????專注于合作精神的探險式賽跑受歡迎程度大幅提高，并在全國掀起一陣旋風。Ragnar接力系列賽屬于眾多通宵團體接力賽之一，賽事聯合創始人譚納?貝爾稱：“我們把這項比賽想象為一份兼職，而不是我們的正職。我們并不清楚這個比賽未來的發展方向。”它的發展方向就是向前、向前、向前： Ragnar現在是這個快速發展領域中規模最大的接力系列賽。2012年，大約有20萬人參加了接力賽。

????盡管沒有組織機構專門追蹤團隊接力賽的年度參與情況（Running USA表示，雖然擁有數據，但尚未能夠進行收集并提供調查結果），Ragnar去年擁有7.2萬參與者，Hood to Coast擁有2萬，Reach the Beach擁有7,600；此外還有數十個規模較小的接力賽，每項通常都能有2,000參與者。網站Relay Guide列出了美國59個不同的接力型比賽，這些比賽的距離從25英里到200多英里不等。美國體育與健身行業（Sports & Fitness Industry of America,SFIA）表示，在2011年120萬人參加了“探險賽跑”。它的定義是任何“極端溫度或者非傳統環境”下的賽跑，包括泥漿賽跑和障礙賽跑。

????貝爾及其大學室友丹?希爾（Dan Hill）2004年提出了Ragnar比賽的設想，當時兩人正在楊百翰大學（Brigham Young University）讀大三。希爾的父親曾參加Hood to Coast。這是一項每年8月在俄勒岡州舉辦的團體接力賽，要求從胡德山跑到海邊小城海濱鎮。這項賽事始于1982年，是2011年一部深受好評的紀實電影的主題?！斑@是一項非常優秀的比賽，”貝爾說?！拔覀冮_始考慮在猶他州也舉辦一個屬于我們自己的比賽?！?/p>

????雖然希爾和貝爾舉辦的比賽直接模仿了Hood to Coast——兩項賽事的距離都超過200英里，通宵進行，并且專為12人團隊設計——但仍然取得了蓬勃的發展。有鑒于此，現在仍然存在容納更多類似比賽的空間，不論是完全原創，還是推陳出新。

????2013年6月是Ragnar的第一場比賽Wasatch Back誕生10周年的日子。這站比賽全程在猶他州內舉行，起點在洛根，終點在帕克城。自此之后，這個系列賽從2010年的12站賽事發展之2011年和2012年的15站。今年，該項比賽將提供21至25站賽事【其中6至8站采用一種新形式“追逐系列賽”（Trail series），是與戶外品牌薩洛蒙（Salomon）共同推出的】，舉辦地點包括麻薩諸塞州科德角、亞利桑那州坦佩、威斯康辛州麥迪遜以及加拿大安大略省尼亞加拉瀑布城。Wasatch Back舉辦的第一年共有264名參賽者，2012年已經達到1.2萬（至于2013年，Ragnar為這項賽事額外增加了一天，因此最終有17.5萬參賽者）。其他比賽的規模也有所擴大：Ragnar的佛羅里達礁島群站比賽的參賽者在兩年內翻了一番，在同一時間拉斯維加斯站比賽的參賽者人數增長了兩倍。

????一切似乎欣欣向榮。Brooks跑鞋公司首席執行官吉姆?韋伯說：“現在，賽跑方面令人興奮的消息是，每一種類型的賽事都在發展——障礙賽、追逐賽、團體接力賽，各種不同的形式。”據Running USA數據顯示，Tough Mudder、Spartan Beast和Warrior Dash 等“泥漿賽跑”已經達到最快的增長速度，現在每年可吸引約100萬名參與者?！皹O限”賽跑也保持著增長。它并不是團體比賽，而且采用非常消耗體力的路線，有時候完全處于黑暗中，且沒有地圖。

????Camaraderie-focused, adventure-style races have exploded in popularity and are taking the country by storm (or, in many cases, by mud). "We imagined this as a side gig, not our main job," says Tanner Bell, co-founder of Ragnar Relay Series, one of many overnight team relays. "We didn't have any idea where it was going to go." Where it has gone is up, up, up: Ragnar is now the largest relay series among a field that has grown quickly. Some 200,000 people likely ran in a relay in 2012.

????Though no organization specifically tracks annual participation in team relays (Running USA says it has data but hasn't yet been able to collect it and present findings), Ragnar had 72,000 participants last year, Hood to Coast had 20,000, and Reach the Beach had 7,600; then there are scores of smaller relays that tend to get 2,000 people each. The web site Relay Guide lists 59 different relay-type events in the U.S., ranging in distance from 25 miles to over 200, and SFIA (Sports & Fitness Industry of America) says 1.2 million people in 2011 participated in "adventure racing," which it defines as any kind of racing "in extreme temperatures or unconventional settings," including mud runs and obstacle races.

????Bell and his college roommate Dan Hill came up with the idea for Ragnar when they were juniors at Brigham Young University in 2004. Hill's father had participated in Hood to Coast, a team relay held every August in Oregon that runs from Mt. Hood to the coastal town of Seaside. The race began in 1982 and was the subject of a well-reviewed 2011 documentary film. "It was such a great event," says Bell, "we started to have visions of doing a race of our own in Utah."

????Considering that Hill and Bell directly modeled their event after Hood to Coast—both are 200+ miles long, continue overnight, and are tailored for teams of 12—the fact that it is thriving suggests that, for now, there is room for more of these events, no matter whether wholly original or derivative.

????June 2013 marks the 10th anniversary of Ragnar's first race, the Wasatch Back, which is run in Utah from from Logan to Park City. Since then the series has grown from 12 races in 2010 to 15 in 2011 and in 2012. This year, it will offer 21-25 races (6-8 of them under a new format, the "Trail series," which it launched in partnership with Salomon) in locations including Cape Cod, Mass., Tempe, Ariz., Madison, Wis., and Niagara Falls in Ontario. The Wasatch Back had 264 runners registered in its first year. It had 12,000 in 2012 (for 2013, Ragnar has added an extra day to the race and will thus end up with 17,500 participants). Other events have also grown: Ragnar's Florida Keys race nearly doubled in participation in two years, and its Las Vegas event tripled participation in the same time frame.

????It appears to be a rising tide. "The exciting thing about running right now is that every single type of event is growing—obstacles, trail, team relays, every single variety," says Jim Weber, CEO of running shoe company Brooks. According to Running USA, "mud runs" like Tough Mudder, Spartan Beast, and Warrior Dash have grown the fastest and now attract some 1 million participants each year. Also continuing to grow are "ultra" races that are not for teams, and are run on physically ruinous courses, sometimes in full darkness and without a map.