Intermediate

外抛（打击）

Also known as: 外抛双手, 棒头外撇, 长挥棒

Definition

外抛是一种挥棒毛病，双手和棒头以宽大的弧线甩离身体，而不是走直接路径接近来球——它会削弱棒速，并限制对内角球的覆盖能力。

在外抛型挥棒中，前手肘过早向外伸展，把棒头拉宽，延长了棒头必须经过的距离，缩短了它停留在接触区内的时间。外抛与“让棒头保持在球的内侧”正好相反。外抛的打者有时还能打中中间偏外的球，但在内角速球上却经常被顶住，因为棒头在本垒板处距双手过远。修正方法通常是纠正手部路径——让握把朝球的方向发力，而不是把棒头向外推。

Beginner tip

Use a resistance band attached to your back elbow during dry-swing practice. This means the band keeps the elbow connected to the body during the early swing and physically prevents the elbow-fly that initiates the casting arc.

Advanced note

Film your swing from directly behind the pitcher's perspective and check that the barrel tip is not visible to the left or right of your body line until the launch phase. This comes from this angle, a pure inside-out swing keeps the barrel invisible behind the body until the barrel fires through the zone.

Example

他每个打席都被内角速球顶住；录像显示出一种外抛动作，接触前棒头就已经在双手外侧。

Why it matters

外抛是SwingVantage在业余打者中检测到的最常见机械性毛病之一。及早发现能避免形成需要更长时间才能纠正的根深蒂固的代偿动作。

How it shows up on video

On video, casting is identified by measuring the position of the barrel tip relative to the hands at the earliest phase of the swing. This means if the barrel moves outside the hands before the knob has directed toward the contact zone, casting is occurring. Common error signatures include the front elbow flying outward visibly in the first frame of the swing (the most recognisable casting tell), the barrel tip appearing in front of the body line. At the same time, the hands are still at load position. The barrel arriving at contact at a steep angle relative to the pitch plane rather than matching it from behind.

Common mistakes

Firing the front elbow outward to generate power. This pulls the barrel outside the hands and sets off the entire casting sequence before the swing has even developed
Using an arm-dominant swing where the hands are pushed rather than pulled. This means pushing the hands outward inherently extends the front elbow and is mechanically identical to casting regardless of intent
Over-correcting for being jammed on inside pitches by moving the contact point forward. This requires earlier barrel commitment and actually makes the casting tendency worse rather than better
Drilling opposite-field hitting in ways that cue hitting "around" the ball rather than through it. This means an around-the-ball cue produces a casting arc on outer-half pitches that then bleeds into all pitch locations

In SwingVantage Motion Lab

SwingVantage measures the barrel-to-hands distance at the onset of the swing and plots how this distance changes through the first 30% of the swing arc. A positive and increasing barrel-to-hands distance in the early swing phase is the quantitative signature of casting. This allows the system to flag and score casting severity before looking at contact outcomes.