Re: [問題] 右手容易放掉
※ 引述《cmvct723d (working on)》之銘言：
: ※ 引述《rr444 (earth scrap)》之銘言：
: : good point. back/fore spin is related to
: : the place of the ball is hit as well as
: : the way of swing.
: : but i don't agree your statement exactly. maybe i don't make myself
: : clearly and meslead you. i should say this way.
: : if you can control to hit the ball at the smae place
: : twice, first time hit the ball by up-to-down swinging and
: : the second time by down-to-up instead. i believe,
: : the flying distance in the first case will be farther
: : than the second time because the back-spin effect.
: : for golf, i don't know too much but based on my
: : observation, it's more making sense this way.
: : when i see a flying golf ball, it is almost no
: : spin. that partly results from the way of swing.
: : so the problem is if you can hit a golf ball
: : by a baseball swing method and hit the ball in the same
: : effort and at the same place when teeing ball, i believe
: : the ball still can go further.
: 我覺得還是怪怪的ㄟ
: 為什麼由上往下揮棒會造成球體的back spin?
: 可以用個例子解釋給我聽嗎?
: 許多強打者都是用撈的阿(尤其是在打低球時)
: 還是能夠打成back spin很強的飛球阿
: 我自己的觀點來看
: 造成back spin的keypoint應該是這樣
: 在進入contact動作
: http://0rz.tw/a42xS
: http://0rz.tw/092Al
: http://0rz.tw/682xn
: 可以看到右手手腕是朝向天空
: 然後雙手是沒有完全伸展開來
: 然後進入max bat speed的那一瞬間
: 也就是雙手用力伸直的動作
: 也就是送球的動作
: 因為circular hand(bat) path的關係雙手會進入交疊的狀態
: http://0rz.tw/bf2x7
: http://0rz.tw/742Bs
: http://0rz.tw/152xz
: 右手手腕會出現內捻的動作
: 以解剖學來說骨骼肌肉位置就是長這樣
: 再用力的狀況下就是會往內旋轉
: 也就是右手會逆時針轉
: 連帶的棒體bat barrel也會有這種現象
: 用圖解來說明的話
: http://0rz.tw/f32yt
: 我是覺得這樣來解讀back spin的成因是比較合理的
the reason is easy.
please see pics at this link.
http://www.wretch.cc/album/show.php?i=rr444&b=2&f=1517823788&p=0
when a bat is swung from up-to-down, the force F can
break into two components F1, F2. And F2 generates a
moment to the center of the ball, making the
ball back spin. in the oppisite conditions, the ball
spins forward when bat force goes down-to-up.
you offer us with a very good point that i know we do that
when we play but maybe have no idea why until now you point it out.
additional comments on this.
http://www.wretch.cc/album/show.php?i=rr444&b=2&f=1517823789&p=1
because the consistence of angular momemtum, a small
angular momentum increment from the bat will generate a bigger
angular momentum on the ball because the weight of the bat
is larger than the ball.
so to me (in a very simplying condition),
spin effects is determined by F1 and m (angular speed on bat) and
W (bat weight).
using this relationship, i can accept that some sluggers can
make the ball back spin (denoated as "+")as you said. this is because they
can generate a bigger angular speed increment than others.
so that amount (+) is larger than that amount (-) by F1 (downward)
to here, we have to give ourself credits bacause we just explain
a lot of things that many pro players and coaches don't know about.
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 128.59.151.115
推
04/07 07:21, , 1F
04/07 07:21, 1F
→
04/07 07:23, , 2F
04/07 07:23, 2F
推
04/07 07:51, , 3F
04/07 07:51, 3F
→
04/07 07:52, , 4F
04/07 07:52, 4F
→
04/07 07:53, , 5F
04/07 07:53, 5F
→
04/07 07:54, , 6F
04/07 07:54, 6F
討論串 (同標題文章)