Intermediate

Taxa de linha (line drive rate)

Also known as: LD%, taxa de bola em linha

Definition

A taxa de linha (LD%) é o percentual de bolas rebatidas classificadas como linhas (geralmente com ângulo de lançamento entre 0° e 25° e contato forte) — o tipo de bola rebatida com a maior média de rebatida esperada.

As bolas em linha têm a maior média de rebatida esperada entre todos os tipos de bola rebatida, porque são rebatidas com força, ficam no ar tempo suficiente para cair em segurança e são difíceis de defender. Uma LD% de elite geralmente é considerada 25% ou mais. Rebatedores podem melhorar sua LD% otimizando a trajetória do barril para permanecer mais tempo no plano do arremesso, reduzindo o rolamento precoce e melhorando o ângulo de ataque para combinar com a trajetória descendente do arremesso. A LD% é um indicador mais estável da qualidade real de contato do que a média de rebatida em amostras pequenas.

Beginner tip

During tee work, focus on hitting the back half of the ball. This means the part furthest from the pitcher. This means and drive it straight back through the imaginary pitcher's mound. This produces the contact geometry that generates the highest line drive rate.

Advanced note

Compare your LD% data across pitch velocity bands in your SwingVantage session reports. This means 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

A taxa de linha de 28% dela era o indicador mais claro da qualidade do contato — ela combinava de forma consistente com o plano do arremesso e acertava a bola em cheio.

Why it matters

A análise do SwingVantage sobre trajetória do barril, ângulo de ataque e consistência de contato se relaciona diretamente com os fatores mecânicos da taxa de linha — melhorias na análise se traduzem em melhorias reais na qualidade da bola rebatida.

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). 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. This means 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. This means middle-height pitches need a flatter approach than low-in-the-zone pitches
Treating LD% as a random outcome rather than a mechanical metric. This means 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

SwingVantage correlates barrel path angle and contact location on the ball's surface with batted-ball outcome categories. This builds a session-level line drive rate estimate from mechanical data alone. Pitchers see a suppressed LD% metric that quantifies how effectively their pitch movement and location is preventing clean barrel contact across rep sequences.