Football player dominant region determined by a novel model based on instantaneous kinematics variables.

Dominant regions are defined as regions of the pitch where a player can reach before any other and are commonly determined without considering the free-spaces in the pitch. We presented an approach to football players' dominant regions analysis, based on movement models created from players' positions, displacement, velocity, and acceleration vectors. 109 Brazilian male professional football players were analysed during official matches, computing over 15 million positional data obtained by video-based tracking system. Movement models were created based on players' instantaneous vectorial kinematics variables, then probabilities models and dominant regions were determined. Accuracy in determining dominant regions by the proposed model was tested for different time-lag windows. We calculated the areas of dominant, free-spaces, and Voronoi regions. Mean correct predictions of dominant region were 96.56%, 88.64%, and 72.31% for one, two, and three seconds, respectively. Dominant regions areas were lower than the ones computed by Voronoi, with median values of 73 and 171 m2, respectively. A median value of 5537 m2 was presented for free-space regions, representing a large part of the pitch. The proposed movement model proved to be more realistic, representing the match dynamics and can be a useful method to evaluate the players' tactical behaviours during matches.

Repercussion of medium and long treatment period with continuous positive airways pressure therapy in heart rate variability of obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea (OSA) is a respiratory sleep disorder. Many of these patients also exhibit autonomic alterations which can be observed through heart rate variability (HRV). Currently, one of the treatments for apnea is continuous positive airway pressure (CPAP). OBJECTIVE: To observe OSA patients treated with CPAP exhibit HRV changes at medium and long treatment period. METHODS: This is an integrative literature review conducted in May of 2018. The databases used for this research were PubMed, Scopus, Scielo and Pedro, the keywords used were "heart rate variability", "obstructive sleep apnea" and "CPAP". In this review was included original, published, randomized and non-randomized articles, released in the English language, before and up to April 2018, which specified the effects of CPAP therapy in autonomic dysfunction through the analysis of the HRV of patients diagnosed with OSA after at least one month of therapy. RESULTS: The research of the literature produced 113 articles. After excluding duplicates and applying the inclusion and exclusion criteria, 8 articles were selected for this review. CONCLUSION: It was concluded that CPAP therapy is related to change in heart rate variability in patients with obstructive sleep apnea.

Development of an application for mobile devices to identify the frailty phenotype among the elderly / Desenvolvimento de aplicativo para dispositivos móveis voltado para identificação do fenótipo de fragilidade em idosos

Abstract Objective: to develop a mobile app to quickly and safely identify frailty syndrome features among the elderly. Method: a cross-sectional study was conducted. The application was developed for the Android platform in the Java programming language and XML markup. The study instrument was based on five frailty phenotype criteria. The tests were conducted with 20 elderly persons living in a long-term care facility. Results: the twenty elderly persons had a mean age of 76.55 (±9.5) years. Thirteen were identified as frail, five were pre-frail and two were non-frail. The comparison of the results of the instruments of analysis coincided in the general evaluation of frailty and in the individual identification of the five criteria. Conclusion: the data suggests that the use of the application for the evaluation of frailty among the elderly was performed safely, with the advantage of quick access to allow the monitoring of the clinical status and prognosis of the patient.

Resumo Objetivo: desenvolver um aplicativo para dispositivos móveis com o intuito de identificar de maneira rápida e segura as características da síndrome de fragilidade em idosos. Método: estudo transversal quantitativo. O aplicativo foi desenvolvido para a plataforma Android, em linguagem de programação Java e marcação em XML. Os fundamentos utilizados foram baseados nos cinco parâmetros para definição do fenótipo de fragilidade. Os testes foram realizados com 20 idosos residentes em uma instituição de longa permanência. Resultados: a média de idade foi de 76,55 (±9,5) anos. Dentre os 20 idosos investigados, 13 foram classificados como frágeis, cinco pré-frágeis e dois não frágeis. A comparação dos resultados entre os instrumentos de análise coincidiram na avaliação geral da fragilidade e na identificação dos cinco critérios individualmente. Conclusão: a utilização do aplicativo para avaliação da fragilidade em idosos foi feita de maneira segura, com a vantagem do acesso rápido às informações para acompanhamento do quadro clínico e prognóstico do paciente.

Coordination analysis of players' distribution in football using cross-correlation and vector coding techniques.

The purpose of this study was to investigate the coordination between teams spread during football matches using cross-correlation and vector coding techniques. Using a video-based tracking system, we obtained the trajectories of 257 players during 10 matches. Team spread was calculated as functions of time. For a general coordination description, we calculated the cross-correlation between the signals. Vector coding was used to identify the coordination patterns between teams during offensive sequences that ended in shots on goal or defensive tackles. Cross-correlation showed that opponent teams have a tendency to present in-phase coordination, with a short time lag. During offensive sequences, vector coding results showed that, although in-phase coordination dominated, other patterns were observed. We verified that during the early stages, offensive sequences ending in shots on goal present greater anti-phase and attacking team phase periods, compared to sequences ending in tackles. Results suggest that the attacking team may seek to present a contrary behaviour of its opponent (or may lead the adversary behaviour) in the beginning of the attacking play, regarding to the distribution strategy, to increase the chances of a shot on goal. The techniques allowed detecting the coordination patterns between teams, providing additional information about football dynamics and players' interaction.

Artificial gait in complete spinal cord injured subjects: how to assess clinical performance.

OBJECTIVE: Adapt the 6 minutes walking test (6MWT) to artificial gait in complete spinal cord injured (SCI) patients aided by neuromuscular electrical stimulation. METHOD: Nine male individuals with paraplegia (AIS A) participated in this study. Lesion levels varied between T4 and T12 and time post injured from 4 to 13 years. Patients performed 6MWT 1 and 6MWT 2. They used neuromuscular electrical stimulation, and were aided by a walker. The differences between two 6MWT were assessed by using a paired t test. Multiple r-squared was also calculated. RESULTS: The 6MWT 1 and 6MWT 2 were not statistically different for heart rate, distance, mean speed and blood pressure. Multiple r-squared (r2 = 0.96) explained 96% of the variation in the distance walked. CONCLUSION: The use of 6MWT in artificial gait towards assessing exercise walking capacity is reproducible and easy to apply. It can be used to assess SCI artificial gait clinical performance.

Artificial gait in complete spinal cord injured subjects: how to assess clinical performance / Marcha artificial em indivíduos com lesão medular completa: como avaliar desempenho clínico

Objective Adapt the 6 minutes walking test (6MWT) to artificial gait in complete spinal cord injured (SCI) patients aided by neuromuscular electrical stimulation. Method Nine male individuals with paraplegia (AIS A) participated in this study. Lesion levels varied between T4 and T12 and time post injured from 4 to 13 years. Patients performed 6MWT 1 and 6MWT 2. They used neuromuscular electrical stimulation, and were aided by a walker. The differences between two 6MWT were assessed by using a paired t test. Multiple r-squared was also calculated. Results The 6MWT 1 and 6MWT 2 were not statistically different for heart rate, distance, mean speed and blood pressure. Multiple r-squared (r2 = 0.96) explained 96% of the variation in the distance walked. Conclusion The use of 6MWT in artificial gait towards assessing exercise walking capacity is reproducible and easy to apply. It can be used to assess SCI artificial gait clinical performance. .

Objetivo Adaptar o teste de caminhada dos 6 minutos (TC6) para marcha artificial de pacientes com lesão medular completa associado a eletroestimulação neuromuscular. Método Nove participantes do sexo masculino com paraplegia (AIS A) participaram do estudo. O nível de lesão variou entre T4 e T12 , tempo de lesão variou entre 4 e 13 anos. Os pacientes realizaram dois TC6 (TC6-1 e TC6-2). Os participantes usaram eletroestimulação neuromuscular e foram auxiliados por andador. As diferenças entre os dois TC6 foram avaliadas pelo teste t pareado e calculado o r2. Resultados Não foi encontrada diferença estatística entre TC6-1 e TC6-2 para frequência cardíaca, distância, velocidade média e pressão arterial. O r2 = 0,96 explica 96% da variação na distância caminhada. Conclusão O uso do TC6 em marcha artificial para avaliação da capacidade de exercício de caminhada é reprodutível e fácil de aplicar. Esse teste pode ser utilizado para avaliar o desempenho clínico da marcha artificial de indivíduos com lesão medular. .

Analysis of football game-related statistics using multivariate techniques.

Abstract The purpose of this study was to explore football game-related statistics during a competition, using principal component and cluster analyses to determine if it is possible to distinguish the winning teams from the drawing and losing ones. We collected the game-related statistics of the group phase matches of the 2006 World Cup and organised them into a matrix. The principal components of the covariance matrix were calculated. The scores of the first and second components were used to represent the new data, and cluster analysis was applied to separate the elements in two groups (G1 and G2). To analyse the degree of separation between the groups, we calculated the Silhouette Coefficient for each group. Finally, we checked if the winning teams were classified into the same group. The Silhouette Coefficients found for G1 and G2 were 0.54 and 0.55, respectively. Results showed that 70.3% of the winning teams were classified into the same group (G1). Similarly, 67.8% of the drawing and losing teams were classified in G2. This study presented a different way to analyse game-related statistics that allowed the multivariate differences to be shown between successful and unsuccessful teams.

A spectral analysis of team dynamics and tactics in Brazilian football.

The purposes of this study were to characterise the total space covered and the distances between players within teams over ten Brazilian First Division Championship matches. Filmed recordings, combined with a tracking system, were used to obtain the trajectories of the players (n = 277), before and after half-time. The team surface area (the area of the convex hull formed by the positions of the players) and spread (the Frobenius norm of the distance-between-player matrix) were calculated as functions of time. A Fast Fourier Transform (FFT) was applied to each time series. The median frequency was then calculated. The results of the surface area time series median frequencies for the first half (0.63 ± 0.10 cycles · min⁻¹) were significantly greater (P < 0.01) than the second-half values (0.47 ± 0.14 cycles · min⁻¹). Similarly, the spread variable median frequencies for the first half (0.60 ± 0.14 cycles · min⁻¹) were significantly greater (P < 0.01) than the second-half values (0.46 ± 0.16 cycles · min⁻¹). The median frequencies allowed the characterisation of the time series oscillations that represent the speed at which players distribute and then compact their team formation during a match. This analysis can provide insights that allow coaches to better control the team organisation on the pitch.

Quantitative analysis of Brazilian football players' organisation on the pitch.

The purpose of this study was to characterise Brazilian teams' coverage area and spread on the pitch while attacking and defending and to analyse the teams' organisation in tackle and shot on goal situations. We obtained the trajectories of 223 players in eight games with a tracking method. Team area was defined as the area of the convex hull formed by players' positions. Team spread was defined as the Frobenius norm of the distance-between-player matrix. We calculated teams' area and spread over time and in situations of shots on goal (n = 233) and tackles (n = 1897). While the players attacked, spread and area (median +/- confidence interval) ranged from 322.9 +/- 0.8 to 387.8 +/- 1.0 m and from 905.4 +/- 4.4 to 1407.6 +/- 5.5 m2, respectively. On defence, the values were smaller (p < 0.05) and ranged from 283.4 +/- 0.9 to 325.8 +/- 0.9 m and from 773.8 +/- 4.6 to 1158.4 +/- 5.5 m2 for the spread and the area. In defending circumstances, the teams presented a greater area and spread when they suffered shots on goal than when the teams performed tackles. In attacking situations, the teams presented a greater area and spread when they suffered tackles than when they performed shots on goal. The results allowed showing the attacking-defending interaction between Brazilian teams.

Reproducibility of an incremental treadmill VO(2)max test with gas exchange analysis for runners.

The evaluation of performance through the application of adequate physical tests during a sportive season may be a useful tool to evaluate training adaptations and determine training intensities. For runners, treadmill incremental VO(2)max tests with gas exchange analysis have been widely used to determine maximal and submaximal parameters such as the ventilatory threshold (VT) and respiratory compensation point (RCP) running speed. However, these tests often differ in methodological characteristics (e.g., stage duration, grade, and speed increment size), and few studies have examined the reproducibility of their protocol. Therefore, the aim of this study was to verify the reproducibility and determine the running speeds related to maximal and submaximal parameters of a specific incremental maximum effort treadmill protocol for amateur runners. Eleven amateur male runners underwent 4 repetitions of the protocol (25-second stages, each increasing by 0.3 km·h in running speed while the treadmill grade remained fixed at 1%) after 3 minutes of warm-up at 8-8.5 km·h. We found no significant differences in any of the analyzed parameters, including VT, RCP, and VO(2)max during the 4 repetitions (p > 0.05). Further, the results related to running speed showed high within-subject reproducibility (coefficient of variation < 5.2%). The typical error (TE) values for running speed related to VT (TE = 0.62 km·h), RCP (TE = 0.35 km·h), and VO(2)max (TE = 0.43 km·h) indicated high sensitivity and reproducibility of this protocol. We conclude that this VO(2)max protocol facilitates a clear determination of the running speeds related to VT, RCP, and VO(2)max and has the potential to enable the evaluation of small training effects on maximal and submaximal parameters.

Força crítica em nado atado para avaliação da capacidade aeróbia e predição de performances em nado livre / Critical force during tethered swimming for the evaluation of aerobic capacity and prediction of performances in freestyle swimming

The present study investigated the relationship of critical force (Fcrit) with lactate threshold (LLNA) and the intensity corresponding to VO2max (iVO2max) in tethered swimming (TS), and their correlation with maximal performance in 400-m (V400) and 30-min (VT30) freestyle swimming (FS). Seven swimmers were submitted to a TS incremental test for the determination of LLNA and iVO2max. For the determination of Fcrit, the swimmers performed four exercises to exhaustion at intensities (F) corresponding to 87%, 104%, 118% and 134% of iVO2max for the calculation of time limits (Tlim). Fcrit corresponded to the linear coefficient of the ratio between F and 1/tlim. The maximal performance in FS corresponded to the mean velocity obtained during maximal exercise of 400-m and 30-min crawl swimming. Fcrit (51.97 ± 4.02 N) was significantly lower than iVO2max (60.21 ± 8.73 N) but not than LLNA (45.89 ± 8.73). Fcrit was significantly correlated with iVO2max (0.97), LLNA (0.88), V400 (0.85), and VT30 (0.86). These data suggest that Fcrit can be used for the determination of aerobic capacity, prescription of a TS training program, and prediction of performance in FS.

The present study investigated the relationship of critical force (Fcrit) with lactate threshold (LLNA) and the intensity corresponding to VO2max (iVO2max) in tethered swimming (TS), and their correlation with maximal performance in 400-m (V400) and 30-min (VT30) freestyle swimming (FS). Seven swimmers were submitted to a TS incremental test for the determination of LLNA and iVO2max. For the determination of Fcrit, the swimmers performed four exercises to exhaustion at intensities (F) corresponding to 87%, 104%, 118% and 134% of iVO2max for the calculation of time limits (Tlim). Fcrit corresponded to the linear coefficient of the ratio between F and 1/tlim. The maximal performance in FS corresponded to the mean velocity obtained during maximal exercise of 400-m and 30-min crawl swimming. Fcrit (51.97 ± 4.02 N) was significantly lower than iVO2max (60.21 ± 8.73 N) but not than LLNA (45.89 ± 8.73). Fcrit was significantly correlated with iVO2max (0.97), LLNA (0.88), V400 (0.85), and VT30 (0.86). These data suggest that Fcrit can be used for the determination of aerobic capacity, prescription of a TS training program, and prediction of performance in FS.

A variação da acuidade visual durante esforços físicos em atletas com baixa visão, participantes de seleção brasileira de atletismo / The visual acuity variability during physical efforts in low vision athletes from the athletics Brazilian team

INTRODUÇÃO E OBJETIVO: Esta pesquisa teve como objetivo avaliar o comportamento da acuidade visual em atletas com baixa visão, durante um protocolo de esforço contínuo. Pesquisas apontam que a acuidade visual apresenta variações de rendimento quando submetida a esforços físicos em sujeitos sem deficiência visual. MÉTODO: A população estudada foi composta por seis pessoas, praticantes de atletismo e integrantes da seleção brasileira em provas de pista. No primeiro dia aplicou-se o teste de esforço físico progressivo, realizado em esteira. No segundo dia realizou-se o teste de esforço contínuo, o qual foi dividido em três níveis, cada um com 15 minutos de duração e 30 minutos de intervalo entre eles. Como delimitador das intensidades aplicadas utilizaram-se os resultados obtidos no teste de físico progressivo (60 por cento do VE pico, limiar de VE e 90 por cento do VE pico). A aferição da acuidade visual aconteceu antes, durante e após cada nível de intensidade no protocolo de esforço contínuo. O teste t de Student foi utilizado para a análise estatística (p < 0,05). RESULTADOS: A acuidade visual apresentou, nos três níveis de esforço, queda de seu desempenho. A variação entre os resultados da aferição da acuidade visual estática inicial e a mensuração da mesma variável ao final da fase de corrida foi de 44,5 por cento no primeiro nível, 52,5 por cento no segundo e 60 por cento no terceiro nível. Os resultados apresentaram maior degradação do componente visual durante as aferições dinâmicas. As fases de recuperação que sucediam os níveis de esforço mais intensos tiveram os melhores resultados da acuidade visual, após o déficit encontrado durante o exercício. CONCLUSÃO: Pode-se inferir que nessa população específica ocorre queda da acuidade visual durante o esforço. Tal fato implica a necessidade de a classificação esportiva ser direcionada para avaliar a funcionalidade visual de cada atleta com baixa visão durante o esforço físico, já que ...

INTRODUCTION AND OBJECTIVE: This study had as an objective to evaluate the visual acuity behavior in athletes with low vision, during a continuous effort protocol. Researches point out that visual acuity presents performance varieties when submitted to physical efforts in subjects without visual impairment. METHOD: The studied population was composed by six peoples, who practiced athletics and were part of the Brazilian team in track events. The progressive physical effort test was applied on the first day in a treadmill. On the second day the continuous effort test was applied, which was divided in three levels, each one had a 15 and 30 minutes break between them. To determine the intensities, the results obtained in the progressive physical effort test (60 percent of VE peak, limiar VE and 90 percent VE peak) were used. The visual acuity was measured before, during and after each level of intensity in the continuous effort protocol. The t Student test was used for statistics analysis (p < 0.05). RESULTS: The visual acuity presented a decrease in the three levels of effort in its performance. The variety between the initial static visual acuity measure results and the measurement of the same variable in the end of the running phase was 44.5 percent in the first level, 52.5 percent in the second and 60 percent in the third level. The results presented higher degradation of the visual component during the dynamic measurements. The recuperation phases, which succeeded the most intense levels of effort, had the results of the visual acuity, after the deficit found during the exercise. CONCLUSION: It can be inferred that in this specific population there is a decrease in the visual acuity during the effort. This fact implies on the necessity of the visual sportive classification being directed to evaluate the visual functionality of each athlete with low vision during the physical effort, since these varieties can occur during it.

Utilização do intercepto-y na avaliação da aptidão anaeróbia e predição da performance de nadadores treinados / Use of the y-intercept in the evaluation of the anaerobic fitness and performance prediction of trained swimmers

O objetivo desse estudo foi verificar a utilização do intercepto-y na avaliação da aptidão anaeróbia e predição da performance de nadadores treinados. Foram participantes do estudo 14 nadadores com idade entre 15 e 18 anos. Os atletas realizaram o teste de nado atado, performance máxima e velocidade crítica (VC) para determinação da capacidade de nado anaeróbio (CTA), todos em nado crawl em um período de três dias. 1) O teste de nado atado consistiu em realizar esforço máximo durante 30 segundos amarrado a um aparato de medição com células de carga para mensuração da força pico (Fpic), aptidão anaeróbia (AP ANA) e concentração de lactato pico ([la-]pic) conforme Papoti et al. (11); 2) Os participantes realizaram também performances máximas nas distâncias de 100, 200, 300, 400 e 600 m, com intervalo mínimo de duas horas entre cada nado; 3) E o teste de VC foi aplicado para determinação da CTA utilizando todas as combinações possíveis dos resultados das performances máximas, através do modelo de regressão linear entre distância versus tempo. Foi encontrada média de 25,07± 4,22 m nas 16 combinações de CTAs encontradas e coeficiente de regressão linear variando entre 0,99 e 1,00 e erro de coeficiente linear de 19,30± 5,9 por cento. Não foram encontradas correlações significativas entre as CTAs e performances máximas, Fpic (227,81± 63,02 N), AP ANA (86,55± 13,05 N) e [la-]pic (6,80± 1,03 mM). Contudo, foram encontradas correlações significativas entre a AP ANA e as performances máximas. Desse modo, é possível concluir que a CTA representada pelo intercepto-y da relação distância versus tempo de nado, parece não ser um bom parâmetro na avaliação da aptidão anaeróbia e predição de performances entre 100 m e 600 m nado crawl.

Freqüência cardíaca de repouso e modulação parassimpática cardíaca em atletas idosos e idosos fisicamente ativos / Resting heart rate and cardiac parasympathetic modulation in old athletes and physically active elderly

Objetivo: Foi comparar atletas idosos a idosos fisicamente ativos, no que diz respeito à freqüência cardíaca e variabilidade da freqüência cardíaca nas condições de repouso em vigília e durante o sono. Métodos: Dezessete voluntários saudáveis do sexo masculino (65,2±4 anos) divididos nos grupos atletas (n=9) e ativos (n=8) foram submetidos à eletrocardiografia dinâmica de 24 horas, para posterior análise dos sinais por meio do sistema Holter for Windows (Rozzin). O índice considerado na análise da variabilidade da freqüência cardíaca foi a rMSSD, ou seja, a raiz quadrada da somatória do quadrado das diferenças entre os iRR em um tempo determinado menos um iRR, tida como indicadora da atividade parassimpática sobre o coração. Resultados: A freqüência cardíaca de repouso nas condições, tanto de vigília (mediana=49vs 57bpm), como de sono (mediana=49vs 56bpm), foram menores (p<0,05) para os atletas, mas não foram encontradas diferenças (p>0,05) entre as referidas condições para um mesmo grupo. Também não foram observadas diferenças (p>0,05) inter ou intra grupos no que se refere ao rMSSD. Os valores da mediana de rMSSD durante a vigília em repouso foram de 42,5 e 27,9ms, enquanto que durante o sono foram de 47,2 e 34,5ms para atletas e ativos, respectivamente. Conclusão: Estes dados sugerem que a maior bradicardia de repouso entre os atletas idosos, em relação aos idosos ativos, não se explica por uma maior atividade parassimpática sobre o nodo sinoatrial. Além disso, para essa população idosa, a magnitude das adaptações autonômicas sobre o coração, advindas do treinamento recreativo de baixa intensidade, parece ser semelhante àquela advinda do treinamento competitivo.

Ajustes cardipovasculares ao exercício físico : efeitos do treinamento aeróbio / Cardiovascular adjustments to physical exercise. Effects of aerobic training

Na presente revisäo säo discutidas as principais adaptaçöes do sistema cardiovascular induzidas pelo treinamento físico aeróbio. Especial ênfase foi dada ao estudo das modificaçöes da freqüência cardíaca em repouso e em exercício, devidas às adaptaçöes do sistema nervoso autônomo simpático e parassimpático atuantes sobre o nódulo sinusal. Finalmente, acena-se para a possibilidade de que, sob condiçöes rigorosamente padronizadas, possa se utilizar a resposta da freqüência cardíaca em exercício dinâmico, como teste de avaliaçäo da capacidade aeróbia em indivíduos normais

Disfunçäo sistólica e diastólica nas formas indeterminada, digestiva e cardíaca crônica da moléstia de Chagas / Systolic and diastolic dysfunction in the indeterminate, digestive and chronic cardiac forms of Chagas' disease

Estudou-se o efeito do esforço isométrico (EI) padronizado (100% CVM), sobre as funçöes sistólica e diastólica do ventrículo esquerdo (VE), mediante ecocardiografia modo M digitizada, em 14 controles normais (N) e em, 40 pacientes chagásicos: 14 com a forma indeterminada (FIMC), 14 cardiopatas crônicos (CCC) e 12 com a forma digestiva (FDMC). Na situaçäo de repouso, os valores da frequência cardíaca e da pressäo arterial sistêmica (PAS) foram superponíveis nos 4 grupos. Quanto à funçäo sistólica do VE, apenas os CCC apresentavam valores da variaço percentuial sistólica do septo (%DeltaES) e da parede posterior (%DeltaEPP), da velocidade de encurtamento circunferencial normalizada (Vcf) e do percentual de encurtamento sistólico da dimensäo transversal (%DeltaD) significativamente (p<0,025) menores que os normais. Os CCC e FDMC foram discriminados dos N enquanto à velocidade (VMN) e à velocidade máxima normalizada (VMNA) de alongamento do VE, utilizados para avaliar a funçäo diastólica cardíaca. O EI induziu incrementos significativos e comparáveis da PAS, nos 4 grupos. A resposta cronotrópica dos CC e FDMC foi apreciavelmente menor que a dos normais. O EI permitiu discriminar, comparativamente aos normais, também o grupo de pacientes com a foma indeterminada da moléstia, quanto ao desempenho diastólico ventricular. Duas conclusöes säo possíveis, a partir desses resultados: a) a disfunçäo diastólica deve preceder o comprometimento sistólico durante o processo de instalaçäo da agressäo chagásica crônica ao coraçäo ; b) o esoforço isométrico mostra-se eficaz como método de sensibilizar o estudo ecocardiográfico para detecçäo de graus incipientes de diminuiçäo da reserva cardiovascular na moléstia Chagas

Utilizaçäo de análise de sistemas no estudo da resposta cardiorespiratória ao esforço físico dinâmico / System analysis applied on the study of cardiorespiratory responses induced by dynamic exercise

Técnicas de análise de sistemas foram aplicadas no estudo da resposta cardiorespiratória em 5 indivíduos normais, que se submeteram a exercício dinâmico em bicicleta ergomátrica, com cargas tipo rampa, degrau e senóide. Para as respostas a entrada tipo rampa, o limiar de anaerobiose ventilatória (L.A.) foi determinado e os testes degrau e senoidais foram executados em valor percentual desta carga. É discutido o processo de determinaçäo do L.A., e a análise teórica desenvolvida está em concordância com os valores achados. Para entradas tipo degrau documentou-se que o decremento do intervalo RR (IRR) com a carga é dependente do IRR de repouso. Para entradas tipo senóide, foram construídos os diagramas de Bode individuais, que se asemelham a filtros passa baixas. Além disso, respostas apresentando freqüência duplicada foram encontradas para a ventilaçäo em períodos menores que 4 min e para o IRR em períodos menores que 2 min. Estes resultados estabelecem padröes clássicos de näo linearidades que podem subsidiar novas pesquisas ou análise de sistemas aplicadas ao esforço físiso dinâmico