Even if they can’t tell you where it hurts, horses with back pain will soon be able to benefit from Scottish and Austrian research focusing on the long muscles of the equine back.

In the article, which is slated for an upcoming edition of The Veterinary Journal, researchers reported that electromyography (EMG) readings on the longissimus dorsi muscles of 15 healthy horses walking on treadmills were used to pinpoint painful areas that might otherwise have gone undetected.

Researchers now have a standard for comparison when mapping EMG activity on horses with suspected back pain.

Electromyography patterns help researchers to precisely track muscle activity within a step cycle. In healthy horses, maximum activity occurs at vertebra T16 (“T” standing for thoracic vertebra), an area located under the middle of a standard saddle’s caudal (rear) padding, according to Theresia Licka, PhD, DVM, senior lecturer in equine surgery at the Royal (Dick) School of Veterinary Studies in Scotland and member of the Movement Science Group in Vienna, where the research was performed.

COURTESY DR. THERESIA LICKA

Measuring the movement of a horse’s back muscles.

“The area of the highest muscle activity is also the area of highest pressures measured under the saddle,” Licka said. “Ill-fitting saddles can be a problem, (but) even the best riders on the best fitting saddles will contribute to a (pre-existing) problem if the muscle is hard.”

The EMG readings also provide information about the use of the equine back muscles in different gaits. Whereas at the trot the muscles control the up-and-down movement of the spine, at the walk these same muscles work more to stabilize the spine’s side-to-side movement.

In either gait, the long back muscles are used much more for stabilization than for movement, said Licka, who has been studying equine back muscles since 1995.

“People need to remember that posture training (an approach to training that emphasizes strengthening the core muscles) should definitively be integrated into the training of strong backs, as well as measures to get the muscle to loosen up from time to time,” she said