Strolling through the Kentucky Horse Park barns on schooling day before last week's show, I heard a familiar, monotonous POW-POW-POW-POW-POW. It was the sound of a horse undergoing extracorporeal shock wave therapy (ESWT). For those who haven't heard a shock wave machine before, I'd liken it to the rapid-fire crack of a dressage whip, but louder.

Shock wave therapy has proven to be highly effective in relieving back and pelvic pain.

Photo: Alexandra Beckstett

While its use at competitions is a bit controversial, shock wave therapy is almost commonplace at hunter/jumper shows. No longer am I surprised to see veterinarians running those noisy probes over a horse's heel area (navicular issues, anyone?), hind end (a sore sacroiliac joint?), or other presumably painful part. Unfortunately, there exists a gray area between using ESWT to mask a horse's pain vs. using it simply for its therapeutic effect.

What does ESWT do, exactly? As sport horse practitioner Dr. Rick Mitchell, of Fairfield Equine Associates, explained to me during a conversation last year, shock wave therapy emits high-pressure force waves that stimulate tissue, causing a nerve desensitizing, pain-relieving effect. It also stimulates blood flow and aids in the tissue's healing capacity. Therefore, veterinarians use it to help treat various soft tissue injuries.

"(ESWT) is very popular in the sport horse realm," Mitchell said. "I see shock wave therapy being used as a treatment modality for tendon and ligament strains and tears, for severe osteoarthritis such as chronic ringbone or severe bone spavin, and we see it being used quite effectively for back pain."

Where people start to go wrong, however, is when they use ESWT as a preventive method or to mask an injury.

"I have seen some use of it routinely on horses for repeated treatments without a lot of diagnostics," he said. "It troubles me a bit because what are you treating, and how bad is it?"

Naturally, national and international governing bodies have implemented restrictions on shock wave therapy prior to competitions. The Federation Equestre Internationale forbids ESWT for five days prior to an event's first horse inspection; the United States Equestrian Federation does not permit ESWT within three days of competition (with the exception of back and pelvic treatments up to 12 hours beforehand); and the Association of Racing Commissioners International prohibits it within 10 days of racing.

But this doesn't necessarily mean the rules are being enforced. As of yet, no test exists that can detect whether a horse has been shock waved. And, who really knows what goes on off show premises?

"I have seen horses just getting blanket shock wave therapy done on their backs, necks, and legs, before they go to horse show," Mitchell said. "It can be abused."

In the meantime, hopefully the treatment is loud and obnoxious (and expensive) enough that trainers aren't secretly shock waving their horses and sending them directly into the show ring.

I'm not against shock wave therapy; I've seen it work wonders on horses' sore backs and think it's a great tool to have available. As Mitchell said nicely, "I think shock wave can be very useful for the athletic horse that has mild, low-grade chronic pain from athletic effort, as long as there's a good understanding of what's wrong with the horse and that it's not overzealously used in such a way as to mask a significant problem that might otherwise respond better to rest or time off."

What's your experience with or thoughts on shock wave therapy?