※ [本文轉錄自 SFGiants 看板] 作者: abc12812 (abc12812) 看板: SFGiants 標題: Crossing the Bridge(4-3) 時間: Wed May 14 09:38:22 2008 I see the same thing happening in Zito's delivery. Seeing these problems is so difficult because at the major league level competition it takes only a small change in mechanics to decrease velocity by 5 mph (or more), making it virtually impossible for the coach or instructor to see the difference. And seeing is only at best half the problem. Seeing is one thing. Fixing is another. The two tools I have found most beneficial for understanding how the body throws the baseball are physics and physiology—the combination is also call biomechanics. Pitching mechanics or throwing mechanics are both poor cousins to what is really happening when the body throws the baseball. In my previous article I tried to show how physics simulations are used to better understand the throwing process. From a physiological (and kinesthetic) perspective I find three-dimensional simulations of the throwing process vitally important to understanding how the body throws the baseball. To create these simulations you have to understand not only the physics of the throwing process but also how each body part is contributing when it throws the baseball. Pushing the ball is the most common and also the most insidious throwing problem. A common form of pushing is also described as muscling the ball. Pushing the ball occurs when there is a break in the rotational sequence (kinetic chain). Attempting to get extension toward home plate is the most common cause of disconnection. Attempting to get a release point out in front or on top of the ball truncates rotation and contributes to a linear finish (disconnection). As previously stated, a north-south delivery has a greater propensity for disconnection. You can be a north-south pitcher if you have a certain amount of east-west (translational) rotation. But even the smallest loss of translational rotation can spell disaster for a north-south pitcher, as is the case with Zito. Disconnection occurs when rotational connection is lost between successive elements of the kinetic sequence. The simulation in Figure 4 demonstrates the disconnection principle. On the left-hand side we have a "connected" compound pendulum. On the right-hand side we have a compound pendulum which is connected until shortly before what would correspond to releasing of the ball (or making contact with the bat). The compound pendulum (on the left) stays connected achieves a maximum velocity at release point of the ball of 70 fps (feet per second). The compound pendulum on the left (that is disconnecting just before release) achieves a velocity just prior to release of 50 fps. There are a number of rotational centers when throwing the baseball. But the most important ones based on my observations are rotation around the front hip joint, rotation of the shoulders around the upper spine, and rotation of the scapular as it slides along the rib cage. These of the primary rotational centers responsible for creating a whipping action. Also critical to the whipping action is creating the “loop” in the throwing arm. This loop is composed of raised-forearm-upper arm-humeral joint. The loop is created primarily by the inertia of the forearm during rotation of the shoulders and bending forward to the upper torso. The key here is rotational connection must be maintained—a constant pulling action of each successive segment of the chain toward a rotational center point. For emphasis I have illustrated the rotational path of the connected pendulum and the rotational/disconnection path of the disconnecting pendulum. In comparing clips of Zito from early 2000 when he was throwing 89-90 mph to now, there are small but significant differences in his delivery. 在Zito的情況中我看見了同樣的事情。 要發現這類的問題是很困難的，因為在大聯盟這種層級的競爭強度中只要有一點微小的改 變就會造成球速大幅衰退，這讓教練團很難發現問題的成因。此外，發現是一件事，修正 又是另一件事。 這裡有兩樣工具可以讓我們認識到身體在投球時的物理和體能狀況—這兩者的結合叫生物 力學。 從生理學的角度看，我找到了一個3D投球模擬軟體可以讓我們了解身體是怎麼投球的。要 做出這樣的模擬系統，你必須先要知道投球過程的物理原理和投球過程中身體各部位的活 動。 "推球"是最常見也最不容易發現的投球問題。關於"推球"的另一種說法是"用力投球"。 "用力投球"的原因是在一連串的身體旋轉過程中有不連貫的情形存在。造成這種現象的一 個常見原因是試著把放球點更往前延伸。這麼做會讓身體的旋轉減少並造成線性的收尾 (不連貫)。之前我有提到過，"南北"投手很容易有這方面的問題。 你可以是個成功的"南北"投手如果你有"東西"方式的旋轉。但任何一點旋轉方式的改變對 "南北"投手而言都是災難。 當身體運動時各個旋轉轉軸不能相互配合時，"不連貫"就發生了。這個動畫可以讓我們了 解到什麼叫"不連貫"。 左手邊這張是完全連貫的投球過程；右手邊這張也幾乎是完全連貫—除了在球出手前的那 一瞬間。 左手邊的動作可以讓出手瞬間的球速達到70 fps，右手邊的動作則只能達到50 fps。 在投球過程中身體有幾個重要的旋轉轉軸—前面的髖關節、上半身的旋轉、肩膀的旋轉。 這幾個重要的旋轉轉軸能產生所謂"揮鞭般的"揮臂動作。 另一個重要的點是手臂的"彎曲"，手臂"彎曲"需要從肩膀到手的各個關節的配合。"彎曲" 的成因是肩膀旋轉和身體下壓產生動量的結果。這其中的關鍵是使各旋轉中心良好配合， 保持身體各部位運動的穩定性。 這張圖可以看出上面那兩個動畫的不同之處。 和Zito的投球動作比對一下，可以發現現在的Zito和以前的Zito投球上微小但影響深遠的 不同之處。 --

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