a Université de Reims Champagne Ardenne , Groupe de Recherche en Sciences pour l'Ingénieur (GRESPI) EA 4694, UFR STAPS , Reims , France.
J Sports Sci. 2013;31(14):1606-13. doi: 10.1080/02640414.2013.792945. Epub 2013 May 28.
Aerodynamic and rolling resistances are the two major resistances that affect road cyclists on level ground. Because of reduced speeds and markedly different tyre-ground interactions, rolling resistance could be more influential in mountain biking than road cycling. The aims of this study were to quantify 1) aerodynamic resistance of mountain-bike cyclists in the seated position and 2) rolling resistances of two types of mountain-bike tyre (smooth and knobby) in three field surfaces (road, sand and grass) with two pressure inflations (200 and 400 kPa). Mountain-bike cyclists have an effective frontal area (product of projected frontal area and drag coefficient) of 0.357 ± 0.023 m², with the mean aerodynamic resistance representing 8-35% of the total resistance to cyclists' motion depending on the magnitude of the rolling resistance. The smooth tyre had 21 ± 15% less rolling resistance than the knobby tyre. Field surface and inflation pressure also affected rolling resistance. These results indicate that aerodynamic resistance influences mountain-biking performance, even with lower speeds than road cycling. Rolling resistance is increased in mountain biking by factors such as tyre type, surface condition and inflation pressure that may also alter performance.
空气动力阻力和滚动阻力是影响平地道路自行车运动员的两大阻力。由于速度降低和轮胎与地面的相互作用明显不同，滚动阻力在山地自行车运动中可能比公路自行车运动更具影响力。本研究的目的是定量分析：1）坐姿山地自行车运动员的空气动力阻力，2）两种山地自行车轮胎（光滑轮胎和越野轮胎）在三种野外表面（道路、沙滩和草地）和两种充气压力（200kPa 和 400kPa）下的滚动阻力。山地自行车运动员的有效正面面积（投影正面面积和阻力系数的乘积）为 0.357±0.023m²，平均空气动力阻力占运动员运动总阻力的 8-35%，具体取决于滚动阻力的大小。光滑轮胎的滚动阻力比越野轮胎低 21±15%。野外表面和充气压力也影响滚动阻力。这些结果表明，即使速度低于公路自行车运动，空气动力阻力也会影响山地自行车运动的表现。滚动阻力会因轮胎类型、地面状况和充气压力等因素而增加，这些因素也可能改变运动表现。
