Syfte Syftet är att undersöka Per-Olof och Irma Åstrands tillvägagångssätt vid skapandet av det submaxirnala cykelergometertest som kallas "Åstrandstestet" samt att reflektera övertestets validitet och reliabilitet. Metod Studien är baserad på litteraturstudier samt en djupintervju med Per-Olof Åstrand. Samtal har förts med Sture Malmgren, en av författarna till boken Konditionstest på cykel samt med Per-Olof Åstrand för att undvika oklarheter. Resultat Vårt huvudfynd visar att vid den ursprungliga utformningen och framtagningen av det submaximala cykelergometertest som kallas Åstrandstestet, genomfördes flera submaximala tester där resultaten från försökspersonernas första test exkluderades. Alla personer som testas submaximalt med hjälp av Åstrandstestet så som det används idag, då resultaten från det första testet används, kan få ett felaktigt värde, I dagsläget finns inga studier som visar hur stort felet kan bli eftersom olika människor påverkas olika av exempelvis nervositet. Därför är det svårt för författarna till detta examensarbete att bedöma vilken betydelse exkluderingen av det första testet har för testets noggrannhet. Slutsats Om Åstrandstestet ska användas som metod för att uppskatta en persons maximala syreupptagningsförmåga är det av största vikt att det används på ett sätt som minskar felmarginalerna. För att uppnå detta bör man låta försökspersonen göra ett förtest för att vänja sig vid metod, utrustning och försöksledare.

Recent research suggests that adding protein (PRO) to a carbohydrate (CHO) supplement can have substantial benefits for endurance exercise performance and recovery beyond that of CHO alone. CHO+PRO supplements are often commercially available formulations consisting of carbohydrates (dextrose, maltodextrin) and whey protein. The effects of a supplement containing moderate protein and a low-CHO mixture on endurance performance has not been investigated. Also, the effects of CHO+PRO supplementation in the form of a natural food, flavored milk, on measures of recovery from acute endurance exercise, as well as on chronic aerobic exercise training adaptations, have not been characterized. Therefore, in this series of four studies, the effects of CHO+PRO supplementation on the following areas of endurance exercise performance, recovery, and adaptation are investigated: acute endurance exercise performance, inflammatory and muscle damage markers, muscle glycogen resynthesis, activation of signaling proteins involved in the initiation of protein synthesis and degradation, subsequent endurance exercise performance, and chronic aerobic training adaptations (maximal oxygen consumption, oxidative enzyme activity, body composition, immune cell levels, and inflammatory markers). Study 1 demonstrated that a supplement containing a low-CHO mixture plus moderate protein significantly improved aerobic endurance when cycling at or below the ventilatory threshold, despite containing 50% less CHO and 30% fewer calories relative to a higher CHO beverage. Study 2 demonstrated that CHO+PRO supplementation in the form of chocolate milk (CM) is an effective post-exercise supplement that can improve subsequent performance and provide a greater intracellular signaling stimulus for protein synthesis compared to CHO and placebo. Study 3 found that post-exercise CM supplementation during 4.5 wks of aerobic exercise training improves the magnitude of cardiovascular adaptations more effectively than isocaloric CHO or placebo, while the fourth study demonstrated that post-exercise CM supplementation during 4.5 wks of aerobic training improves body composition more effectively than isocaloric CHO or placebo. The fourth study also demonstrated that 4.5 wks of training does not appear to perturb resting immune cell concentrations or markers of inflammation and muscle damage. Taken together, the results of this research series suggest that CHO+PRO supplementation extends endurance performance, improves recovery, and increases training adaptations more effectively than CHO or placebo. / text

Tyrimo objektas – didelio meistriškumo rankininkių kvėpavimo sistemos funkcija ir aerobinis pajėgumas. Tyrimo aktualumas. Aerobinis pajėgumas yra labai svarbus rankinyje siekiant aukštų sportinių rezultatų. Kiekvienoje sporto šakoje sportininkai skiriasi savo aerobiniu pajėgumu, todėl mūsų darbas yra aktualus, nes informatyviais tyrimo metodais nustatėme skirtingo amžiaus rankininkių aerobinį pajėgumą ir kvėpavimo sistemos funkcinius rodiklius. Tyrimo problema. Kokią įtaką amžius turi rankininkių aerobiniam pajėgumui bei kvėpavimo sistemos funkcijoms? Tyrimo tikslas: Nustatyti skirtingo amžiaus rankininkių kvėpavimo funkcijos ir aerobinio pajėgumo ypatumus. Uždaviniai: 1. Nustatyti skirtingo amžiaus rankininkių kvėpavimo sistemos pajėgumą ramybėje ir nuosekliai didėjančio fizinio krūvio metu. 2. Nustatyti skirtingo amžiaus rankininkių aerobinį pajėgumą. 3. Palyginti jaunesnio ir vyresnio amžiaus rankininkių aerobinį pajėgumą ir kvėpavimo funkcinius rodiklius. Išvados 1. Jaunesniųjų rankininkių maksimalūs plaučių ventiliacijos rodikliai buvo didesni, tiek testuojant ramybėje (maksimali valinga ventiliacija), tiek ir nuosekliai greitėjančio bėgimo metu (didžiausios pasiektos reikšmės). 2. Absoliučios plaučių talpos reikšmingai nesiskyrė lyginant skirtingo amžiaus rankininkių, tačiau lyginant su atitinkamo amžiaus norminėmis reikšmėmis forsuota iškvėpimo talpa buvo santykinai geresnė vyresnių rankininkių. 3. Jaunesnių rankininkių maksimalus deguonies suvartojimas... [toliau žr. visą tekstą] / The object of research – respiratory system and aerobic capacity of professional female handball players. The relevance of research. The efficiency of aerobic capacity is important in handball play. In every sports athletes differs in aerobic theme capacity, thats why our study is relevant, because we obtained the results about on aerobic capacity of the female handball players in different age group. Question of research – what influence has age for the aerobic capacity and respiratory system function of female handball players. The purpose of research: to determine the respiratory function and aerobic capacity of the professional female handball players of different age. Goals: 1. To determine the capacity of respiratory system of the female handball players. 2. To determine the aerobic capacity of female handball players. 3. To compare the data of senior and junior female hanball players. Conclusions 1. The rates of the maximal lungs ventilation of junior female handball players were greater in both while testing at rest and maximal ventilation continuously accelerating running (maximal achieved value). 2. Absolute lungs capacity did not change significantly between different age female handball players, although comparing the forced exhalation capacity of appropriate age standard value, senior handball players had relatively better data. 3. The maximal oxygen uptake, ventilation threshold and correspondent values of vegetative system (HR, maximal oxygen... [to full text]

Background: Working within the military as a ground combat solider is very physically demanding. Soldiers are required to handle situations ranging from peacekeeping to counterinsurgency and combat, while faced with the task of load carriage either in form of the military gear or other additional loads. Therefore, a good aerobic and anaerobic fitness is necessary. The aerobic and anaerobic fitness can be assessed with a wide range is methods such as measuring the peak oxygen uptake (VO2peak), ventilator threshold, blood lactate concentration and heart rate. However research is rather spares regarding the effects of load carriage on the aerobic capacity. Aim: The aim of the current study was to investigate if military gear affects VO2peak, ventilatory threshold, blood lactate concentration and heart rate in ground combat soldiers. Methods: A total of eight soldiers (seven men and one woman) participated in the current study. All participants completed two biological calibrations and VO2max tests (one without and one with military gear) using a modified Bruce protocol, where VO2 (L/min), absolute and relative VO2peck (L/min and ml/kg/min respectively), heart rate (beats/min) and blood lactate concentration (mM/L) were assessed. After the completion of the tests, the soldier’s individual ventilatory threshold (VT) was visually located using the V-slope method. The Wilcoxon test was used for the not normally distributed variables (blood lactate concentration and stage when VT occurred) and the paired sample t-test for the others. The significance level was set to 0.05. Results: The results showed that the soldier had 10.6 % lower absolute VO2peak and 23.7 % lower relative VO2peak while wearing military gear compared to without (p=0.002 and p=0.001 respectively). The soldiers also had 11.8 % higher VO2 at VT with military gear (p=0.003) and reached a higher percentage of the VO2peak (p=0.023) at VT. The blood lactate concentration was significantly higher when marching at 5.4 km/h and a trend of a higher blood lactate concentration while standing was observed without military gear compared to with military gear. Conclusion: The findings from the present study shows that performing load carriage in form of the military gear significantly decreased the VO2peak. Wearing a military gear also increased the VO2 at the individual VT and made the soldier reach a higher percentage of the VO2peak at VT. These results can act as guidance when recruiting and training soldiers, along with providing important information to other professions and sports that involve load carriage.

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Made available in DSpace on 2016-12-06T17:07:28Z (GMT). No. of bitstreams: 1 Leonardo.pdf: 1619585 bytes, checksum: 4de10ca640ab043428d053c99d123b01 (MD5) Previous issue date: 2011-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of the study is to analyse the effects of fatigue on kinematics characteristics during running at maximal oxygen uptake velocity. Eleven healthy males, team sports recreational players volunteered for this study. Firstly, subjects performed an incremental running test until volitional exhaustion to determine the maximal oxygen uptake velocity. The second phase consisted to a constant running velocity test at maximal oxygen uptake velocity to determine time to exhaustion at this velocity and acquire kinematical data. Subjects were filmed continuously from the left sagital plane at 210 Hz. Video cuts from five consecutive strides from 2 different times of the run were taken for analysis: a) 20 seconds after the onset of the run; b) 10 seconds prior the end of the run. Dependent t-tests were used to assess mean values across the two time points in the test. Multiple linear regression were used to assess the contribution of kinematical changes in the time limit. The increase in maximal plantar flexion during swing (p=0,009) and knee range of motion (p=0,05) were the only changes found for the whole group. Time Limit were predicted by changes in six variables: support time, knee flexion at contact, maximal knee flexion during stance, maximal knee flexion during swing, hip angle at toe-off and hip range of motion. These finding suggest that muscle fatigue during latter stages of run at vVO2max causes individual specific kinematical changes in ankle, knee and hip joints, moreover the absence of significant kinematic changes. Nevertheless, time limit can be predicted by kinematic changes throughout vVO2máx. / O objetivo do estudo foi analisar os efeitos da fadiga sobre características cinemáticas durante a corrida na velocidade do consumo máximo de oxigênio determinada durante teste incremental. Participaram deste estudo 11 sujeitos ativos fisicamente, estudantes de Educação Física, praticantes de esportes coletivos. Primeiramente os sujeitos foram submetidos a um protocolo progressivo de corrida até a exaustão voluntária para determinar a velocidade do consumo máximo de oxigênio. Na sequência, os sujeitos foram submetidos a um teste de velocidade constante para identificar o tempo limite na velocidade do consumo máximo de oxigênio e adquirir os dados cinemáticos a 210 Hz referentes a 5 ciclos completos de passadas em dois instantes diferentes da corrida: a) fase inicial: 20 segundos após o início da corrida; b) fase final: último contato do pé com o solo da última passada de interesse ocorrendo 10 segundos antes do término da corrida. Os valores foram calculados pelo software APAS. Foi utilizada a estatística descritiva, o Teste t Pareado para comparação entre as médias dos dois instantes analisados e a regressão linear múltipla para verificar a contribuição das modificações cinemáticas no Tempo Limite. O nível de confiabilidade adotado foi de 95%. O aumento da máxima plantiflexão no balanço (p=0,009) e amplitude de movimento do joelho (p=0,05) foram as únicas diferenças significativas encontradas para o grupo todo. O tempo limite pôde ser predito pelas modificações em 6 variáveis: tempo de suporte, máxima dorsiflexão no suporte, ângulo do joelho no contato, máxima flexão do joelho no suporte, máxima flexão do joelho no balanço e ângulo do quadril na retirada do hálux. Foi possível concluir que a fadiga muscular nos estágios finais da corrida na vVO2máx causa alterações cinemáticas individuais específicas nas articulações do tornozelo joelho e quadril, apesar da ausência de alterações cinemáticas significativas para a ampla maioria das variáveis. Além disso, o tempo limite pode ser predito por modificações cinemáticas ao longo da corrida na vVO2máx.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-08-11T12:24:29Z No. of bitstreams: 1 cristianodasilvabrum.pdf: 18446282 bytes, checksum: 7310bb73832b9312a18b83babb7d931d (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-11T13:00:25Z (GMT) No. of bitstreams: 1 cristianodasilvabrum.pdf: 18446282 bytes, checksum: 7310bb73832b9312a18b83babb7d931d (MD5) / Made available in DSpace on 2017-08-11T13:00:25Z (GMT). No. of bitstreams: 1 cristianodasilvabrum.pdf: 18446282 bytes, checksum: 7310bb73832b9312a18b83babb7d931d (MD5) Previous issue date: 2012-11-23 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / INTRODUÇÃO. Os sintomas do trato urinário inferior (LUTS) têm alta prevalência, ocorrendo em 50 % dos homens com mais de 50 anos e em 90% após 80 anos e está associado à hiperplasia prostática benigna (HPB) em 50% das vezes. LUTS e HPB têm sido associados mais recentemente à síndrome metabólica, a fatores de risco cardiovascular e ao baixo nível de atividade física, porém estas associações são complexas e nãe estão bem esclarecidas. A atividade física para ser adequada deve gerar melhora da aptidão cardiorrespiratória, sendo esta avaliada pelo volume máximo de oxigênio (Vo2max). O objetivo deste trabalho é avaliar a associação do LUTS com Vo2max, flexibilidade, o nível de atividade física e variáveis antropométricas em homens com 50 a 59 anos. PACIENTES E MÉTODOS. Foi realizado um estudo caso-controle no qual o LUTS foi considerado como o desfecho e o Vo2max, a flexibilidade, o nível de atividade física e variáveis antropométricas como a exposição. Foram avaliados 100 homens com idade entre 50 e 59 anos provenientes do ambulatório de especialidades clínicas do Hospital Universitário (HU-CAS) da Universidade Federal de Juiz de Fora, sendo alocados 49 pacientes no grupo caso (com LUTS) e 51 no grupo controle (sem LUTS). Os pacientes passaram pelo seguinte protocolo experimental: anamnese, avaliação do nível de atividade física pelo Questionário Internacional de Atividade Física (IPAQ) em sua versão curta, avaliação do LUTS pelo Questionário Internacional de Sintomas Prostáticos (IPSS), avaliação antropométrica com a medida do índice de massa corpórea (IMC), relação cintura quadril (RCQ) e circunferência abdominal. Para a avaliação do Vo2max foi realizado o Polar Fitness Test e para avaliar a flexibilidade foi utilizado o teste de Sentar e Alcançar. RESULTADOS: na análise bi-variada foi identificada associação estatisticamente significativa do LUTS com o nível de atividade física (OR = 0,37, IC95% = 0,16 a 0,84, p= 0,02); com o Vo2max (OR = 0,206, IC95% = 0,086 a 0,495, p<0,001) e com a flexibilidade (OR = 0,309, IC95% = 0,130 a 0,337, p= 0,01). Porém, o modelo multivariado adotado indicou que controlando o efeito da flexibilidade e do nível de atividade física, o Vo2max foi a única variável associada de forma estatisticamente significativa com o LUTS, com Odds ratio ajustada de 0,30 ( IC95% = 0,105 a 0,875, p= 0,027). CONCLUSÃO: Homens com idade entre 50 a 59 anos com Vo2max adequado, têm aproximadamente 70% a menos de chance de desenvolver LUTS. / INTRODUCTION. Lower urinary tract symptoms (LUTS) are highly prevalent, occurring in 50% of men over 50 years old and in 90% of men over 80, and is associated with benign prostatic hyperplasia (BPH) in 50% of the cases. LUTS and BPH have more recently been associated with metabolic syndrome, cardiovascular risk factors, and low physical activity level, but these associations are complex and not well understood. Physical activity, to be considered adequate, should generate improved cardiorespiratory fitness, which is assessed by maximal oxygen uptake (VO2max). The objective of this study is to evaluate the association of LUTS with VO2max, flexibility, physical activity level, and anthropometric variables in men aged 50 to 59 years. PATIENTS AND METHODS. We conducted a case-control study in which LUTS was considered as the outcome and VO2max, flexibility, physical activity level, and anthropometric variables as the exposure variables. We evaluated 100 men aged between 50 and 59 years from the outpatient specialty clinics of the University Hospital (HU-CAS), Federal University of Juiz de Fora, assigning 49 patients to the case group (with LUTS) and 51 to the control group (without LUTS). The patients underwent the following experimental protocol: anamnesis, physical activity level assessment using the International Physical Activity Questionnaire (IPAQ) in its short version, LUTS assessment using the International Prostate Symptom Score (IPSS) Questionnaire, anthropometric assessment measuring body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference. For the assessment of VO2max, the Polar Fitness Test was performed, and to assess flexibility, the Sit and Reach test was used. RESULTS: In bivariate analysis a statistically significant association was identified for LUTS with physical activity level (OR = 0.37, 95% CI = 0.16 to 0.84, p = 0.02); with VO2max (OR = 0.206, 95% CI = 0.086 to 0.495, p <0.001); and with flexibility (OR = 0.309, 95% CI = 0.130 to 0.337, p = 0.01). However, the multivariate model adopted indicated that, controlling for the effect of flexibility and of physical activity level, VO2max was the only statistically significant variable associated with LUTS, with an adjusted odds ratio of 0.30 (95% CI = 0.105 to 0.875 , p = 0.027). CONCLUSION: Men aged 50 to 59 years, with adequate VO2max, have approximately a 70% less chance of developing LUTS.

Background: Physiologic functional capacity through maximal oxygen uptake (V̇O2max) can be measured in many different ways depending on sport and qualities needed to be assessed.In handball a demanding 3000 meter (m) running test is used to evaluate V̇O2max. If this test is sport specific or if it could be replaced by a less strenuous test is unknown. Aim: The aim ofthis study was to compare performance on 3000-meter running with predicted V̇O2max from a submaximal treadmill jogging test (SMTJ) and performance of the Yo-Yo intermittentrecovery test 1 (IR1). Methods: Male handball players (n = 12) performed the 3000 m running test, the Submaximal Treadmill Jogging test and the Yo-Yo Intermittent Recovery test level 1. Measurements in seconds (s), ml ∙ kg-1 ∙ min-1 and meters where collected and correlated using Pearson r, interclass correlation. Results: A strong significant linear correlation (p &lt; 0.01) was found between performance in 3000 m running (s) and Yo-Yo IR1 performance (m), r = - 0.724 (r2 = 0.524). A weak, not significant linear correlation (p &gt; 0.05)was found between performance in 3000 m running (s) and predicted V̇O2max from submaximal treadmill test (ml ∙ kg-1 ∙ min-1), r = - 0.309 (r2 = 0.095). Conclusion: According to this study the 3000 m running test could be replaced by the Yo-Yo IR1 test or vice versa in adolescent male handball players. The submaximal treadmill test used in this study had several potential errors in estimating V̇O2max, this is probably the reason why only a weak correlation was found between the SMTJ and the 3000 m running test.

Introduction Researchers have, for decades, contributed to an increased collective understanding of the physiological demands in cross-country skiing; however, almost all of these studies have used either non-elite subjects and/or performances that emulate cross-country skiing. To establish the physiological demands of cross-country skiing, it is important to relate the investigated physiological variables to the competitive performance of elite skiers. The overall aim of this doctoral thesis was, therefore, to investigate the external validity of physiological test variables to determine the physiological demands in competitive elite cross-country skiing. Methods The subjects in Study I – IV were elite male (I – III) and female (III – IV) cross-country skiers. In all studies, the relationship between test variables (general and ski-specific) and competitive performances (i.e. the results from competitions or the overall ski-ranking points of the International Ski Federation (FIS) for sprint (FISsprint) and distance (FISdist) races) were analysed. Test variables reflecting the subject’s general strength, upper-body and whole-body oxygen uptake, oxygen uptake and work intensity at the lactate threshold, mean upper-body power, lean mass, and maximal double-poling speed were investigated. Results The ability to maintain a high work rate without accumulating lactate is an indicator of distance performance, independent of sex (I, IV). Independent of sex, high oxygen uptake in whole-body and upper-body exercise was important for both sprint (II, IV) and distance (I, IV) performance. The maximal double-poling speed and 60-s double-poling mean power output were indicators of sprint (IV) and distance performance (I), respectively. Lean mass was correlated with distance performance for women (III), whereas correlations were found between lean mass and sprint performance among both male and female skiers (III). Moreover, no correlations between distance performance and test variables were derived from tests of knee-extension peak torque, vertical jumps, or double poling on a ski-ergometer with 20-s and 360-s durations (I), whereas gross efficiency while treadmill roller skiing showed no correlation with either distance or sprint performance in cross-country skiing (IV). Conclusion The results in this thesis show that, depending on discipline and sex, maximal and peak oxygen uptake, work intensity at the lactate threshold, lean mass, double-poling mean power output, and double-poling maximal speed are all externally valid physiological test variables for evaluation of performance capability among elite cross-country skiers; however, to optimally indicate performance capability different test-variable expressions should be used; in general, the absolute expression appears to be a better indicator of competitive sprint performance whereas the influence of body mass should be considered when evaluating competitive distance performance capability of elite cross-country skiers.

Les objectifs de ce travail étaient d'analyser les réponses physiologiques au cours d’exercices intermittents en course à pied et de déterminer i) un test d'évaluation de la vitesse maximale aérobie (VMA) adapté aux exercices intermittents ; ii) les exercices intermittents permettant une sollicitation maximale de la consommation d'oxygène (VO2max) ; iii) les facteurs physiologiques et neuromusculaires limitant la durée des exercices intermittents.La première étude a permis de montrer que la réalisation d’un exercice intermittent alternant des périodes d'effort de 30 s avec des périodes de récupération de 30 s (30s-30s), à la VMA atteinte à la fin du test intermittent incrémental 45-15FIT, permettait à la fois de réaliser un grand nombre de répétitions et de solliciter un fort pourcentage de la VO2max pendant la durée de l'exercice. Lors de la seconde étude nous avons montré que les exercices intermittents de type 5s-15s, 30s-30s et 60s-60s, courus à la VMA permettaient de solliciter un fort pourcentage de la VO2max. L'exercice intermittent de type 30s-30s est celui qui permet néanmoins de réaliser le plus grand nombre de répétitions. Une part plus importante de la glycolyse dans la production d'énergie réduit le nombre de répétitions lors de l'exercice de type 60s-60s par rapport à l'exercice de type 30s-30s ; une fatigue musculaire causée par un plus grand nombre d'accélérations et de décélérations réduit quant à elle le nombre de répétitions lors de l'exercice de type 15s-15s, par rapport à l'exercice de type 30s-30s. Les résultats de la troisième étude ont confirmé que les exercices intermittents de type 5s-15s, courus à la VMA, induisaient une fatigue musculaire plus importante, due essentiellement aux nombreuses accélérations et décélérations. Il a également été montré qu'à la suite d'un exercice pré-fatigant des muscles extenseurs du genou (contractions musculaires évoquées par électromyostimulation vs contractions volontaires isométriques), le nombre de répétitions lors de l'exercice intermittent 30s-30s était réduit, mais que le pourcentage de temps passé à plus de 90% de la VO2max n'était pas diminué par rapport à la réalisation sans pré-fatigue.L'ensemble de nos travaux permettent de définir un ensemble d'exercices intermittents qui, lorsqu'ils sont courus à la VMA évaluée lors du test 45-15FIT, permettent d'atteindre un niveau élevé de sollicitation du système aérobie, dont l'exercice de type 30s-30s pourrait constituer un exercice "standard" / The aims of the present work were to analyze the physiological responses during intermittent exercise and to determine; i) an field test to assess the maximal aerobic velocity (MAV) for intermittent exercise; ii) the type of intermittent exercise could elicit maximal oxygen uptake (VO2max); iii) the physiological and neuromuscular factors that could limit intermittent exercise duration.The first study demonstrated that the MAV (MAV45-15) reached at the end of an incremental intermittent (45s run/ 15s rest) field test (45-15FIT) was relevant to elicit a high percentage of VO2max during a 30s-30s intermittent training session. The second and third studies demonstrated that intermittent exercises performed at MAV45-15 such as 5s-15s, 15s-15s, 30s-30s, and 60s-60s, were relevant to elicit a high percentage of VO2max. In the 60s-60s intermittent exercise, the lowest endurance time compared to 30s-30s, was explained by the predominance of the anaerobic system in the energy supply. In the 15s-15s and 5s-15s intermittent exercises, the lowest endurance time in comparison with 30s-30s was explained by the greater neuromuscular fatigue. The fourth study showed that a pre-fatigue induced by evoked contractions by electrostimulation, and isometric voluntary contraction of the knee extensor muscles reduced the time to exhaustion in a 30s-30s intermittent exercise, but was relevant to elicit a high percentage of VO2max. These results give new insights in the field of intermittent exercise training