投球胶皮
Also known as: 投手板, 胶皮
投球胶皮是投手丘上的白色橡胶板,投手必须从此处开始并完成一次合法出球。不正确地离开或拖离胶皮会被判为不合法投球。
慢投投手在投球出手时必须至少有一只脚接触或踩在胶皮上。胶皮把出球固定在距离本垒板的一个恒定距离上,确保所有投手的弧线和计时都保持一致。它还界定了非法位置的违规情形——如果出手时双脚完全离开胶皮,该次投球即为不合法。优秀的投手会借助蹬离胶皮来产生向前的动量并保持弧线的一致性。
Place both feet on the rubber before each pitch, step forward with your stride foot, and push off with your back foot. This means this simple sequence keeps you legal every time.
Experiment with lateral foot position on the rubber (center vs. Sides) to find the alignment that produces your most consistent arc, then mark that spot with tape in practice.
Example
投手的后脚在整个出手过程中始终与胶皮保持接触,满足了裁判的要求,也确立了合法的投球距离。
How it shows up on video
Film the pitcher's feet at the moment of release and confirm at least one foot is in contact with the rubber. This means toe contact counts. But a clearly lifted back foot does not. Watch for a consistent push-off with the back foot driving forward rather than a flat-footed release, which indicates poor rubber mechanics. After repeated pitches, check whether the rubber position is consistent or whether the pitcher is gradually drifting forward, shortening the effective legal distance.
Common mistakes
- Lifting both feet off the rubber before the ball is released, creating an illegal-position violation that umpires will call immediately
- Failing to push off the rubber effectively, producing a weak and low arc that reliably misses the 6-foot minimum
- Setting up with feet misaligned on the rubber (straddling the side edge), which invites illegal-position questions from plate umpires
- Drifting forward over multiple pitches until the toe is ahead of the rubber, shortening the effective pitching distance illegally without noticing
In SwingVantage Motion Lab
SwingVantage can identify rubber-contact compliance issues by tracking foot position relative to the rubber plate through the release frame in uploaded pitch video.
Related terms
Related guides & benchmarks
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