PLAY LIKE THE PROS
b4-app lets you
Endorsed by
Every swing powered by
future-ready AI insights.
Measure how well you hit the ball
at the moment of impact.
How clean
was your contact?
Most tools measure what happens after contact. Zero-In by b4-app measures the moment of impact itself. Every impact is described through these perspectives:
Flush Factor
shows how clean the contact is
Attack Angle
shows how the bat arrives
Bat Impact Point
shows where on the ball is struck
Launch Angle
shows how the ball leaves
These are not separate ideas.
They are key elements to understand the same event:
the instant your swing meets the ball
Why
hitting through
the center matters?
At impact, the goal is simple
Drive the bat through
the center of the ball
When this happens...
energy transfer is more efficient
less energy is lost to vibration
contact become more repeatable
Physics research shows that even small offsets in contact reduce efficiency and change the resulting trajectory (Nathan, 2000; Nathan, 2003).
This means:
Better contact does not come from power alone.
It comes from precision at the moment of impact.
Nathan, A. M. (2000). Dynamics of the baseball-bat collision. American Journal of Physics, 68(11), 979–990. https://doi.org/10.1119/1.1285884
Nathan, A. M. (2003). Characterizing the performance of baseball bats. American Journal of Physics, 71(2), 134–143. https://doi.org/10.1119/1.1522709
Flush Factor, FF
Flush Factor (FF) represents how well your swing moved through the center of the ball. It reflects the efficiency of the collision at impact.
FF = 0.99 means near perfect center contact
FF = 0.00 means far off center contact
Flush Factor captures what players describe as clean contact or flush hit. It is a direct measure of contact quality, not raw power.
Ball Impact Point, BIP
Ball Impact Point (BIP) is the point of contact on the ball. It shows whether the bat struck. Small changes in where the ball is struck can change launch direction, spin, and trajectory (Cross & Nathan, 2009; Kensrud et al., 2021). BIP reflects how accurately you met the surface of the ball.
Cross, R., & Nathan, A. M. (2009). Performance of baseball bats. American Journal of Physics, 77(10), 896–904. https://doi.org/10.1119/1.3182863
Kensrud, J. R., Smith, L. V., & Nathan, A. M. (2021). Effect of oblique impact on baseball trajectory and spin. Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology.
Attack Angle, AA
Attack Angle describes how the bat moves
into the ball. It reflects: swing path、timing
approach. Adjusting Attack Angle helps guide
how the bat enters the collision. It is one of the key controls you have over contact quality.
Launch Angle, LA
Launch Angle describes the direction of
the ball immediately after contact.
It reflects the outcome of the collision.
Improving Launch Angle is not only about
mechanics. It is the result of how the bat
arrives and how the ball is struck.
These four measures describe the same
moment from different angles:
Flush Factor
captures how clean the contact was
Attack Angle
helps you adjust your swing path
Bat Impact Point
shows how accurately you met the ball
Launch Angle
reflects the resulting ball flight
Together, they describe:
How well your hand–eye
coordination translated into contact
Enhance Performance Scientifically
With simply an iPhone, b4-app helps improve your athletic performance, prevent injuries, and record your progress data, allowing you to achieve optimal performance, and surpass your limits.
Access your sports data anytime anywhere
With simply your iPhone to instantly capture advanced data no matter where you are.
Developing Partner
Former MLB star,
H.C. KUO
Proud Partner Of
“Through our continued collaboration, coaches and players alike will have access to invaluable insights thanks to b4-app’s innovative AI technology.”
- Craig Keilitz,
ABCA Executive Director
Proud Partner Of
“Their user-friendly training technology product will help coaches and student-athletes perform at a high level. b4 app is committed to the sport of softball and to growing the game. We look forward to working with them.”
- Carol Bruggeman,
NFCA CEO
Discover Your
Bat Contact Point
Uncover the precise moment of impact with Bat Contact Point (BCP), our advanced AI-powered visual tracking metric. BCP pinpoints the exact location and timing of bat-ball contact, transforming each swing into actionable data. The resulting insights reveal contact patterns, support mechanical adjustments, and empower players and coaches to train smarter and perform better.
Nathan, A. M. (2003). Characterizing the performance of baseball bats. American Journal of Physics, 71(2), 134–143. https://doi.org/10.1119/1.1522699
BCP measures where the ball makes contact with the bat, scaled from .00 (knob) to .99 (barrel end), making it the perfect metric to explore your bat’s “sweet spot,” where power meets precision. On a standard 34-inch bat, this zone often falls 4–6 inches from the barrel end of the bat, which translates to around .82–.88 BCP (Nathan, American Journal of Physics, 2003). Every bat is unique, so experiment with yours to discover its exact sweet spot.
Explore Your Bat's
Sweet Spot with BCP
Every session generates a unique Bat Contact Point (BCP) profile. By reviewing today’s minimum, maximum, and bar distribution, you can see exactly where contact occurred across your swings. This snapshot helps you visualize your contact range and pinpoint how the ball met the bat throughout the session.
Understand
Your BCP Today
BCP
Discover Your BCP
Consistency
Consistency is key to better hitting. With the 70% Range, you can compare today’s BCP distribution against previous sessions to see how often contact falls within a controlled zone. A tighter range signals repeatable mechanics, while shifts across days highlight opportunities for adjustment and growth.
Review how your exit velocity (EV) shifts based on contact location along the bat. Our AI report highlights the highest, lowest, and average EVs at different Bat Contact Points (BCP), helping you spot where your swing generates the most power, where it drops off, and where you’re most consistent.
EV Breakdown
Along the Bat
See how often you connect in the sweet spot launch angle range (8°–32°) at each BCP segment. Each segment’s count is paired with a shaded curve showing the total across all BCPs for context. This reveals not only where you’re making contact, but also how often those contacts produce optimal, game-ready results.
Sweet Spot
Count by BCP
Exit velocity, launch angle, and key numbers
Capture astonishing moments of impact with industry-leading AI visual algorithms providing the most accurate key data and captivating visualization of advanced scientific data for training.
Bat Path
Biomechanics
EV / LA / BCP
Exit Velocity,EV
Launch Angle, LA
Exit Velocity refers to the speed when the ball leaves the barrel during batting. Generally, the higher the exit velocity is, the better.
Bat Contact Point, BCP
Launch Angle refers to the angle between the trajectory of a batted ball and the horizon. Generally, there is an optimum range of launch angles which has a higher probability of being a hit. (about 15~35 degrees)
Bat Contact Points refer to the location on the bat where the ball makes contact during the swing. This is represented as a ratio from the knob to the far end of the barrel. Different bats may have different optimal BCP ranges for best performance.
Bat Path
Gain in-depth insights into your bat control and make informed adjustments.
Carry a collection of all your swings with you
Every perfect and imperfect swing is in your pocket, allowing you to review your progress anytime.
beyond brilliant batting breakdown
The innovative Immersive Pitch refines your timing and reaction speed down to the millisecond.
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