: effect of the maturity status on the physical capacity components performance

The aim of this study was to compare the speed and the agility between Brazilian soccer players and non-players, regarding maturity status in adolescents 11-15 years old. Forty and two soccer players (age – 159.30±17.28 months old; weight – 48.45±9.96 kg; height – 1.53±0.10 m) and 45 non-players (age – 162.62±24.92 months old; weight – 48.30±8.35 kg; height – 1.54±0.12 m) participated of this study. Participants were classified by maturity status. On 2 different days with 1 week of differences between the assessments the participants were evaluated the agility, by Shuttle Run test, and the speed, by 30 m maximum speed test. The results showed that the maturity status was an influential factor in the performance with better results for individuals in a more advanced stage. The soccer practice does not seem to interfere in the performance of the physical capacity components analyzed, only effective when different maturity levels are involved in the analysis. It is also possible that late maturing boys selectively drop-out of soccer as age and sport specialization increase

Treinamento intervalado de corrida de velocidade: efeitos da duração da pausa sobre o lactato sanguíneo e a cinemática da corrida

A realização de exercícios intervalados reduz a fadiga e aumenta o trabalho muscular realizado, razão pela qual tem sido recomendada como método de treinamento de velocidade. Em estudos que trataram de exercício de alta intensidade e duração de até aproximadamente 10 s, observou-se decréscimo rápido na performance e aumento do lactato, especialmente quando a recuperação é curta (30 a 60 s). As mudanças biomecânicas devidas à fadiga tem sido estudadas somente em exercícios de maior duração e intensidade menor, especialmente em corridas de fundo e meio-fundo. O presente estudo pretendeu verificar a possibilidade de identificar mudanças cinemáticas e no lactato sanguíneo em corridas de máxima velocidade, em diferentes regimes de pausa, no treinamento intervalado. Seis sujeitos executaram 3 séries de 5 tiros de 50 m, em máxima velocidade, com regimes de pausa de 30, 60 e 120 s respectivamente. Para cada sujeito foram coletados: a) após o primeiro, terceiro e quinto tiros e aos 1, 3, 5, 7 e 10 min de recuperação amostras de sangue para análise de lactato sanguíneo por método eletroquímico; b) imagens em vídeo do primeiro, terceiro e quinto tiros utilizando-se a técnica de "panning" acompanhando toda a corrida, com marcas de referência colocadas a cada 5 m. Foram extraídas a velocidade, a frequência e a amplitude de passadas, para cada trecho de 5 metros. Não houve diferença significativa entre as concentrações de lactato nos diferentes regimes de pausa. Contudo, com pausas de 30 s, houve diminuição da velocidade e da frequência e aumento da amplitude ao longo dos cinco tiros, enquanto que com pausas de 120 s, essas diferenças foram atenuadas. Observou-se também que a frequência foi, dentre as variáveis analisadas, a mais sensível às condições experimentais

Blood lactate response to a complete and isolated short triathlon: implications to the performance

In an attempt to understand the blood lactate response to the triathlon, and its effects upon the performance, eight male triathletes were submitted to three test sessions. In the former, the subjects did a complete race session, which consisted of: 750 m swimming, 20 km cycling and 5 km miming. In the later two sessions (isolated) they did the cycling or the running after, at least, 24 hours rest. During the transitions in the first session and after the completion of all sessions, blood was taken for lactate analysis. The cycling and running speeds were greater in the isolated than the complete session (respectively, 4.1% and 8.0%). The mean blood lactate ranged from 6.68 to 9.11 mM but no significant difference was detected between the sessions. However, the lime and lactate differences in the isolated and complete race were inversely correlated (r = -0.53). These findings suggest that the decreased performance in the complete race is due to the elevated acidosis resulting from any of the triathon eventsCom o propósito de verificar a variação do lactato sangüíneo em provas de Short Triathlon e sua repercussão sobre o desempenho, oito atletas foram submetidos a três sessões de avaliações. Na primeira, os atletas realizaram a prova completa do Short Triathlon constituída de 750 m de natação, 20 km de ciclismo e 5 km de corrida. Na segunda e terceira sessões, os atletas realizaram, respectivamente a prova de ciclismo e de corrida isoladamente. Ao final de cada uma das provas e na transição na prova combinada, foram coletadas amostras de sangue para análise de lactato. As velocidades em ciclismo e corrida foram maiores quando realizadas isoladamente do que quando combinadas (aumento de respectivamente, 4,1% e 8,0%). Não houve diferença significativa entre os valores da concentração de lactato, que variou entre 6,68 a 9,11 mM. Contudo, as diferenças de tempo e de lactato entre as provas combinadas e isoladas apresentaram correlação significativa (r = -0,53). Esses resultados sugerem que a diminuição do desempenho na prova combinada pode ser atribuída à alta acidose que se verifica em qualquer uma das três prova

Influência da música preferida e não preferida no estado de ânimo e no desempenho de exercícios realizados na intensidade vigorosa

The study aimed to investigate the preferred and non - preferred music influence upon mood and performance during heavy exercise domain. Four women and six men physically active were submitted to the study. Ten preferred songs and ten non - preferred songs were chosen by the subjects to listen during a cycle ergometer exercise. Each subject performed three protocols, Preferred Music (PM), Non - Preferred Music (NPM) and No Music (NM), with three rectangular exhausting tests (high, medium and low) on ergometer cycle. The mood was evaluated through the List of Mood- Reduced and Illustrated (LM-RI) wich was applied in the beginning and at the end of the test. Such list was composed of seven positive adjectives (happy, active, calm, light, pleasant, full of energy and spiritual) and seven negative adjectives (bashful, sad, weighted, unpleasant, anxious, afraid e useless).Time to exhaustion and work were examined in all protocols. Listening to the preferred music resulted in positive adjectives compared to the non - preferred music and no music conditions. The negative adjectives had been increased on the time to exhaustion. No significant differences (p >; 0.05) were found in heart rate, blood lactate concentration, ratings of perceived exertion and performance between protocols. Thus, listening to preferred music and no-preferred music do not influence the performance during heavy exercises. Therefore, preferred music increases positive adjectives.O objetivo do presente estudo foi investigar a influência da música preferida e não preferida nos estados de ânimo e no desempenho do exercício realizado em intensidades vigorosas. A amostra foi constituída por quatro mulheres e seis homens universitários fisicamente ativos. Os sujeitos escolheram 10 músicas de preferência e 10 músicas de não preferência para a prática de exercício no cicloergômetro. Em seguida, realizaram três protocolos de testes no cicloergômetro (Música Preferida, Música Não Preferida e Sem Música) constituídos por três testes exaustivos retangulares (alta, média e baixa). Para a avaliação dos estados de ânimo foi utilizado a Lista de Estado de Ânimorreduzida e Ilustrada (LEA-RI) que foi aplicado no inicio e no final do teste. Essa lista é composta por sete adjetivos positivos (feliz, ativo, calmo, leve, agradável, cheio de energia e espiritual) e sete adjetivos negativos (tímido, triste, pesado, desagradável, agitado, com medo e inútil). Foram registrados o trabalho final e o tempo até a exaustão em todos os protocolos. Foi verificado que o exercício realizado em intensidades vigorosas com a presença da música preferida apresenta maiores valores dos adjetivos positivos (p ; 0,05). Portanto, a audição da música preferida e não preferida não influenciam o desempenho em exercícios vigorosos. Entretanto, a música preferida é capaz de melhorar os estados de ânimo positivos

Can off-training physical behaviors influence recovery in athletes? A sccoping review

Recently, the attention on recovery in sport increased enormously although there is lack of scientific evidence on the role of lifestyle in terms of movement [i.e., physical behaviors (PBs)], apart from sleep. Few studies assessed physical activity (PA) and sedentary behavior (SB) in athletes. The aims of this scoping review were to answer to the following scientific questions: (1) How active/inactive are competitive athletes out of training? (2) Do off-training PBs affect recovery, performance, and health? (3) What strategies can be implemented to improve recovery using off-training PBs, apart from sleep? From 1,116 potentially relevant articles, nine were eligible for inclusion in this review. The main issues identified were related to the heterogeneity concerning the types of sports, age category, gender, competitive level, sample size, and instruments/devices adopted, the paucity of studies investigating the effects of PBs while awake on recovery, and the lack of experimental designs manipulating PBs while awake to accelerate recovery. Furthermore, PA and SB domains were rarely investigated, while no research articles focused on the combined effect of 24-h PBs. Eight out of nine studies measured PA, seven SB, and two included sleep. Three studies included training practice into PA measurement by the means of accelerometry. Overall, almost the totality of the athletes achieved recommended PA levels although they sustained prolonged SB. In conclusion, more descriptive researches are needed in different athletic populations and settings. Furthermore, experimental designs aimed at investigating the effects of PBs manipulation on recovery and the putative mechanisms are encouraged

Aerobic Fitness Evaluation during Walking Tests Identifies the Maximal Lactate Steady State

Objective. The aim of this study was to verify the possibility of lactate minimum (LM) determination during a walking test and the validity of such LM protocol on predicting the maximal lactate steady-state (MLSS) intensity. Design. Eleven healthy subjects (24.2 ± 4.5 yr; 74.3 ± 7.7 kg; 176.9 ± 4.1 cm) performed LM tests on a treadmill, consisting of walking at 5.5 km · h−1 and with 20–22% of inclination until voluntary exhaustion to induce metabolic acidosis. After 7 minutes of recovery the participants performed an incremental test starting at 7% incline with increments of 2% at each 3 minutes until exhaustion. A polynomial modeling approach (LMp) and a visual inspection (LMv) were used to identify the LM as the exercise intensity associated to the lowest [bLac] during the test. Participants also underwent to 2–4 constant intensity tests of 30 minutes to determine the MLSS intensity. Results. There were no differences among LMv (12.6 ± 1.7%), LMp (13.1 ± 1.5%), and MLSS (13.6 ± 2.1%) and the Bland and Altman plots evidenced acceptable agreement between them. Conclusion. It was possible to identify the LM during walking tests with intensity imposed by treadmill inclination, and it seemed to be valid on identifying the exercise intensity associated to the MLSS

EXERCÍCIO FÍSICO COMO ESTÍMULO PARA O AUMENTO DA PRODUÇÃO E BIODISPONIBILIDADE DO OXIDO NÍTRICO E SEU EFEITO NO CONTROLE DA PRESSÃO ARTERIAL

O xido ntrico (NO) tem sido considerado como um dos importantes mecanismos para o controle da presso arterial. Proveniente do metabolismo da L-arginina, a partir da ativao da xido ntrico sintase endotelial (eNOS), o NO contribui para aumentar o grau de vasodilatao e, consequentemente, diminuio da presso arterial. Mas, existem alguns mecanismos que podem contribuir para a diminuio das concentraes de NO, como por exemplo, o polimorfismo T-786C do gene da eNOS e a biodisponibilidade do NO. Vrias substncias atuam no sentido de neutralizar o efeito do NO, impedindo a vasodilatao. Contrapondo-se a esses efeitos, o exerccio fsico tem sido considerado uma importante ferramenta para o aumento das concentraes de NO. Este efeito ocorre, basicamente, pelo aumento do shear stress proveniente do prprio exerccio fsico, que possui a capacidade de estimular um aumento na expresso do gene da eNOS, combatendo a deficincia provocada pelo polimorfismo e, tambm, devido capacidade de aumentar a produo de superxido dismutase (SOD), enzima que tem a capacidade de reagir com as substncias que estariam neutralizando o NO. Desta forma, o exerccio fsico pode ser considerado como um importante mecanismo para aumentar a produo e a biodisponibilidade do NO