词条 | Cross-country cycling |
释义 |
TerrainCross-country cycling is defined by the terrain on which it is performed. XC courses and trails consist of a mix of rough forest paths and singletrack (also referred to as doubletrack depending on width), smooth fireroads, and even paved paths connecting other trails. Until recently cross-country trails were deemed "easy" or "intermediate", due to the concept that this discipline of mountain biking relies more on physical prowess than technical ability. These days however, some paths can be difficult and challenging including grade 3 and 4 trails consist of technical rooty and rocky sections and small and other elements like drops and steep descents to challenge even the experienced riders in the XC World Cup and Summer Olympic Games. Bikes and equipment{{further|Mountain bike}}Cross-country bicycles are some of the lightest mountain bikes, typically between {{convert|7|and|16|kg|lb|lk=on}}. They usually feature suspension forks in front and sometimes have suspension in the rear. In both the front and rear, most XC bicycles have approximately {{convert|100|mm|cm in|1|lk=on}} of suspension travel, although some riders prefer {{convert|125|to|150|mm|cm in|1|lk=on}} of travel as bicycle frame strength and technology advance. The geometry of the frames generally place the rider in a little more upright position than on a road bicycle but much less than on a downhill bike.{{citation needed|date=August 2012}} Bicycle helmets are often used for cross-country riding.[2] However, XC riders only rarely wear full-face helmets and do not wear the full body "armour" employed by downhill riders. Cross-country cyclists are more prone to injuries than road cyclists; however, the injuries sustained by XC riders are usually not as severe.[3]RacingCross-country racing emphasizes endurance above technical prowess, and races vary from 30 minutes to 24 hours in length. Additionally, many mountain bike races are divided up into stages so as to span several days. Races can be either point-to-point or lap-based. Short-track cross-country consists of many very short laps so as to be spectator-friendly. Unlike downhill races, which are conducted in a time trial format, cross-country races traditionally feature a mass start or interval start, where riders are released in several large groups divided by age and/or ability. Races with very large fields that do not wish to stagger starts will sometimes employ a Le Mans start where racers begin by running to their bikes. Globally, XC racing is governed by the Union Cycliste Internationale. In the United States, it is under the purview of USACMTB a division of USA Cycling. In the United Kingdom, British Cycling is the governing body. Racing disciplinesThere are some XC racing disciplines, like XCE ( Cross-Country eliminator ), XCO ( Cross-Country Olympic ) or XCM ( Cross-Country Marathon ). Cross-Country Eliminator (XCE)A race where the last person or the last two people who go through the finish line are out of the race. Cross-Country Olympic (XCO)Consists of a lap racing around a short circuit. It's the only discipline which is in the Olympics, and high mountain bike skills are required. Cross-Country Marathon (XCM){{main|Marathon mountain bike races}}With a route usually between 65 and 100 km. It has gained popularity in the last years, because XCM competition participation is open to everyone, including beginners. Just finishing the race is an achievement for some people. Wheel sizeIn cross-country, more than other areas of mountain biking, a debate has begun over the optimal wheel size. The 26-inch wheel size that was settled on with the inception of the current age of mountain biking has all but died off at the top level of cross-country racing as 27.5 inch (650b) and 29 inch wheels are much more popular now. 650b wheels are 584 mm diameter wheels, and approximately 27.5" with a mounted tire. 650b bikes are becoming ever more prevalent, while 29" bikes, or "29ers" experienced rapidly gaining popularity in the mid to late 2000s, and having some success in cross-country racing, but more so in marathon cross-country. A notable boost to their popularity came with Lance Armstrong, racing and winning on a Gary Fisher 29er.[4] Advantages to the larger wheel formats are less need for suspension due to a decreased angle of attack, and also less loss of momentum. Disadvantages include increased weight, decreased acceleration, higher rolling inertia, rider fit issues for those under 5'5" (165 cm), and slower handling, although handling issues are being addressed successfully in newer designs with geometry changes like steeper head tube angles and higher fork offsets. A further disadvantage is that, all other variables (spoke number, rim design and material, etc.) being equal, a 26" wheel will be much stronger than a 29" one. See also
References1. ^{{cite web |url=http://gorp.away.com/gorp/activity/biking/expert/olympic.htm |title=Archived copy |accessdate=2007-02-20 |deadurl=no |archiveurl=http://archive.wikiwix.com/cache/20110223204706/http://gorp.away.com/gorp/activity/biking/expert/olympic.htm |archivedate=2011-02-23 |df= }} Mountain Biking in the Olympics 2. ^{{cite journal |vauthors=Attewell RG, Glase K, McFadden M |title=Bicycle helmet efficacy: a meta-analysis |journal=Accid Anal Prev |volume=33 |issue=3 |pages=345–52 |date=May 2001 |pmid=11235796 |doi=10.1016/S0001-4575(00)00048-8 |url=http://linkinghub.elsevier.com/retrieve/pii/S0001-4575(00)00048-8 |deadurl=no |archiveurl=https://web.archive.org/web/20180504202644/https://linkinghub.elsevier.com/retrieve/pii/S0001-4575(00)00048-8 |archivedate=2018-05-04 |df= }} 3. ^{{cite journal |vauthors=Chow TK, Bracker MD, Patrick K |title=Acute injuries from mountain biking |journal=West. J. Med. |volume=159 |issue=2 |pages=145–8 |date=August 1993 |pmid=8212679 |pmc=1022220 |doi= |url=}} 4. ^{{cite web|url=http://quickstopbike.blogspot.com/2008/12/lance-armstrong-winning-on-gary-fisher.html|title=Quick Stop Bike Shop: Lance Armstrong Winning on a Gary Fisher Superfly|first=Quick Stop Bike|last=Shop|date=17 December 2008|website=quickstopbike.blogspot.com|accessdate=4 May 2018|deadurl=no|archiveurl=https://web.archive.org/web/20180314104647/http://quickstopbike.blogspot.com/2008/12/lance-armstrong-winning-on-gary-fisher.html|archivedate=14 March 2018|df=}} External links{{commons category-inline|Cross-country mountain biking}}
2 : Endurance games|Mountain biking |
随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识,基本涵盖了大多数领域的百科知识,是一部内容自由、开放的电子版国际百科全书。