Tip of the hat to the Plastics Blog for pointing out this joke. I certainly didn't get it at first and I doubt many readers here will either. I'm don't follow horse racing (although I loved the movie "Seabiscuit" for the racing scenes. It greatly reminded me of when I use to race bicycles - everyone packed close together, a little gentile pushing and shoving, trying to get some space to make a move, but knowing that a crash or fall is disaster because everyone else will just pile right over you.) But also surprisingly, I've been exposed in my current job to some running horse and the physiology of them. They are fascinating in that regard, but that is for another day.
I didn't know that such "plastic" surfaces exist.Finding out more about the surface is a bit of a challenge. The Pro-Ride Racing website is awful on the eyes and lacking in information. I couldn't find any US issued patents or applications with an assignee of Pro-Ride, but a search of "horse track surface polymer" provided a few hits, with the application US 2008/0017826 (available at FreePatentsOnline with registration or elsewhere) looking particularly relevant (the inventor is an Aussie). Real simply, a binder composition of some oils and elastomers (EPM or SBS block copolymer) are mixed with a sieved mix of sand. The oil swollen elastomer will stick to the sand some and provide a springiness to the surface.
So that is one tie-in to rheology. But I can also find a larger analogy when looking at what was at the root of the joke.
Certainly if I had a million dollar race horse, I'd extremely cautious about even letting it go for a walk in the garden pasture and nibble on flowers, let alone run on a "new" surface. New? Sure, it's been used for a few years, but look at this from the perspective of the Deborah number, where you compare the relaxation time of the polymer to the observation time. Horses have been bred for thousands of years to run on natural surfaces, while this new track has only been available for a short time. In this case, you have a very high "Horse-Development Deborah Number", suggesting that the horse is not going to change quickly to the new surface, that it might break rather than adapt.
You can see this analogy in other areas of breeding and evolution. We've been able to get pure sugar from plants far faster than our bodies have been able to evolve to the change in diet. Same for other food products that are of dubious nutritional value. The same is true for chemicals that we're exposed to in the environment.