Perhaps the most frustrating of all problems that affect the athletic horse is the syndrome known as tying-up. Tying-up is a broad term that frequently is used to describe a wide variety of muscle disorders that affect the performance horse. Other names given to this syndrome include exertional rhabdomyolysis, Monday morning disease, and azoturia. Historically, the commonality of the clinical signs associated with an episode of tying-up led to the conclusion that all horses showing evidence of muscle cramping and soreness have the same condition. However, research over the past decade or so has clearly shown that there are a number of specific disorders that fall under the umbrella term tying-up. This research has provided a much better understanding of the causes of tying-up and has led to improved methods for prevention of recurrent episodes. Much of this research has been conducted at the College of Veterinary Medicine, University of Minnesota.

In this article, we will discuss some of the specific causes of exertional rhabdomyolysis (ER) or tying-up, with particular attention to methods that can be used to prevent repeat episodes of tying-up in horses predisposed to recurrences.

Create a free account with to view this content. is home to thousands of free articles about horse health care. In order to access some of our exclusive free content, you must be signed into Start your free account today!

Sign UpAlready have an account?