文章基本信息

标题：Does a Non-Circular Chainring Improve Performance in the Bicycle Motocross Cycling Start Sprint?
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作者：Manuel Mateo-March ; Manuel Mateo-March ; Manuel Mateo-March 等
期刊名称：Journal of Sports Science and Medicine
印刷版ISSN：1303-2968
出版年度：2014
卷号：13
期号：1
页码：97-104
语种：English
出版社：University of Uludag
摘要：Maximising power output during the initial acceleration phase of a bicycle motocross (BMX) race increases the chance to lead the group for the rest of the race. The purpose of this study was to investigate the effect of non-circular chainrings (Q-ring) on performance during the initial acceleration phase of a BMX race. Sixteen male cyclists (Spanish National BMX team) performed two counterbalanced and randomized initial sprints (3.95s), using Q- ring vs. circular chainring, on a BMX track. The sample was divided into two different groups according to their performance (Elite; n = 8 vs. Cadet; n = 8). Elite group covered a greater distance using Q-ring (+0.26 m, p = 0.02; D = 0.23), whilst the improvement for the Cadet (+0.04 m) was not significant (p = 0.87; D = -0.02). Also, there was no significant difference in power output for the Elite group, while the Cadet group revealed larger peak power with the circular chainring. Neither lactate level, nor heart rate showed significant differences due to the different chainring used. The non-circular chainring improved the initial acceleration capacity only in the Elite riders.
关键词：Power;efficiency;pedalling;biomechanics;lactate