RESUMO O objetivo do presente estudo foi investigar o efeito hipotensivo induzido pela corrida aeróbica em jovens adultos. Trinta e um indivíduos (18 mulheres e 13 homens) foram submetidos a uma avaliação antropométrica e o protocolo de corrida proposto em uma esteira ergométrica durante 40 min entre 60 a 70% da frequência cardíaca de reserva. Realizaram-se medidas da pressão arterial sistólica (PAS) e pressão arterial diastólica (PAD) que posteriormente foram comparados antes e ao final do protocolo de corrida através do teste t de Student para as variáveis dependentes. Todos os testes foram assumidos com α = 0,05. Em comparação com a PAS antes (127,1 ± 11,5 mmHg) e após (119,9 ± 10,2 mmHg) a corrida, os resultados obtidos evidenciaram uma diminuição da pressão arterial sistólica, o qual resultou uma diferença média de -7,2 ± 6,2 mmHg, demonstrando uma diferença significativa (p = 0,00001). Entretanto, na PAD antes (73,6 ± 8,6 mmHg) e após (72,5 ± 7,8 mmHg) não demonstrou uma diferença significativa (p = 0,36) como efeito agudo na diminuição após a corrida. Portanto, conclui-se que a corrida em moderada intensidade e longa duração pode ser auxiliado no tratamento não farmacológico da hipertensão arterial e como melhoria na saúde cardiovascular.

ABSTRACT The aim of the present study was to investigate the acute effects of blood pressure induced by moderate intensity aerobic exercise in young adults. Thirty-one individuals (18 women and 13 men) were submitted an anthropometric evaluation and a 40-min running protocol between 60% and 70% of the reserve heart rate. Hemodynamic measurements, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were carried out before and after the running protocol through Student's t-test for the dependent variables. All tests assumed α = 0.05. Significant differences were recorded between SBP before (127.1 ± 11.5 mmHg) and after (119.9 ± 10.2 mmHg) the running protocol. The results showed a decrease in systolic blood pressure, which resulted in a mean difference of -7.2 ± 6.2 mmHg, demonstrating a significant difference (p = 0.00001). However, in the DBP before (73.6 ± 8.6 mmHg) and after (72.5 ± 7.8 mmHg) no showing a significant difference (p = 0.36) as an acute effect on the decrease the running protocol. In conclusion, that moderate intensity and long duration running exercise can be aided in the non-pharmacological treatment of arterial hypertension and as an improvement in cardiovascular health.

This study aimed to determine a model for stratifying the maximum oxygen uptake (VO2max) based on heart rate variability (HRV) parameters at rest. It was applied 70 young adult physically active male. After recording the resting tachogram with a heart rate monitor for 5 min, a maximal incremental test was performed to measure VO2max. Based on VO2max percentile, participants were divided into two groups of 35: high (HG) and low (LG) aerobic fitness group. Groups were compared according to: (1) VO2max; (2) Classical HRV parameters and the cardiac deceleration rate (CDR). HG presented significant higher VO2max than LG (48.61 ± 6.70 vs 34.62 ± 3.81 ml.kg-1.min-1). The HG higher values in the time domain HRV parameters, as well as in the high frequency contents in the frequency domain. Also, CDR index was significant higher for HG than LG (p<0.01). The model for predicting VO2max was obtained by backward stepwise multivariate logistic regression assuming as independent variables CDR and pNN50. This model presented 85.74% positive predictive value, 88.51% negative predictive value and 87.16% total accuracy. In conclusion, the use of the proposed model was able to stratify the level of aerobic fitness in young healthy adult males at rest.

Introduction This study aims at investigating the coupling of the cardiac and locomotor systems during running in trained and untrained males. Methods Sixteen healthy young males subjects were submitted to an anthropometric evaluation, followed by a treadmill test at 70% to 75% of heart rate reserve. Based on the average velocity, they were divided into two groups of eight, trained group (TG) and untrained group (UT). The electrocardiogram and the electromyogram of the vastus lateralis muscle of the right thigh were digitized at a sampling rate of 1000 Hz, and processed off-line. Each cardiac and electromyographic cycle was detected to further investigate the coupling between cardiac and running rates in time domain, using the cross-correlation, and in the frequency domain, using a phase synchronization measure based on the Hilbert transform. A Shannon entropy index and magnitude squared coherence were also applied to improve analysis. Results Both groups presented low cross-correlation (0.18 ± 0.07 TG and 0.15 ± 0.08 UG) values between these signals, and only four from 16 subjects presented short epochs of phase synchronization (4.1 ± 8.6% TG and 3.2±7.3% UG) between signals, occurring at a low frequency band and random phase differences. The low to moderate coherence (0.67 ± 0.16 TG and 0.64 ± 0.16 UG) observed at 0.1 Hz appears to be an effect of the simultaneous action of sympathetic system over both cardiac and muscular rhythms. Conclusion The combined results suggest that the chosen exercise protocol was not able to cause cardiolocomotor synchronization.

O objetivo do presente estudo foi desenvolver uma equação para predição da carga de uma repetição máxima (1RM) em homens e mulheres, usando exclusivamente as características antropométricas. Participaram deste estudo 44 jovens de baixo risco, com experiência em treinamento de força, sendo 22 do sexo masculino (23 ± 4 anos, 76,6 ± 12,7kg, 173,9 ± 5,5cm, 11 ± 4,5% de gordura) e 22 do feminino (22 ± 4 anos, 54 ± 6,0kg, 161 ± 5,8cm, 18 ± 2,2% de gordura). Inicialmente, eles passaram por uma avaliação antropométrica seguida de um teste de 1RM de familiarização no exercício de desenvolvimento, que foi repetido após 48h. A repetibilidade do teste de 1RM foi testada pelo Wilcoxon matched paired test. Finalmente, a carga de 1RM foi modelada em função das variáveis antropométricas por regressão linear múltipla (forward stepwise) usando como critério de corte das variáveis independentes deltar² < 0,01. A confiabilidade dos modelos foi expressa pela análise de Bland e Altman. Adotou-se em todos os testes alfa = 0,05. Não se registraram diferenças entre teste e reteste, resultando em 44,6 ± 13,2kg e 12,2 ± 3,2kg nos indivíduos do sexo masculino (SM) e feminino (SF), respectivamente. Além das variáveis antropométricas, incluiu-se aos modelos o tempo de experiência em treinamento de força. No SM, o modelo resultou em 84% da variância explicada, com erro padrão equivalente a 12%. Por outro lado, no SF, a capacidade preditiva do modelo obtido foi mais fraca, resultando em 56% da variância explicada e erro padrão equivalente a 20%. Em conclusão, os modelos obtidos mostraram adequada confiabilidade, de forma que podem ser utilizados como ferramentas para predição da carga de 1RM.

The goal of the present study was to develop an equation for predicting the workload of one maximal repetition (1RM) in women and men, based exclusively on anthropometrical characteristics. Forty-four low-risk and experienced in strength training young subjects, being 22 male (23 ± 4 years, 76.6 ± 12.7 kg, 173.9 ± 5.5 cm, 11 ± 4.5 % of body fat) and 22 female (22 ± 4 years, 54 ± 6.0 kg, 161 ± 5.8 cm, 18 ± 2.2 % of body fat) volunteered for this study. All subjects were submitted to an anthropometrical evaluation followed by a 1RM familiarization test (shoulder press), which was repeated after 48h. The repeatability was tested using Wilcoxon Matched paired test. Finally, the 1RM workload was modeled in relation to the anthropometrical variables through multiple linear regression (forward stepwise) using as cutoff criteria for the independent variables deltar² < 0.01. The models reliability was expressed by the Bland and Altman analysis. All tests assumed alpha = 0.05. No significant differences were recorded between the two tests, resulting 44.6 ± 13.2 kg and 12.2 ± 3.2kg, for male (MS) and female (FS) subjects respectively. The time of practice in strength training was also included in the models. The model resulted in 84% of explained variance and a standard error of 12% for the MS. On the other hand, for the FS the predictive capacity was weaker than for = the MS, resulting in 56% of the explained variance and a standard error of 20%. In conclusion, the obtained models showed acceptable reliability so that they can be currently used as a tool for predicting the 1RM workload.

El objetivo del presente estudio ha sido desarrollar una ecuación para predecir la carga de una repetición máxima (1RM) en hombres y mujeres, usando exclusivamente las características antropométricas. Participaron de este estudio 44 jóvenes de bajo riesgo, con experiencia en entrenamiento de fuerza, 22 del sexo masculino (23 ± 4 años, 76,6 ± 12,7 kg, 173,9 ± 5,5 cm, 11 ± 4,5% de grasa) y 22 del sexo femenino (22 ± 4 años, 54 ± 6,0 kg, 161 ± 5,8 cm, 18 ± 2,2% de grasa). Al inicio, estos pasaron por una evaluación antropométrica seguida de un test de 1RM de familiarización en el ejercicio en desarrollo, que fue repetido después de 48 h. La repetibilidad del test de 1RM fue probada por Wilcoxon matched paired test. Finalmente la carga de 1RM fue modelada en función de las variables antropométricas por regresión lineal múltiple (forward stepwise) usando como criterio de aglomeración de las variables independientes deltar² < 0,01. La confiabilidad de los modelos se expresó por el análisis de Bland y Altman. En todos los tests se adoptó alfa = 0,05. No se registraron diferencias entre el test y el retest, resultando en 44,6 ± 13,2 kg y 12,2 ± 3,2kg en los individuos del sexo masculino (SM) y femenino (SF), respectivamente. Fuera de las variables antropométricas, se incluyó a los modelos el tiempo de experiencia en la actividad de fuerza. En el SM, el modelo resultó en 84% de la varianza explicada, con un error padrón equivalente a 12%. Por otro lado, en el SF, la capacidad predictiva del modelo obtenido no fue tan eficaz, resultando en 56% de la varianza explicada y un error padrón equivalente a 20%. En conclusión, los modelos obtenidos mostraron adecuada confiabilidad, de forma que pueden ser utilizados como herramientas para predecir la carga de 1RM.