Pickleball Paddles are generally rigid. This is a more or less desirable trait as the ball we play with is so elastic that it precludes much elasticity being useful in paddles. With the CoR being implemented in Q4 it's interesting to look at some documents of data collection published by the UPA's lab PPL. Aside from these documents being labeled confidential but being available on Google, it's not hard to see why Selkirk was critical of their scientific capability. The paper assumes without qualification that a trampoline effect in paddles is now a major factor at play in the sport and associate it with ball speed, deflection, and CoR. 

Never in this paper is the perspective of ball performance even approached. All while the ball is much more elastic than any certified paddle. Not only are assumptions made without any accreditation of data, the methods used indeed are not sound and do not consider the effects of elasticity being demanded of current pickleballs.

This is why CoR is not needed and being implemented to control materials. In essence, if the USAP wants to lower ball velocity, more elastic paddles are desirable.

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