Influence of aerobic fitness on the correspondence between heart rate variability and ventilatory threshold

The aims of this study were to verify the correspondence between heart rate variability (HRV) and ventilatory thresholds during a progressive exercise test and the relationship with low and high aerobic fitness levels. Twenty male volunteers (29.5±6.2 years; 75.9±13.0 kg; 175.0±7.4 cm) were recruited. The subjects were allocated to two groups according to their VO2max <48.8 ml•kg−1•min−1 (low cardiorespiratory fitness group) (n=10) and >48.81 ml•kg−1•min−1 (high cardiorespiratory fitness group) (n=10). A progressive test was performed, consisting of 3-min stages beginning at 25 watts and increasing by 25 watts every 3-min. The HRV threshold (HRVT) and ventilatory threshold (VT) analyses were performed through visual inspection. The comparisons with RMSSD values in percentage of maximum workload resulted in a higher effect size (ES) than the SDNN values. The VO2 in the high cardiorespiratory fitness group at VT (+32%), HRVTRMSSD (+27%), and HRVTSDNN (+31%) was signifi cantly higher compared to the group with low cardiorespiratory fitness. Higher values were observed for relative load (W•kg-1) at VT and HRVTSDNN in the high cardiorespiratory fitness group in comparison with the low cardiorespiratory fitness group (P<0.05), but no difference for VT and HRVTRMSSD. Signifi cant correlations between at VT and HRVTSDNN (r=0.77) were found only in the low cardiorespiratory fitness group. Cardiorespiratory fitness should be regarded as a factor for HRVT evaluation. The HRVTSDNN was closer to the VT in the low cardiorespiratory fitness group than the HRVTRMSSD, however, the use of vagal modulation assessed using the HRV parameter was more sensitive to observe possible differences regarding cardiorespiratory fitness.The aims of this study were to verify the correspondence between heart rate variability (HRV) and ventilatory thresholds during a progressive exercise test and the relationship with low and high aerobic fitness levels. Twenty male volunteers (29.5±6.2 years; 75.9±13.0 kg; 175.0±7.4 cm) were recruited. The subjects were allocated to two groups according to their VO2max <48.8 ml•kg−1•min−1 (low cardiorespiratory fitness group) (n=10) and >48.81 ml•kg−1•min−1 (high cardiorespiratory fitness group) (n=10). A progressive test was performed, consisting of 3-min stages beginning at 25 watts and increasing by 25 watts every 3-min. The HRV threshold (HRVT) and ventilatory threshold (VT) analyses were performed through visual inspection. The comparisons with RMSSD values in percentage of maximum workload resulted in a higher effect size (ES) than the SDNN values. The VO2 in the high cardiorespiratory fitness group at VT (+32%), HRVTRMSSD (+27%), and HRVTSDNN (+31%) was signifi cantly higher compared to the group with low cardiorespiratory fitness. Higher values were observed for relative load (W•kg-1) at VT and HRVTSDNN in the high cardiorespiratory fitness group in comparison with the low cardiorespiratory fitness group (P<0.05), but no difference for VT and HRVTRMSSD. Signifi cant correlations between at VT and HRVTSDNN (r=0.77) were found only in the low cardiorespiratory fitness group. Cardiorespiratory fitness should be regarded as a factor for HRVT evaluation. The HRVTSDNN was closer to the VT in the low cardiorespiratory fitness group than the HRVTRMSSD, however, the use of vagal modulation assessed using the HRV parameter was more sensitive to observe possible differences regarding cardiorespiratory fitness

Atividade física habitual e variabilidade da frequência cardíaca de repouso em nipo-brasileiros praticantes e não praticantes de PARK GOLF

The aims of this study were to compare the habitual physical activity (HPA) level by means of steps.day-1 and the resting heart rate variability (HRV) parameters of nipo-brazilians practitioners (GPG) and non-practitioners (GNP) of Park Golf and verify the correlations between HPA and HRV. Thirty three subjects of both genders (68.2±6.3 years) participated of this study, being 20 subjects in GPG (68.3±6.3 years) and 13 in GNP (68.2±6.4 years). The subjects wore the pedometer for one week to measure the HPA. The HRV was analyzed beat-to-beat at rest in the supine position using a heart rate monitor and the respiratory frequency was controlled in 12 respiratory cycles per minute. The HPA level was higher in GPG when compared to GNP. There were no differences in the HRV between groups. Regarding gender, women presented higher mean steps.day-1 and parasympathetic indices of HRV. Men presented higher sympathetic indices. The HPA level was significantly correlated with body mass index (BMI) and with the mean R-R intervals. The greater HPA level reported in GPG was not sufficient to induce a more favorable resting HRV than in GNP.Os objetivos deste estudo foram comparar o nível de atividade física habitual (AFH) por meio do número de passos.dia-1 e os parâmetros da variabilidade da frequência cardíaca (VFC) de repouso em nipo-brasileiros praticantes (GPG) e não praticantes (GNP) de Park Golf e verificar as correlações entre o nível de AFH e a VFC. Trinta e três indivíduos de ambos os gêneros (68,2±6,3 anos) fizeram parte do estudo, sendo 20 sujeitos no GPG (68,3±6,3 anos) e 13 no GNP (68,2±6,4 anos). Os sujeitos utilizaram o pedômetro por uma semana para mensurar a AFH. A VFC foi analisada batimento-a-batimento no repouso em decúbito dorsal por meio de um cardiofrequencímetro. Durante a avaliação da VFC, houve controle da freqüência respiratória em 12 respirações por minuto. A AFH foi maior no GPG quando comparado ao GNP. Não foram observadas diferenças nos indicadores da VFC entre os grupos. Em relação aos gêneros, as mulheres apresentaram maiores médias de passos.dia-1 e valores de índices parassimpáticos pela VFC. Os homens obtiveram maiores índices simpáticos. O nível de AFH apresentou correlação significante com o índice de massa corporal (IMC) e com a média dos intervalos R-R. O maior nível de AFH encontrado no GPG não foi suficiente para promover VFC de repouso mais favorável em relação ao GNP

Avaliação da capacidade de realizar sprints repetidos no futebol.doi: http://dx.doi.org/10.5016/1980-6574.2010v16n4p1006

The most of team sports football, basketball, handball) is characterized by intermittency, fluctuating between brief periods of maximum effort or near the maximum followed by periods and forms of recovery. Some authors have proposed several tests to measure the ability of these athletes to perform repeated sprints (repeated sprint ability - RSA), which would be directly related to the decisive moments during match. Then, this study aimed to describe the different test protocols to assess RSA in soccer players, based on original articles and reviews selected in some databases (Medline). Therefore, we suggest four protocols, two involving sprints linear (Aziz et al. 2008; Reilly, 2001) and two involving sprints with changes of direction (Bangsbo, 2008; Impellizzeri et al., 2008) to evaluate the RSA in soccer players, generating important performance parameters, which allow to develop training programs to improve that capacity. We also recommend the use of average and/or total time as a general measure of ability to perform repeated sprints and the partial duration of each sprint to identify strengths and weakness of each athlete.A maioria dos esportes coletivos (futebol, basquete, handebol) tem como característica a intermitência, flutuando entre breves períodos de esforços máximos ou próximos ao máximo seguidos de períodos e formas de recuperação. Alguns autores têm proposto diversos testes que tem por finalidade mensurar a capacidade desses atletas em realizar esforços repetidos máximos (RSA), a qual estaria diretamente relacionada aos momentos decisivos durante partida. Dessa forma, o presente estudo teve como objetivo descrever os diferentes protocolos de testes para avaliar a RSA em jogadores de futebol, com base em artigos originais e algumas revisões levantadas em cases de dados (Medline). Diante dos achados, sugerimos a utilização de quatro protocolos, dois envolvendo sprints lineares (AZIZ et al., 2008; REILLY, 2001) e dois utilizando sprints com mudanças de direção (BANGSBO, 2008; IMPELLIZZERI et al., 2008) para avaliação da RSA em jogadores de futebol, gerando importantes parâmetros de desempenho, que permitem ainda a elaboração de programas de treinamento para a melhora dessa capacidade. Recomendamos ainda, a utilização do tempo médio e/ou total como uma medida geral da capacidade de realizar sprints repetidos e as parciais de tempo de cada sprint para identificar possíveis pontos fortes e fraco de cada atleta

Avaliação da capacidade de realizar sprints repetidos no futebol

A maioria dos esportes coletivos (ex.: futebol, basquete, handebol) tem como característica a intermitência, flutuando entre breves períodos de esforços máximos ou próximos ao máximo seguidos de períodos e formas de recuperação. Alguns autores têm proposto diversos testes que tem por finalidade mensurar a capacidade desses atletas em realizar esforços repetidos máximos (RSA), a qual estaria diretamente relacionada aos momentos decisivos durante partida. Dessa forma, o presente estudo teve como objetivo descrever os diferentes protocolos de testes para avaliar a RSA em jogadores de futebol, com base em artigos originais e algumas revisões levantadas na base de dados Medline. Diante dos achados, sugerimos a utilização de quatro protocolos, dois envolvendo sprints lineares (AZIZ et al., 2008; REILLY, 2001) e dois utilizando sprints com mudanças de direção (BANGSBO, 2008; IMPELLIZZERI et al., 2008) para avaliação da RSA em jogadores de futebol, gerando importantes parâmetros de desempenho, que permitem ainda a elaboração de programas de treinamento para a melhora dessa capacidade. Recomendamos ainda, a utilização do tempo médio e/ou total como uma medida geral da capacidade de realizar sprints repetidos e as parciais de tempo de cada sprint para identificar possíveis pontos fortes e fraco de cada atleta

Métodos de quantificação de carga de treinamento em exercício realizado no máximo estado estável de lactato. doi: http://dx.doi.org/10.5016/1980-6574.2010v16n2p311

The aim of the present study was to compare and correlate training impulse (TRIMP) estimates proposed by Banister (TRIMPBanister), Stagno (TRIMPStagno) and Manzi (TRIMPManzi). The subjects were submitted to an incremental test on cycle ergometer with heart rate and blood lactate concentration measurements. In the second occasion, they performed 30 min. of exercise at the intensity corresponding to maximal lactate steady state, and TRIMPBanister, TRIMPStagno and TRIMPManzi were calculated. The mean values of TRIMPBanister (56.5 ± 8.2 u.a.) and TRIMPStagno (51.2 ± 12.4 u.a.) were not different (P > 0.05) and were highly correlated (r = 0.90). Besides this, they presented a good agreement level, which means low bias and relatively narrow limits of agreement. On the other hand, despite highly correlated (r = 0.93), TRIMPStagno and TRIMPManzi (73.4 ± 17.6 u.a.) were different (P 0,05) e foram altamente correlacionados (r = 0,90), com boa concordância, ou seja, viés reduzido e limites de concordância relativamente estreitos. O TRIMPStagno e TRIMPManzi (73,4 ± 17,6 u.a.) apresentarem alta correlação (r = 0,93), mas com diferença significantes entre eles; ainda, se mostraram pouco concordantes. As estimativas de TRIMPBanister e TRIMPManzi não foram diferentes (P = 0,06) e apresentaram alta correlação (r = 0,82), com baixa concordância. Assim, conclui-se que os métodos de TRIMP não são equivalentes. Na prática, parece ser prudente monitorar o processo de treinamento assumindo apenas uma das estimativas

Relationship between vagal withdrawal and reactivation indices and aerobic capacity in taekwondo athletes

The aim of this study was to evaluate the relationship between vagal withdrawal and reactivation indices and maximal running velocity (Vmax) in taekwondo athletes. Eleven elite taekwondo athletes (seven men: 23.7±2.2 years, 72.4±7.0 kg, 178.8±7.5 cm, 51.9±2.9 ml.kg-1.min-1, and four women: 18.8±1.5 years, 61.8±1.8 kg, 168.0±4.4 cm, 41.6±2.4 ml.kg-1.min-1) performed a graded exercise test until exhaustion, with the last complete stage performed corresponding to Vmax. Heart rate variability (HRV) parameters were calculated at 1-minute intervals until 85% of maximum HR and plotted against time for the estimation of vagal withdrawal indices (τ, amplitude (A) and area under the curve (AUC)). Vagal reactivation indices were determined based on HR recovery during the first 60 s (HRR60s) and negative reciprocal of the slope of the regression line obtained during the first 30 s of HRR (T30). The vagal withdrawal parameters A and AUC were moderately and significantly correlated with Vmax (r = 0.61-0.71, P < 0.05), whereas τ presented a low correlation (r = 0.22-0.40, P > 0.05). T30 and HRR60s were also significantly correlated with Vmax (r = -0.77 and 0.64, P < 0.05, respectively). The present results showed that vagal withdrawal (A and AUC) and vagal reactivation (T30 and HRR60s) indices were significantly correlated with Vmax, suggesting that these indices can be used for the evaluation and monitoring of aerobic fitness in taekwondo athletes

Relationship between vagal withdrawaland reactivation indices and aerobic capacity in taekwondo athletes

The aim of this study was to evaluate the relationship between vagal withdrawal and reactivation indices and maximal running velocity (Vmax) in taekwondo athletes. Eleven elite taekwondo athletes (seven men: 23.7±2.2 years, 72.4±7.0 kg, 178.8±7.5 cm, 51.9±2.9 ml.kg-1.min-1, and four women: 18.8±1.5 years, 61.8±1.8 kg, 168.0±4.4 cm, 41.6±2.4 ml.kg-1.min-1) performed a graded exercise test until exhaustion, with the last complete stage performed corresponding to Vmax. Heart rate variability (HRV) parameters were calculated at 1-minute intervals until 85% of maximum HR and plotted against time for the estimation of vagal withdrawal indices (τ, amplitude (A) and area under the curve (AUC)). Vagal reactivation indices were determined based on HR recovery during the first 60 s (HRR60s) and negative reciprocal of the slope of the regression line obtained during the first 30 s of HRR (T30). The vagal withdrawal parameters A and AUC were moderately and significantly correlated with Vmax (r = 0.61-0.71, P 0.05). T30 and HRR60s were also significantly correlated with Vmax (r = -0.77 and 0.64, P < 0.05, respectively). The present results showed that vagal withdrawal (A and AUC) and vagal reactivation (T30 and HRR60s) indices were significantly correlated with Vmax, suggesting that these indices can be used for the evaluation and monitoring of aerobic fitness in taekwondo athletes