Korff Thomas, Romer Lee M, Mayhew Ian, Martin James C
Brunel University, Centre for Sports Medicine and Human Performance, Uxbridge, Middlesex, UK.
Med Sci Sports Exerc. 2007 Jun;39(6):991-5. doi: 10.1249/mss.0b013e318043a235.
To optimize endurance cycling performance, it is important to maximize efficiency. Power-measuring cranks and force-sensing pedals can be used to determine the mechanical effectiveness of cycling. From both a coaching and basic science perspective, it is of interest if a mechanically effective pedaling technique leads to greater efficiency. Thus, the purpose of this study was to determine the effect of different pedaling techniques on mechanical effectiveness and gross efficiency during steady-state cycling.
Eight male cyclists exercised on a cycle ergometer at 90 rpm and 200 W using four different pedaling techniques: preferred pedaling; pedaling in circles; emphasizing the pull during the upstroke; and emphasizing the push during the downstroke. Each exercise bout lasted 6 min and was interspersed with 6 min of passive rest. We obtained mechanical effectiveness and gross efficiency using pedal-reaction forces and respiratory measures, respectively.
When the participants were instructed to pull on the pedal during the upstroke, mechanical effectiveness was greater (index of force effectiveness=62.4+/-9.8%) and gross efficiency was lower (gross efficiency=19.0+/-0.7%) compared with the other pedaling conditions (index of force effectiveness=48.2+/-5.1% and gross efficiency=20.2+/-0.6%; means and standard deviations collapsed across preferred, circling, and pushing conditions). Mechanical effectiveness and gross efficiency during the circling and pushing conditions did not differ significantly from the preferred pedaling condition.
Mechanical effectiveness is not indicative of gross efficiency across pedaling techniques. These results thereby provide coaches and athletes with useful information for interpreting measures of mechanical effectiveness.
为了优化耐力骑行表现,最大化效率很重要。功率测量曲柄和力感应踏板可用于确定骑行的机械效率。从教练指导和基础科学的角度来看,机械效率高的蹬踏技术是否能带来更高的效率是个有趣的问题。因此,本研究的目的是确定不同蹬踏技术对稳态骑行时机械效率和总效率的影响。
八名男性自行车运动员在自行车测力计上以90转/分钟和200瓦的功率进行锻炼,采用四种不同的蹬踏技术:习惯蹬踏方式;圆周蹬踏;上冲程时强调提拉;下冲程时强调推压。每次锻炼持续6分钟,并穿插6分钟的被动休息。我们分别使用踏板反作用力和呼吸测量来获得机械效率和总效率。
当参与者被要求在上冲程时提拉踏板时,与其他蹬踏条件相比,机械效率更高(力效率指数=62.4±9.8%),总效率更低(总效率=19.0±0.7%)(力效率指数=48.2±5.1%,总效率=20.2±0.6%;平均值和标准差是综合习惯、圆周和推压条件得出的)。圆周蹬踏和推压条件下的机械效率和总效率与习惯蹬踏条件相比没有显著差异。
机械效率并不能表明不同蹬踏技术下的总效率。因此,这些结果为教练和运动员提供了有用信息,以便他们解读机械效率的测量结果。