the whole not moving thing sounds more like a condition called "tying up". i dont really know a whole lot about it but i think it is when after exercise the horses muscles tense up (plus other things). here is a link
tying-up, muscle tension treatments for horses and spasm relief with Recovery eq - Technical information for veterinarians
when i worked with race horses i had a couple of horses tie up. we had to have the vet administer drugs to help with the tying up. i would get your vet out if possible.
tying-up, muscle tension treatments for horses and spasm relief with Recovery eq - Technical information for veterinarians
when i worked with race horses i had a couple of horses tie up. we had to have the vet administer drugs to help with the tying up. i would get your vet out if possible.