My 11-year-old grandsons, Stefan and Tomas, weigh about 80 pounds each. On the 20-minute walk to their middle school and the uphill walk home, they carry backpacks that weigh about 12 pounds each, or 15 percent of their body weight.
我的两个孙子斯蒂芬(Stefan)和托马斯(Tomas)现年11岁，体重都是80来磅（合36公斤）。他们每天要步行去初中上学，回家时还得走一段上坡路，在这段20分钟的路程里，他俩要各自背着12磅（合5.4公斤）的书包，也就是说，书包的重量达到他们体重的15%。
When extra books or clothing, a musical instrument or other equipment are added, the weight they carry can reach 20 pounds. But whatever the figure, those packs are simply too heavy for their still-forming bones and muscles.
如果加上额外的书本、衣服、一件乐器或别的用品，他们要背的书包很可能达到20磅重（合9公斤）。但不管究竟有多重，他们的书包对于仍在发育中的骨骼和肌肉来说，未免过于沉重了。
Heavy backpacks don't just sap children of energy that might be better used doing schoolwork or playing sports. Lugging them can also lead to chronic back pain, accidents and possibly lifelong orthopedic damage.
沉重的书包不仅会消耗孩子们本可以用来更好地做功课或参加体育活动的精力。负担过重，可会导致慢性背痛、发生意外，甚至有可能带来终生的骨骼伤害。
Among the risks described by Dr. Pierre D'Hemecourt, a sports medicine specialist at Children's Hospital Boston, are stress fractures in the back, inflammation of growth cartilage, back and neck strain, and nerve damage in the neck and shoulders.
波士顿儿童医院(Children's Hospital Boston)的运动医学专家皮埃尔·戴米库(Pierre D'Hemecourt)描述了一系列危害，包括背部应力性骨折、生长板软骨发炎、后背和颈部压力、以及背部和肩膀的神经损害。

The federal Consumer Product Safety Commission calculated that carrying a 12-pound backpack to and from school and lifting it 10 times a day for an entire school year puts a cumulative load on youngsters' bodies of 21,600 pounds — the equivalent of six mid-sized cars.
联邦消费者产品安全委员会(Consumer Product Safety Commission )计算得出：假设一个学生每天背着12磅的书包往返，每天抬起书包的次数以10次计，一学年下来，这个孩子的身体总共要承担21600磅（约合9800公斤）的负担——相当于6台中型小汽车。
The issue has been raised repeatedly in countries all over the world for more than a decade. In December 1999, doctors in Milan reported in The Lancet that 34.8 percent of Italian schoolchildren carried more than 30 percent of their body weight at least once a week, "exceeding limits proposed for adults."
在过去这十几年来，世界各国都在反复探讨这个问题。1999年12月，米兰的医生们在《柳叶刀》(The Lancet)上发表报告称，每周至少有一次，34.8%的意大利学童要背负超过自身体重30%的书包，“这超出了向成年人推荐的负重上限。”
The load carried by these sixth-graders was equivalent to a 176-pound man hauling around a 39-pound backpack each day.
而这些六年级学生所扛的书包重量，相当于一个176磅（合80公斤）的男性每天扛着39磅（合17.8公斤）的背包四处走。
But even in this digital era, when at least some schoolwork can be done online, there has been no apparent decrease in the burdens we ask the younger generation to tote around all day.
可是就算身处这个数字时代，当至少部分作业可以在线完成时，我们让孩子们每天背负的书包重量却并没有显著的减轻。
Pack Animals
小小蜗牛背着壳
In the newest study, published in March in the Archives of Disease in Childhood, researchers in Spain assessed the backpacks and back health of 1,403 pupils ages 12 to 17. More than 60 percent were carrying packs weighing more than 10 percent of their body weight, and nearly one in five had schoolbags that weighed more than 15 percent of their own weight.
在3月发表在《儿童疾病档案》(Archives of Disease in Childhood)最新研究中，西班牙的研究人员评估了1403名12-17岁儿童的书包重量和背部健康。超过60%的学生所背的书包重量超过其体重的10%，近五分之一书包重量超过体重的15%。
Not surprisingly, one in four students said they had suffered back pain for more than 15 days during the previous year; scoliosis — curvature of the spine — accounted for 70 percent of those with pain. The remaining 30 percent had either low back pain or contractures — continuous, involuntary muscle contractions. Girls faced a greater risk of back pain than boys, and their risk increased with age (and, presumably, years of lugging around their heavy packs).
这个结果也不出所料：在以上学生中，每四人中就有一人说，自己在前一年感到背痛的天数超过了15天；脊椎侧弯——脊椎出现弯曲）——在出现背痛孩子中的比例达70%。剩下的这30%学生，要么有腰痛，要么有挛缩——肌肉持续的、非随意的紧缩。比起男孩，女孩出现背痛的风险更大，而且风险随年纪增长而上升（可以推想，这跟年复一年背着重重的书包有关）。
Pain often results when the weight of the pack pulls children backward, prompting them to bend forward or to arch their backs to keep the pack centered. This position can compress the spine, pressing the vertebrae on the discs between them.
沉重的书包会压得孩子往后仰，为了保持后背的中立位置，他们得往前弓背或者猫起腰来，疼痛往往因此发生。这种姿势可以挤压脊柱，压迫腰椎间盘。
If the child has to lean forward when walking with a loaded pack, it is too heavy. At the very least, it is a recipe for poor posture and chronically rounded shoulders. And if these forward-bending children must raise their heads to see where they are going, neck pain and pinched nerves can be the result.
如果孩子在背着书包走路时身体前倾，就说明书包太重了。这样至少会导致孩子姿势不佳，长此以往会出现圆肩（即肩胛骨向前挤——译注）。如果这些身体前倾的孩子还得抬起头来看看自己走到哪里去了，则会导致颈部疼痛和神经病变。
Children also accidentally whack schoolmates with heavy backpacks while walking in crowded hallways. Sometimes the pack falls from a shelf or desk, or trips someone while resting on the floor. A too-heavy pack can throw the wearer off-balance on a staircase.
在背着重重的书包走过拥挤的走廊时，孩子们可能不小心抡到别的同学。有时书包会从架子或课桌上坠落，搁在地上时则会绊倒别人。背着过重的书包，孩子甚至有可能在上下楼梯时失去平衡。
Reducing the Load
减轻负累
In the interest of sanity and safety, my son (the twins' father) purchased used instruments for them to keep at home so they would not have to lug a trombone or clarinet back and forth to school along with their other paraphernalia.
考虑到卫生和安全因素，我的儿子（也就是这对双胞胎的父亲）为他们购买了二手乐器，供他们在家中使用，这样孩子们就不会在带着其他学习用品的同时，还得拖着长号或单簧管往返于学校和家了。
Then he conducted an inventory of their packs and sent it by e-mail to their teachers to find out just how many of the items had to be carried to and from school each day.
然后他对孩子们书包里装的东西列了份目录，通过邮件发给老师们，好确认每天有哪些东西必须背到学校再背回家。
One teacher responded with some helpful suggestions, including having the boys take a few minutes at the end of the school day to determine what they really needed to take home with them.
一位老师提供了一些有益的建议，包括两个孩子每天放学时，先花几分钟考虑下，有哪些东西他们觉得非得带回家不可。
"They don't have to bring everything home every night," Aimee Fournier, their English teacher, wrote. "But a lot of kids don't take much time at their lockers to sort out what they do need."
英语老师艾米·弗涅尔(Aimee Fournier)在信中写道：“他们没必要每晚把所有东西都背回家，但很多孩子不会在储物柜前驻足停留，考虑自己的真实需要。”
Rather than lug around the entire load all day, most books can be left in the child's locker, if there is enough time between classes. Only those needed for the next class or two need be taken along.
大部分书并不需要整天背来背去，如果课间休息的时间够用，可以把书放在孩子的储物柜里，只带下面一两节课要用的教材即可。
In schools facing less of a financial pinch than New York City's, teachers might be able to provide duplicates of at least some of the often-used heavy textbooks to keep at home.
在那些经费不像纽约市这么捉襟见肘的校区，老师们也许可以给学生提供至少部分备用书，好让家里也存一套常用的厚重教材。
Dr. Bryan Lane, an osteopath in Temple, Tex., urges parents to peek inside their children's backpacks and suggest items that could be left at home or at school. He studied 188 children in kindergarten through fifth grade and found that on average the children toted packs equaling 14 percent of their body weight. A third of the parents had never checked the contents of the packs, and 96 percent had never weighed them.
德克萨斯州坦普尔市的整骨医师布莱恩·兰(Bryan Lane)提醒家长们，他们应当了解孩子们书包中放了哪些物品，同时对孩子该把哪些留在家里，哪些带去学校提出建议。他研究了从幼儿园到小学五年级的188名儿童，发现平均来说，孩子们所背的书包重量达到其体重的14%。三分之一的家长从来没有查看孩子的书包，96%的家长从未称过重量。
Also helpful is selecting a well-designed backpack and adjusting it to sit properly on the child's back. Although for the last 15 years I have used a rolling backpack to go to and from work, I know that teens and preteens today consider them unfashionable. Plus, they can be a trip hazard in hallways and difficult to carry up and down stairs.
挑选设计上佳、可以调适到完全适合孩子背部的书包也有用。过去这15年来，我上下班一直使用的是一个拉杆包，不过我知道对于青春期和青春期前的孩子来说，这种包不那么时髦。此外，它可能会在过道里绊倒人，也很难提起来上下楼梯。
Select a backpack that is no bigger than absolutely necessary — the more room in the pack, the more the child is likely to carry. The pack should have wide, padded, adjustable shoulder straps (narrow ones can cause nerve damage), a padded back, and compartments within so that the heaviest items can rest against the child's back.
选择一个不超出所需大小的书包——背包的空间越宽裕，孩子就越有可能往里面装更多东西。书包应该有宽大的肩带、有衬垫并且可调（窄窄的肩带可能会引起神经病变），书包背部应有软垫，里面也要有隔层，这样最重的物品可以贴在孩子的后背上。
A waist strap would be ideal, but I doubt many children would use it. Adjust the shoulder straps so that the bottom of the pack when filled lands no lower than four inches below the waist.
如果书包有腰带，这自然最好不过，但我怀疑有多少孩子愿意系腰带。调整好腰带，要确保在装好物品后，书包底端距离腰部不低于4英寸。
Children should be cautioned never to carry the pack on one shoulder. Decades of carrying nearly everything heavy on my right shoulder has left me with significant scoliosis that I'm now trying to minimize with a yoga exercise.
人们应提醒孩子，千万不要单肩背书包。几十年来，我一直用右肩背重重的包，导致出现了严重的脊椎侧弯，现在只好通过瑜伽练习尽量减轻症状。
Digital Textbooks May Help Ease Backpack Burden
数字教材可能有助于为书包减负
The issue of overloaded backpacks could well become moot if President Obama and his education gurus have their way. The president wants every student to be using e-textbooks by 2017.
如果奥巴马和他的教育高参们能够一路凯歌，过重的书包有可能将成为过去式。总统希望在2017年前，所有学生都能使用数字教材。
In January, Education Secretary Arne Duncan and Julius Genachowski, the chairman of the Federal Communications Commission, recommended that states redirect budgets for printed books to the purchase of iPads, Kindles and the like and the software needed to foster modern education.
1月份，教育部长阿恩·邓肯(Arne Duncan)和联邦通信委员会主度朱利斯·格纳科斯其(Julius Genachowski)建议政府将原用于纸质教材的预算划拨用于购买iPad、Kindle和其他类似电子产品，以及用于健全现代化教育的各类软件。
Publishers and tablet makers will be urged to work together, and to lower costs, in order to supply the nation's 50 million schoolchildren with electronic products for educational use.
当局将敦促出版商和平板电脑厂商合作，同时降低产品费用，以向全美5000万在校学生提供电教产品。
Although not everyone endorses the idea of moving from words printed on paper to those delivered electronically, there are certain undeniable advantages.
尽管对于将注意力从白纸黑字转移到电子书上的想法，并非所有人都支持，但它确实拥有一些不可辩驳的优势。
For one, updates to e-textbooks are relatively easy to make, which means schools with limited finances would not have to replace outdated texts every five or six years. Learning would be more efficient and interactive, and materials supplied by teachers could be tailored to better meet individual student needs.
其中一项是，更新电子书相对更易行，这就意味着经费有限的学校不必面对每隔五六年就要换过时教材的问题。学习将更有效，互动性更强，而且由老师挑选的教材将能更好地满足学生的个体化需求。
In addressing a summit of industry and education officials in January, Mr. Genachowski said that $7 billion a year is now being spent on textbooks that often are out-of-date. He predicted that in five years, "we could be spending less as a society on textbooks and getting more for it."
在1月份一个面向产业界和教育官员的峰会上，格纳科斯基先生说，现在每年要在教材上花费70亿美元，而这些教材的内容往往已经落伍。他预言，在五年内，“作为一个社会，我们在教材上花的钱将更少，而所得的回报将更多。”
He acknowledged the greater up-front costs of moving from paper to digital books and other materials but insisted that in the long run the switch would bring huge savings to the country's educational system.
他承认，将教材和其他教辅材料从纸质换成数字版本，先期投入会更高，但坚信长远来看，这种转变将为美国的教育体系节省巨大开支。
The first challenge will probably be finding the money with which schools could buy devices like the iPad, which runs about $500 at retail. In school districts that cannot afford such purchases, strategies will be needed to help low-income students get their own.
首当其冲的挑战是寻找资金，用于学校购买电子设备，像iPad这样的设备零售价可达500美元左右。在一些买不起这类硬件的校区，还需要想办法帮助低收入家庭学生购买自己的器材。
Then there is the issue of safekeeping (although if every child has one, the risk of theft is somewhat diminished).
其次是安全保管问题（不过如果孩子们人手一台，失窃的危险将会减少些）。
Costs aside, the educational advantages are perhaps limitless on devices that allow students to do research, check their work and get feedback from teachers without leaving their classrooms or homes. Digital books can also provide interactive diagrams, audio and video that are not possible with traditional texts.
花费姑且不论，这类器材带来的教育优势将可能是无穷无尽的，学生们无需离开教室或走出家门，就可以进行研究、检查功课并得到老师的反馈。电子教材同时还可以提供交互式图表、音频和视频，这是传统课本无法企及的。
Apple has already introduced three types of educational software intended to make the iPad a fixture in the classroom: an updated electronic bookstore called iBooks 2 that allows students to download more interactive textbooks; iBooks Author, a program for creating books; and iTunes U, an app that instructors can use to produce digital curricula and share course materials with students.
苹果公司已经引入了三种教育软件，好让iPad适应课堂环境：一种是称为iBook 2的更新版在线书店，学生可在这里下载更多的互动教材；iBood Author，这是一个自成生成图书的应用程序；以及iTunes U，老师们可以使用这个应用来制作数字课程，并与学生们分享教学课件。
Protections are needed to prevent students from cheating — say, by e-mailing test answers to their pals or submitting work that someone else has created. And much to the distress of one of my digitally oriented grandsons, whose penmanship is atrocious, students still must learn how to write with a pen or pencil.
还需要提防学生作弊——比方说，用email将考试答案发给同学，或者提交别的同学已经完成的作业。此外，学生们仍然应当学习用钢笔或铅笔写字，这个要求肯定会让我的那个字写得特别烂、对数码产品十分痴迷的小孙子感到悲愤不已。
A remaining impediment: Will e-textbooks permit students who once complained that "the dog ate my homework" to find a new ream of excuses?
还有一个障碍：有了电子教材，原先抱怨“我的作业被狗吃了”的同学们，还能想到什么新的借口吗？
"The battery died, and I couldn't charge it." "My iPad got wet in the rain/a puddle/the bathtub."
“没电了，我没法充电。”“我的iPad被雨/水坑/浴缸给泡湿了。”
Or even: "My little brother hammered it to death."
甚至是：“我的弟弟把它摔坏了。”