5月17日午間英語新聞：科學揭秘為什么有的人跑得那么快？

> The science of speed 
科學揭秘：為什么有的人跑得那么快？

Usain Bolt, the world's fastest person, ran a 100-meter sprint at a speed of 23.35 miles per hour (37.57 kilometers per hour).
世界上跑得最快的人是尤塞恩·博爾特，他百米短跑的速度為每小時23.35英里（37.57公里）。

That's mind-blowingly fast for a human. It's about the same speed as cruising in a car through your neighborhood or in a school zone. It might not seem that fast when you're in the car, but for a person? Few runners in the world can even come close.

對于人類而言，這個速度真是快得驚人。這大約相當于在社區或學校周邊區域開車的速度。當你坐在車里時，可能不覺得車跑得有多快，但對于一個人來說就不同了。世界上很少有跑步者能接近這個速度。 

There are several reasons some people can run very fast while others tend to run more slowly. Genetics play a role, but so do your choices and experiences.
有幾個原因可以解釋為什么有些人能跑得非?？?，而其他人則跑得比較慢。來自父母的遺傳基因是一個因素，但你的個人選擇和經歷也會產生影響。

One major factor that influences your ability to run fast is the structure of your body, including how your muscles work.
影響你快速奔跑能力的一個主要因素是你的身體結構，包括你的肌肉是如何工作的。

The human body has more than 600 muscles that work together, allowing you to move in different directions and at various speeds. These muscles are made up of groups of fibers. There are two main types: fast twitch and slow twitch.
人體有600多塊肌肉協同工作，讓你能夠向不同的方向移動，并以不同的速度移動。這些肌肉由纖維群組成。纖維群主要有兩種類型：快肌纖維和慢肌纖維。

Muscles have different mixes of these fiber types. For example, two muscles make up the calf: One is predominantly fast twitch – that's the gastrocnemius, used for sprinting and jumping. The other is mostly slow twitch – that's the soleus, used for walking and jogging.
肌肉由不同類型的纖維群混合組成。例如，小腿由兩塊肌肉組成：一塊主要是快肌纖維——那是腓腸肌，用于短跑和跳躍。另一塊主要是慢肌纖維——那是比目魚肌，用于走路和慢跑。

Fast-twitch muscle fibers are larger and help your body move quickly and generate significant force. Sprinters tend to have an abundance of fast-twitch muscle fibers. However, this muscle fiber type also tires quickly, which limits how long you can run at top speed to relatively short distances.
快肌纖維較大，幫助你的身體快速移動并產生巨大的力量。短跑運動員往往有大量的快肌纖維。然而，這種肌肉纖維類型也很容易疲勞，這限制了你以最高速度跑步的時間，只能維持相對較短的距離。

Slow-twitch muscle fibers are smaller and help you run at slower speeds, but with greater endurance. Long-distance runners and competitive cyclists tend to have a lot of these muscles.
慢肌纖維較小，幫助你以較慢的速度但更強的耐力跑步。長跑運動員和競技自行車手往往有很多這種肌肉。

How much you have of each type of muscle fiber – fast twitch and slow twitch – is mostly determined by your genes, so you'll have to work with what you're born with when it comes to muscle types. But exercise can help train those muscles.
你擁有的每種肌肉纖維——快肌纖維和慢肌纖維——的數量主要由你的基因決定，所以在肌肉類型方面，你將不得不使用你出生時所擁有的肌肉纖維。但是鍛煉可以幫助訓練這些肌肉。

Physical ability isn't just about muscle. Your brain plays an important role, too.
身體能力不僅僅關乎于肌肉。你的大腦也扮演著重要的角色。

Your skeletal muscles are controlled by your brain – you think about your actions and then execute the movements. For example, you can control how long your stride is, how your arms move, how your feet hit the ground and even the techniques you use to breathe.
你的骨骼肌由大腦控制——你在行動前思考，然后執行動作。例如，你可以控制你的步幅有多大，你的手臂如何移動，你的腳如何接觸地面，甚至你使用的呼吸技巧。

You can teach your body to use the best running techniques. That includes proper posture, so your body is standing tall, and an economical stride, so your feet land below you rather than too far out in front, where they can slow you down.
你可以教會你的身體使用最佳的跑步技術。這包括正確的姿勢，讓你的身體保持挺直，以及合理的步幅，讓你的腳落在你的下方而不是太靠前，這樣會減慢你的速度。

You can also improve your running form by using your whole body, with your arms pumping in opposition to the legs, running on your toes and maximizing the time spent in flight phase with both feet off the ground. Using proper running techniques helps the muscles create more force and work together, which helps you run faster.
你還可以通過動用全身上下來改善你的跑步姿勢，讓你的手臂與腿部交替擺動，用腳尖跑步，并最大限度地增加雙腳離地的“飛行”時間。使用正確的跑步技術有助于肌肉產生更多的力量并協同發力，這有助于你跑得更快。

重點詞匯
1、mind-blowing
英/ ?ma?nd bl???? /
美/ ?ma?nd blo??? /
令人印象極深刻的；令人極震驚的

2、twitch
英/ tw?t? / 美/ tw?t? /
v. （使）抽搐，（使）抽動；猛拉，急扯；扯繩勒（馬）
n. （肌肉的）抽搐，顫動；猛的一拉，一動；（一陣）感覺；馬勒

3、predominantly
英/ pr??d?m?n?ntli / 
美/ pr??dɑ?m?n?ntli /
adv. 絕大多數，主要地

4、gastrocnemius
英/ ?ɡ?str?k?ni?m??s /
美/ ?ɡ?strɑ?k?ni?mi?s /
n. [解剖] 腓腸?。ㄎ挥谛⊥群蠓剑?/p>

5、stride
英/ stra?d /  美/ stra?d /
n. 大步，闊步；步態，步伐；步距，步幅；步速；進展，進步；<非正式>褲子（strides）；鋼琴跨越彈奏法
v. 大步走，闊步走；跨越，跨過；<文>跨坐在……上，跨立在……上

>每日一詞丨免簽政策  Visa-free policy

To promote exchanges between Chinese and foreign nationals, China has decided to extend its visa-free policy to Dec. 31, 2025, for citizens of France, Germany, Italy, the Netherlands, Spain, Malaysia, Switzerland, Ireland, Hungary, Austria, Belgium, and Luxembourg.

為進一步促進中外人員往來，中方決定延長對法國、德國、意大利、荷蘭、西班牙、馬來西亞、瑞士、愛爾蘭、匈牙利、奧地利、比利時、盧森堡12個國家免簽政策至2025年12月31日。

【知識點】
一段時間以來，中方持續推出多項來華簽證優化措施，包括減少簽證申請表填報內容、階段性調減簽證費、簡化來華留學審批手續、免采部分申請人指紋、免簽證預約、對部分國家試行免簽政策等，進一步破解外籍人員來華的難點、堵點。
中方決定延長對法國、德國、意大利、荷蘭、西班牙、馬來西亞、瑞士、愛爾蘭、匈牙利、奧地利、比利時、盧森堡12個國家免簽政策至2025年12月31日。上述國家持普通護照人員來華經商、旅游觀光、探親訪友和過境不超過15天可免辦簽證入境，不符合免簽條件人員需在入境前辦妥來華簽證。