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BACKGROUND: A cardiopulmonary exercise test (CPET) is used to determine the ventilatory thresholds and to directly assess cardiorespiratory capacity. However, its reproducibility should be tested in people with stroke as sequelae imposed by the stroke may induce important variations among and within each subject, affecting the reproducibility of the physiological responses to CPET. PURPOSE: This cross-sectional repeated measures study design aims to determine the reproducibility of anaerobic threshold (AT), respiratory compensation point (RCP), and maximal cardiorespiratory capacity assessed during a CPET in people with stroke. METHODS: Twenty-eight subjects with hemiparesis after stroke aging 60 ± 13 years were submitted to two treadmill CPETs with identical protocols. DATA ANALYSIS: The reproducibility of heart rate (HR) and oxygen consumption (VO2) obtained at AT, RCP, and peak effort was evaluated by systematic error (paired t-test); reliability (ICC and 95% confidence interval); and agreement (typical error and coefficient of variation). RESULTS: There were no systematic errors for HR and VO2assessed at AT, RCP, and peak effort (p > 0,05). Reliability was high for these variables during CPET (ICCs > 0.93). Agreement was good for all variables. Typical errors for HR and VO2 assessed at AT, RCP, and peak effort were, respectively, 7, 7, and 8 bpm, and 1.51, 1.44, and 1.57 ml.kg-1.min-1. Coefficients of variation assessed at AT, RCP, and peak effort were, respectively, 5.7, 5.1, and 6.0% for HR and 8.7, 7.3, and 7.5% for VO2. CONCLUSIONS: HR and VO2 measured at AT, RCP, and peak effort during a treadmill CPET present good reproducibility in people with stroke, showing high reliability and good agreement.

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Male athletes tend to outperform female athletes in several endurance sports. Maximum cardiac output can be estimated by maximal oxygen consumption (V˙O2max), and it has been established that men present V˙O2max values about 20% higher than women. Although sex differences in V˙O2max have already been well studied, few studies have assessed sex differences with regard to muscle oxidative capacity. The aim of this study was to compare aerobic muscle quality, accessed by V˙O2max and adjusted by lower limb lean mass, between male and female amateur triathletes. The study also aimed to compare sex differences according to V˙O2 submaximal values assessed at ventilatory thresholds. A total of 57 participants (23 women and 34 men), who had been training for Olympic-distance triathlon races, underwent body composition evaluation by dual-energy X-ray absorptiometry and performed a cardiorespiratory maximal test on a treadmill. Male athletes had significantly higher V˙O2max, both absolutely and when adjusted to body mass. Conversely, when V˙O2max was adjusted for lean mass, there was no significant difference between sexes. The same was observed at submaximal exercise intensities. In conclusion, differences in V˙O2max adjusted to body mass but not lean mass may explain, at least in part, sex differences in performance in triathlons, marathons, cycling, and other endurance sports.

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Maximal oxygen uptake (V˙O2max), ventilatory threshold (VT) and respiratory compensation point (RCP) can be used to monitor the training intensity and the race strategy, and the elucidation of the specificities existing between the sexes can be interesting for coaches and athletes. The aim of the study was to compare ventilatory threshold (VT), respiratory compensation point (RCP), and the percentage of the maximal aerobic speed (MAS) that can be maintained in a triathlon race between sexes. Forty-one triathletes (22 men and 19 women), 42.1 ± 8.4 (26 to 60) years old, that raced the same Olympic triathlon underwent a cardiorespiratory maximal treadmill test to assess their VT, RPC, and MAS, and race speed. The maximal oxygen uptake (V˙O2max) (54.0 ± 5.1 vs. 49.8 ± 7.7 mL/kg/min, p < 0.001) and MAS (17 ± 2 vs. 15 ± 2 km/h, p = 0.001) were significantly higher in male than in female athletes. Conversely, there were no sex differences according to the percentage of V˙O2max reached at VT (74.4 ± 4.9 vs. 76.1 ± 5.4%, p = 0.298) and RCP (89.9 ± 3.6 vs. 90.6 ± 4.0%, p = 0.560). The mean speed during the race did not differ between sexes (12.1 ± 1.7 km/h and 11.7 ± 1.8 km/h, p = 0.506, respectively). Finally, men performed the running split at a lower percentage of speed at RCP than women (84.0 ± 8.7 vs. 91.2 ± 7.0%, respectively, p = 0.005). Therefore, male and female athletes accomplished the running split in an Olympic triathlon distance at distinct relative intensities, as female athletes run at a higher RCP percentage.

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This study aimed to evaluate if the changes in oxygen saturation levels at intercostal muscles (SmO2-m.intercostales) assessed by near-infrared spectroscopy (NIRS) using a wearable device could determine the respiratory compensation point (RCP) during exercise. Fifteen healthy competitive triathletes (eight males; 29 ± 6 years; height 167.6 ± 25.6 cm; weight 69.2 ± 9.4 kg; V˙O2-máx 58.4 ± 8.1 mL·kg−1·min−1) were evaluated in a cycle ergometer during the maximal oxygen-uptake test (V˙O2-máx), while lung ventilation (V˙E), power output (watts, W) and SmO2-m.intercostales were measured. RCP was determined by visual method (RCPvisual: changes at ventilatory equivalents (V˙E·V˙CO2−1, V˙E·V˙O2−1) and end-tidal respiratory pressure (PetO2, PetCO2) and NIRS method (RCPNIRS: breakpoint of fall in SmO2-m.intercostales). During exercise, SmO2-m.intercostales decreased continuously showing a higher decrease when V˙E increased abruptly. A good agreement between methods used to determine RCP was found (visual vs NIRS) at %V˙O2-máx, V˙O2, V˙E, and W (Bland-Altman test). Correlations were found to each parameters analyzed (r = 0.854; r = 0.865; r = 0.981; and r = 0,968; respectively. p < 0.001 in all variables, Pearson test), with no differences (p < 0.001 in all variables, Student's t-test) between methods used (RCPvisual and RCPNIRS). We concluded that changes at SmO2-m.intercostales measured by NIRS could adequately determine RCP in triathletes.

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The purpose of this study was to investigate whether a tethered-swimming incremental test comprising small increases in resistive force applied every 60 seconds could delineate the isocapnic region during rapidly-incremented exercise. Sixteen competitive swimmers (male, n = 11; female, n = 5) performed: (a) a test to determine highest force during 30 seconds of all-out tethered swimming (Favg) and the ΔF, which represented the difference between Favg and the force required to maintain body alignment (Fbase), and (b) an incremental test beginning with 60 seconds of tethered swimming against a load that exceeded Fbase by 30% of ΔF followed by increments of 5% of ΔF every 60 seconds. This incremental test was continued until the limit of tolerance with pulmonary gas exchange (rates of oxygen uptake and carbon dioxide production) and ventilatory (rate of minute ventilation) data collected breath by breath. These data were subsequently analyzed to determine whether two breakpoints defining the isocapnic region (i.e., gas exchange threshold and respiratory compensation point) were present. We also determined the peak rate of O2 uptake and exercise economy during the incremental test. The gas exchange threshold and respiratory compensation point were observed for each test such that the associated metabolic rates, which bound the heavy-intensity domain during constant-work-rate exercise, could be determined. Significant correlations (Spearman's) were observed for exercise economy along with (a) peak rate of oxygen uptake (ρ = .562; p < 0.025), and (b) metabolic rate at gas exchange threshold (ρ = -.759; p < 0.005). A rapidly-incremented tethered-swimming test allows for determination of the metabolic rates that define zones for domain-specific constant-work-rate training.

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The objective of this study was to analyze the influence of the presence and absence of competitors on pacing, overall running performance, and mood state during a self-paced 3-km run. Nine recreational runners participated in this study. They performed the following tests: a) an incremental test to exhaustion to measure the respiratory compensation point (RCP), maximal oxygen uptake, and peak treadmill speed; b) a submaximal speed constant test to measure running economy; and c) two 3-km running time trials performed collectively (COL, head-to-head competition) or individually (IND, performed alone) to establish pacing and running performance. The COL condition was formed of a group of four runners or five runners. Runners were grouped by matched performance times and to retain head-to-head characteristics.A mood state profile questionnaire was completed before and after the 3-km running time trial. The overall performance was better in the COL than in the IND (11.75 ± 0.05 min vs. 12.25 ± 0.06 min, respectively; p = 0.04). The running speeds during the first 500 m were significantly greater in COL (16.8 ± 2.16 km·h−1) than in IND (15.3 ± 2.45 km·h−1) (p = 0.03).The gain in running speed from IND to COL during the first 400 m (i.e. running speed in COL less running speed in IND) was significantly correlated with the RCP (r = 0.88; p = 0.05). The vigor score significantly decreased from pre- to post-running in COL (p=0.05), but not in IND (p=0.20). Additionally, the post running vigor was significantly higher in IND compared to COL (p = 0.03).These findings suggested that the presence of competitors induces a fast start, which results in an improved overall performance and reduced post-exercise vigor scores, compared to an individual run.

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O objetivo do presente estudo foi comparar as intensidades do ponto de compensação respiratório (PCR), limiar anaeróbio de concentração fixa (OBLA3,5) e limiar anaeróbio de lactato de aumento abrupto lactacidêmico (LAnLAC) determinadas em diferentes ergômetros. Para isso, onze mesatenistas (19±1 anos) realizaram testes incrementais máximos no cicloergômetro, ergômetro de braço, esteira e em teste específico para o tênis de mesa. Durante esses esforços, foram mensuradas as repostas lactacidêmica e respiratória. Na análise intraergômetro, não foram encontradas diferenças significativas entre o PCR, LAnLAC e OBLA3,5 no ergômetro de braço (63,4±4,8W, 66,9±4,5W e 64,5±6,1W, respectivamente), esteira (11,4±0,4km.h-1, 11,3±0,3km.h-1 e 11,1±0,3km.h-1, respectivamente) e teste específico (40,5±1,8bolas.min-1, 42,6±3,6bolas.min-1 e 42,8±5,6bolas.min-1, respectivamente); apenas no cicloergômetro foi verificado menor valor de OBLA3,5 (131,9±6,6W) em relação ao PCR (149,3±4,9W) e o LAnLAC (149,3±4,7W). No entanto, fortes e significativas correlações foram verificadas no teste específico entre todos esses métodos (r entre 0,83 a 0,95), entre o PCR e OBLA3,5 no ergômetro de braço (r=0,78) e entre OBLA3,5 e LAnLAC na esteira (r=0,76). Desse modo, podemos concluir que o PCR, OBLA3,5 e LAnLAC parecem corresponder ao mesmo fenômeno fisiológico, principalmente, no teste específico para o tênis de mesa.

The objective of the study was to compare intensities of respiratory compensation point (RCP), anaerobic threshold at onset blood lactate accumulation (OBLA3,5), and anaerobic threshold at lactate abrupt increase (AnT LAC) determined in four different ergometers. Hence, eleven table tennis players (19±1 years) performed graded exercise tests on cycle ergometer, arm cranking ergometer, treadmill and specific table tennis test. The respiratory response and lactatemia were measured during the tests. We did not find significant differences among RCP, AnT LAC and OBLA3,5 in arm cranking ergometer (63.4±4.8W, 66.9±4.5W and 64.5±6.1W, respectively), treadmill (11.4±0.4km.h-1, 11.3±0.3km.h-1 and 11.1±0.3km.h-1, respectively), and specific table tennis test (40.5±1.8bolas.min-1, 42.6±3.6bolas.min-1 and 42.8±5.6bolas.min-1, respectively). However, the OBLA3,5 (131.9±6.6W) was significantly lower than RCP (149.3±4.9W) and AnT LAC (149.3±4.7W) in the cycle ergometer. Strong and significant correlation coefficients were found in the specific test for all methods (r range 0.83 to 0.95), in arm cranking ergometer between RCP and OBLA3,5 (r=0.78), and on treadmill running between OBLA3,5 and AnT LAC (r=0.76). Therefore, we conclude that RCP, OBLA3,5 and AnT LAC seem to correspond to the same physiological phenomenon, mostly during specific table tennis test.

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Os objetivos do estudo foram verificar a associação entre os métodos de quantificação da carga de treinamento, PSE da sessão e impulso de treinamento proposto por Lucía (LuciaTRIMP) e descrever a distribuição da intensidade de treinamento no futsal semiprofissional da categoria sub 18. Quinze jogadores (média e DP; idade: 17 ± 1 ano; massa corporal: 70,4 ± 6,5 kg; estatura: 175 ± 4 cm e IMC 23 ± 2 kg.m-2) foram submetidos a um teste de corrida incremental para determinar o limiar ventilatório (LVmax), o ponto de compensação respiratória (PCR) e o consumo máximo de oxigênio (VO2max). Apenas oito atletas foram monitorados por meio dos métodos PSE da sessão e LuciaTRIMP durante 78 sessões de treinamento antes da principal competição da temporada. Foram encontradas correlações individuais de magnitudes alta a quase perfeita (r = 0,64 - 0,91) entre os métodos PSE da sessão e LuciaTRIMP. O padrão de distribuição da intensidade de treinamento foi 76, 18 e 6% do tempo abaixo do LV (zona 1), entre LV e PCR (zona 2) e acima do PCR (zona 3), respectivamente. O método PSE da sessão se mostrou altamente relacionado com um método objetivo de quantificação da carga de treinamento. Além disso, as sessões de treinamento de uma equipe de futsal semiprofissional da categoria sub 18 apresentaram um padrão decrescente de distribuição das intensidades de treinamento.

The aims of this study were to verify the association between the methods of training load quantification session-RPE and training impulse -proposed by Lucia (LuciaTRIMP) -and to describe the training intensity distribution in under-18 semi-professional futsal. Fifteen male players (mean and SD; age: 17 ± 1 years; body mass: 70.4 ± 6.5 kg; height: 175 ± 4 cm and BMI 23 ± 2 kg.m²) performed an incremental treadmill test to determine the ventilatory threshold (VT), respiratory compensation point (RCP), and maximal oxygen consumption (VO2max). Only eight athletes had their training loads quantified by means of session-RPE and Lucia methods over a total of 78 training sessions before the main competition of the season. High to almost perfect correlations (r = 0.64 - 0.91) were found between session-RPE and LuciaTRIMP methods. The distribution of the training intensity was, respectively, 76, 18 e 6% of training duration below VT (zone 1), between VT and RCP (zone 2), and above RCP (zone 3). The session-RPE method was highly associated with an objective method of training load quantification. Furthermore, the training sessions of a semi-professional under-18 futsal team showed a decreasing training intensity distribution.

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