Horizontal Break
Also known as: arm-side run, glove-side cut, horizontal movement
Horizontal break is the lateral movement a pitch generates from spin, measured in inches to the arm side (positive) or glove side (negative).
Like IVB, horizontal break is measured after stripping out the natural drift that a spinless ball would have. Sinkers and two-seamers carry positive (arm-side) horizontal break; cutters and sliders carry negative (glove-side) break. The combination of horizontal and vertical movement defines a pitch's shape and is used to pair pitches that tunnel well together. Extreme horizontal movers — sweeping sliders with 15+ inches of horizontal break — have become increasingly prominent as tracking data made movement profiles actionable.
Example — On a tracking system report
His sweeper showed 17 inches of horizontal break, generating swing-and-miss when hitters expected a fastball and got a pitch that ran a foot and a half away.
Related terms
- Induced Vertical Break (IVB)Induced vertical break is the vertical movement a pitch achieves purely from spin, measured against a hypothetical spinless ball — isolating the Magnus effect from gravity.
- SliderThe slider is a breaking ball with lateral movement and some downward tilt, faster than a curveball and typically sharper in its late break.
- Cut FastballThe cutter is a fastball with late glove-side movement — harder than a slider, smaller break than a slider — that jams or cuts away from hitters.
- Two-Seam Fastball / SinkerThe two-seam fastball is gripped along two seams and typically moves arm-side and downward, inducing ground balls rather than strikeouts.
- Seam-Shifted Wake (SSW)Seam-Shifted Wake is an aerodynamic effect where an off-center seam orientation disrupts airflow asymmetrically, producing movement that cannot be predicted from spin rate or axis alone.
- Spin Rate (Pitching)Spin rate is how fast the ball rotates in revolutions per minute (RPM) after leaving the hand — higher spin amplifies the Magnus effect and increases pitch movement.
Related guides & benchmarks
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