Efeitos de diferentes sistemas de pedivela sobre a ativação muscular durante ciclismo incremental máximo

Abstract

Previous studies evaluating noncircular chainrings suggest that changes in muscle activation would occur. However, no previous study addressed this question. The aim of this study was to compare the level of muscular activity between a conventional and a noncircular chairing system (Rotor Cranks®) during incremental maximal cycling. Seven MTB cyclists completed two incremental tests, separated for 48 hours, one for each crank system. After five minuts of warm up, the test started with workload of 100 W, which was increased in 30W every minute until exhaustion. Power output, pedaling cadence heart rate and surface EMG were monitored. EMG was recorded from the right rectus femoris, vastus medialis, biceps femoris and gastrocnemius medialis. Power output, pedaling cadence heart rate were compared using paired t-test. The EMG data were normalized to the 100 W workload and compared using a general linear model considering crank system and workload and α = 0.05. No significant effects or interaction were found for the variables analyzed. The present results do not support effects of the noncircular chainring tested on lower limb muscle activation during incremental cycling in trained MTB cyclists.