人類動作的歷史，為什麼人體動作，長現在這個樣子 Some Histories of Human Movement How things got to be the way they are

人類動作的歷史，為什麼人體動作，長現在這個樣子
Some Histories of Human Movement
How things got to be the way they are

作者Todd Hargrove 原文連結  如果你喜歡這篇文章，成為Todd 文章會員訂閱。

偉大的生物學家達西·湯普森 (D'Arcy Thompson) 說：「世界上的萬物，都有一套它的運行方式，因為它必須是那樣。」他的意思是，要理解一件事物最好的方法，就是研究它的歷史。 許多其他偉大的思想家也表達了類似的想法：

「人們被歷史困住，歷史也被困在人們裡面。”」— 詹姆斯鮑德溫

「過去永遠不會結束，甚至根本還沒有過去。」 —威廉福克納

「如果你不了解歷史，那麼你就什麼都不知道。 這就像如果你是一片葉子，而你不知道你是樹的一部分。 」 —邁克爾克萊頓

「如果不了解進化論，生物學就沒有任何意義 」—Theodosius Dobzhansky

The great biologist D’Arcy Thompson said that “everything is the way it is because it got to be that way.” What he meant was that the best way to understand something is to study its history. Many other great thinkers have expressed similar ideas: 

“People are trapped in history and history is trapped in them.” - - James Baldwin

“The past is never dead, its not even past.” - - William Faulkner

“If you don't know history, then you don't know anything. You are a leaf that doesn't know it is part of a tree. ” - - Michael Crichton

“Nothing in biology makes sense except in light of evolution. ” - - Theodosius Dobzhansky

心理學家保羅·布魯姆指出，所有人的內心都有兩種歷史。 第一個是我們物種的歷史，寫入我們的 DNA 並影響我們的先天本性。 第二個歷史，是我們從嬰兒期到青春期，及之後的發展和教育的一系列事件。 如果不了解這些歷史，就無法全面了解人類的心智、思想，尤其是個人的心智、思想。

我認為人類動作也是如此。 如果不知道爬行、走路和跑步等身體動作，是如何在演化與發展時間軸上出現的，我們就無法真正理解動作的本質。 這篇文章提供了這些動作如何產生的一些歷史。 它涵蓋了大約 5 億年，所以我保證，我只會關注一些重點。 那為什麼要回朔這麼久的時間？ 因為當我們把時間軸拉長來看，我們會看到在近距離觀察不到的格局。

The psychologist Paul Bloom points out that all humans have two histories living inside them. The first is the history of our species, written into our DNA and affecting our innate nature. The second history is the series of events surrounding our development and education from infancy through to adolescence and beyond. You can't understand the human mind in general, and individual human minds in particular, without knowing something about these histories.

I think the same is true for human movement. We can't really understand the nature of physical actions like crawling, walking, and running without knowing how they emerged on evolutionary and developmental time scales. This post offers some history of how these movements came into existence. It covers about 500 million years, so I promise I will only focus on the highlights. Why go back so far? When you zoom out, you can see patterns that are invisible when you look up close. 

演化史

脊椎動物的基本身體設計，是在大約 5.25 億年前從魚開始出現的：一端是頭，另一端是尾，和一堆靈活的椎骨，以及連接脊椎的肋骨。 魚主要是通過脊柱側彎來回游動。 透過左右移動尾巴的動作，推動魚在水中前進。 側面的鰭片不提供任何向前推進力，它們只是為了轉向。

但是這些鰭在大約 3.5 億年前，開始為移動做出貢獻，當時第一批兩棲動物開始在淺水中「行走」，然後走到陸地上幾吋。 他們用鰭作為原始的四肢，將腹部抬離地面一點點，就好像他們在做一個迷你伏地挺身一樣。

A drawing of tiktaalik, one of the first tetrapods. Credit Wikipedia commons..

提塔力克魚屬的一張畫，第一個四足動物

Evolutionary History 

The basic body design for vertebrates was invented by fish about 525 million years ago: head at one end, tail on the other, and a stack of flexible vertebrae and ribs connecting them. Fish swim mostly through side bending of the spine back and forth. This moves the tail left and right and powers the fish forward through water. The fins on the sides don’t provide any forward propulsion, they are just there for steering.

But the fins started contributing to locomotion about 350 million years ago, when the first amphibians started “walking” in shallow water, and then a few feet onto land. They used their fins as proto-limbs to elevate their bellies just a little bit from the ground, as if they were doing a mini-pushup. 

儘管他們的四肢是原始的，但他們創造了一個基本公式，現在地球上每一個四足動物，都共享這個藍圖：一根長骨（人類的肱骨或股骨），連接到兩根長骨（例如橈骨/ 尺骨或脛骨/腓骨），連接到許多小骨頭（例如腕骨或跗骨），連接成五個放射線狀（例如手指或腳趾）。 

有關此基本原則公式（同源性），如何在各種不同生物形式（包括人體）中一直出現的更多實例，請參見下圖。

Limb homologies in tetrapods. Credit wikipedia commons.

四足動物的四肢同質性

一些兩棲動物進化成爬行動物，它們使用與魚相同的側彎脊柱運動模式，在陸地上行走。 想像一下鱷魚走路的樣子：腹部低到地面，四肢向外張開，每向前一步，脊柱的側旋運動都會輔助。

Abducted limbs, side bent spine. Credit wikipedia commons.

外展的四肢，側彎的脊椎

當這些爬行動物中，一些進化成哺乳動物時，它們對向前移動（locomotion）的模式進行了關鍵的改變。 他們的腳直接在身體下方移動，因此四肢可以用更少的力量來支撐體重。

Reptiles sprawl and mammals stack. Credit wikipedia commons.

爬蟲類四肢往外，哺乳類在身體下方

Although their limbs were primitive, they created a basic blueprint which is now shared by every four-limbed animal (tetrapod) on earth: one long bone (in a human the humerus or femur), connecting to two long bones (e.g. the radius/ulna or tibia/fibula), connecting to many small bones (e.g. the carpals or tarsals), connecting to five rays (e.g. the fingers or toes). See the picture below for more examples of how this basic formula (a homology) remains constant in a variety of modified forms, including the human body. 

Some of the amphibians evolved into reptiles, which walk over land using the same side-bending spinal movement patterns as fish. Picture how an alligator walks: belly low to the ground, limbs splayed out the sides, with each forward step assisted by a sidewinding movement of the spine. 

When some of these reptiles evolved into mammals, they made a key change to the locomotive pattern. Their feet moved directly under the body, so the limbs could support the bodyweight with less work. 

現在腹部離地面更遠，四肢可以通過屈曲/伸展運動，更直接地向前和向後移動，而不是向兩側外展。 脊柱可以幫助他們，通過上下彎曲和伸展，而不是左右側彎來進一步向前。 這是一種更加強大和高效的前行模式。 想像一下獵豹衝刺時的運動：隨著腿向前和向後猛衝，脊椎交替拱起和彎曲。

Credit wikipedia commons.

有趣的是，你會看到在鯨魚和海豚等海洋哺乳動物中，脊柱是用屈曲/伸展的方式來向前移動。 它們通過上下擺動尾巴來游泳，而不是像魚一樣左右擺動。 所以它們的尾巴是水平的，而不是垂直的。

With the belly now further away from the ground, the limbs were free to reach more directly forward and back with flexion/extension movements, instead of abducted out to the sides. And the spine could help them reach further through flexing and extending up and down instead of side to side. This is a much more powerful and efficient locomotive pattern. Picture the movement of a cheetah as it sprints: the spine alternately arches and rounds as the legs surge forward and back. 

Interestingly, the shift to a flexion/extension based pattern of spinal movement in locomotion is preserved in water-based mammals like whales and dolphins. They swim by moving their tail up and down, not side to side like a fish. So their tails are horizontal, not vertical.

大約 5000 萬年前，一些哺乳動物遷入樹木並進化成第一批靈長類動物。 樹棲環境需要一套全新的運動“硬體”，例如抓手和腳抓住樹枝、移動肩膀，以各種角度和距離接觸樹枝和果實。 還有新“軟體”：更好的視力和更大的大腦，用於手眼協調和手部靈巧。

某些靈長類動物，用四肢在樹枝上行走，另一些靈長類動物，則透過從一個樹枝跳到另一個樹枝來活動。 其他（我們的祖先）則進化出一種懸吊的運動方式，稱為臂式（brachiation）—懸掛在頭頂的樹枝上，並以泰山式的方式從一個樹枝擺動到另一個。 這需要對當今人類的肩部和軀幹進行改變：長臂、靈活的旋轉手腕、高度靈活的肩關節、更窄的胸腔、更直立的姿勢，以及允許往頭頂方向動的肩胛骨。

About 50 million  years ago, some mammals moved into the trees and evolved into the first primates. The arboreal environment required a whole new set of hardware for movement, such as grasping hands and feet to grab branches, and mobile shoulders to reach branches and fruits at a variety of angles and distances. New software too: better vision and bigger brains for hand-eye coordination and manual dexterity.

Some of these primates walked on branches using all fours, others got around by leaping from branch to branch. Others (our ancestors) evolved a suspensory mode of locomotion called brachiation - hanging from overhead branches and swinging Tarzan-style from one to another. This required changes to the shoulder and trunk that remain with humans today: long arms, flexible rotating wrists, highly mobile shoulder joints, a more narrow and broad rib cage, a more upright (orthograde) posture, and scapulas that allow overhead reaching. 

大約 200 萬年前，其中一些靈長類動物，從樹上下來的時間足夠長了，可以學會如何用兩條腿走路。樹棲生活已經為這種直立的姿態，做好了過渡的準備，因為要能抓到頭頂上的樹枝，需要一個直立的姿勢。

許多猿類可以用兩條腿直立行走，但這不是一件優雅的事情。人體解剖學的進化，使雙腳前行變得更有效率，即使不是快速或敏捷，我們最終還是成為了地球上最好的耐力跑者之一。雖然難以置信，但在馬拉松的距離上，人類可以跟馬匹敵。

這種耐力跑的天賦，加上獨特的投擲能力，可能是對長距離、持久狩獵的適應而來，解放雙手讓我們可以遠距離攜帶武器、水、食物、嬰兒和工具。

最終，我們還學會了跳舞、演奏樂器、發明不同種運動，以及在工作和娛樂中，以各種其他新穎的方式移動。在某些時候，我們的技術進步如此之大，以至於我們開始在 Zoom 會議和電視遊戲等虛擬世界中，比在自然世界中走得更遠，許多人忘記了人體如何形成以及它們的用途。 （希望這段歷史是一個很好的提醒。）

About 2 million years ago, some of these primates descended from the trees long enough to learn how to walk on two legs. Tree life had prepared them for this transition to verticality, because reaching a branch overhead requires an upright posture. Many apes can walk upright on two legs, but it is not an elegant thing. Human anatomy evolved to make bipedal locomotion highly efficient, if not speedy or agile, and we eventually became some of the best endurance runners on the planet. Although it is hard to believe, humans are rivals for horses at marathon distances. This talent for endurance running, along with a unique ability to throw, may have been an adaptation to long distance persistence hunting. Getting our arms free allowed us to carry weapons, water, food, babies, and tools long distances. Eventually, we also learned to dance, play instruments, invent sports, and move in a thousand other novel ways for both work and play. At some point our technologies improved so much that we began to move around more in virtual worlds like Zoom conferences and video games than the natural world, and many forgot where humans bodies came from and what they are for.  (Hopefully this history is a good reminder.)

人體動作發展

這裡有一個較短的人體動作發展的故事，它與上面講述的演化故事，有著驚人的相似之處。

人類嬰兒如何在短短五六年內，從無助的小生物，轉變為有能力的多元移動者（versatile mover），而且無需任何訓練。

人類胚胎經歷了與演化階段相似的發育歷史。 在子宮內，有一個階段我們有像鰓的階段，另一個階段我們看起來像小蠑螈。 當我們出生時，我們像離開水的魚一樣在地上扭動，但很快就會學會像第一批兩棲動物一樣，推靠在我們的手臂上。

我們最初的運動可能看起來像爬行動物：身體靠近地面，腿和手臂放在兩側。 當我們四肢開始更位於軀幹下方，變得更像哺乳動物的模式時，我們的爬行會得到更多改善。 當我們可以爬行(crawl)時，我們中的許多人也可以攀爬(climb)，因為這是一種類似的運動模式，只是是垂直的而不是水平。

事實上，所有的孩子在幾個月大的時候都可以像猴子一樣從頭頂的支撐物上吊起來。

Developmental history

Here is a shorter story of gradual change to the human body that has striking parallels to the evolutionary story told above.1 It is about how human infants transform from helpless blobs into competent and versatile movers in just five or six years, without any training. Human embryos pass through developmental stages that are similar to the stages of evolution. Inside the womb, there is one stage where we have the equivalent of gills, and another where we look like little salamanders. When we are born, we wriggle on the ground like a fish out of water, but soon learn to push up on to our arms like the first amphibians.  

Our first efforts at locomotion may look reptilian: body close to the ground, legs and arms to the sides. Our crawling improves when we shift to a more mammalian pattern, with the limbs underneath the torso. By the time we can crawl, many of us can also climb, because it’s a similar movement pattern, just directed vertically not horizontally. In fact, all kids can hang like monkeys from overhead supports by the time they are even a few months old. 

像第一批靈長類動物一樣，我們第一次嘗試用兩條腿站立，是透過從頭頂的物體（例如沙發或成年人的手）獲得支撐來穩定的。 

坐姿和站姿之間的頻繁轉換，形成了基本的下蹲模式，也就是腿部的三個主要關節推遠離地板，就像一開始兩棲動物上岸時所做的那樣。 深蹲中，下肢三個主要關節的伸展（extension），也是跳躍和跑步的基礎。

像所有其他哺乳動物一樣，孩子們會自發地玩類似捉迷藏、木頭人的遊戲。 這訓練了敏捷的基本技能，即根據視覺提示快速改變方向的能力。 與大多數哺乳動物不同，人類幼兒花費大量時間抓取物體，這是人類的一項關鍵技能。 這讓他們為需要手眼協調的任務做好準備，例如投擲和熟練工具的使用。

當我們進入青春期時，我們開始採用這些基本的運動模式—伸手、下蹲、步態和物體操作—並將它們以各種方式，組合在一起，形成更複雜的動作、舞蹈或使用工具的動作。 例如，大多數球類運動是跑步、敏捷、跳躍、物體操作、投擲和/或踢腿的組合。

Like the first primates, our first attempts at standing on two legs are stabilized by reaching for support from overhead objects, such as a couch or hand from an adult. Frequent transitions between sitting and standing trains a basic squat pattern, where the three major joints in the legs extend to push away from floor, just like the first amphibian did when they came on shore. The triple extension used in the squat is also the basis for jumping and running.  

Like all other mammals, kids spontaneously engage in games of tag or navigating obstacles. This trains the fundamental skill of agility, which is the ability to rapidly change direction in response to a visual cue. Unlike most mammals, human toddlers spend a lot of time handling objects, which is a key skillset for humans. This gets them ready for tasks requiring hand eye coordination, such as throwing and skillful tool use.   

As we get into adolescence we start taking these basic movement patterns - reaches, squats, gaits and object manipulations - and putting them together in various combinations to form the more complex movements used in sport, dance, or tool use. For example, most ball sports are combinations of running, agility, jumping, object manipulation, throwing and/or kicking. 

一些歷史教訓

我們可以從這段歷史中吸取什麼教訓？ 一是我們的祖先經歷了許多不同的環境，我們至少保留了他們進化出的一些能力。 進化的每個階段都會保持一種或另一種形式的適應。 我們的脊椎可以像魚一樣左右彎曲，我們可以像大多數陸地動物一樣四肢行走，我們可以像靈長類動物一樣懸掛在樹枝上。 我們的身體就像一座已經建造了數十億年的房子。 每個新住戶都進行了一些改造，但這些變化是漸進和累積的。 當舊房間年久失修，新房間會被添加，但地基從未被拆除。

從某種意義上說，我們體內生活著許多不同的動物，我們可以使用它們的一些身體功能。 這也解釋人類為什麼會有令人難以置信的多功能性的運動方式。 我們不是最快或最強壯的跑者、登山者或游泳者，但我們可以做所有這些動作，甚至更多。 這就是為什麼有這麼多不同的運動方式。

其中，有些鍛煉方式會感覺比其他方式更有意義，這主要是出於歷史原因，可能是基於個人的，也可能是演化的。 例如，你可能真的很喜歡打籃球，因為你的個人經歷——這是你小時候喜歡的事情，你是 NBA 的球迷，你所有的朋友都在打球等等。有些練習很有意義，因為你是人類。 步行、攀爬和游泳等運動具有內在意義，因為它們與存在於您 DNA 中的數百萬年歷史有關。 當我出去跑步時，我喜歡提醒自己這一點。

作者Todd Hargrove 原文連結  如果你喜歡這篇文章，成為Todd 文章會員訂閱。

Some lessons from history

What lessons can we learn from this history? One is that our ancestors moved through many different environments, and we retain at least some of the abilities they evolved. Each stage of evolution lead to adaptations that remain in one form or another. Our spines can bend side to side like a fish, we can walk on all fours like most land animals, and we can hang from branches like a primate. Our bodies are like a house that has been in construction for billions of years. Each new occupant did some remodeling, but the changes were gradual and cumulative. New rooms were added while others fell into disrepair, but the foundation was never torn down.

In some sense there are many different animals living inside us, and we have access to some of their physical abilities. This is one way to explain the incredible versatility of human movement. We're not the fastest or strongest runners, or climbers, or swimmers, but we can do all these movements and more. This is why there are so many different ways to exercise.

Of these, some ways to exercise will feel more meaningful than others, and this will be primarily for historical reasons, which may be either personal or evolutionary. For example, you may really enjoy playing basketball because of your personal history - it's something you enjoyed as a kid, you are a fan of the NBA, all your friends play, etc. And some exercises are meaningful simply because you are a human. Movements like walking, climbing, and swimming have inherent meaning because they relate to millions of years of history living inside your DNA. I like to remind myself of this when I go out for a run.

作者Todd Hargrove 原文連結  如果你喜歡這篇文章，成為Todd 文章會員訂閱。