蓄力
Also known as: 卷紧, 收拢
蓄力是指在挥棒启动之前，双手和重心向后的小幅聚拢动作——把身体像弹簧一样卷紧，储存弹性能量，在挥棒开始时释放进球中。
蓄力同时服务于两个目的：它把弹性能量储存在躯干、髋部和肩部的肌肉与肌腱中，并把双手安置在一个稳固、可重复的起挥位置，让挥棒能从这个位置高效地启动。一次完整的蓄力，会把重心聚拢到后腿上（蓄力峰值时后脚大约承担60%到65%的体重），前肩略微内转，髋部则顶着前侧的阻力卷紧。这与弹簧被压缩的原理相同：身体向后卷得越远、越充分，向前释放穿过触球点时可用的能量就越多。
蓄力的时机与其力学动作同样重要。蓄力应该从投手的出手提示开始触发——通常是投手双手从固定姿势分开的瞬间，或来自投手扬臂动作的节奏提示。蓄力太晚（在投球已经飞过一半以上距离时才开始向后聚拢）会让打者显得仓促——双手在必须发力之前，永远无法到达完整的起挥位置，触球随之变得又晚又软，而且通常偏向拉打方向。蓄力太早（在投手出手之前就开始聚拢）会让卷紧的能量停滞，导致打者在投球到达之前就把重心提前压向前方，形成一次前扑，在触球之前就耗尽了旋转能量。
蓄力还建立起髋肩分离——即挥棒开始时髋部朝向与肩部朝向之间的偏移角度。正确的蓄力会让肩部保持向内卷紧，同时允许髋部开始打开——这种分离正是驱动由下而上旋转力量的张力所在。没有充分蓄力的打者，分离幅度会减小，进而导致髋部旋转变少，迫使手臂额外发力来弥补。大多数打击教练在触碰挥棒路径之前，会先从蓄力环节入手解决时机和力量问题，因为纠正身体蓄力的时机和方式，会向下游传导，改善整个挥棒序列。
Think of the load as rocking back gently. This means no more than a few inches of weight shift onto the back foot. This means. At the same time, slightly turning the front shoulder in. It should feel quiet and controlled, not a dramatic weight transfer. The load is preparation, not a swing move.
Match your load trigger to each pitcher's tempo. Against a quick-rhythm pitcher, your trigger cue fires earlier; against a deliberate, slow-delivery pitcher, it fires later. A load that is timed to the pitcher's release rather than a fixed personal rhythm stays consistent regardless of who is on the mound.
Example
随着投手双手分开，打者把60%的体重转移到后腿，前肩略微内转——在蓄力峰值时完全卷紧——随时准备在投球到达时爆发出击。
Why it matters
大多数时机和力量问题都可以追溯到蓄力环节。蓄力太早会导致前扑；蓄力太晚会导致仓促。把蓄力做对，能让整个挥棒序列从正确的起始位置开始运转。
How it shows up on video
From a side-view camera, pause the video at the pitcher's hand break or release. A proper load shows weight visibly shifted to the back foot, the front shoulder slightly closed (rotated inward). The hands at or near the rear shoulder. This means set and ready. A late loader shows the weight still balanced or forward at this moment. An early loader shows the front foot already striding forward with the hands already committed.
Common mistakes
- Loading too late. This means waiting until the pitch is close to the plate before gathering. This leaves the hands in a weak position at the moment the swing must begin.
- Loading too far back, drifting the weight. As a result, far toward the back fence that the front foot picks up and the hitter is off-balance before the swing starts.
- Arming the load. This means pulling the hands back excessively without engaging the torso and hip coil. This produces a load that stores energy in the arms rather than the body.
- Loading on a fixed schedule rather than from a pitcher cue, which causes the timing to break down against pitchers with varying delivery rhythms.
In SwingVantage Motion Lab
SwingVantage reads the weight-shift timing and shoulder-turn angle during the load phase, identifying whether you are loading on time relative to the pitch, whether the coil is complete, and whether hip-shoulder separation is being established correctly.
Frequently asked questions
蓄力和跨步是一回事吗？
不是——蓄力是双手和重心向后的卷紧动作；跨步是前脚向前的迈步。它们按顺序发生：蓄力先触发，随后跨步在挥棒发力时把重心送向前方。打者可能只跨步不蓄力（形成前扑），也可能只蓄力不跨步（无跨步挥棒），但在一次完整的挥棒中，它们是两个先后发生的独立事件。
我应该对每种球种都做同样的蓄力，还是要针对变速球调整？
蓄力本身对每一种投球都应该保持一致——蓄力是对投手出手节奏的身体反应，而不是对球种的反应。真正针对变速球改变的，是蓄力之后保持重心不前移的能力（维持前侧的耐心），这样双手才不会在一颗较慢的球上提前发力。稳定的蓄力，配合耐心的前侧，是应对球速变化的基础。
Related terms
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