Gnehm P, Reichenbach S, Altpeter E, Widmer H, Hoppeler H
Department of Anatomy, University of Bern, Switzerland.
Med Sci Sports Exerc. 1997 Jun;29(6):818-23. doi: 10.1097/00005768-199706000-00013.
The spectacular improvements of the 1-h world record in cycling in the last four years have highlighted the importance of aerodynamics in modern bicycle racing. We have investigated the metabolic consequences of the low-crouched aero-positions necessary to reduce air drag. In this study, 14 elite male bicycle racers (24.0 +/- 1.0 yr, VO2max 69.4 +/- 0.5 mL.kg-1.min-1) were tested for oxygen consumption (VO2) and heart rate (HR) at 70% (302.6 +/- 5.3 W) of their individual VO2max in three different riding positions during a single test run. The subjects rode their racing bicycles on a wind braked roller; the sequence of the three following positions was randomized: 1) upright cycling (UP), cadence 90 rpm; 2) hands on drops (DP), 90 rpm; and 3) hands on clip-on aero-handlebars (AP), 90 rpm. VO2 and HR values in AP were significantly higher by 1.5 mL.kg-1.min-1 and 5 beats.min-1, respectively, compared with UP. We concluded that riding a bicycle in an extreme aero-position increases the metabolic cost of cycling when wind resistance is not taken into account. However, when the mechanical power losses of 9 W (estimated by the VO2 increase) are compared with the expected aerodynamic power savings of approximately 100 W, it appears that aerodynamic advantages by far outweight their metabolic cost.
过去四年里，自行车项目1小时世界纪录的显著提升凸显了空气动力学在现代自行车比赛中的重要性。我们研究了为减少空气阻力而采用的低蹲姿空气动力学姿势所带来的代谢影响。在本研究中，14名精英男性自行车赛车手（年龄24.0±1.0岁，最大摄氧量69.4±0.5 mL·kg⁻¹·min⁻¹）在单次测试骑行中，于三种不同骑行姿势下，以其个人最大摄氧量的70%（302.6±5.3瓦）测试耗氧量（VO₂）和心率（HR）。受试者在带风阻刹车的滚筒上骑他们的赛车；以下三种姿势的顺序是随机的：1）直立骑行（UP），踏频90转/分钟；2）手握下把位（DP），踏频90转/分钟；3）手握夹式空气动力学车把（AP），踏频90转/分钟。与UP相比，AP的VO₂和HR值分别显著高出1.5 mL·kg⁻¹·min⁻¹和5次/分钟。我们得出结论，在不考虑风阻的情况下，以极端空气动力学姿势骑自行车会增加骑行的代谢成本。然而，当将9瓦的机械功率损失（通过VO₂增加估算）与预计约100瓦的空气动力学功率节省相比较时，空气动力学优势似乎远远超过其代谢成本。
