Tying Up & Muscular Health

By: Dr. Lydia Gray

SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.

Brief Description

“Tying up” or exertional rhabdomyolysis refers to muscle stiffness and pain after exercise. It can occur sporadically or chronically. Sporadic “tying up” is due to a temporary problem in muscle cells caused by fatigue, heat exhaustion or electrolyte imbalance, and can occur in any breed. Chronic “tying up” is an inherited problem with the way muscle cells use calcium, and is mainly seen in Thoroughbreds, Arabians and Standardbreds. Signs range from a slight shortening of stride to reluctance to move or even laying down.

Supplements that May Lend Support

Horses with the sporadic version of “tying up” may have imbalances in their diet or inconsistencies in their training program. These issues may be corrected through the use of dietary supplements, a change of feed or a more regular training schedule. When modifying the diet, particular attention should be paid to whether or not Vitamin E and Selenium supplementation is necessary. The horse’s electrolyte requirements should also be considered.

Horses with the chronic version of “tying up” should also have their diet examined for the nutrients mentioned above. In addition, research has shown some benefit to supplementing with the minerals Chromium and Magnesium. There are also anecdotal reports of benefit from adding Dimethylglycine (DMG) to the diet.

Possible Diagnostic Tests

“Tying up” can usually be diagnosed by simple bloodwork, but in more complicated cases, veterinarians may need to perform a urinalysis, muscle biopsy or exercise challenge tests to figure out the underlying problem.

Prescription Medications Available

Fluids may be used to rehydrate the horse. Tranquilizers and pain relievers such as bute (phenylbutazone) and Banamine® (flunixin meglumine) may be administered to make him more comfortable. Robaxin (methocarbamol) and Dantrium (dantrolene) are muscle relaxants frequently prescribed for this condition.

Other Management Suggestions


Horses that chronically tie up may benefit from a low-sugar/high-fat diet. Reducing sugar in the diet may help reduce excitement and anxiety, while adding fat replaces sugars and starches (simple carbohydrates) for both energy and weight maintenance.


Owners of horses that tie up should try to avoid stress and “trigger factors.” Beneficial management practices include increasing turnout and decreasing stall-time. Providing controlled exercise such hand walking, lunging or riding on a daily basis may also help, as well as avoiding activities that upset that particular horse.

Questions to Ask Your Veterinarian

  • Does my horse have sporadic or chronic “tying up”?
  • Could my horse have Polysaccharide Storage Myopathy (PSSM) (a health condition that causes chronic “tying up”)?
  • How soon after a bout of “tying up” can I return my horse to work?

Additional Resources

Further Reading for You

From our site:
Tying Up: Complicated syndrome, simple management
From the SmartPak Ask the Vet Blog:
Tying Up in Horses (exertional rhabomyolysis)
From The Horse Journal:
  • Tying up in Horses
  • Muscles, Lies and Lactic Acid
  • Tying Up: Protect Your Horse Before It Hits

Further Reading for Your Veterinarian

Drankchak PK, Valber SJ, Onan GW, et al. Inheritance of recurrent exertional rhabdomyolysis in Thoroughbreds. J Am Vet Med Assoc. 2005 Sep I;227(5):762-767.

McKenzie EC, Valberg SJ, Pagan JD. Nutritional management of exertional rhabdomyolysis. Current therapy in equine medicine, 5th edition. St. Louis (MO). Elsevier Science; 2003.pp727-734.

Valberg SJ. Exertional rhabdomyolysis, in Proceedings. 52nd Annu Conv Am Assoc Equine Pract 2006;52:365-372.

About Dr. Lydia Gray

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