There are two simple words that describe painful, exercise-associated muscle cramping in a horse: tying up. While the traditional tying up usually occurs after a long hard ride, some horses can tie up repeatedly for no immediately obvious reason. Regardless of the underlying cause, the clinical signs are similar. And in most cases, affected horses require immediate veterinary care, says Dr. Fabienne Uehlinger of the Western College of Veterinary Medicine (WCVM) in Saskatoon, Saskatchewan.