Efeitos do posicionamento na bicicleta sobre respostas fisiológicas e potência gerada por ciclistas em contrarrelógio de 5km

Abstract

Introduction: the handlebar in road bikes allows the rider to put the hands in different positions, thus changing body position and might influence the performance. Objective: To evaluate the effects of body position during cycling on physiological responses and power output during a maximum incremental test and a 5km time trial. Methodology: Eight cyclists participated in the study and performed two incremental and two 5km time trials using different positions on the handlebar (drop and hoods). Cyclists used their own bikes attached to a roller (Computrainer). Data on oxygen consumption, thresholds 1 and 2, time elapsed, distance, heart rate and power output were collected during the incremental test. Data on time elapsed, heart rate and power output were collected on the time trial. Statistical tests performed were the Mann-Whitney test, two way anova for repeated data and linear trend analyses. Results: Regarding the incremental test, cyclists had higher maximal aerobic power and peak power output with the hands on the hoods compared to the drops. Other physiological variables were similar for the two positions during the incremental test. There was no difference in time to complete the time trial regarding the hands position. However, the highest peak power output and speed were observed with the hands on the hoods compared to the drops. There was an interaction between distance covered and hands position (p=0.017): having the hands on the hoods was better (i.e. faster) at the 4km mark of the time trial. Power output during the time trial was similar between the positions and across the distance covered. Time to cover each km was shorter at every km, evidencing a linear trend for the hands on the hoods, but not on the drops. Heart rate increased throughout the time trial similarly for both positions. Conclusion: Cyclists performed better at the incremental test when holding the handlebar in the hoods. Higher peak power outputs and speed were also observed with the hands in hoods during the 5km time trial.