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BACKGROUND: Supplementation with Angiotensin-(1-7) [(Ang-1-7)] has received considerable attention due to its possible ergogenic effects on physical performance. The effects of a single dose of Ang-(1-7) on the performance of mountain bike (MTB) athletes during progressive load tests performed until the onset of voluntary fatigue have previously been demonstrated. This study tested the effects of Ang-(1-7) in two different exercise protocols with different metabolic demands: aerobic (time trial) and anaerobic (repeated sprint). METHODS: Twenty one male recreational athletes were given capsules containing an oral formulation of HPßCD-Ang-(1-7) (0.8 mg) and HPßCD-placebo (only HPßCD) over a 7-day interval; a double-blind randomized crossover design was used. Physical performance was examined using two protocols: a 20-km cycling time trial or 4 × 30-s repeated all-out sprints on a leg cycle ergometer. Data were collected before and after physical tests to assess fatigue parameters, and included lactate levels, and muscle activation during the sprint protocol as evaluated by electromyography (EMG); cardiovascular parameters: diastolic and systolic blood pressure and heart rate; and performance parameters, time to complete (time trial), maximum power and mean power (repeated sprint). RESULTS: Supplementation with an oral formulation of HPßCD-Ang-(1-7) reduced basal plasma lactate levels and promoted the maintenance of plasma glucose levels after repeated sprints. Supplementation with HPßCD-Ang-(1-7) also increased baseline plasma nitrite levels and reduced resting diastolic blood pressure in a time trial protocol. HPßCD-Ang-(1-7) had no effect on the time trial or repeat sprint performance, or on the EMG recordings of the vastus lateralis and vastus medialis. CONCLUSIONS: Supplementation with HPßCD-Ang-(1-7) did not improve physical performance in time trial or in repeated sprints; however, it promoted the maintenance of plasma glucose and lactate levels after the sprint protocol and at rest, respectively. In addition, HPßCD-Ang-(1-7) also increased resting plasma nitrite levels and reduced diastolic blood pressure in the time trial protocol. TRIAL REGISTRATION: RBR-2nbmpbc, registered January 6th, 2023. The study was prospectively registered.

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This study examined the relationship between mood and rating of perceived exertion (RPE) during a simulated multiple-lap time trial (MLTT). Nineteen male cyclists performed a MLTT consisting of four 9.9 km laps, each lap with a gradient ranging from 0 to 10 %. Mood as measured by the Profile of Mood States Questionnaire (POMS) and perceived exertion as measured by the Borg CR100 scale (RPE) were obtained at the end of each lap. A categorical multiple regressive model, having median of POMS subscales as independent variables, was obtained to explain the variance in median RPE responses. Increases in POMS fatigue scores and decreases in POMS vigour scores were observed throughout the MLTT (P < 0.001). A linear increase in RPE during the MLTT was also observed (P < 0.001). POMS fatigue subscale scores accounted for 88 % of the variance in RPE during the MLTT (R(2) = 0.88, P = 0.002), and no other POMS subscale improved the final predictive model. With the exception of fatigue these results suggest that most aspects of mood do not have a discernable effect on RPE during a MLTT. The rate of increase in RPE can predict the MLTT endpoint.

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The validity of the Running-based Anaerobic Sprint Test (RAST) was investigated to evaluate the anaerobic power performance in comparison to Wingate test in cycling athletes. Ten mountain-bike male cyclists (28.0±7.3 years) randomly performed Wingate Test and RAST with two trials each. After several anthropometric measurements, peak power (PP), mean power (MP) and fatigue index (FI) for RAST and Wingate Test were analyzed using Student's paired t-test, Pearson's linear correlation test (r) and Bland and Altman's plots. Results showed that, with the exception of FI (33.8±4.6% vs. 37.8±7.9%; r=0.172), significant differences were detected between the Wingate and RAST tests with regard to PP and MP. Although there was a strong correlation for PP and MP, or rather, 0.831 and 0.714 respectively, agreement of analysis between Wingate and RAST protocols was low. The above suggested that RAST was not appropriate to evaluate the performance of anaerobic power by Wingate test in cycling athletes.

O objetivo foi investigar a validade do teste de RAST (Running-based Anaerobic Sprint Test) em avaliar o desempenho da potência anaeróbia a partir do teste de Wingate em ciclistas treinados. Participaram do estudo 10 ciclistas do sexo masculino (28,0±7,3 anos) da modalidade de Mountain bike. Após a mensuração das variáveis antropométricas, a potência pico (PP), média (PM) e o índice de fadiga (IF) foram determinados randomicamente a partir de dois testes de Wingate e dois testes de RAST. Foram utilizados o teste t independente de Student, a análise de correlação linear de Pearson (r) e o teste de Bland-Altman. Os resultados demonstraram, exceto para o IF (33.8±4.6% vs. 37.8±7.9%; r=0.172), diferenças significativas entre o teste de Wingate e o RAST para PP e PM (W.kg-1 e W). Embora os valores de correlação para a PP e PM (W) tenham sido fortes (0.831 e 0.714, respectivamente) a concordância entre os protocolos de Wingate e RAST foi baixa, sugerindo que o teste de RAST não é válido para avaliar o desempenho da potência anaeróbica a partir do teste de Wingate em ciclistas.

El objetivo fue investigar la validad del teste de RAST (Running-based Anaerobic Sprint Test) en evaluar el desempeño de la potencia anaeróbica través del uso del teste de Wingate en ciclistas trenados. Participaron del estudio 10 ciclistas masculinos (28,0±7,3 años) de la modalidad de Mountain bike. Después de la mensuración de las variables antropométricas, la potencia pico (PP), media (PM) y el índice de fatiga (IF) fueron determinados al acaso a partir de dos testes de Wingate y de dos testes de RAST. Fueron utilizados el test t independiente de Student, el análisis de correlación linear de Pearson (r) y el test de Bland-Altman. Los resultados demostraron, contrariamente al IF (33.8±4.6% vs. 37.8±7.9%; r=0.172), diferencias significativas entre el teste de Wingate y el RAST para PP y PM (W.kg-1 e W). Mismo que los valores de correlación de PP e PM (W) tengan sido fortes (0,831 e 0,714, respectivamente), la concordancia entre los protocolos de Wingate y RAST fue baja, sugiriendo que el teste de RAST no es válido para evaluar el desempeño de la potencia anaeróbica a partir del teste de Wingate en este grupo.

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O objetivo deste estudo foi verificar a resposta de frequência cardíaca (FC) durante as competições de "Cross-country" Olímpico (XCO). Quatorze "mountain bikers" foram separados em dois grupos: elite (n = 6; 26,5 ± 3,6 anos; 69,1 ± 2,1 kg; 174,0 ± 1,2 cm; 5,9 ± 0,9 por cento G; 9,0 ± 1,3 anos de treinamento) e amadores (n = 8; 25,6 ± 7,7 anos; 67,7 ± 7,0 kg; 175,5 ± 5,5 cm; 5,8 ± 2,1 por cento G; 8,3 ± 5,7 anos de treinamento). Os participantes foram submetidos a um teste progressivo para a identificação dos limiares metabólicos e seus respectivos valores de frequência cardíaca (FC) em cada zona de intensidade de esforço. Após intervalo mínimo de quatro dias os atletas da categoria elite foram avaliados através de monitores de FC durante a etapa brasileira da Copa do Mundo de XCO. Após 15 dias, todos os atletas foram avaliados no Campeonato Brasileiro de XCO. Os resultados indicaram que em ambas as competições, a média percentual da FC foi correspondente a 91-92 por cento da FCmáx. Nas competições, os atletas permaneceram durante diferentes tempos percentuais nas zonas de intensidade de esforço sendo 10,0-14,8 por cento no domínio leve; 23,1-30,1 por cento moderado e 55,1-66,9 por cento intenso. Assim, este estudo apresenta que as competições de XCO são realizadas em alta intensidade, principalmente após a largada.

The aim of this study was to verify and describe the intensity profile of cross-country mountain-biking races using heart rate (HR) recorded during races. Fourteen mountain bikers participated in two groups: elite (n = 6; 26.5 ± 3.6 years old; 69.1 ± 2.1 kg; 174.0 ± 1.2 cm; 5.9 ± 0.9 percent BF; 9.0 ± 1.3 years of training) and amateurs (n = 8; 25.6 ± 7.7 years; 67.7 ± 7.0 kg; 175.5 ± 5.5 cm; 5.8 ± 2.1 percent BF; 8.3 ± 5.7 years of training). Each cyclist was submitted to an incremental exercise test to determine the metabolic thresholds and the HR values at each threshold. After four days, only the athletes of elite category were tested during Brazilian round of XCO World Cup. Two weeks later both groups were evaluated in XCO Brazilian National Championship. The results showed that HR averaged 91-92 percent of HRmax. The exercise intensity zones showed different percentage of time spent during the races (10.0-14.8 percent easy; 23.1-30.1 percent moderate; 55.1-66.9 percent hard). This study shows that cross-country events are conducted at very high intensity, especially at the start of the race.

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