A corrida de aventura (CA) é um esporte multiesportivo que vem adquirindo cada vez mais adeptos no mundo todo. A corrida é uma das etapas da prova de CA, e para tanto os atletas devem transportar mochilas de diferentes massas (kg) com os equipamentos obrigatórios. Entretanto, sabe-se pouco sobre os efeitos da carga transportada nos parâmetros cardiorrespiratórios e economia de corrida (Eco). O objetivo do presente estudo foi verificar e analisar os efeitos do transporte de carga referentes a 0%, 7% e 15% da massa corporal (MC) em parâmetros cardiorrespiratórios: consumo máximo de oxigênio (VO2max), frequência cardíaca (FC) e limiares ventilatórios (LV’s), taxa de troca respiratória (RER), taxa de percepção de esforço (RPE) e Eco, em corredores de aventura. A amostra foi constituída por 12 atletas corredores de aventura que realizaram três testes máximos e submáximos de forma randomizada. Para todos os testes máximos de corrida os indivíduos realizaram aquecimento prévio de 5 minutos em velocidade constante de 6 km.h-1, com incremento de 1 km.h-1 a cada minuto até a exaustão para fins de registro das variáveis cardiorrespiratórias e da velocidade correspondente ao VO2máx, primeiro limiar ventilatório (LV1) e segundo limiar ventilatório (LV2).. Para se obter os valores da Eco foram realizados três testes submáximos na esteira rolante durante 6 minutos, com velocidade constante referente a 10% abaixo do LV2, a partir dos dados dos testes máximos, com cargas referente a 0, 7 e 15% da MC, e o intervalo entre cada teste era de aproximadamente 10 minutos. Para análise estatística foi utilizado o pacote SPSS versão 18.0 com aplicação do teste de ANOVA de medidas repetidas para as variáveis analisadas. Os resultados mostraram que não houve diferenças estatísticas na maioria das variáveis. No entanto, o teste ANOVA (F, efeito geral da carga) de vLV2, vVO2máx, LV1% e vLV1% apresentam diferenças estatísticas significativas, indicando que os atletas reduziram as velocidades em valores absolutos referente ao LV2 e VO2max e em percentual do LV1 e da velocidade do LV1. Desta forma, os achados desse estudo indicam que os parâmetros cardiorrespiratórios e Eco não foram afetados pelo transporte de carga. / Adventure running (AR) is a multi-sport which has more and more adepts worldwide. Running is one of the steps of the AR competition and the athletes must carry backpacks of different masses (kg) with the required equipment. However, little is known about the effects of the load carried on the cardiorespiratory parameters and running economy (Eco). The aim of this study was to identify and analyze the effects of load transportation with 0%, 7% and 15% of body mass (BM) on cardiorespiratory parameters: maximal oxygen uptake (VO2max), heart rate (HR) and ventilatory thresholds (VT), respiratory exchange ratio (RER), rate of perceived exertion (RPE) and Eco in adventure running athletes. The sample consisted of 12 athletes who performed three submaximal and maximal tests randomly. For all maximal running tests subjects had a warm up on the treadmill for 5 minutes at a constant speed of 6 km.h-1. For the test the speed increased by 1 km.h-1 every one minute and subjects ran until exhaustion to record the cardiorespiratory variables and the speed corresponding to VO2máx, first ventilatory threshold (VT1) and second ventilatory threshold (VT2). To obtain the values of Eco three submaximal tests on the treadmill were performed for six minutes with constant speed corresponding to 10% below the VT2, obtained from the maximum test with load transport corresponding to 0, 7 and 15% BM, and the interval between each test was approximately 10 minutes. For statistical analysis we used SPSS version 18.0 with application of ANOVA test of repeated measures for the variables analyzed. The results showed no statistical differences in most variables. However, the ANOVA (F, overall effect of the load) of sVT2, sVO2max, VT1% and sVT1% presented statistical significant differences, indicating that athletes reduced absolute running speeds for the VT2 and VO2max and percentage of VT1 and sVT1, so the findings of this study indicate that the Eco cardiorespiratory parameters were not affected by transportation load.

O consumo máximo de oxigênio (VO2máx), o limiar ventilatório (LV), ponto de compensação respiratória (PCR) e a economia de corrida (EC) são importantes variáveis fisiológicas associadas com a aptidão aeróbia em corrida. Acredita-se que o polimorfismo da enzima conversora de angiotensina (ECA) possa estar influenciando nos valores dessas variáveis. Contudo, essa relação causal não tem sido amplamente estudada durante a corrida. Dessa forma, o objetivo do presente trabalho foi investigar a associação entre os genótipos da ECA e o VO2máx, LV, PCR e EC mensuradas durante a corrida em esteira. Cento e cinquenta (n = 150) voluntários fisicamente ativos realizaram os seguintes testes: a) teste incremental máximo para determinação do VO2máx, LV e PCR; b) dois testes de velocidade constante (10 km/h e 12 km/h) em esteira para determinação da EC. Os genótipos apresentaram a frequência de: II = 21% ; ID = 52% e DD = 27%. Os resultados apresentaram uma tendência dos indivíduos com o genótipo II apresentarem maiores valores do VO2máx (p = 0.08), bem como a análise do efeito prático apresentou um possível efeito benéfico desse genótipo. No entanto, não foi constatada diferença entre os valores do LV, PCR, e EC entre os indivíduos. Esses resultados sugerem que o genótipo II da ECA pode estar influenciando nos valores da variável máxima relacionada com o consumo de oxigênio / The maximal oxygen uptake (VO2máx), ventilatory threshold (VT), respiratory compensation point (RCP), and running economy (RE) are important variables associated with running aerobic fitness. However, the influence of Angiotensin Converting Enzyme (ACE) polymorphism on these variables determined in running has not been largely investigated. Therefore, the present study aimed to investigate the relationship between ACE genotypes and maximal oxygen uptake, respiratory compensation point, and running economy measured in running. One hundred and fifty (n = 150) physically active young men performed the following tests: a) a maximal incremental treadmill test to determine VO2máx and RCP, b) two constant-speed running test (10 km.h-1 and 12 km.h-1) to determine the RE. The genotype frequency were II = 21 %; ID = 52 %; DD = 27 %. There were a likely beneficial effect and a tendency for the participants with ACE II genotype to have higher VO2max values than DD or ID genotypes (p = 0.08) and the smallest worthwhile effects show a beneficial effect. There were not associations between the genotypes for RCP and RE. These findings suggest that II ACE genotype would influence in maximal variable correlated with oxygen consumption

Title: Analysis of running technique and efficiency when using Nike Air Zoom Alphafly shoes. Objectives: The main goal is to identify possible changes in selected physiological parameters and biomechanics of running when using Nike Air Zoom Alphafly shoes compared to standard running shoes. Methods: A 3D treadmill (H/P Cosmos Gaitway II S, Germany) was used in the analysis of running biomechanics. For the analysis of physiological parameters, the Metalyzer device was used within the spiroergometric examination of the run. The Borg scale was used to analyze the subjective assessment of the load. A paired T-test of Excel software was used to process the results. Results: The results of the work partially show a change in the biomechanics of running. A statistically significant difference was recorded at all speeds (15 km/h, 18 km/h, 21 km/h) in loading rate (p15 = 0,003; p18 = 0,000; p21 = 0,001) and time to impact peak (p15 = 0,017; p18 = 0,022; p21 = 0,003). At a speed of 15 km/h, an additional difference in running cadence (p = 0,044) was noted. The results show a statistically significant change in the economics of running all measured parameters, in oxygen intake converted to kilograms of weight (p = 0,003), minute ventilation (p = 0,000), respiratory rate (p = 0,000), respiratory coefficient (p...

Much is known about running economy while running on level ground surfaces. However, with the dynamic of elevation changes during running, more research is needed to understand how various grades that will favor respective mechanics. PURPOSE: In this study, we focused on determining whether certain running mechanics and anatomy would predict a runner's oxygen uptake between downhill versus uphill running. METHODS: Twenty-one experienced runners completed six 5-min running trials (1 shoe x 3 grades x 2 visits) in a Saucony marathon racing shoe model (Type A) on level (3.83 m/s), uphill (+4% grade at 3.35 m/s), and downhill ( ˆ’4% grade at 4.46 m/s) conditions. These treadmill speeds at each grade were predicted as metabolic equivalents through all grades. We measured submaximal oxygen uptake and carbon dioxide production during the entire trial duration with the last 3 min of each trial being averaged. A best-fitting line was generated through oxygen uptake versus grade to classify whether runners were more economical in uphill or downhill conditions relative to other subjects. The slope of this line indicated whether runners were more economical at uphill or downhill running, where a positive slope represented a more economical uphill versus downhill runner. Various running mechanics were measured using Vicon Nexus and a Bertec treadmill. A linear regression determined any correlations between peak vertical force, stride rate, plantar velocity, and ground time against uphill/downhill running ability. RESULTS: Peak vertical force was the only factor associated with the slope of oxygen uptake versus grade (running grade ability; p < 0.01). The slope of oxygen uptake versus grade averaged 0.076 ± 0.278 ((ml/kg/min) / % grade). CONCLUSION: Runners that naturally prefer a higher peak vertical force when running on level ground led to a lower running grade ability (lower oxygen uptake during downhill versus uphill running).

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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

ABSTRACT Male subjects are invariably used to study the physiological determinants of middle distance running performance. Studies that do include females have examined only the aerobic contribution to middle distance running performance. The aim of the present study was to investigate aerobic, anaerobic and muscle function factors that could be used to predict middle distance running performance in female runners. This study was performed at an altitude of 1800m. Eleven middle distance female runners aged 18-20 were selected for the study. Aerobic capacity was assessed by measuring the maximal oxygen consumption (VO2max), running velocity at maximal oxygen consumption (vVO2max), running economy (RE) and onset of blood lactate accumulation (OBLA). The blood lactate curve of each subject was constructed by relating the oxygen consumption, to the plasma lactate concentrations. Anaerobic capacity was determined by measuring the maximum accumulated oxygen deficit (MAOD) on a treadmill. Muscle function was assessed by having the subjects cycle as fast as possible against changing brake weights ranging from heavy to light using a Monark cycle ergometer. The brake force (kg) was related to velocity (rpm).

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Running economy is well established as a primary determinant of endurance running performance. However, there is a lack of clarity about the preferred measurement of running economy, its primary limiting factors and the most robust methods enhance running economy in highly trained athletes. Therefore, this thesis investigated the running economy of highly trained runners, exploring the reliability and validity of measures of running economy to deduce its most appropriate quantification, the application of innovative methods to enhance our understanding of an athlete s running economy, and a novel training method to enhance running economy. Chapter 3 revealed that energy cost and oxygen cost were shown to provide similarly high levels of reliability (typical error of measurement ~3%) for highly trained endurance runners when assessed using a short-duration incremental submaximal exercise protocol. In chapter 4, the analysis of a large cohort of highly trained endurance runners revealed that energy cost increased in a stepwise manner with increments in running speed (P<0.001), however oxygen cost remained consistent (P=0.54) across running speed; indicating that oxygen cost might not be an appropriate measure of running economy. Chapter 5 demonstrated that the inter-individual variation in the magnitude of changes in energy cost between different gradients (i.e. from flat running to uphill/downhill running) in highly trained runners was low. However, a disparity between the energy saving of running on a -5% gradient (-17%) and the additional energy cost of running on a +5% gradient (+32%) was evident. The cross-sectional and longitudinal analysis of a large cohort of highly trained runners in chapter 6 revealed a small (r=0.25) and moderate (r=0.35) association between energy cost and maximal oxygen uptake, respectively. Finally, chapter 7 demonstrated that eight weeks of supplementary downhill run training at vLTP in existing training programmes does not enhance running economy in already well trained runners (1.22 vs 1.20 kcal kg-1 km-1; P=0.41), despite a significant increase (+2.4%) in the velocity at lactate turnpoint. In conclusion, this thesis demonstrates that energy cost, expressed as kcal kg-1 km-1, provides a reliable and valid method to quantify running economy in trained distance runners. However, further investigation is required to identify robust training methods to enhance running economy in this already highly trained population.