边走路边发短信为什么更容易摔跤

The cognitive challenges of walking while texting are well known, both to scientists and to those of us who have ambled into a light pole or a fellow pedestrian or have been on the receiving end of someone else's distracted movements. Strolling while talking on the phone — or, more particular, texting — ties up the brain's relatively limited working attentional resources, most researchers would agree, much as those activities do when you are driving.

边走边发短信会带来认知挑战，这一点不仅仅为科学家，也为那些曾经一头撞上电线杆或者别的路人，或者曾被走神的人撞上的人来说所熟知。边走边使用电话——或者更具体地说，发短信——涉及到的工作记忆资源相对有限，至少不会超过你开车时发短信涉及的大脑资源，对此大部分研究人员都认同。

But walking is not driving. In some ways, it's more demanding. You sit while you drive. Walking requires a multitude of orchestrated actions and reactions. But whether and how using a phone affects the physical process of walking and whether those impacts might have health costs have been little explored.

但走路跟开车不同。在某种角度来说，它提出的要求更高。开车时你是坐着的，而走路需要多种行为和反应协调一致。不过，用手机是否或如何影响走路这种生理过程，以及这种影响是否会产生健康损害，这些还甚少得到研究。

So researchers at the University of Queensland in Brisbane, Australia, rounded up 26 healthy adults for a study, published last month in PLOS One, and sent them strolling repeatedly along a 28-foot stretch of hallway while cameras captured their steps. In one setup, the volunteers walked without a phone; in another, they read a long text on a phone's screen; and in a third, they texted "The quick brown fox jumps over the lazy dog." The volunteers were told to hold the phone and type as they usually would. They were also asked to try to walk as normally as possible.

澳大利亚布里斯班的昆士兰大学(University of Queensland)研究人员因此做了一项试验，征集了26名健康成人，并请他们在一条长为28英尺的走廊上反复行走，用摄像机记录下他们的脚步。一次安排这些志愿者在走路时不拿手机；另一次边走边在手机上看一条长长的短信；第三次则是边走边发短信，内容为：敏捷的褐色狐狸跳过了懒狗。志愿者需要手持手机，用习惯的方式来编辑短信内容，同时需要走起路来尽量跟平常一样。这份研究上月发表在《公共科学图书馆·综合》(PLOS One)上。

As it turned out, texting significantly distorted their gait and walking form, whether they intended to contort themselves or not. Most noticeable, the volunteers began to walk with a more upright and rigid body position. Their heads froze into cocked and largely unchanging positions, eyes on the screen, chins bent toward their chests. Their necks and lower back joints had significantly less range of motion. They displayed "tighter mechanical constraint" in their upper bodies and midsections, according to the researchers; arms stopped swinging loosely and were bent and locked into place. The pelvic joints likewise stiffened, making leg motion jerkier. In general, the texters moved "like robots," said Siobhan Schabrun, an honorary senior fellow at the University of Queensland, who led the study.

研究发现，不管人们是否会有意识地加以控制，发短信都会显著扭曲人们的姿势和步态。最值得注意的是，这些志愿者走起路来时，身体的姿势变得更为挺直、僵硬。他们的头歪了起来，而且角度没怎么变化，眼睛盯着屏幕，下巴垂到胸前。他们的脖子和后腰关节活动范围显著变小。据研究人员说，这些参试人员的上半身和腰腹部出现了“更紧张的力学约束”，上臂不再松弛摆动，而是弯了起来，固定在身体两侧。骨盆关节同样僵硬，这令双腿动作变得不再稳定。这项研究的领导者、昆士兰大学荣誉资深研究员西沃恩·斯格布兰(Siobhan Schabrun)介绍说，总的来看，发短信的人走起路来“像是机器人”。

Simultaneously, their gait patterns changed. Texters took significantly shorter steps, and their pace slowed. They also "deviated more from a straight line," the study's authors wrote, meaning that with almost every step, they set their feet farther to the side.

与此同时，他们的步态模式也改变了。发短信的人走的步伐明显变小，速度放慢。研究的作者在论文中指出，他们同时“常常偏离直线”，这指的是参试人员每走一步，步子都会往路边凑近一点。

These adjustments, although relatively slight, could result in both immediate and longer-term physical consequences, Dr. Schabrun said. In the short term, they increase the likelihood that you will trip, and not merely because you neglect to look where you are going while texting. "Previous studies, many in elderly populations, have shown that a more rigid posture, such as this, can put you at greater risk of falling," Dr. Schabrun said.

斯格布兰博士说，这些调整尽管较为微妙，但可能会产生即时和远期的生理后果。短期来说，这会加剧人们绊倒的可能性，而且这不仅仅是因为你在走路时没看路。“此前很多在年长人群中进行的研究已经显示，出现这一类僵硬体态，更容易加大你摔跤的危险，”斯格布兰说。

Frequent peripatetic texting also may cause or worsen neck and shoulder pain, Dr. Schabrun suggested, by reducing the neck joint's natural range of motion. If you walk and text, occasionally move out of pedestrian traffic and gently tilt your head forward and back, an easy exercise to combat neck stiffness.

斯格布兰博士还认为，频繁在走路时发短信会限制脖子的自然活动范围，引发或加剧脖子和肩膀疼痛。如果你非得走路时发短信，那么最好是能不时离开人行道，轻轻地前后扭动头部，这种简单运动可以应对脖子僵硬。

This brief intermission from texting may also reorient your body's relationship with space, Dr. Schabrun said. Normally, the body prioritizes maintaining balance over almost all other demands, she pointed out. But in perhaps the most significant implication of her study, her volunteers' bodies and brains appeared to be "prioritizing texting."

斯格布兰说，发短信时短暂休息下，还有可能让你的身体调整与空间的关系。她指出，我们的身体通常把保持平衡放在其他所有需求之上，但在她的研究中，一个最重要的发现也许在于，参试者的身体和大脑似乎把“发短信视为重中之重”。