ライナー率
Also known as: LD%, ライナー率
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.
ライナーはどの打球タイプよりも高い期待打率を持つ。強く打たれ、安全に落ちるだけの滞空時間があり、守備が難しいためだ。一流のLD%は一般的に25%以上とされる。打者は、投球の軌道面により長くバレルを保つようバレルパスを最適化し、ロールオーバーを減らし、投球の下向きの軌道に合わせてアタックアングルを改善することでLD%を高められる。LD%は、少ないサンプルにおいては打率よりも安定した真のコンタクトの質の指標だ。
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
彼女のライナー率28%は、コンタクトの質を最も明確に示す指標だった。彼女は一貫して投球の軌道面に合わせ、芯で捉え続けていた。
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
- ゴロ率ゴロ率(GB%)は打球のうちゴロになった割合のことで、パワーヒッターにとっては一般的にマイナスの指標だが、コンタクトヒッターは戦略的に利用することもある。
- ポップアップ(打撃)ポップアップとは、極端なバックスピンと非常に急な打球角度(50度以上)を伴う打球のことで、ほぼ真上に上がり、ほとんどの場合アウトになる。
- バレルバレルとは、高い打球速度と最適な打球角度を同時に満たした打球のことで、長打になる可能性が最も高い、特定の組み合わせを指す。
- 強打球率(ハードヒット率)強打球率とは、一定の打球速度の基準値——MLBでは通常95mph、アマチュアレベルではより低く設定される——を上回った打球の割合のことだ。運とは切り離してコンタクトの質を測る。
- 打球速度(EV)打球速度とは、ボールがバットから飛び出す速さのことで、マイル毎時(mph)で表される。上限を示す指標であり、強く打つほど打球はより遠くまで飛ぶ可能性を持つ。
- 打球角度(バッティング)バッティングにおける打球角度とは、ボールがバットから飛び出す際の垂直方向の角度のことだ。おおむね10〜25°が、最も強く生産的なコンタクトを生む。
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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