我从小不喜欢跑步。虽然知道校友用跑步治疗好“多病的”体质。我没有那么多病，也就没有想学跑步。

来美国后，听朋友说年轻时跑步伤了他们的膝盖。“跑步会伤膝盖”，成为我的“信仰”。直到昨天，我想劝小朋友别跑“过了”，于是上网搜“证据”，才发现我out了。

Why Running Won’t Ruin Your Knees

为什么跑步不会毁了你的膝盖

Running pummels knees more than walking does, but in the process it may fortify and bulk up cartilage, helping stave off knee arthritis.

跑步比走路更能敲击膝盖，但在这个过程中，它可以强化和增加软骨，帮助避免膝关节炎。

By Gretchen Reynolds

Published Oct. 21, 2020

Updated Oct. 22, 2020

https://www.nytimes.com/2020/10/21/well/move/why-running-wont-ruin-your-knees.html?referringSource=articleShare

Could running actually be good for your knees?

跑步真的对膝盖有好处吗？

That idea is at the heart of a fascinating new study of the differing effects of running and walking on the knee joint. Using motion capture and sophisticated computer modeling, the study confirms that running pummels knees more than walking does. But in the process, the authors conclude, running likely also fortifies and bulks up the cartilage, the rubbery tissue that cushions the ends of bones. The findings raise the beguiling possibility that, instead of harming knees, running might fortify them and help to stave off knee arthritis.

这个想法是一项关于跑步和步行对膝关节的不同影响的迷人新研究的核心。 使用动作捕捉和复杂的计算机建模，该研究证实跑步比走路更能敲击膝盖。 但在此过程中，作者得出结论，跑步可能还会强化和增大软骨，即缓冲骨骼末端的橡胶组织。 研究结果提出了一个令人着迷的可能性，即跑步不会伤害膝盖，而是可以强化它们并有助于避免膝关节炎。

Of course, the notion that running wrecks knees is widespread and entrenched. Almost anyone who runs is familiar with warnings from well-meaning, nonrunning family members, friends and strangers that their knees are doomed.

当然，跑步会破坏膝盖的观念是普遍且根深蒂固的。 几乎所有跑步的人都熟悉来自善意、不跑步的家人、朋友和陌生人的警告：你们的膝盖注定要受伤。

This concern is not unwarranted. Running involves substantial joint bending and pounding, which can fray the cushioning cartilage inside the knee. Cartilage, which does not have its own blood supply, generally is thought to have little ability to repair itself when damaged or to change much at all after childhood. So, repeated running conceivably wears away fragile cartilage and almost inevitably should lead to crippling knee arthritis.

这种担忧并非没有根据。 跑步涉及大量的关节弯曲和撞击，这会磨损膝盖内的缓冲软骨。 软骨没有自己的血液供应，通常被认为在受损时几乎没有自我修复的能力，或者在童年后根本没有改变。 因此，可以想象，反复跑步会磨损脆弱的软骨，几乎不可避免地会导致严重的膝关节炎。

But in real life, it does not. Some runners develop knee arthritis, but not all. As a group, in fact, runners may be statistically less likely to become arthritic than nonrunners.

但在现实生活中，并非如此。 一些跑步者会患上膝关节炎，但不是全部。 事实上，作为一个群体，跑步者在统计上可能比不跑步者患关节炎的可能性更小。

The question of why running spares so many runners’ knees has long intrigued Ross Miller, an associate professor of kinesiology at the University of Maryland in College Park. In earlier research, he and his colleagues had looked into whether running mechanics matter, by asking volunteers to walk and run along a track outfitted with plates to measure the forces generated with each step.

长期以来，马里兰大学帕克分校的运动机能学副教授罗斯·米勒一直对为什么跑步能保护这么多跑者的膝盖这个问题很感兴趣。 在早期的研究中，他和他的同事研究了跑步力学是否重要，通过要求志愿者沿着装有板的轨道行走和跑步，以测量每一步产生的力。

The resulting data showed that people hit the ground harder while running, clobbering their knees far more with each stride. But they also spent more time aloft between strides, meaning they took fewer strides while covering the same distance as when walking. So, the cumulative forces moving through their knees over time should be about the same, the researchers concluded, whether someone walked or ran.

结果数据显示，人们在跑步时着地更重，每迈出一步，膝盖撞击得更厉害。 但他们在两步之间也花费了更多的时间，这意味着他们在行走的距离相同的情况下步幅更少。 因此，研究人员得出结论，随着时间的推移，通过膝盖移动的累积力应该大致相同，无论是走路还是跑步。

But, recently, Dr. Miller had begun to doubt whether this finding really explained why running wasn’t wrecking more knees. He knew that some recent studies with animals intimated that cartilage might be more resilient than researchers previously had believed. In those studies, animals that ran tended to have thicker, healthier knee cartilage than comparable tissues from sedentary animals, suggesting that the active animals’ cartilage had changed in response to their running.

但是，最近米勒博士开始怀疑这一发现是否真的解释了为什么跑步并没有破坏更多的膝盖。 他知道最近对动物的一些研究表明，软骨可能比研究人员以前认为的更有弹性。 在这些研究中，与久坐动物的类似组织相比，跑步的动物往往具有更厚、更健康的膝关节软骨，这表明活跃动物的软骨因跑步而发生了变化。

Perhaps, Dr. Miller speculated, cartilage in human runners’ knees likewise might alter and adapt.

米勒博士推测，也许人类跑步者膝盖中的软骨同样可能会改变和适应。

To find out, he again asked a group of healthy young men and women to walk and run along a track containing force plates, while he and his colleagues filmed them. The researchers then computed the forces the volunteers had generated while strolling and running. Finally, they modeled what the future might hold for the volunteers’ knees.

为了找出答案，他再次让一群健康的年轻男女沿着装有测力板的轨道行走和奔跑，同时他和他的同事对他们进行拍摄。 然后，研究人员计算了志愿者在散步和跑步时产生的力量。 最后，他们模拟了志愿者膝盖的未来。

More specifically, they used the force-plate numbers, plus extensive additional data from past studies of biopsied cartilage pulled and pummeled in the lab until it fell apart and other sources to create computer simulations. They wanted to see what, theoretically, would happen to healthy knee cartilage if an adult walked for six kilometers (about 3.7 miles) every day for years, compared to if they walked for three kilometers and ran for another three kilometers each of those days.

更具体地说，他们使用测力板数字，加上过去研究中的大量额外数据，这些数据来自过去对活检软骨在实验室中拉扯和撞击直到它分崩离析，以及其他来源来创建计算机模拟。 他们想看看，如果一个成年人连续多年每天步行 6 公里（约 3.7 英里），与他们每天步行 3 公里然后再跑 3 公里相比，健康的膝关节软骨会发生什么变化。

They also tested two additional theoretical situations. For one, the researchers programmed in the possibility that people’s knee cartilage would slightly repair itself after repeated small damage from walking or running — but not otherwise change. And for the last scenario, they presumed that the cartilage would actively remodel itself and adapt to the demands of moving, growing thicker and stronger, much as muscle does when we exercise.

他们还测试了另外两种理论化的情况。 一方面，研究人员对人们的膝关节软骨在步行或跑步造成的反复小损伤后会轻微自我修复的可能性进行了编程，但不会发生其他变化。对于最后一种情况，他们假设软骨会主动重塑自身并适应移动的需求，变得更厚更强壮，就像我们锻炼时肌肉所做的那样。

The models’ final results were eye-opening. According to the simulations, daily walkers faced about a 36 percent chance of developing arthritis by the age of 55, if the model did not include the possibility of the knee cartilage adapting or repairing itself. That risk dropped to about 13 percent if cartilage were assumed to be able to repair or adapt, which is about what studies predict to be the real-world arthritis risk for otherwise healthy people.

模型的最终结果令人大开眼界。 根据模拟，如果模型不包括膝关节软骨适应或自我修复的可能性，每天步行者在 55 岁时面临大约 36% 的患关节炎的机会。 如果假设软骨能够修复或适应，则该风险降至约 13%，这与研究预测的其他健康人在现实世界中的关节炎风险有关。

The numbers for running were more worrisome. When the model assumed cartilage cannot change, the runners’ risk of eventual arthritis was a whopping 98 percent, declining only to 95 percent if the model factored in the possibility of cartilage repair. In effect, according to this scenario, the damage to cartilage from frequent running would overwhelm any ability of the tissue to fix itself.

跑步的数字更令人担忧。 当模型假设软骨无法改变时，跑步者最终患关节炎的风险高达98%，如果模型考虑到软骨修复的可能性，则仅下降至 95%。 实际上，根据这种情况，频繁跑步对软骨造成的损害会压倒组织自我修复的任何能力。

But if the model included the likelihood of the cartilage actively adapting — growing thicker and cushier — when people ran, the odds of runners developing arthritis fell to about 13 percent, the same as for healthy walkers.

但如果模型包括人们跑步时软骨积极适应的可能性——变得更厚更软——跑步者患关节炎的几率下降到约 13%，与健康步行者相同。

What these results suggest is that cartilage is malleable, Dr. Ross says. It must be able to sense the strains and slight damage from running and rebuild itself, becoming stronger. In this scenario, running bolsters cartilage health.

罗斯博士说，这些结果表明软骨具有延展性。 它必须能够感知跑步和重建自身所带来的压力和轻微损伤，变得更强大。 在这种情况下，跑步可以促进软骨健康。

Modeled results like these are theoretical, though, and limited. They do not explain how cartilage remodels itself without a blood supply or if genetics, nutrition, body weight, knee injuries and other factors affect individual arthritis risks. Such models also do not tell us if different distances, speeds or running forms would alter the outcomes. To learn more, we will need direct measures of molecular and other changes in living human cartilage after running, Dr. Miller says, but such tests are difficult.

然而，像这样的建模结果是理论上的，而且是有限的。 他们没有解释软骨如何在没有血液供应的情况下自我重塑，或者遗传、营养、体重、膝关节损伤和其他因素是否会影响个体关节炎风险。 这些模型也没有告诉我们不同的距离、速度或跑步方式是否会改变结果。 米勒博士说，要了解更多信息，我们需要直接测量跑步后活体人体软骨的分子和其他变化，但这样的测试很困难。

Still, this study may quiet some runners’ qualms — and those of their families and friends. “It looks like running is unlikely to cause knee arthritis by wearing out cartilage,” Dr. Ross says.

尽管如此，这项研究可能会平息一些跑步者的疑虑——以及他们的家人和朋友的疑虑。“看起来跑步不太可能通过磨损软骨而导致膝关节炎，”罗斯博士说。

To Avoid Running Injuries, Don’t Shake Up Your Routine Too Much

Runners who made eight or more changes to their running routines were at high risk of injury, especially if they were feeling stressed.

By Gretchen Reynolds

Published June 30, 2021