平飞球率
Also known as: LD%, 平飞球比例
Line drive rate (LD%) is the share of batted balls that are line drives, launched at 10 to 25 degrees in Statcast's definition. Liners have the highest expected batting average.
平飞球在所有击球类型中拥有最高的预期打击率，因为它们击球力量强劲、在空中停留时间足以安全落地，同时又难以被防守方处理。一般认为25%以上的LD%属于顶尖水平。打者可以通过优化棒头路径、让其更长时间保持在投球平面上，减少翻腕，以及改善攻角以匹配来球的下行轨迹，来提高自己的LD%。相比小样本下的打击率，LD%是衡量真实接触质量更稳定的指标。
Tips by skill level
During tee work, focus on hitting the back half of the ball. The part furthest from the pitcher — and drive it straight back through the imaginary pitcher's mound. This produces the contact geometry that generates the highest line drive rate.
Compare your LD% data across pitch velocity bands in your SwingVantage session reports. A significant LD% drop on high-velocity pitches confirms a timing cause. A consistent LD% decline across all pitch speeds confirms a barrel-path or contact-point cause that does not depend on timing.
Example
她28%的平飞球率是其接触质量最清晰的证明——她持续稳定地匹配投球平面，扎实地打中球心。
Why it matters
Line drives come from a bat path that matches the pitch and meets it squarely. Motion Lab estimates your attack angle and path tilt from your arm movement, but it does not track batted balls, so judge the results yourself.
How it shows up on video
On video, line drive production is associated with a barrel that arrives at the contact point on a matching plane to the pitch trajectory. This makes contact at or slightly above the ball's equator. Common errors that suppress line drive rate include a barrel arriving below the pitch plane (undercutting. This produces pop-ups), a barrel arriving from above the pitch plane (chopping. This produces grounders), and a barrel arriving after the optimal contact zone with the arms still bent (producing weak, pull-side flares rather than hard-hit drives).
Common mistakes
- Confusing line drives with "contact hitting" and reducing swing aggressiveness in an attempt to make more contact — line drives require hard barrel contact, and pulling back swing intensity produces soft grounders and flares rather than true line drives
- Using a barrel path that is too flat or downward across all pitch heights rather than adjusting attack angle to match specific pitch locations — middle-height pitches need a flatter approach than low-in-the-zone pitches
- Treating LD% as a random outcome rather than a mechanical metric — over a sufficient sample, LD% is one of the most mechanically stable statistics available and should be used as a training target
- Neglecting the attack angle dimension of line drive production and working only on barrel path without also verifying that the approach angle at contact is in the 10–25 degree window that produces true line drives rather than flat grounders
In SwingVantage Motion Lab
Motion Lab does not track the ball, so it cannot estimate your line-drive rate. It estimates your attack angle and bat-path tilt from your arm movement, the swing shape behind line drives.
Sources
Related terms
- 滚地球率滚地球率（GB%）是指打成滚地球的击球所占的百分比——对长打型打者而言通常是负面指标，不过强调接触的打者有时会策略性地利用它。
- 内飞球（打击）内飞球是一种带有极强后旋、发射角极陡（超过50°）的击球，几乎笔直向上飞起，几乎总是会被接杀出局。
- 棒心球（Barrel）棒心球是指同时结合了高击球初速和理想发射角度的打出球——这正是最有可能产生长打的确切组合。
- 强击率强击率是指打出球中，击球初速超过设定门槛的比例——MLB通常设为95英里，业余级别相应下调。它衡量的是不受运气影响的接触质量。
- 击球初速（EV）击球初速是指球离开球棒时的速度，以英里每小时计算。这是一项天花板指标——打得越用力，球就能飞得越远。
- 发射角度（打击）打击中的发射角度是指球离开球棒时的垂直角度。大约10到25度会产生最扎实、最有效的接触。
Available in other languages
Related guides & benchmarks
Work on the cause
Video shows how you move, not the ball itself. Film one swing to find the movement behind this result — free to start.
See a sample Baseball report first