The video was interesting. Did they say which synthetic surface they were showing?
Yes, at the start it says the video was shot at Keeneland (and shows the track/grandstand), thus Polytrack.
The root of the problem with synthetics is that the hoof sticks as you can see; that\'s very bad - if you\'ll notice, the hoof slides on the dirt and the force of impact is spread out more
Whoa - respectfully, no, that\'s backwards. It may seem counter-intuitive, but the measurements in the video clearly show how the above assumption is wrong.
The very problem synthetics primarily address is that yes, that the hoof does slide around alot more on dirt, as you say - but
that instability is what is extremely dangerous.You can see it in the video of dirt, with the hoof sliding, eventually sliding to an abrupt stop, and the pastern, fetlock/ankle, lower leg (cannon) wiggling all over the place while the horses weight carries over it.
Also notice the difference in breakover (the circular roll forward) on dirt vs synthetic vs turf. The synthetic is very smooth, the dirt is abrupt, jerky.
The manner in which synthetics absorb the force without the foot sliding all over the place is exactly what they were designed to do. That is what makes them
safer.
That force is not spread around on dirt, and that force is clearly higher on dirt than on Polytrack. It can be clearly seen on the graphs within the video that measure the impact force off the horseshoe.
Go to 1:48 in the video, where the graphs start, and you will see the following:
Synthetic:
vertical force peak at about 12 N/kg, spread over about 250 milliseconds.
Dirt:
vertical force peak at about 16-17 N/kg (markedly higher), spread over less than 200 milliseconds.
Turf:
vertical force peak at about 18-19 N/kg (higher yet), spread over slightly longer time than dirt.
The synthetic clearly decreases the force, and spreads it over a longer time, than any of the three surfaces. Dirt has increased force, spread over shorter time period.
