A Site Exploring the Physics of the Paddle Ball Collision
I love pickleball! I have time to play every day. I listen to the YouTube reviewers (Johnkew is my favorite) as they muse about power, pop, swing weight, balance point, hand speed, PBCOR, spin, break-in, delamination, the trampoline effect, delisted paddles, etc.
But, in addition to being a pickleball aficionado, I'm also an engineer and I have a need to understand the details. So, I read the technical literature, especially the research papers on the baseball-bat collision since the concepts are applicable to the paddle-ball collision. I'm familiar with the USAP and UPA-A test procedures. When interested, I'll purchase or build test equipment. I've gotten so far into the weeds that I've duplicated the USAP and UPA-A test equipment to evaluate a paddle's PBCOR - an air cannon, a speed gate and a pivoting paddle clamp.
This website documents the results of some of my experimentation. I hope I've presented those results in a manner that is understandable to a technically inclined pickleball player. Let me know if something is not clear or if there are errors.
Contact me at info@technicalpickleball.net
Understanding PBCOR
PBCOR testing jumped into the pickleball news when the Joola Gen 3 paddles were not approved for tournament play by USAP in November 2023 because they were too powerful. USAP, in part, used PBCOR testing to evaluate the power of the Joola paddles. The non-approval was a financial loss for Joola. A lawsuit was filed initiated (still in litigation as of March 2025) against USAP to recover a portion of the loss. Subsequently, both governing bodies for pickleball, USAP and UPA , have universally adopted PBCOR testing to limit paddle power.
Simply stated, a ball, at high speed (50 or 60 mph) is shot at a paddle and the rebound speed of the ball is measured. A few physical parameter of the paddle (weight, etc) along with the rebound speed are entered into an equation which results in the PBCOR number for that paddle.
Is PBCOR the Best Metric?
For safety reasons and to prevent pickleball from becoming a power only sport the two governing agencies have adopted PBCOR as a way to limit ball velocity. But PBCOR is only and indirect measure of ball velocity. Let's take a look at the data from a PBCOR determination to explore the relationship between PBCOR and ball velocity. The graph below shows the rebound velocity (Vre) and resultant PBCOR value at different locations on a Pickleball Apes Pulse V paddle face from a Franklin X40 ball shot toward the paddle at 50 mph.
Two things to note:
- The maximum ball rebound velocity (Vre) of about 12.5 mph is found up toward the paddle throat at about 7" from the tip.
- The maximum PBCOR value of about 0.38 is obtained at an impact point about 3" from the tip of the paddle. The rebound velocity (Vre) at that point is only about 8.5 mph.
This seems counterintuitive. Why would the maximum PBCOR value occur at a point where the rebound velocity is at a minimum?
As can be inferred from the graph, the PBCOR formula assigns more "weight" to rebound velocities near the tip of the paddle by assigning a higher PBCOR values. Why? The answer has to do with the difference between the laboratory test where the paddle is stationary and on-court play where the paddle is in motion.
When a player swings the paddle, it pivots around a point about 2" away from the butt. The paddle velocity at 8" from the pivot point (10" from the butt) is moving twice as fast as the paddle face at 4" from the pivot point. The PBCOR formula compensates for the higher paddle speeds near the tip.
How good is the PBCOR formula in predicting ball speeds? We don't really know. One would hope that 10 paddles ranked by PBCOR would have the same ranking for on-court ball speed. Unfortunately, neither agency has run an experiment where a variety of players each use 10 paddles where balls speeds are measured with a radar gun.
It's still an open question - Does the on-court ball speed reliably mirror the PBCOR ranking?
Note: Baseball had the same question. Does on-field ball speed mirror the BBCOR (ball bat coefficient of restitution) ranking of bats? The answer for baseball was Yes. The question was answered in the study A Comparative Study of Baseball Bat Performance Alan M. Nathan et al
The Paddle-Ball Impact
Here's a taste of what happens in my basement. See the picture below. A paddle is hung vertically on a pivot so the paddle can rotate when struck by the ball. The wires attach to a small accelerometer on the paddle face to measure the force of the impact. A pickleball is shot from an air cannon (not shown) toward the paddle. Before it gets to the paddle, the ball travels through a speed gate (multiple red laser beams) to measure the inbound velocity. After the collision the ball travels back through the speed gate to measure the rebound velocity.
Pictured below is a three frame sequence of a paddle/ball collision taken with an iPhone at 240 frames per second. Left: Ball approaching stationary paddle at about 50 mph. Center: Collision lasting about 2 milliseconds. Right: Ball rebounding back toward the speed gate at about 12 mph and paddle recoiling at 7 mph.
Paddle Break-In
A Pulse V Example
I purchased a Pickleball Apes Pulse V paddle in November 2024. It got hot and hotter as I used it! The sound got deep. Opponents noticed my flicks were unusually fast. I heard multiple times, "Is that a legal paddle?"
I measured the collision efficiency and calculated that the PBCOR was far above the UPA-A 0.385 limit and the USAP limit of 0.43. Pickleball Apes replaced the paddle free of charge and explained the problem was isolated to early batches and had been corrected. The performance of my old Pulse V, my new Pulse V on arrival, my new Pulse V after 3 weeks of play and a new Neonic Flare is documented.
