Intermediate

Extension at Contact

Also known as: full extension, driving through the ball

Definition

Extension at contact adalah titik dalam swing di mana lengan mencapai panjang hampir-penuh melalui zona kontak, mentransfer energi maksimum dari kinetic chain ke dalam bola.

Ekstensi yang tepat berarti tangan dan barrel men-drive melalui bola alih-alih berhenti pada saat kontak. Ekstensi penuh menghasilkan exit velocity lebih tinggi dan lintasan bola yang lebih sejati. Pemukul yang kolaps lebih awal — menarik lengan kembali sebelum menyelesaikan melalui zone — menghasilkan pukulan lemah dan meleset. Ekstensi sangat kritis untuk kontak outside pitch, di mana bola dipertemukan lebih dalam di zone dan lengan harus mencapai penuh untuk menghantarkan gaya dari sudut yang benar.

Beginner tip

Think of hitting through two imaginary balls positioned 6 inches apart. This means the first is where you make contact and the second is where your hands are driving through. This means keeping extension alive through both contact points.

Advanced note

Film your swing from the side and measure the angle between your forearms at the contact frame. This means optimal extension shows roughly 150–170 degrees, with full lockout (180 degrees) indicating over-extension and significant fold indicating early deceleration.

Example

Pemukul men-drive melalui outside pitch dengan kedua lengan terekstensi saat kontak, menghasilkan line drive keras ke gap lapangan berlawanan.

How it shows up on video

At the contact frame the arms should appear near-fully extended with a slight bend remaining in the lead elbow. This means fully locked-out arms can indicate over-extension that collapses the swing before follow-through. The bat head should be ahead of the hands at contact on all middle-to-outside pitches, confirming full extension reached the ball rather than stopping at impact. Hitters who decelerate through contact will show the elbows folding back before the ball leaves the bat.

Common mistakes

Collapsing the lead arm at contact — pulling the elbow back before the ball leaves the bat — which kills exit velocity mid-swing
Over-extending by fully locking both elbows at contact, which reduces bat speed and produces a casting motion rather than a whipping extension
Confusing extension through the ball with follow-through — extension is at and just after contact, not the circular finish of the swing
On inside pitches, reaching for full extension when the contact point requires the arms to be shorter and the barrel to be more pulled through the zone

In SwingVantage Motion Lab

Motion Lab measures arm extension angle at contact and tracks the rate of arm acceleration and deceleration through the contact zone, identifying whether the hitter drives through the ball or decelerates at impact.

Frequently asked questions

Apakah ekstensi penuh benar-benar menambah exit velocity?

Ya — ekstensi penuh memaksimalkan panjang lengan-pengungkit saat kontak, yang mentransfer lebih banyak energi kinetik dari rotasi tubuh ke dalam bola dibanding posisi lengan yang pendek dan kolaps.

Bagaimana ekstensi berbeda pada inside versus outside pitch?

Inside pitch membutuhkan kontak sebelum ekstensi penuh karena titik kontaknya di depan — ekstensi hampir selesai saat kontak; outside pitch membutuhkan lengan mencapai ekstensi lengkap saat kontak karena bola lebih dalam di zone.