A wider base腳張開，底面變大
Seen from above, the green base more than doubles when the feet move apart. The gold dot is now far from the left and right edges.
從正上方看，腳一張開，綠色的底面就變成兩倍多。金點離左右兩邊的邊緣都遠了。
Sports and Movement · Unit 1 · Lesson 1 · 體育 單元一 第一課
How Do You Keep Your Balance?怎麼站得穩？
Lean a 3D figure until it tips over, and find the rule that decides when it falls. See why athletes spread their feet and bend their knees, then take eight classroom phrases out to the field.
讓 3D 人偶一直歪到倒下去，找出決定它什麼時候倒的那條規則。看看運動員為什麼要把腳張開、把膝蓋彎下來，再把八句課室英語帶到操場上用。
Big idea · 一句話看懂
You stay on your feet as long as your center of gravity is above your base of support, the patch of floor that your feet mark out. Spread your feet and the base gets bigger. Bend your knees and your center of gravity gets lower. Either way, you are harder to tip over.
只要重心落在支撐底面的上方，你就站得住；支撐底面就是雙腳在地上圍出來的那一塊範圍。把腳張開，底面變大；把膝蓋彎下來，重心變低。兩種做法都讓你更不容易倒。
3D Model · 3D 模型
A Figure That Can Tip Over 一個會倒的人偶
The green shape on the floor is the base of support. The gold ball is the center of gravity, and the gold dot is the spot on the floor straight below it. Drag the figure, or press the lean buttons, and watch the dot. The moment it leaves the green shape, the figure tips over. Then change the pose and try again.
地上的綠色區域是支撐底面。金色的球是重心，地上的金點是重心正下方的位置。拖動人偶，或按「讓它歪」的按鈕，盯著金點看：它一離開綠色區域，人偶就倒了。然後換一個姿勢再試。
Drag the figure to lean it · 拖動人偶讓它歪 Drag the background to turn · 拖曳背景旋轉 Scroll or pinch to zoom · 滾輪／雙指縮放
- Base of support: the floor under and between the feet that are on the ground
支撐底面：著地的腳底下、加上兩腳之間的地面 - Center of gravity, and the dot on the floor straight below it
重心，以及它正下方地上的金點 - Mass of each body part (switch it on below): a bigger ball is a heavier part
各部位的質量（在下方打開）：球越大，那個部位越重
The figure is 140 cm tall, and one square on the mat is 20 cm. Its body parts have roughly the proportions of an average person. Their masses are averages from a classic study (Dempster, 1955, as given by Winter, 2009): head and neck 8.1%, trunk 49.7%, each arm 5.0%, each leg 16.1%.
人偶身高 140 公分，墊子上一格是 20 公分。身體各部位的長度大致是一般人的比例；各部位的質量則用一份經典研究的平均值（Dempster 1955，轉引自 Winter 2009）：頭與頸 8.1%、軀幹 49.7%、每隻手臂 5.0%、每條腿 16.1%。
This is a simplified sketch, not a measurement of any person. The figure is made of stiff parts with average masses, and it has no muscles, so it cannot catch itself. Real people differ from one another, and they balance by moving all the time. · 這是簡化的示意，不是任何一個人的測量值。人偶由硬邦邦的幾節組成，質量用的是平均值，而且沒有肌肉，所以不會自己站穩。真實的人每個都不一樣，而且是靠不停地微調來保持平衡的。
Reading · 英文閱讀
1
Unit 1: How Do You Keep Your Balance?
Stand up and put your feet together. Now lift one foot off the floor. You wobble, and your arms fly out to the sides. Nobody taught you to do that. Your body works all the time to keep you from falling, even when you think you are standing still. To see how it does this, you need two ideas: the center of gravity and the base of support.
站起來，雙腳併攏。現在把一隻腳抬離地面。你會晃，兩隻手臂會自己往兩邊張開。這個動作沒有人教過你。你的身體一直在工作，不讓你跌倒，就連你以為自己站著不動的時候也一樣。要知道它是怎麼做到的，得先認識兩個觀念：重心和支撐底面。
Every part of you has weight: your head, your arms, your legs. But you can think of all that weight as pulling down at one single point. That point is your center of gravity. When an adult stands up straight, it is inside the body, about 55 percent of the way up from the floor, near the height of the navel. It does not stay in one place. Raise your arms and it moves up. Bend your knees and it moves down.
你身上的每個部位都有重量：頭、手臂、腿。不過，你可以把全部的重量想成集中在一個點上往下拉。那個點就是你的重心。大人站直的時候，重心在身體裡面，離地大約是身高的百分之五十五，差不多在肚臍的高度。它不會待在同一個地方。把手舉起來，它就往上移；把膝蓋彎下來，它就往下移。
Now look at the floor. Your base of support is the area marked out by the parts of you that touch the ground. When you stand on two feet, it is more than two footprints. It also includes the floor between them. Stand on one foot, and the base shrinks to a single footprint. Rise onto your toes, and it shrinks again.
現在看看地板。你的支撐底面，就是身體碰到地面的部位所圍出來的範圍。兩隻腳站著的時候，它不只是兩個腳印，還包括兩個腳印之間的地面。單腳站，底面就縮成一個腳印。踮起腳尖，它又縮得更小。
Here is the rule. Imagine a line that drops straight down from your center of gravity to the floor. As long as that line lands inside your base of support, you stay up. When it lands outside, you begin to tip, and you have to take a step, grab something, or fall. Try the 3D model above: the figure tips at the very moment the gold dot leaves the green shape.
規則是這樣的。想像一條線，從你的重心筆直往下掉到地板。只要這條線落在支撐底面裡面，你就站得住。它一落到外面，你就開始倒，這時你得跨出一步、抓住東西，不然就會跌倒。試試上面的 3D 模型：金點離開綠色區域的那一刻，人偶就倒了。
There are two ways to make yourself harder to tip. First, spread your feet. A bigger base gives that line more room to move before it reaches the edge. Second, bend your knees. A lower center of gravity has to swing farther before the line reaches the edge. Athletes do both. Watch a judo player or a basketball defender: feet wide, knees bent. But a base is only wide in the direction you spread your feet. Feet side by side resist a push from the side. One foot in front resists a push from the front.
要讓自己更不容易倒，有兩個方法。第一，把腳張開。底面變大，那條線要移動更遠才會到邊緣。第二，把膝蓋彎下來。重心變低，身體要歪得更多，那條線才會到邊緣。運動員兩樣都做。看看柔道選手或籃球的防守球員：腳張得開、膝蓋彎著。不過，腳往哪個方向張開，底面就只往那個方向變寬。雙腳左右張開，擋得住從旁邊來的推力；一腳在前、一腳在後，擋得住從前面來的推力。
Balance is not something you have. It is something you do. Your eyes, the balance organs in your inner ears, and sensors in your muscles and joints keep telling your brain where your body is, and your muscles keep making small corrections. Even when you stand quietly, you sway a little the whole time. Stand on one foot and close your eyes, and you will feel how much your eyes were helping.
平衡不是你「有」的東西，而是你一直在「做」的事。你的眼睛、內耳裡管平衡的器官，還有肌肉和關節裡的感覺器，不停地告訴大腦身體在哪裡，肌肉也不停地做小小的修正。就算你安靜地站著，身體其實一直在輕輕地晃。單腳站著再閉上眼睛，你就會感覺到眼睛原來幫了多大的忙。
Read aloud · 課文朗讀
Questions · 閱讀理解
Why is it harder to stand on one foot than on two feet?
On one foot, the base of support is only as big as one footprint, so the line from your center of gravity has very little room to move before it lands outside the base. On two feet, the base also includes the floor between the feet, so there is much more room.
A friend says, "When I hold my arms out, my base of support gets bigger." Is your friend right? What do the arms really do?
No. The base of support is made only by the parts of the body that touch the ground, and the arms do not touch it. Moving your arms shifts your center of gravity, so you can bring it back over your foot when you start to tip.
You are standing on a moving bus and holding the handrail. The bus is about to brake. How would you place your feet, and why?
Put one foot in front of the other along the length of the bus and bend your knees a little. When the bus brakes, your body is thrown toward the front, so you want a base that is long from front to back and a center of gravity that is low. Keep holding the handrail too.
Words & Phrases · 生字及片語
balance(n.)平衡She lost her balance and had to take a step.她失去平衡，只好跨出一步。center of gravity(n.)重心Bending your knees lowers your center of gravity.彎下膝蓋會讓重心降低。base of support(n.)支撐底面Standing on one foot gives you a small base of support.單腳站的時候，支撐底面很小。stable(adj.)穩的；穩定的A wide, low stance is more stable than a tall, narrow one.又寬又低的站姿，比又高又窄的站姿穩。tip over(v.)倒下；翻倒The tall vase will tip over if you bump the table.你要是撞到桌子，那個高花瓶就會倒。stance(n.)站姿The coach showed us a good defensive stance.教練示範了一個好的防守站姿。lean(v.)傾斜；歪向一邊Do not lean too far over the railing.身體不要探出欄杆太多。sway(v.)搖晃；擺動The tall grass began to sway in the wind.長長的草在風裡搖了起來。
Quick Check · 小測驗
1. What is your base of support?
2. You stay up as long as the line straight down from your center of gravity lands ___.
3. Which change makes you harder to tip over?
4. Your feet are side by side, far apart. From which direction is it still fairly easy to push you over?
5. Besides the inner ears, what does your body use to keep its balance?
Try It in the Model · 在模型裡試試
Four things to watch 四件值得看的事
Then try it yourself. In which pose can the figure lean the farthest before it tips, and in which direction?
然後自己動手試試。哪一個姿勢可以歪得最多才倒？是往哪個方向？
A lower center of gravity蹲低，重心變低
The feet stay where they are. Only the knees bend, and the gold ball drops by more than ten centimeters.
腳留在原地，只有膝蓋彎下去，金色的球就降了十幾公分。
One foot, one small base單腳站，底面只剩一隻腳
The whole body shifts sideways to bring the gold dot over the standing foot. Then a lean of only a few degrees is enough to tip it.
整個身體往旁邊移，把金點帶到站著的那隻腳上方。接著只要歪幾度，就倒了。
Past the edge越過邊緣就倒
The figure leans forward a little at a time. Watch the gold dot move toward the toes, and see what happens when it passes them.
人偶一點一點往前歪。看金點往腳尖移動，再看它越過腳尖時發生什麼事。
Game · 小遊戲
Which Pose Is the Most Stable? 哪一個姿勢最穩？
Eight questions. Each one shows two or three poses. Choose the one that is the hardest to tip over. The game counts the questions you get right on the first try. After each answer you will see each pose's base of support, its center of gravity, and how far it can lean.
八道題。每一題有兩到三個姿勢，選出最不容易被推倒的那一個。遊戲會記下你第一次就答對的題數。每答完一題，就會看到每個姿勢的支撐底面、重心，以及它可以歪幾度。
Right on the first try · 第一次就答對
Try It · 動手試試
Push It and See 推推看
Choose a stance and a push, then push the figure from the front, the back, and each side. Before you press, guess what will happen. The view on the right is from straight above, and the figure's front is toward the bottom.
選一個站姿、選力道，再從前面、後面和左右兩邊推人偶。按下去之前，先猜猜看會怎樣。右邊是從正上方看的畫面，人偶的前方朝下。
Seen from the front · 從正面看
| Push · 怎麼推 | Gentle輕 | Medium中 | Firm重 |
|---|---|---|---|
| From the front從前面推 | |||
| From the back從後面推 | |||
| From its left從它的左邊推 | |||
| From its right從它的右邊推 |
In this game, a push simply tilts the figure's center of gravity by a set angle: 3°, 7°, or 11°. A real push depends on how hard it is, how fast it comes, and where it lands, and a real person steps or bends to recover.在這個遊戲裡，「推」只是讓人偶的重心歪一個固定的角度：3°、7° 或 11°。真正的推還要看力道多大、來得多快、推在哪裡，而且真實的人會跨步或彎身體把自己救回來。
Classroom English for PE · 體育課的課室英語
Eight things to say in this lesson 這堂課用得到的八句話
Short commands that a PE teacher can use for the balance activities below. Press the speaker to hear each one, then say it out loud.
老師帶下面的平衡活動時用得上的簡短指令。按喇叭聽一遍，再大聲說一遍。
Find your own space.
找一個自己的位置。
Say it first, so that nobody can bump into anyone else.一開始就說，這樣大家才不會互相碰到。
Spread your feet apart.
把雙腳張開。
To make a wider base of support.讓支撐底面變寬的時候。
Bend your knees.
膝蓋彎曲。
To bring the center of gravity lower.讓重心降低的時候。
Stand on one foot.
單腳站。
To start the one-foot balance.開始單腳平衡的時候。
Hold your arms out to the sides.
雙手往兩邊張開。
When students begin to wobble.學生開始晃的時候。
Look straight ahead.
眼睛看正前方。
Looking at one spot makes it easier to stay steady.盯著一個點看，比較容易站穩。
Hold it for ten seconds.
維持十秒鐘。
Then count out loud together.接著大家一起大聲數。
Switch feet.
換腳。
So that both sides get a turn.讓兩邊都練到。
The topics follow the bilingual teaching handbooks for health and physical education that the University of Taipei compiled for the Ministry of Education (about 2024), which include classroom lines such as "find the proper space," "bend your knees," and "eyes front," and the teaching cues in Sport New Zealand's balance guide. The wording of these eight sentences is ours, in everyday American English.主題參考教育部委託臺北市立大學彙編的健康與體育領域雙語教學資源手冊（約 2024 年；手冊裡有 find the proper space、bend your knees、eyes front 這類課堂用語），以及紐西蘭運動署平衡教材裡的教學提示。這八句的實際用字是本教材自己寫的，用的是日常的美式英語。
Balance in Sports · 運動裡的平衡
A throw, a ring, a beam, and two Chinese words 一記摔、一個土俵、一根平衡木，和兩個中文詞
Four places where the rule of this lesson decides what happens.
四個例子：這一課的規則，在這些地方說了算。
Judo · 柔道
First, break the balance先破壞對手的平衡
Judo has a word for unbalancing an opponent: kuzushi. A throw begins by moving the other person's center of gravity toward the edge of their base. Judo also names two basic postures. In shizentai, the natural posture, you simply stand upright. In jigotai, the defensive posture, you lower your hips and set your feet wide.
柔道有一個詞專門指「破壞對手的平衡」，叫做「崩し」（kuzushi）。一記摔技，是從把對方的重心帶向底面的邊緣開始的。柔道也給兩種基本姿勢取了名字：「自然體」就是自然地站直；「自護體」是防守的姿勢，要把腰放低、雙腳張得很開。
Sumo · 相撲
Only the soles may touch只有腳底可以碰地
A sumo wrestler loses by being pushed out of a ring about 4.6 meters across, or by touching the ground with any part of the body other than the soles of the feet. So the match is this lesson in action: keep your own center of gravity over your feet, and move the other wrestler's past the edge.
相撲力士只要被推出直徑大約 4.6 公尺的土俵，或是腳底以外的任何部位碰到地面，就輸了。所以整場比賽就是這一課的內容：把自己的重心留在雙腳上方，並且把對手的重心推過邊緣。
Gymnastics · 體操
A base ten centimeters wide十公分寬的底面
The balance beam in women's gymnastics is 5 meters long, 10 centimeters wide, and 125 centimeters above the floor. A gymnast on it can never have a base wider than the beam. Try the heel-to-toe pose in the game above. Its base is long from front to back and very narrow from side to side.
女子競技體操的平衡木長 5 公尺、寬 10 公分、離地 125 公分。選手站在上面，支撐底面再怎麼樣也不會比木頭寬。試試上面小遊戲裡「腳跟接腳尖」的姿勢：它的底面前後很長，左右卻非常窄。
Two Chinese Words · 兩個中文詞
Horse stance and golden rooster馬步與金雞獨立
Chinese has everyday names for two of the poses in this lesson. The Ministry of Education dictionary defines mabu, the horse stance, as legs apart, wider than the shoulders, in a half squat: a wide base and a low center of gravity. It gives jinji duli, "golden rooster stands on one leg," as a martial arts pose and also simply as standing on one foot: the smallest base in our model.
這一課的兩個姿勢，中文裡本來就有名字。教育部《重編國語辭典修訂本》說「馬步」是「兩腿分開，超過肩寬，採半蹲姿勢」，也就是寬的底面加上低的重心。「金雞獨立」是中國武術的一種姿勢，辭典也收了「以一隻腳站立」這個意思；在我們的模型裡，它的底面最小。
In the Curriculum · 對應課綱
Where this lesson fits 這一課對應的課綱
The learning area is called Health and Physical Education. Its curriculum guidelines (2018) do not use the words center of gravity or base of support. These are the closest entries, and the links to this lesson are our reading of them.
這個領域的正式名稱是「健康與體育」。它的課程綱要（2018 年）沒有出現「重心」或「支撐底面」這兩個詞。下面是最接近的條目；它們和這一課的連結，是本教材的解讀。
Ia-Ⅱ-1學習內容・體操（國小三、四年級） · Learning content, gymnastics (grades 3–4)
滾翻、支撐、平衡與擺盪動作。
Balance is named here as one of the basic movements of gymnastics.這一條把「平衡」列為體操的基本動作之一。
3c-Ⅲ-1學習表現・技能（國小五、六年級） · Learning performance, skills (grades 5–6)
表現穩定的身體控制和協調能力。
Steady control of the body is what the two activities in this lesson practice.這一課的兩個活動，練的就是穩定的身體控制。
1d-Ⅲ-1學習表現・認知（國小五、六年級） · Learning performance, knowledge (grades 5–6)
了解運動技能的要素和要領。
A wide base and a low center of gravity are two key points behind many sports stances.底面寬、重心低，是許多運動站姿背後的兩個要領。
3c-Ⅳ-1學習表現・技能（國中） · Learning performance, skills (grades 7–9)
表現局部或全身性的身體控制能力，發展專項運動技能。
Whole-body control is the starting point for the skills of each sport.全身的身體控制，是各項運動技能的起點。
Myth vs. Fact · 常見迷思
Four things people get wrong 四個常見的誤會
✗ Myth · 迷思Your center of gravity is a fixed spot behind your navel.重心是肚臍後面一個固定的點。
✓ Fact · 事實It moves every time you change your pose. It can even be outside your body: a high jumper who arches over the bar can clear it while the center of gravity passes below it.每換一個姿勢，重心就跟著移動。它甚至可以跑到身體外面：跳高選手弓著身體過竿的時候，身體越過了橫竿，重心卻可以從橫竿下面通過。
✗ Myth · 迷思Balance comes only from your ears.平衡只靠耳朵。
✓ Fact · 事實The balance organs of the inner ear work together with your eyes and with the sensors in your muscles and joints.內耳裡管平衡的器官，是和眼睛、肌肉與關節裡的感覺器一起工作的。
✗ Myth · 迷思When you stand still, your body is doing nothing.站著不動的時候，身體什麼都沒做。
✓ Fact · 事實Even in quiet standing, the body's center of mass keeps drifting a little. Scientists call this postural sway.就算安靜地站著，身體的質心也一直在微微移動。科學家把這個現象叫做姿勢擺動。
✗ Myth · 迷思A wide stance is stable in every direction.腳張得開，每個方向都穩。
✓ Fact · 事實A base is only wide in the direction the feet are spread. In our model, feet set wide side by side can lean about 27° to the side but only about 8° forward.腳往哪個方向張開，底面才往哪個方向變寬。在我們的模型裡，雙腳左右大大張開時，往旁邊可以歪大約 27°，往前卻只能歪大約 8°。
Remember It · 記憶口訣
Balance in a sentence 一句話記住平衡
Dot inside, you stay up點在裡面，人就站著
The spot under your center of gravity has to stay inside your base of support.
重心正下方的那一點，要留在支撐底面裡。
Wide and low寬一點，低一點
Feet apart, knees bent. That is the ready stance of many sports.
腳張開、膝蓋彎。很多運動的預備姿勢都是這樣。
Spread toward the push往被推的方向張開
Pushed from the side, set your feet side by side. Pushed from the front, put one foot forward.
從旁邊被推，腳就左右張開；從前面被推，就一腳往前站。
Eyes, ears, muscles眼睛、內耳、肌肉關節
Three kinds of sensors report to your brain, and your muscles do the correcting.
三種感覺器向大腦回報，肌肉負責修正。
Stay Safe · 安全提醒
Before you try the activities 做活動之前
These are general rules for a class, not medical advice. Your teacher decides what is right for your group.
以下是上課的一般規則，不是醫療建議。適不適合你們班，由老師判斷。
- Use a flat, dry floor that is not slippery. Make sure the space is big enough that nobody feels crowded, and keep away from walls with sharp corners, desks, and stairs.在平坦、乾燥、不滑的地面上做。空間要夠大，不會覺得擠；遠離有尖角的牆面、桌子和樓梯。
- Wear shoes with the laces tied, or go barefoot on a floor that is not slippery. Do not do balance activities in socks on a smooth floor.穿鞋要把鞋帶綁好；地面不滑的話也可以赤腳。不要只穿襪子在光滑的地板上做平衡活動。
- If you feel unwell or dizzy, or if you are hurt, stop and tell your teacher. Anyone in that situation should sit the activity out.覺得身體不舒服、頭暈，或是有傷在身，就停下來告訴老師。有這些情況的人，這個活動先不要做。
- A partner push is slow and gentle, with the fingertips, and only on the shoulder. Agree on a stop word first. Never push anyone by surprise.兩人一組的「推」要慢、要輕，只用指尖，而且只推肩膀。先約定好一個喊停的字。絕對不可以突然推別人。
Classroom Activity 1 · 課堂活動一
How Long Can You Stand on One Foot? 單腳可以站多久？
You need · 準備材料
- A stopwatch or a clock with a second hand碼錶，或有秒針的時鐘
- A flat floor that is not slippery平坦、不滑的地面
- A wall or a sturdy chair within reach伸手就碰得到的牆，或一張穩固的椅子
- A notebook for the results記錄結果的筆記本
Steps · 步驟
- Work in pairs. One person balances, and the other keeps time and stands close by.兩人一組。一個人做，另一個人計時，並且站在旁邊。
- Stand on one foot with your arms at your sides. Look straight ahead. Time how long you can hold it, up to 30 seconds.單腳站，雙手放在身體兩側，眼睛看正前方。計時看可以維持多久，最多 30 秒。
- Do it again with your arms held out to the sides. Is it easier?再做一次，這次雙手往兩邊張開。有比較容易嗎？
- Stand next to the wall. Stand on one foot, then close your eyes. Compare the time. Open your eyes and touch the wall as soon as you wobble.站到牆邊。單腳站好，再閉上眼睛，比較一下時間。一開始晃，就張開眼睛、扶住牆。
- Switch roles. Then talk about it: which change made the biggest difference, and why?兩人交換。然後討論：哪一個改變影響最大？為什麼？
Most people wobble much sooner with their eyes closed, because the eyes are one of the body's three sources of balance information. Times differ a lot from person to person, so compare each person only with themselves.
大多數人閉上眼睛之後，很快就開始晃，因為眼睛是身體三種平衡訊息的來源之一。每個人能站的時間差很多，所以只和自己比。
Space · 場地
A flat, dry floor that is not slippery, with at least one arm's length of clear space on every side. For the eyes-closed step, stand within reach of a wall.平坦、乾燥、不滑的地面，四周至少空出一隻手臂的距離。閉眼的那一步，要站在伸手就能扶到牆的地方。
Sit this one out if · 這些情況先不要做
You are hurt, you feel dizzy or unwell, or an adult who looks after your health has asked you to avoid this kind of movement. Tell your teacher. You can be the timekeeper.有傷在身、覺得頭暈或不舒服，或是照顧你健康的大人交代過不要做這類動作。告訴老師；你可以負責計時。
Another way to do it · 換個做法也可以
Keep one fingertip on the wall or on the back of a chair the whole time. Or do it sitting down: sit tall on a chair without leaning back, lift one foot and both arms, and time that.全程用一根指尖輕輕扶著牆或椅背。或者坐著做：坐在椅子上、挺直不靠椅背，抬起一隻腳和雙手，計時看看。
Classroom Activity 2 · 課堂活動二
The Gentle Push 輕輕推推看
You need · 準備材料
- A partner一位同伴
- A flat floor that is not slippery, with clear space all around平坦、不滑、四周淨空的地面
- A notebook for the results記錄結果的筆記本
Steps · 步驟
- Agree on a stop word. The person who is pushed is in charge: when they say it, the push ends at once.先約定一個喊停的字。被推的人說了算：一喊，馬上停。
- Stand with your feet together. Your partner puts two fingertips on the side of your shoulder and pushes slowly, as if closing a door quietly. Stop when you have to move a foot.雙腳併攏站好。同伴用兩根指尖放在你肩膀的側面，慢慢地推，像輕輕把門關上那樣。你必須移動腳的時候就停。
- Now spread your feet apart, side by side, and try the same slow push. Does it take more of a push?現在把雙腳左右張開，用同樣慢的方式再推一次。要推得比較多才會動嗎？
- Keep your feet apart and bend your knees. Try again.腳繼續張開，再把膝蓋彎下來。再試一次。
- Put one foot in front of the other and try the push from the side once more. Then switch roles and write down what you found.改成一腳在前、一腳在後，再從旁邊推一次。然後兩人交換，把發現寫下來。
This is an experiment, not a contest, so nobody wins by pushing someone over. Feet side by side resist a push from the side, and one foot in front of the other does not. Compare your results with the Push It and See game above.
這是實驗，不是比賽，把人推倒並不算贏。雙腳左右張開，擋得住從旁邊來的推力；一腳在前、一腳在後就擋不住。把你們的結果和上面「推推看」的結果比一比。
Space · 場地
A flat, dry floor that is not slippery. Keep each pair at least two arm's lengths from other pairs, from walls, and from furniture.平坦、乾燥、不滑的地面。每一組和別組、牆壁、桌椅之間，至少隔兩隻手臂的距離。
Sit this one out if · 這些情況先不要做
You are hurt, you feel dizzy or unwell, or you do not want to be touched. Tell your teacher. You can be the recorder, or use the other way to do it.有傷在身、覺得頭暈或不舒服，或是不想被別人碰。告訴老師；你可以負責記錄，或用右邊「換個做法」的方式。
Another way to do it · 換個做法也可以
Do it alone, with no push. Lean slowly to the side until you feel that you need to step, first with your feet together and then with your feet apart, and compare how far you could lean. Or sit on a stool and reach to the side with your feet together and then apart.自己一個人做，不用推。慢慢往旁邊歪，歪到覺得必須跨步為止；先雙腳併攏做一次，再雙腳張開做一次，比較可以歪多遠。或者坐在凳子上，先雙腳併攏、再雙腳張開，往旁邊伸手試試。
Go Further · 延伸閱讀
Inside the body, and what comes next 身體裡面的事，以及下一課
The Human Body · Lesson 9 · 人體探索・第九課How Do Your Ears Hear?耳朵怎麼聽見聲音？That lesson shows the three liquid-filled loops in the inner ear that tell your brain which way your head is moving. This lesson does not repeat it.那一課介紹內耳裡三個裝著液體的圓環，它們告訴大腦頭往哪個方向動。這一課不再重複。Go to the lesson · 前往這一課 →The Human Body · Lesson 25 · 人體探索・第二十五課How Do You Walk?你是怎麼走路的？Walking is falling forward and catching yourself, again and again. For part of every step you are balanced on one leg.走路就是一次又一次往前倒、再接住自己。每一步都有一段時間，是靠一條腿保持平衡的。Go to the lesson · 前往這一課 →The Human Body · Lesson 5 · 人體探索・第五課How Do Your Joints Move?關節怎麼活動？Getting low means bending at the hips, knees, and ankles. That lesson shows how the shape of each joint decides the way it moves.要蹲低，就得彎髖、膝、踝三個關節。那一課說明每個關節的形狀怎麼決定它的活動方式。Go to the lesson · 前往這一課 →
Sports and Movement · Lesson 2 · 體育・第二課Why Do We Warm Up?為什麼要暖身？What changes in your body in the first few minutes of moving, and what the evidence says about stretching.開始活動的頭幾分鐘，身體有什麼改變？關於伸展，證據又怎麼說？Coming soon · 製作中
Sources · 資料出處
Definitions, numbers, rules, and quotations on this page were checked against these sources (October 2026). The base areas, heights, and angles shown in the model and the games are computed by the page itself from a simplified figure, and are covered by automatic tests. · 本頁的定義、數字、規則與引文依下列資料查證（2026 年 10 月）；模型與小遊戲裡的底面積、高度與角度，是頁面用簡化的人偶自己算出來的，並有自動測試。
- A person tips when the center of gravity is no longer above the base of support; spreading the feet gives a larger base, and bending the knees lowers the center of gravity重心不在支撐底面上方就會倒；腳張開底面變大、彎膝蓋重心變低OpenStax, College Physics 2e, 9.3 Stability ↗
- Center of gravity: the point where the total weight of a body may be thought to be concentrated重心：可以把物體全部重量看成集中在那裡的一個點Britannica, “Center of gravity” ↗
- 重心: the point of action of the resultant of the gravitational forces on an object重心：「物理學上指一物體所受重力之合力的作用點」教育部《重編國語辭典修訂本》〈重心〉 ↗
- Chinese terms: center of gravity is 重心 and balance is 平衡 in the national term base; it has no entry for base of support, so 支撐底面 is this page's own wording中文名詞：樂詞網 center of gravity 作「重心」、balance 作「平衡」；查不到 base of support 的譯名，「支撐底面」是本教材的用語國家教育研究院 樂詞網 ↗
- Standing adults: the center of mass is often in front of the second sacral vertebra, at about 55% of body height成年人站立時，質心多半在第二薦椎前方，約在身高的 55%Yang & Pai (2014), Journal of Biomechanics 47(16) ↗
- An object is in balance if its center of gravity is above its base of support; an adult's center of gravity is at about the height of the navel; holding the arms out lets you shift it from side to side重心在支撐底面上方就平衡；成年人的重心約在肚臍的高度；張開雙臂可以左右移動重心PE Central, “Balancing Foot Jenga” (2019) ↗
- Body segment masses as fractions of body mass (Dempster's model as adapted by Winter, 2009), based on eight cadavers of older men身體各節質量占體重的比例（Dempster 的模型，Winter 2009 整理）；資料來自 8 位年長男性的大體Duarte, BMClab: Body Segment Parameters ↗
- The balance organs of the inner ear work with vision and the musculoskeletal sensory system to control the position of the body內耳的平衡器官和視覺、肌肉骨骼的感覺系統一起控制身體的位置NIDCD (NIH), “Balance Disorders” (2018) ↗
- Quiet standing: the center of mass shows a natural migration called postural sway安靜站立時，質心會自然地移動，稱為姿勢擺動Danna-Dos-Santos et al. (2008), Journal of Motor Behavior ↗
- Children aged 6–12 standing on one leg move more with their eyes closed than with their eyes open (316 children)6–12 歲兒童單腳站立時，閉眼比張眼晃得多（316 位兒童）García-Liñeira et al. (2021), Diagnostics 11(4) ↗
- A high jumper's body can fly over the bar while the center of gravity passes below it跳高選手的身體越過橫竿時，重心可以從橫竿下方通過Scientific American (2012), “The Physics of the Olympic High Jump” ↗
- Judo: the two postures shizentai (natural) and jigotai (defensive)柔道的兩種姿勢：自然體與自護體Asami, Matsumoto & Kawamura (1972), Bulletin of the Association for the Scientific Studies on Judo, Kodokan ↗
- Judo: jigotai lowers the hips and opens both feet widely; kuzushi means unbalancing柔道：自護體是把腰放低、雙腳大大張開；崩し是破壞平衡Judo Info, “Shisei (Posture)”; University of Pittsburgh judo terminology ↗
- Sumo: the ring is about 4.6 m across; a wrestler loses by leaving it or by touching the ground with anything but the soles of the feet相撲：土俵直徑約 4.6 公尺；出界或腳底以外的部位著地就輸Britannica, “Sumo” ↗
- Balance beam: 5 m long, 10 cm wide, 125 cm above the floor平衡木：長 5 公尺、寬 10 公分、離地 125 公分Britannica, “Balance beam” ↗
- 馬步 (horse stance): legs apart, wider than the shoulders, in a half squat馬步：「兩腿分開，超過肩寬，採半蹲姿勢」教育部《重編國語辭典修訂本》〈馬步〉 ↗
- 金雞獨立: a martial arts pose on one leg; also, to stand on one foot金雞獨立：中國武術的一種姿勢；也指「以一隻腳站立」教育部《重編國語辭典修訂本》〈金雞獨立〉 ↗
- Curriculum entries Ia-Ⅱ-1, 3c-Ⅲ-1, 1d-Ⅲ-1, and 3c-Ⅳ-1, quoted word for word課綱條目 Ia-Ⅱ-1、3c-Ⅲ-1、1d-Ⅲ-1、3c-Ⅳ-1 的原文教育部《十二年國民基本教育課程綱要 健康與體育領域》（2018） ↗
- Bilingual handbook for high school health and physical education: the martial arts unit lists “body center of gravity,” “balance,” and “horse squat”高中健康與體育雙語教學資源手冊：武術單元列有 body center of gravity（身體重心）、balance（平衡）、horse squat（馬步）教育部師資培育及藝術教育司／臺北市立大學雙語教學研究中心（約 2024） ↗
- Bilingual handbook for grades 1–2 health and physical education: classroom lines for lining up, finding space, and bending the knees國小低年級健康與體育雙語教學資源手冊：排隊、找位置、彎膝蓋等課堂用語教育部師資培育及藝術教育司／臺北市立大學雙語教學研究中心（約 2024） ↗
- Teaching cues for balance: a wide base of support, bend the knees to lower the body, extend body parts to counterbalance, focus the eyes on an object平衡的教學提示：底面要寬、彎膝蓋把身體放低、伸出肢體來平衡、眼睛盯著一個物體Sport New Zealand, Developing Fundamental Movement Skills: Balance ↗
- Standards for grades K–1: holding still on different bases of support美國幼兒園到一年級的標準：在不同的支撐底面上保持不動SHAPE America, Grade-Level Outcomes for K–12 Physical Education (2013) ↗
- School sports safety: make sure the space is big enough; anyone who feels unwell or is injured should stop; keep proper spacing between students學校運動安全：場地空間要夠大；自覺身體不適或有傷在身者應停止活動；學生的間隔距離要恰當國立臺灣大學編印《103年度學校運動安全管理參考手冊》（2014） ↗
- Schools must have procedures for sports injuries and teach students to prevent them (Article 17)學校應訂定運動意外傷害處理程序，並指導學生預防運動傷害（第 17 條）教育部《高級中等以下學校及專科學校五年制前三年體育實施辦法》 ↗