Tying Up & Other Tongue-Tying Muscle Disorders

August 09, 2017
horse with muscle disorder

If you own a performance horse, you’ve probably experienced at least one episode of tying up. If not, you’ve probably heard about it. You may also have heard that it's a muscle disorder often associated with stringent exercise.

What you may not know is that there are different types of tying up, and that  other muscle disorders may plague your equine friend. There are tests available for some disorders and treatments for others — and still others can be managed with diet and exercise.

In order to help your horse with muscle problems, it's important to be able to recognize the symptoms and know what treatments may be available. Here's a rundown on the causes of a few equine muscle disorders you may encounter, how to identify them, and ways they can be treated or managed:

Equine Muscle Disorders
Exertional Rhabdomyolysis

The technical term for the most common form of tying up is exertional rhabdomyolysis (ER). Symptoms of ER vary, and often include:

  • Shaking
  • Sweating
  • Pawing
  • Flaring nostrils
  • Muscle cramping

ER can be sporadic or chronic. An episode can sporadically occur after a rigorous and/or long exercise session; it’s believed that extreme heat or cold can trigger an episode as well. But according to new research on ER, chronic episodes are probably tied to genetics. 

Polysaccharide Storage Myopathy

If your horse is experiencing chronic episodes of ER, you may want to have him tested for polysaccharide storage myopathy (PSSM), a disorder that affects glycogen storage. It’s believed that PSSM may be the underlying cause of chronic ER. A DNA test is available to check.

If your horse tests positive, there are things you can do. With your vet’s help, proper nutrition, and a customized training schedule, your horse can lead a normal life.

Supplementing can also help. Certain nutrients can help prevent tying up episodes. The high-quality ingredients in Un-Lock have been shown to reduce muscle fatigue and cramping. (Check out these testimonials from our brand ambassadors, who use BRL Equine products.)

Recurrent Exertional Rhabdomyolysis

RER is a form of tying up, but no evidence has been found to prove it’s genetic. RER seems to affect mostly young, skittish female thoroughbreds and may be caused by deficient calcium absorption/regulation in muscle cells. Unfortunately, there are no treatments or cure for RER, but there’s hope. You and your vet can successfully manage it with proper nutrition and carefully monitored exercise.

Hyperkalemic Periodic Paralysis

Also known as Impressive Syndrome (the disorder was traced to a horse named Impressive), HYPP affects the way muscles utilize electrolytes. The condition is genetic and — as the name implies — can cause unpredictable paralysis, even death.

Muscle twitching can signal HYPP and may precede a significant episode. In most cases, the cause of death is heart attack and/or respiratory failure. Since electrolyte regulation is important to exercise duration and recovery, it’s important to know if your horse has HYPP and how to treat it.

HYPP is genetic and can cause unpredictable paralysis, even death.

Luckily, there’s a test for HYPP; it can be treated with medication and dietary changes.


Equine shivers affects the hind limbs and tail, causing spasms. Although the cause is unknown, some experts think shivers may be a neurological disease, rather than a muscular disorder.

Problems associated with shivers include:

  • difficulty backing up
  • difficulty holding hind legs up during flexion
  • trembling during flexion
  • possible eye/ear twitching during trembling 

There are no medical treatments currently available for shivers, but a diet higher in fat and lower in carbs may be beneficial.

Be Proactive to Prevent Equine Muscle Disorders

If you think your horse could have a muscle disorder, contact your vet. A customized plan that includes dietary changes, exercise recommendations and a high-quality muscle supplementation like Un-Lock may prevent flare-ups and ease symptoms.

Then you both can enjoy the ride!

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