The PBCoR test protocol, as described in the as presented has several limitations that make it misleading as a measure of paddle elasticity. CoR is not a measure elasticity, stiffness, or energy. This test ignores the opportunity to measure actually significant physical effects. Its implementation in terms of application and intention is either misunderstood or misused.
1. Single impact speed: The test uses only a 60 mph inbound velocity. True elasticity is a material property that should be consistent across different impact speeds. By testing at only one speed, the protocol fails to capture the potentially non-linear elastic response of the paddle material.
2. Energy dissipation: The test doesn't account for energy lost to vibration, heat, or sound. A more elastic paddle might actually have a lower PBCoR if it dissipates less energy through these mechanisms.
3. Non-standard ball: Using a modified ball without holes significantly alters the impact dynamics compared to actual gameplay. This makes it difficult to correlate test results with real-world performance.
4. Limited impact locations: While the test examines multiple points, it doesn't provide a comprehensive map of elasticity across the entire paddle face. Elasticity may vary significantly in areas not tested. The significant contribution of the effect of the area around the edges is ignored. What this means is not even clearly explained, but the effect of the area of a paddles edges is certainly relevant to its performance. The burden of making a machine or accurately recreate the collision is cumbersome when alternate methods such as drop test exist and lend themselves to this application.
5. Clamping effects: The rigid clamping of the paddle handle doesn't accurately replicate how a player holds the paddle, potentially altering the paddle's elastic response.
6. Arbitrary performance limits: The maximum allowable PBCoR values set by USAP appear to lack clear scientific justification linking them to actual gameplay effects or player safety concerns. The outbound azimuth limit has no derivation.
7. Conflation of factors: The PBCoR measurement combines multiple factors beyond just elasticity, including the paddle's mass distribution, moment of inertia, and overall construction. This makes it an indirect and potentially misleading measure of pure material elasticity. In fact, the means and methods to directly measure elasticity are simply ignored here. Elasticity is not measured whatsoever and stiffness is not considered at all when we have an excellent opportunity to measure it. With all this elaborate setup why not? But we will consider it as a non-factor. Trampoline effect, I don't know what causes it, magic? It maybe a quantum effect unique to this sport.
8. Lack of material characterization: True elasticity measurement would involve direct testing of the paddle face material's stress-strain relationship, which this protocol doesn't address
9. Temperature and humidity effects: The protocol doesn't account for how environmental factors might affect the paddle's elastic properties. These are the least among many factors in recreation of this test that are overly complex.
10. Long-term elasticity changes: The test doesn't consider how a paddle's elasticity might change over time with repeated use. Also the contribution of the ball in gameplay is deflated. We are blaming too much on paddles here and it is not realistic.
In summary, while the PBCoR test provides a standardized way to compare paddle performance, it's misleading to present it as a direct or comprehensive measure of paddle elasticity. A more accurate assessment of elasticity would require additional testing methods and a more nuanced analysis of the paddle's material properties and behavior under various conditions.
