USAP CoR Method is not Repeatable

As we have shown in the documents posted earlier in our blog then USAP test for coefficient of restitution is esoteric to say the least. Not only is the use of coefficient of restitution to attempt to control ball velocity unheard of and inappropriate, the test assumes stiffness to be an integer across tested paddles. The test assumes static stiffness, that is all paddles are the same stiffness. What happened to the trampoline problem that's caused by elasticity? Not only that but the test ignores the contribution of the effect of the area around the edges. This writes a pass for all Joola paddles and draws a limit for the introduction of mass into the paddle face. 

The requirement of a rebound on a 10 degree azimuth of the initial impact angle is just honestly another piece of arbitrary nonsense. Frankly a piece of arbitrary nonsense can only be made of arbitrary nonsense I suppose. We don't know what this requirement for rebound angle derived from and no one makes any attempt to justify it like the majority of the test. It also ignores much more materially simple methods that could be deployed easier in field testing. I guess we should all do prototyping with USAP :).

This kind of thing is laughable and the usap shouldn't be in any doubt that they are the first organization in pickleball for a reason. They will not be the last. Presenting this to players as exit velocity is even more directly misleading. A rule that attempts to deal with elasticity has nothing to do with it. It won't control power and it makes no attempt to. Coefficient of restitution is frankly just an arbitrary rule that is meant to be applied as a filter. 

To be brutally honest from a personal view even going to recplay I talk to people that are smarter than this and would laugh at the proposition that this is an attempt from the premiere organization for the sport. The United States pickleball association is living in another world. So are very many players and brands. This is a sport that will be international at some point and already is. If you want to be an Olympic level organization you need to produce rules that make sense and exhibit professionalism. These are something that USAP lacks and the UPA is dead in the water it's obvious it's just a scam at worst or best in attempt to create a syndicate. 

Coefficient of restitution shouldn't be considered different. It will create a syndicate among larger brands and less smaller brands players take action now. We will take both legal and civil action against this insane rule. If I may interject a personal point again I don't think the usap will be around to see it through it's implementation in all honesty. 

It would be difficult for even a large company for example a big brand to reproduce their setup with any accuracy. It's telling that specific details are lacking so that we cannot reproduce it if we wanted to. No information was provided on how to procure a version of the test ball which apparently every company that wants to build to usap standards will need. Apparently the difference in structural elasticity between a solid circle and a ball with cutouts wasn't considered either, but there was no need to consider it as stiffness is considered static here. We're not even testing our paddles with a ball that they will ever encounter and play. We had to make one up that isn't even representitive. So we will be holding off on building our own pickleball cannon for a little bit. This is unfortunate as it would be fun, but coefficient restitution is a property of a collision not a property of a paddle or a ball. So reproduction here is incredibly important. If the usapa had any interest in fairness they would be testing it at a lower velocity to make things simpler. 

Building anything to accurately project a pickleball at a paddle at 60 mph will be mechanicaly complex. It does not make sense when much simpler methods exists but they cannot be used CoR is a property of a collision. 

Coefficient of restitution varies with velocity so they need to test to the 60 mph. Testing it at something more simple like in free fall would be much more reasonable and much more deployable and frankly would be a rational thing which has no place in this.

Brian Laposa 

CoreTek Pickleball