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我们为什么做不了五周跳?

Why It's Almost Impossible to Do a Quintuple Jump | WIRED

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连线杂志 ・ WIRED

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今年是属于“四周”的一年
This is the year of the quad.
自上届冬奥会以来
Since the last Olympic games,
单板双板滑雪运动员们已经把向后歪轴转体(cork)四周练得炉火纯青
snowboarders and skiers have perfected a trick called the quad cork,
这确实让人难以置信
which looks and sounds ridiculous because it is.
包含旋转五周和空翻四周
It’s five full spins and four full flips,
所有动作要在三秒内完成
all in the span of about three seconds.
但你知道谁能转得更快吗?
But you know who spins a lot faster than that in way less time?
花样滑冰运动员
Figure skaters.
我们来寻找瞬间在空中旋转四周的秘诀
We’re gonna find out what it takes to spin your body four times in the air in a fraction of a second.
以及为什么旋转五周是几乎不可能的事
And why spinning five times could be almost impossible.
三年前 英国单板滑雪运动员Billy Morgan完成了世界上第一个向后歪轴转体四周
Three years ago British snowboarder Billy Morgan pulled off the world’s first quad cork.
Morgan和Andri Ragettli一样也会参加奥运会
Morgan will be at the Olympics as well Andri Ragettli.
而去年 Andri Ragettli成为第一个在双板上完成这个动作的人
who last year became the first person to do a quad cork on skis.
提醒一下 这些可是世界上优秀的运动员
Mind you these are some of the world’s best athletes.
今年秋季 Ragettli的疯狂跑酷训练迅速风靡
Ragettli’s crazy parkour workout went viral this fall
因为这个训练就像健身房里的神奇鲁布·戈德堡机械
because it’s like a superhuman Rube Goldberg, in the gym.
但是仅在几年之前
But only a few years ago,
单板和双板滑雪者都不确定是否有可能完成这个动作
skiers and snowboarders weren’t even sure the quad cork was possible,
这引出一个有趣的问题:
which raises an interesting question:
我们人类是否达到了空中翻转次数的极限呢?
Are we at the limit of how much a human can turn and flip through the air?
虽然向后歪轴转体难度惊人 但它或许不是我们的极限
As amazing as the quad cork is, it might not be the limit
一个物理学家做了计算
One physicist calculated that
单板滑雪运动员实际上可以完成六周甚至更多的向后歪轴转体
a boarder could actually complete six or more cork screws.
这是因为单板和双板滑雪运动员
That’s because snowboarders and skiers
腾空时间接近三秒
get hang times of close to three seconds.
这点时间听起来可能不长 
That may not sound like much
但对16岁花样滑冰运动员Dinh Tran来说这个时间很长了
but it is a lot of time to a figure skater like 16-year-old Dinh Tran.
他是旧金山滑冰选手里的后起之秀
He’s an up-and-coming skater in San Francisco.
在今年全国青少年组锦标赛上获得了银牌
He took home the silver at Junior Nationals this year.
你今天到这是来练习四周跳的吗?
So you’re here today to practice quads right?
是的
Yeah.
-是吗?-是的 来试试
-Yeah? -Yeah, a try.
-是吗?-是啊
-Yeah? -Yeah.
重在尝试?
Emphasis on try?
是啊
Yeah.
然而想要完美完成四周跳
But getting that quad done perfect
十分困难
is tough.
Dinh和其他滑冰者没有斜坡来帮助起跳
Dinh and other skaters don’t get a ramp to launch from.
他们仅用腿部肌肉驱动身体
They have only their leg muscles to propel them
在冰面上跃起约一英尺半的高度
about a foot and a half off the ice.
然后在约0.6秒的时间内
And then they’ve got just about six tenths of a second
完成旋转和落冰
to rotate and land.
这一套动作很快
It’s one really big fast motion,
你得跳到空中
so, you jump up in the air
然后差不多同时内收胳膊和腿
and then you kind of pull your arms in and your legs in at the same time.
如果你曾经见过滑冰运动员旋转 你就会明白
If you’ve ever seen the skaters spin you’ve got the idea.
他们从伸展胳膊开始
They start with their arms extended.
然后收回胳膊
And then they pull their arms in
这样能使旋转加速
it causes the rotation to speed up.
空中旋转也是这样
Same thing when they’re in the air.
其中原理就是角动量守恒
That’s because of something called the conservation of angular momentum.
角动量取决于运动员的旋转速度
Angular momentum depends on both the speed of the skaters’ rotation,
和身体与轴线的相对位置
and the position of the skaters’ body relative to the axis.
即他们旋转所围绕的中心
That’s the center of their rotation.
运动员身体各部分离轴线越近
The closer the body parts are to the axis of rotation,
旋转就越快
the faster they spin.
然后当然就是落冰了
And then of course there’s the landing.
在触冰前伸开手臂
Or you have to open them before you make contact with the ice,
可以在落冰时降低旋转速度
which soften the rotation under the definition of the landing.
对于顶尖男子滑冰选手 四周跳几乎是必备构成
Quads have become pretty much mandatory for the top male skaters
部分要归功于全美锦标赛冠军陈巍(Nathan Chen)
thanks in part to US national champion Nathan Chen,
他是首个在一套节目中完成五个四周跳的选手
the first man to land five of them in one program.
为了更好地了解完成这个动作的要求
To get a better sense of what it takes,
我和一个奥运滑冰选手一起蹦床
I bounced with an Olympic skater,
把自己弄得头晕目眩
got insanely dizzy on this thing.
和这个人讨论一分钟能旋转几周
And talked revolutions per minute with this guy.
我是Jim Richards
My name is Jim Richards.
是特拉华大学的一名教授
I’m a professor in the University of Delaware.
我和美国花样滑冰协会一同
I worked with the United States Figure Skating
协助教练和滑冰选手们
to assist coaches and skaters,
完成多周跳跃
and performing multiple revolution jumps.
Richards是运动学教授
Richards is a professor of kinesiology.
他运用动作捕捉技术
And he uses motion capture technology
绘制运动员跳跃轨迹帮助他们纠正轻微的不平衡问题
to map jumps and help correct slight imbalances
这种轻微的不平衡甚至能影响顶尖运动员
that can throw off even elite skaters.
我们很早之前就发现 其实大多运动员都跳得足够高
We learned a long time ago that most of the skaters jump high enough.
他们也大都获得了足够的角动量来完成跳跃
And most of them leave the ice with enough angular momentum to complete the jump.
但大多数在腾空时就失败了
But most of them failed in the air.
因为他们旋转的位置使他们
They adopt the position that doesn’t enable them
无法达到足够的旋转速度 来完成整个跳跃
to spin as fast as they need to complete the jump.
为了了解空中旋转是什么感觉
To learn what that kind of rotation feels like
我得到了Tim Goebel的帮助
I got some help from Tim Goebel.
他是第一个在赛场上完成四周跳的美国人
He was the first American to land a quad in competition,
在2002年的奥运会上他完成了三个四周跳 赢得了铜牌
and did three of them on his way to a bronze medal at the 2002 Olympics.
被誉为“四周跳之王”
They called him the quad king.
大家称你为“四周跳之王”对吗?
You’re actually known as the quad king right?
我曾经是“四周跳之王” 直到陈巍来取代了我
I was the quad king until Nathan Chen came along and unseated me.
所以怎么样才能算是“四周跳之王”呢?
So what did it take to become the quad king?
我觉得需要无畏 或许还有一点愚蠢
I think it took a lack of fear and probably a little stupidity.
还需要花时间在蹦床上练习
And some time on the trampoline,
滑冰运动员们以此来练习跳跃
which skaters use to practice their jumps.
使用蹦床可以获得更长的腾空时间
I mean you’ve got more hang time on a trampoline
这样可以更多地体会技巧和空中旋转的位置
you can experiment with the technique and the air position a little bit more,
同时减少对身体的损伤
with a lot less wear and tear on your body.
我关注的就是减少身体损伤
I’m all about less wear and tear on the body.
所以一个轻松的转身
So just one easy turn.
Goebel做起来得心应手
And Goebel made it look pretty easy.
但对我来说完全就是另一回事了
But for me, a totally different story.
Tim教了我许多关于如何调动身体核心
Tim gave me a lot of pointers on how to engage my core
以及高效旋转的技巧
and spin more efficiently.
-伸出右手-伸出右手
-Right arm is out.-Right arm is out.
调动身体核心
Core is engaged.
然后…… 转!
And… turn!
-好的-做得好 朋友
-All right. -Well done my friend.
3秒后开始!
Three to go!
我让他在我做漂亮转体的时候帮我计时
I asked him to time me while I went for my magnificent spin and a half.
1.08秒
And 1.08.
你完成动作的腾空时间足够
Well you’ve got enough hang time to successfully complete a quad.
-我的腾空时间足够完成……-这点很好
– I get enough hang time to successfully…- So that’s impressive.
即使跳了几十次 我也没能跳出两周跳
Even after dozens of jumps I never made it to even two revolutions,
更别提四周了
much less four.
在蹦床上训练的其中之一个原因是
One of the reasons to train on a trampoline is
尽管滑冰很优美
that ice skating for all its grace
但这也是项残酷的运动
is a brutal sport.
杨百翰大学的研究者们
Researchers at Brigham Young University
给滑冰鞋装上传感器
actually attached sensors to skates
来记录跳跃落冰时的冲击力
to record the impact forces of landing big jumps.
通过冰刀上传感器收集到的数据
From the data that we’ve collected with the instrumented blade,
我们发现滑冰运动员落地时的冲击力
we found that skaters land with
是他们体重的五至八倍
somewhere between five to eight times their body weight.
如果无法加快旋转速度
Even on the safety of a trampoline
即使在安全如蹦床的这种地方
there was no way I was ever gonna
我也无法像顶尖滑冰运动员那样
pull off a quad like the elite skaters,
完成四周跳
if I couldn’t spin faster.
要成功完成四周跳
If they are going to successfully land a quad,
最高旋转速度要达到400转每分
peak rotation velocity going to have to be 400 rpm.
难以置信
That’s crazy.
而要完成五周跳 需要更快的速度
To pull off a quint would involve even faster speeds.
Richards认为达到这种速度是不可能的
So fast that Richards doesn’t really think they’re possible.
运动员要完成五周跳
In order to land the quint,
平均转速要达到400转每分左右
which puts their average rotation velocity around 400 rpm
这样最高转速就接近500转每分
that would put their peak rotation volecity closer to 500rpm.

Wow.
我们见过的最高转速大约是430-440这个范围内
The highest we have ever actually seen is about 430, 440 in that range.
你还记得内收胳膊可以加快旋转速度吗?
So you remember how pulling your arms in can actually make you spin faster?
有一个可以让你在家练习的方法
There’s a way to practice that at home.
你需要这样一个东西
It’s with one of these things.
叫金牌专业旋转训练器
It’s called a gold medal pro spin trainer.
实际上就是个训练人旋转的转盘
And it’s basically a human turntable.
操作指南上说
It is per the instructions
它是给严格训练的滑冰运动员用的
for serious skaters.
当然我也用它来练习了
So naturally I tried practicing with it
但这个转盘只让我感到头晕
and basically just made myself sick.
然后我把它拿到我工作的地方
And then I brought it into work
让我同事也试试
for my co-workers to try.
可以肯定 我们中没有人能接近400转每分
Pretty sure none of us got anywhere close to hitting 400rpm
虽然我们都感觉转得够快
even if we all felt that way.
但这里或许还有一种让专业运动员们
But there might be a way for professionals
达到五周跳所需速度的方法
to get the speeds they need to do a Quint.
就是用这个
And that’s with these.
它们就是负重手套
They’re weighted gloves.
在一项实验中
And in an experiment
Sara Ridge和Jim Richards 让运动员们
Sara Ridge and Jim Richards had athletes
做跳跃旋转时戴着它们
wear them while performing jump spins.
我会在这个安全椅中
I’m going to show you why
向你展示其中原理
from the safety of this chair.
如果你有更大的角动量
So if you have a greater amount of angular momentum,
是因为你的手臂向外伸远
because your arms were out wide
一部分重量远离了你的旋转轴心
and because you had an extra mass further away from your axis of rotation.
一旦你在空中时收回胳膊
Once you’re in the air and you bring your arms in
使这部分的重量靠近你的旋转轴心
that extra mass is that close to your axis rotation.
这样就提高了转速
All that’s left is you’re going to increase your rotation speed.
确实有用
And it works.
或许
Kind of.
至少对于最初的几次跳跃有用
At least for the first few jumps.
所有的运动员都旋转过度
All of the skaters were over rotated which meant
表明这个手套起到了作用
that the gloves are doing their job.
但是在几次跳跃后
But after a few more jumps
所有运动员都恢复到了
All of the skaters adapted back
他们使用手套之前的状态
to spinning the way they did before the gloves.
但即使运动员能学会利用这部分重量
But even if skaters could learn to use the weight to their advantage,
也不能保证这样能让他们完成五次旋转
there’s no guarantee that it would be enough to spin them around five times.
更别说在比赛中被允许了
Let alone that it would be legal.
所以短时间内我们可能看不到五周跳了
So we’re probably not gonna see a quint any time soon.
其原因不难理解
And it’s not hard to see why.
(跳跃中)旋转的难度让人难以置信
Spinning is absurdly difficult.
即使是在蹦床上
Even on a trampoline
腾空时间是专业运动员的两倍
getting twice the air that the pros get,
我也转不了一周半
I can barely do it one and a half times.
而且动作很难看
And it looked terrible.
只是稍微转一会儿
Spinning even a little bit
就让我感到恶心反胃
made me feel nauseous.
我还没有在冰上试过
And I never even tried it out on the ice
因为这个地方不允许我试
because this place would not let me.
所以在今年的比赛中
So at this year’s games
当你看到选手们轻松地完成旋转时
when you see people spinning and they make it look really easy,
记住事实远不是看起来那样简单
remember that it really really is not.
实际上 这个动作已经处于人类的极限了
In fact, it’s right at the edge of what is humanly possible.


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