教練,壁球的步法要怎麼練習?
#不是就繞米字?
然後1步2步3步4步…望著天?
咳咳….是看著球、揮著拍就好了嗎?
首先要瞭解壁球有哪些腳步;
👇
啟動步
Drop Step落下步
Split Step 開合
Lunge Step弓箭跨步(向前)
👇
啟動發力後再去銜接不同方向的移位
👇
Crossover Steps交叉步
Shuffle Steps側併步
Hip Turn轉髖的腳步 (向前衝刺或向後)
👇
再轉換成擊球時的
Lunge弓箭步
Lateral Lunge側弓箭步
Squat Landing深蹲步
👇
最後是退回T點的
Back Track倒退步
Cut-Step側移減速(從後場回T煞車的)
腳尖受力的輕盈碎步
這下明白了吧
為什麼我會建議,在時間有限之下。
✅做步法而非跑步。
#所以腳步不是跑米字?
這只是基本觀念。
但真實對打中,又有許多時候是
「沒時間去繞外圍切入」
平常如果只這樣練習,就產生許多落差。
步法練習要100%自然沿用進比賽中才行。
所以從T點到球-直線距離之下:
✅怎麼轉髖、轉肩膀來創造空間更是重要。
#我拿反應訓練燈或繩梯去練習步法還不錯吧?
重點不在工具本身
而是:
你打算要如何去做?
做了之後能幫助你什麼?
你在注意哪一支腳?
你在注意哪邊去發力?
你打算怎麼去減速才有效率?
你的弓箭步後腳要不要收?
☑️你怎麼練習才是重點呀。
#那教練有什麼簡單的建議嗎?
⚠️就來說說大部分較容易忽略的部分。
➡️你的「啟動」
通常你追不到球,有很大部分是啟動沒做到。
➡️你的「轉髖」
就是你的屁股。不要只想轉肩膀。
你屁股不轉,限制了你轉肩膀的幅度。
➡️你的「退位」
到位、打球是不夠的。還要瞭解怎麼退給對手,同時又在有利或能更快回中場的位置。
➡️你的「效率」
要用左腳還右腳?要幾步?要怎麼切入?為什麼?很複雜嗎?練熟了跟跳舞一樣自然。
#常常對手打出去之後都來不及啟動?
順序就像是:
👇
記得嗎?
眼睛看著或偷看美女….咳咳….
我是說看球。
👇
想對手的情況「能回擊什麼球?」
👇
沒想到?
(1)注意自己是否沒注意對手出手瞬間?
(2)注意自己是不是忘記思考對手要打什麼?
有想到?(卻還是跑不到)
(1)注意自己是不是還來不及回T?
(2)注意自己是不是回了T但位置不適合啟動?
(例如太偏向左邊、或退後時重心太往後?)
#怎樣能幫助自己在T點的啟動?
首先也是最重要的
➡️「放鬆」
壓力、緊繃下是進不了Zone的。
➡️「掌握節奏」
壁球比賽時快時慢,步法也絕對不是單一節奏。
想像自己在台北街頭開車,怎樣才能有效率又省油?
明白哪時加速超車,遇到紅燈快轉綠燈時不要急停,慢慢待速前行,綠燈後才快速啟動。
而我在說的交通燈號
「就是我經過T點時的節奏」
#對方啟動爆發力很大呀
對方是開大馬力跑車,我沒得比了?!
雖然啟動爆發力很有優勢。
但壁球不是單純百米衝刺競賽,
在室內空間下;
如何有效煞車再快速回T點有時候更重要。
勝負往往反而是在這邊。
Repeat Sprint 重複衝刺
Change Direction Speed 換方向速度
老話一句:
✅效率勝過蠻力
#步法為什麼兩腳都要練習?
因為沒有對錯,只有哪時候用哪一支腳才有效率。
舉例來說:
➡️考量「延展度」
有時候正手就是要用右腳才能救到球
➡️考量「穩定度」
有時候就是要用左腳才能更穩定
➡️考量「回擊可能性」
哪一支腳、幾步才能回多種球路才能騙對手
➡️考量每個人的「獨特性」
最後才能設計出適合自己的腳步
當然也不要忘記
➡️考量「更有效率的回T點」
如何更有效率防守各種凌虐的攻擊球。
而所謂的防守,不只是回一個防守球、爭取多少時間。
✅多有效率(省力)的方式回到解除對手壓迫的位置。
甚至利用退位來技術性的「移位假動作」
就算是防守卻也可以累積你對手的心理壓力。
#有沒有給初學者腳步建議
注意啟動,但放慢半秒在開跑。
壁球老手一定有印象,
剛開始打壁球的時候都跑太快,盲目的追著球跑。
放慢一點,多觀察幾次,很多就來得及了。
就算是老手了,還是能時時提醒自己這個原則。
#這樣步法練習要注意的細節好多怎沿用比賽裡?
步法的分配,是不能先預設的。
不能在對手出手前就先想好
你可以猜測對手接著要打什麼球路(直線、斜線、或者小球…等等)
但是對手打出來的那一瞬間,你做出判斷後才能開始計算、分配。
所以平常練習時,要多留意並嘗試熟悉。
最後才能自然的沿用進比賽中。
Work Smart
但我沒有說壁球不暴力
所以請也Work Hard 😉
James.H
Sep 29th 2021
#教學文
#AJ Squash Academy
#Taiwan Squash
————————————
我的訓練、我的教學。
一直以來壁球佔據了我生活的大部分時間。
今年卻不一樣,在台灣疫情爆發同時剛好我也當了父親的角色。
在這邊容我工商一下:
如果有人想找我學球,歡迎直接私訊詢問,
不管程度如何,只要時間對的上,我都會盡量安排。
學費上我不可能會打折,因為教學上也不會打折。
明年2022年學費一定會漲價。
雖然不敢說自己專業,但至少跟我打球一樣時時在更新、進修、進步。
所以有多的時間也好,我也多陪陪自己小孩。
但是舊生放心,我不會漲價。
也謝謝你們看的起我,一路支持到現在🙏
James
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shuffle 在 Taipei Ethereum Meetup Facebook 的最佳解答
📜 [專欄新文章] Gas Efficient Card Drawing in Solidity
✍️ Ping Chen
📥 歡迎投稿: https://medium.com/taipei-ethereum-meetup #徵技術分享文 #使用心得 #教學文 #medium
Assign random numbers as the index of newly minted NFTs
Scenario
The fun of generative art NFT projects depends on randomness. The industry standard is “blind box”, where both the images’ serial number and the NFTs’ index are predetermined but will be shifted randomly when the selling period ends. (They call it “reveal”) This approach effectively solves the randomness issue. However, it also requires buyers to wait until the campaign terminates. What if buyers want to know the exact card right away? We’ll need a reliable onchain card drawing solution.
The creator of Astrogator🐊 isn’t a fan of blind boxes; instead, it thinks unpacking cards right after purchase is more interesting.
Spec
When initializing this NFT contract, the creator will determine the total supply of it. And there will be an iterable function that is randomly picking a number from the remaining pool. The number must be in range and must not collide with any existing ones.
Our top priority is accessibility/gas efficiency. Given that gas cost on Ethereum is damn high nowadays, we need an elegant algorithm to control gas expanse at an acceptable range.
Achieving robust randomness isn’t the primary goal here. We assume there’s no strong financial incentive to cheat, so the RNG isn’t specified. Implementers can bring their own source of randomness that they think is good enough.
Implementation
Overview
The implementation is pretty short and straightforward. Imagine there’s an array that contains all remaining(unsold) cards. When drawIndex() is called, it generates a (uniform) random seed to draw a card from the array, shortens the array, and returns the selected card.
Algorithm
Drawing X cards from a deck with the same X amount of cards is equal to shuffling the deck and dealing them sequentially. It’s not a surprise that our algorithm is similar to random shuffling, and the only difference is turning that classic algo into an interactive version.
A typical random shuffle looks like this: for an array with N elements, you randomly pick a number i in (0,N), swap array[0] and array[i], then choose another number i in (1,N), swap array[1] and array[i], and so on. Eventually, you’ll get a mathematically random array in O(N) time.
So, the concept of our random card dealing is the same. When a user mints a new card, the smart contract picks a number in the array as NFT index, then grabs a number from the tail to fill the vacancy, in order to keep the array continuous.
Tweak
Furthermore, as long as the space of the NFT index is known, we don’t need to declare/initialize an array(which is super gas-intensive). Instead, assume there’s such an array that the n-th element is n, we don’t actually initialize it (so it is an array only contains “0”) until the rule is broken.
For the convenience of explanation, let’s call that mapping cache. If cache[i] is empty, it should be interpreted as i instead of 0. On the other hand, when a number is chosen and used, we’ll need to fill it up with another unused number. An intuitive method is to pick a number from the end of the array, since the length of the array is going to decrease by 1.
By doing so, the gas cost in the worst-case scenario is bound to be constant.
Performance and limitation
Comparing with the normal ascending index NFT minting, our random NFT implementation requires two extra SSTORE and one extra SLOAD, which cost 12600 ~ 27600 (5000+20000+2600) excess gas per token minted.
Theoretically, any instantly generated onchain random number is vulnerable. We can restrict contract interaction to mitigate risk. The mitigation is far from perfect, but it is the tradeoff that we have to accept.
ping.eth
Gas Efficient Card Drawing in Solidity was originally published in Taipei Ethereum Meetup on Medium, where people are continuing the conversation by highlighting and responding to this story.
👏 歡迎轉載分享鼓掌
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特に具体的な答えは出てません。なんだろうなぁって💭
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https://youtu.be/DVEUcbPkb-c
A Night Alone
Free Download: http://bit.ly/3bpz2yg
Almost A Year Ago
Free Download: http://bit.ly/3s7Eiwd
Bet On It
Free Download: http://bit.ly/3nsFgzO
Bluesy Vibes
Free Download: http://bit.ly/35lKqY7
Book Bag
Free Download: http://bit.ly/3bm0pcs
Ersatz Bossa
Free Download: http://bit.ly/38z6h0l
George Street Shuffle
Free Download: http://bit.ly/2Lieddl
Home for the Holidays
Free Download: http://bit.ly/2MGXAIA
Just As Soon
Free Download: http://bit.ly/3nsF7wg
Long Stroll
Free Download: http://bit.ly/3hZAxVd
shuffle 在 TOEIC コーチ Haruka Youtube 的精選貼文
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<音楽提供>
フリーBGM・音楽素材MusMus様
https://musmus.main.jp/
プレイリスト
https://youtu.be/DVEUcbPkb-c
A Night Alone
Free Download: http://bit.ly/3bpz2yg
Almost A Year Ago
Free Download: http://bit.ly/3s7Eiwd
Bet On It
Free Download: http://bit.ly/3nsFgzO
Bluesy Vibes
Free Download: http://bit.ly/35lKqY7
Book Bag
Free Download: http://bit.ly/3bm0pcs
Ersatz Bossa
Free Download: http://bit.ly/38z6h0l
George Street Shuffle
Free Download: http://bit.ly/2Lieddl
Home for the Holidays
Free Download: http://bit.ly/2MGXAIA
Just As Soon
Free Download: http://bit.ly/3nsF7wg
Long Stroll
Free Download: http://bit.ly/3hZAxVd
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