Soring is the deliberate infliction of pain on a horse’s legs or hooves to alter the way it moves. The practice is most closely associated with Tennessee Walking Horses, where trainers use chemicals, weighted chains, and abusive shoeing techniques to force an exaggerated, high-stepping gait known as the “Big Lick.” Soring has been illegal under federal law since 1970, yet it persists in certain corners of the show horse industry despite decades of enforcement efforts.
Why Soring Exists
Tennessee Walking Horses are naturally gaited, meaning they have a smooth, gliding stride called a “running walk” that’s prized for trail riding and pleasure classes. In the show ring, however, some competition divisions reward an extreme version of this gait: the front legs snap high into the air while the hind legs drive low to the ground. This flashy, exaggerated movement is the Big Lick, and it is not something most horses produce on their own.
To create the Big Lick, a horse needs to lift its front legs dramatically with every step. The simplest way to force that reaction is to make the lower legs so painful that the horse flinches them upward on contact with the ground. That is soring. The horse isn’t performing willingly. It’s reacting to pain with every stride.
Chemical Methods
One common approach involves applying caustic substances to the skin around the pastern, the area just above the hoof. Mustard oil, diesel fuel, and croton oil are among the chemicals that have been used. These agents cause burning, blistering, and inflammation of the skin. Once the area is raw and sensitive, trainers strap weighted chains or rollers around the pastern. Every time the horse moves, the chains strike the irritated skin, compounding the pain and causing the horse to jerk its legs higher.
Trainers often wrap the legs afterward to conceal the damage, and some apply numbing agents before a show inspection to mask the horse’s pain response. The chemical burns can leave lasting scars, which inspectors later look for as evidence of abuse.
Mechanical Methods
Soring doesn’t always involve chemicals. Mechanical techniques can produce the same exaggerated gait through direct physical trauma to the hooves and lower legs.
- Pressure shoeing: The sole of the hoof is trimmed or ground down until it reaches the sensitive tissue underneath, sometimes until beads of blood appear on the surface. A shoe is then nailed tightly onto this exposed area. Some trainers insert hard objects between the sole and the shoe, including stacked quarters wrapped in electrical tape, wooden wedges, golf balls, or acrylic compounds that harden like steel. The effect is comparable to walking on a sharp rock with every step.
- Stacks (performance packages): Multiple pads are layered between the hoof and the horseshoe, building up a tall, heavy platform. These add weight to the front feet and raise the angle of the hoof, which changes the mechanics of the gait. When combined with a sore sole underneath, they amplify the pain response.
- Action devices: Bracelet-like chains or rollers are strapped around the pastern. On a healthy horse, these add some animation to the gait. On a horse with chemically burned or mechanically damaged skin, they act as a constant source of additional pain.
- Hoof bands: Metal bands are tightened over the hoof wall, sometimes after the outer layer has been sanded down to the quick. The pressure on the sensitive inner hoof tissue creates chronic pain with each step.
False soles are sometimes glued over the bottom of the hoof to hide pressure shoeing or foreign objects during inspections.
How Inspectors Detect Soring
Before a horse can enter the show ring at a sanctioned event, it must pass a physical inspection. Inspectors examine the front limbs from the knee down to the hoof, paying close attention to the pasterns and fetlocks. They use a specific palpation technique, pressing with the flat of the thumb firmly enough to blanch the thumbnail. This level of pressure is well below the threshold that would cause a normal, healthy horse to react. A sored horse, by contrast, will flinch, try to pull away, or show visible changes in facial expression.
Inspectors also look for physical signs of abuse: inflammation, swelling, scar tissue, and a condition called proliferating granuloma tissue, which is abnormal tissue growth caused by repeated chemical injury. Between 2009 and 2016, the USDA also used thermal imaging cameras at some events. Thermography measures heat radiating from the skin, and elevated temperatures in the pastern area indicate increased blood flow from inflammation or injury. The cameras proved effective at revealing chemical irritants, chronic inflammatory conditions, and even the use of numbing agents applied to mask soreness before inspection.
The Law and Its Limits
The Horse Protection Act, passed by Congress in 1970, makes it a federal violation to show, sell, auction, or transport a sored horse. The law is enforced by the USDA’s Animal and Plant Health Inspection Service (APHIS), which sends veterinary medical officers to attend horse shows and conduct inspections. The industry also uses its own inspectors, called Designated Qualified Persons, who are trained to examine horses before competition.
Enforcement has been a persistent challenge. In May 2024, APHIS published a sweeping final rule that would have imposed a blanket ban on pads, action devices, and foreign substances for Tennessee Walking Horses and racking horses. It also aimed to replace older scar-detection standards with updated criteria. The rule was set to take effect in February 2025, but a court struck down several of its key provisions, ruling that APHIS had exceeded its authority with the blanket ban and that certain parts of the rule lacked adequate due process protections. As of early 2026, the remaining (non-vacated) portions of the rule have been postponed until December 31, 2026.
The result is a legal landscape that remains in flux. The core prohibition against soring still stands, but the more aggressive regulatory tools the USDA tried to introduce are either blocked or delayed.
The Flat-Shod Alternative
Not everyone in the Tennessee Walking Horse world supports the Big Lick. A growing segment of the industry competes in “flat shod” and “pleasure” classes, where horses wear normal, lightweight shoes and are judged on the quality of their natural gait rather than exaggerated leg action. No weighted chains, no stacks, no chemical agents. These classes showcase the breed’s smooth running walk as it naturally occurs.
In surveys of Walking Horse trainers, the majority reported working with flat-shod pleasure horses rather than heavy-shod performance horses. Many trainers have expressed interest in more research on leg health, particularly around the damage caused by soring. The flat-shod movement represents a shift toward valuing the horse’s natural ability and long-term soundness over the dramatic spectacle that soring was designed to produce.