Caracterização das respostas fisiológicas e desempenho físico em um simulado contrarrelógio de 20 km com ritmo auto-selecionado em ciclistas categoria master

Abstract

A cycling time trial (TT) consists of covering a fixed distance in the shortest time possible. Being characterized as an aerobic activity of high intensity and high metabolic demands. The aim of the study was to characterize the self-selected pacing strategies used to maintain performance and physiological responses in a simulated 20 km time trial (20TT) in masters’ athletes. Methodology: Eight male master category cyclists participated in the study (mean age 42.00±9.20 years and experience with cycling 19.00±9.20 years). Rest Measures: Before starting the experimental session, the participants rested for 10 minutes on a stretcher in a climate-controlled environment (21° to 22 °C) and silent. Soon after, the measurement of heart rate (HR) was performed for 5 minutes. Subsequently, venous blood samples, anthropometric measurements, and muscle functionality markers were collected. The following muscle functionality markers were used in this study: joint range of motion (ROM), pressure pain threshold-muscle soreness (PPT), thigh circumference (CIR) and vertical jump-squat jump (VJ). Participants ate a standardized breakfast after collections at rest. Afterwards, the exercise session was carried out. 20TT test: first, an individual cycling warm-up was performed with a self-selected pace for 10 minutes, then, five minutes of rest were allowed. Finally, participants were instructed to perform the 20TT in the shortest time possible and use their strategy for rhythm distribution, and how to classify the rating of perceived exertion (RPE). During the 20TT performance, the HR, PSE, test time, speed, cadence, and power collected throughout the test. Measurements after the test: immediately after completion of 20TT, and 30 minutes after testing, venous blood samples were again collected to analyze cell-free DNA (cfDNA). In addition, after 30 minutes of recovery, muscle functionality markers were reassessed. Results: The cyclists chose a “U-shaped parabolic pacing profile as higher powers were used at the beginning, attenuated over the distances covered, and at the end similar power values from the beginning of the time trial were observed. The 20TT had an average duration of 34.36 minutes, and they preferred to pedal with high cadences (98 rpm in the best km). In addition, the cyclists obtained a mean HR (185.19±8.41 bpm) in the last 10% of the RC that was significantly higher compared to the other moments. RPE increased linearly with the peak value corresponding to the end of the test. Cell-free DNA and vertical jump did not show significant differences after 20TT. For muscle function markers, PPT, and ROM showed a significant reduction 30 (minutes) after the test, and CIR increased statistically. Conclusion: Considering this, the present study provides evidence that in a simulated 20TT with self-selected intensity, a “U-shaped pacing profile with high cadences was spontaneously selected by the cyclists. And it did not impair quadriceps muscle function, despite high cardiovascular demands.