According to the Livescience of October 21, a new study promises a mathematical solution to keep marathoners far from "hitting the wall"。

　　By taking into account the energy it takes to run a marathon, the body's energy storage capacity and the runner's power, the researchers were able to accurately calculate how many energy-rich carbohydrates a runner needed to eat before race day and how fast to run to complete all 26.2 miles (42 kilometers)。

　　"Quantification is really important for a competitive athlete who wants to know, 'can I run at a target pace of six minutes per mile, or is that too fast, or do I have to go six minutes and 10 seconds per mile?'" study researcher Benjamin Rapoport, an M.D.-Ph.D. student in the Harvard-MIT Division of Health Sciences and Technology, told LiveScience. "That difference can make the difference between hitting the wall and actually meeting your goal."

　　Rapoport knows what it's like to hit the wall. He's been running marathons for years, and experienced the exhaustion and pain of running out of fuel in the 2005 New York City Marathon。

　　"It feels a bit like you might feel if you're on a crash diet," Rapoport said. "Except that when you diet, it happens over the course of a few days, whereas a runner experiences it in the course of a few minutes."

　　The ability to run long distances depends mainly on three factors, Rapoport said. The major one — the one that separates casual runners from elite athletes — is aerobic capacity, also known as VO2max. The VO2max is like the power output of a motor, Rapoport said. It's the maximum rate at which the muscles can take up oxygen to keep working。

　　The next factor is the energy cost of running, which is the equivalent to miles per gallon in an automobile. The final factor is the body's gas tank: the storage space available for carbohydrates, particularly glycogen stored in the liver and muscles that is the body's main fuel during exercise。

　　By combining these factors, Rapoport created a mathematical model of how long and how fast runners of any size can go without hitting the wall. The model also helps define how much "carbo-loading," or consumption of carbohydrates, the runner should complete in the days before the race。

　　The model also reveals a physiological basis to one of running's biggest challenges, the Boston Marathon. Men aged 19 to 34 who want to run in the Boston Marathon must have a qualifying time of three hours and 10 minutes or less. Women of the same age must have a qualifying time of three hours and 40 minutes or less. These numbers aren't based on science, Rapoport said, but rather set to weed out all but about the top 10 percent of runners。

　　据生活科学网站10月21日报道，一项最近研究发现，一种数学方法可以帮助马拉松运动员远离“速度障碍”。

　　研究人员将一项马拉松运动需要消耗的能量、人体体内能量储存量和运动员的能量等因素综合考虑之后，他们精确计算出一个马拉松运动员在赛前应该补充的高能量碳水化合物的量以及如何快速跑完26.2英里的比赛全程(42千米)。

　　研究人员、哈佛大学和麻省理工大学健康科学与技术学院双博士本杰明•拉波波特告诉生活科学网站，“量化对竞技运动员非常重要，他们经常问‘我能够达到既定6分钟一英里的速度吗？这个速度是不是太快？或我必须每英里用时6分10秒吗？’这些问题。量化的不同或者给运动员带来‘速度障碍’，或者让他们完成自己的目标。”

　　拉波波特非常了解“速度障碍”，多年来他参加过很多场马拉松比赛，在2005年纽约城市马拉松比赛中他也体验过身体疲惫的状态，感受到体内能量耗尽的感觉。

　　拉波波特说：“‘速度障碍’就像你在进行突然的节食，不同在于节食发生在几天这样的阶段中，而马拉松跑步发生在几分钟的时间里。”

　　拉波波特说，长距离跑步的能力主要取决于三个因素：第一个因素是有氧代谢能力，它能让优秀运动员在普通运动员中脱颖而出，它也被称为最大氧耗量。最大氧耗量就像机动车的能量输出功率，就是肌肉吸收氧气继续工作的最高速度。

　　第二个因素是运动能量消耗，相当于汽车每英里消耗汽油加仑量。最后一个因素是人体气体存储：用于存储碳水化合物的空间，尤其是肝脏和肌肉内的糖原，它是人体进行运动时主要能量元素。

　　通过结合这三个因素，拉波波特创造出一个数学公式，这个公式可以让任何体型的运动员知道跑多远和多快才能避免‘速度障碍’。这个公式还帮助测定运动员在赛前需要吸收的碳水化合物的负担量，即碳水化合物的消耗量。

　　这个公式还揭示了面对最大的挑战波士顿马拉松时运动员的生理基础。年龄在19岁到34岁之间的男性必须有有3小时10分或更少的时间才能跑完波士顿马拉松排位赛全程，同龄女性必须用3小时40分或更少的时间。拉波波特说，这些数据不是建立在科学基础之上，但是可以进行选手淘汰，只留下前十名运动员。