Core Crushed Paddle Performance
10/19/25
Two "hot" Pickleball Apes Pulse V "core crushed" paddles are compared to a stock Pulse V to explore the differences in performance. Many players have noticed their paddles (multiple manufacturers) becoming more responsive and powerful with use. Balls seem to pop off the face with more velocity. Probably the sound has changed to a more bass tone. You've got a "hot" and probably illegal paddle.
Three Pulse Vs were obtained. One, a fairly new, stock Pulse. Two, a gently used Pulse V from Bob M. Three, a heavily used Pulse V from Keith K. Keith's and Bob's paddle had the distinct crackle sound when pressing in on the face indicating core crushing.
Each paddle was measured for KKCOR (Keith K Coefficient of Restitution) and rebound velocity using an air cannon and speed gate.
Core Crushed or Delaminated?
There's some confusion about the causation of "hot" paddles - paddles that, after use, become more powerful. Some websites blame delamination - the breakdown of the glue between the carbon fiber face layer and the polypropylene core. Others blame core crushing - the weakening of the polypropylene core due the stress of multiple ball hits. This article will use the term core crushed as shorthand to describe "hot paddles".
KKCOR v PBCOR v PEF
All three metrics are similar in that they measure the coefficient of restitution (paddle power) by shooting a ball at a paddle and recording the resultant rebound speed. The differences are the brand of ball used and the inbound velocity of the ball. USAP calls their metric PBCOR (Paddle Ball Coefficient or Restitution) and shoots a holeless Franklin X40 ball toward the paddle at 60 mph. UPA calls their metric PEF (Performance Efficiency Factor) and shoots a Vulcan Pro ball toward the paddle at 50 mph. I call my metric KKCOR and shoot a Penn40 ball toward the paddle at 50 mph.
So, why create a third metric? Why not duplicate USAP's or UPA's metric?
Reason: USAP's ball is impossible to purchase. UPA's ball goes out of round and breaks easily.
The graph clearly shows the two crushed paddles are above the legal power limit and would be disqualified for tournament play. The stock paddle is safely below the limit at every impact location.
The graph shows the large increase in rebound velocity for both of the core crushed paddles.
There are multiple problems with core crushed paddles.
1. The increased ball speed leads to an unfair competitive advantage.
2. The increased ball speed creates the danger of eye/face injury since players are 14 feet apart at the kitchen lines and cannot react fast enough to avoid the ball.
3. The variation in ball speed with impact location creates control problems for recreational players who can't precisely contact the ball at the same paddle face location. For instance, the difference in rebound speed for the stock paddle at 4.8" v 2.8" is 1.5 mph (10-8.5). The difference in rebound speed for Keith's crushed paddle at 4.8" v 2.8" is 3.2 mph (18.2-15) making the ball more prone to hitting the net or becoming a pop-up.
