When hind hooves are out of balance, horses could have poor posture. This, could lead to a “perpetual cycle” of issues in the foot—and, consequently, the entire musculoskeletal system, all the way up through the back, neck, and even head, reports one research team.

In particular, the combination of long toes and low heels in the hind limbs—which is common in domestic sport horses is a form of poor hoof balance that can lead to a “canted-in,” or standing-under, posture that can be linked to joint in the jaw. Therapeutic farriery, as part of a holistic approach, might help stop the cycle and contribute to better overall musculoskeletal health, said Yogi Sharp, Dipl. WCF, BSc (Hons), a PhD candidate at Hartpury University, and a farrier in Pevensey, East Sussex, in the U.K.

“I just wanted to specifically test the theory of the hoof being a neurosensory organ that informs posture because, you know, that’s been suggested, but no one’s ever actually quantified or tested it,” Sharp said.

“Our study hopefully informs both the practitioners’ world that they’ve got to look down and the farriers’ world that they’ve got to look up,” he said. “It’s kind of joining the two worlds together by saying, ‘Guys, we’re having a massive effect on one another here.’”

As a farrier, Sharp said he regularly manages horses with a canted-in posture—in which horses stand with their hind limbs pulled in under their trunks—and has noted it’s frequently associated with low heels and long toes in the hind limb. Scientists have suggested the condition, also called abnormal compensatory posture (ACP), could be a result of distorted neural inputs and requires increased muscular effort to maintain.

This ACP posture might be an effect of the horse’s environment more than genetics, said Sharp. Conformation—which is not to be confused with posture—refers to the length and shape of bones, whereas posture refers to the way horses orientate and support those bones, he said. While farriers and veterinarians often consider conformation to be a contributor to physical health problems and injuries, he added, that’s rarely the case for posture.

“I had noticed, on all the horses that I’d been working on as a farrier which had come to me for referral for poor hind foot balance, that they all had this horrendous posture,” Sharp said. “I believe a lot of it comes down to domestication, essentially. So, confinement, riding styles, how we feed them, and that kind of thing. And for me, posture was really an elephant in the room. Nobody had put two and two together, that there was this functional link between the (musculoskeletal) pathologies that we were seeing and the hoof morphology.”

To address this “elephant in the room”, Sharp teamed up with Gillian Tabor, ACPAT chartered physiotherapist, DPhil, at Hartpury University’s Equestrian Performance Research Centre, in Gloucestershire. Sharp examined 12 horses referred to him for negative plantar angles (NPLA, referring to the angle the bottom of the coffin bone makes with the ground). The horses were Thoroughbreds, Thoroughbred mixes, or Irish Sport Horses, aged 5 to 20. Three of the horses were mares; the other nine were geldings. Sharp’s analysis revealed they all showed signs of ACP, he said.

He trimmed and shod each horse to create a straight hoof-pastern axis with therapeutic methods such as, wedge pads or 3D-printed synthetic forms. Photographs and X rays were taken before therapeutic farrier care; afterward, they took additional photographs to measure angles for assessing stance and posture.

In the seven horses for which they had full data before and after farrier intervention, the researchers found significant improvements in angles—and, hence, posture—stemming from the hind limbs, Sharp said.

“It was obvious to me that the position and orientation of the hoof was potentially going to affect the position and orientation of everything else,” he said. “But nobody had ever quantified that. It’s a very new way of thinking, really.”

The findings indicate hind limb hoof balance is strongly associated with posture and could, therefore, affect musculoskeletal health, said Sharp.

“If you follow the dorsal myofascial line, which starts in the hind foot, it extends all the way up the limb, all the way along the back, all the way up the neck all the way into the TMJ area,” he said. “So yeah, it’s a problem.”

That problem is likely related to management issues in sport horses or in domesticated horses in general, he added.

“There’s pretty much an epidemic of long toes and long heels in the hind limbs in the equine industry, and the hind foot has been overlooked for a long time because everyone’s been focused on the front feet,” he said.

While further research is warranted based on these results, he said, the findings suggest correcting hind limb hoof balance could set horses up for better posture. This could play an important role in overall musculoskeletal health, he said.

“The links between NPLA and pathology in the hind limb and into the trunk of the horse could be more extensive than the current research suggests,” Tabor and Sharp report.

“This study really is only a tiny picture of the bigger happenings,” Sharp told The Horse. “This is only the beginning of the story.”

The study, “An investigation into the Effecrs of Changing Dorso-Plantar Hoof Balance on Equine Hind Limb Posture,” appeared in the journal- Animals in December 2022.