投球圈
Also known as: 圈, 投手圈
投球圈是围绕投手板画出的半径8英尺的圆环;脚部落位规则针对的是投手板本身,而投球圈在规则中最主要的作用是“回视规则”——一旦投手在圈内持球,离垒的跑垒员必须立即前进或返回垒位。
在快投规则中,投球圈通常是以投球胶皮为圆心、半径8英尺的圆环。投球时合法的脚部落位由投手板本身规定,而投球圈在规则书中的作用是“回视规则”:一旦投手在圈内控球,离垒的跑垒员必须立即选择前进或返回。对于研究录像的击球员或教练来说,投球圈是衡量其他所有投球动作——跨步距离、蹬地距离、出手点——的固定参照系,因为胶皮位于圈心,所有距离都以它为基准来描述。
Before analyzing any pitching mechanic, first locate the circle in the video frame — it gives you a fixed scale for everything else the pitcher does.
Example
投手站位时双脚都接触位于投球圈中心的投手板;当球在圈内回到她手中时,正在一垒附近试探的跑垒员必须立即前进或返回。
Why it matters
本词汇表中的每一个投球动作——跨步、蹬地、出手点——都是以投球圈为基准向外测量的,因此理解这个参照系能让你更容易在录像中定位其他所有术语。
How it shows up on video
On a broadcast or overhead angle, the circle appears as a chalked or painted ring around the rubber. The pitcher's starting foot position on the pitcher's plate at the circle's center is the first thing to confirm before evaluating any other mechanic.
Common mistakes
- Assuming the circle governs legal foot placement — delivery-position rules attach to the pitcher's plate, while the circle's job is the look-back rule on runners
- Confusing the circle boundary with the batter's box distance when estimating stride length on video
Frequently asked questions
快投投球圈有多大?
大多数快投规则采用以投球胶皮为圆心、半径8英尺的圆环,不过青少年组和不同联盟会有所差异。
投手投球后必须留在圈内吗?
不需要——投手可以自由离开投球圈去做防守动作;投球圈在规则上的意义在于“回视规则”,它只在投手于圈内持球时限制跑垒员。
Related terms
Related guides & benchmarks
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