Effect of the underwater torque on the energy cost, drag and efficiency of front crawl swimming
Effect of the underwater torque on the energy cost, drag and efficiency of front crawl swimming
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水下扭矩对前泳的能量消耗、阻力和效率的影响
DOI：
10.1007/bf02425476
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
P. Prampero
中科院分区：
文献类型：
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作者：
P. Zamparo;C. Capelli;B. Termin;D. Pendergast;P. Prampero
水下扭矩（T’）被定义为游泳者的脚倾向于下沉的力乘以脚到肺容积中心之间的距离的乘积。先前的研究表明，在游泳者的腰上系上一根塑料管，在不同的场合装满空气、水或2公斤重的铅，从而得到的ofT '的实验变化伴随着在任何给定速度下每单位距离（CS）游泳的能量消耗的变化。本研究的目的是探讨在前爬泳中观察到的CSwithT '的增加是由于主动体阻力（Db）的增加，还是由于阻力效率（ηd）的降低，或者两者兼而有之。因此，我们以8名优秀男子游泳运动员为实验对象，在两个次最大速度（1.00和1.23 m·s−1）下，研究了实验变化对CS、Dband η的影响。为了比较不同受试者和不同速度，将CS、Db、η、dt的个体数据归一化，除以相应的个体平均值。这些是根据从该受试者在该速度下获得的所有个人数据（CS, Db, η, dt '）计算得出的。结果发现，在本研究的两个极端（充气管和充2kg铅管）之间，T′增加了73%，CS， Dband η随T′线性增加。在这两个极端之间，cs的增加介于Db（≈35%）和ηd（≈16%）之间（≈20%）。因此，游泳者采取的实际策略是容忍分贝的大幅增加。这也导致了大量（尽管较小）的增长，其效果是减少了原本会出现的增长。
Underwater torque (T′) is defined as the product of the force with which the swimmer's feet tend to sink times the distance between the feet and the centre of volume of the lungs. It has previously been shown that experimental changes ofT′, obtained by securing around the swimmer's waist a plastic tube filled, on different occasions, with air, water or 2-kg lead, were accompanied by changes in the energy cost of swimming per unit of distance (CS) at any given speed. The aim of this study was to investigate whether the observed increases of CSwithT′ during front crawl swimming were due to an increase of active body drag (Db), a decrease of drag efficiency (ηd) or both. The effect of experimental changes ofT′ on CS, Dband ηdwere therefore studied on a group of eight male elite swimmers at two submaximal speeds (1.00 and 1.23 m · s−1). To compare different subjects and different speeds, the individual data for CS, Db,ηdandT′ were normalized dividing them by the corresponding individual averages. These were calculated from all individual data (of CS, Db, ηdandT′) obtained from that subject at that speed. It was found that, between the two extremes of this study (tube filled with air and with 2-kg lead),T′ increased by 73% and that CS, Dband ηdincreased linearly withT′. The increase of CSbetween the two extremes was intermediate ( ≈ 20%) between that of Db(≈ 35%) and of ηd( ≈ 16%). Thus, the actual strategy implemented by the swimmers to counteractT′, was to tolerate a large increase of Db. This led also to a substantial (albeit smaller) increase of did, the effect of which was to reduce the increase of CSthat would otherwise have occurred.