Observing a horse move with a post legged gait immediately draws the eye, creating a distinct visual rhythm that differs significantly from the fluid walk, trot, or canter. This specific movement pattern, where the horse appears to move with a stiff, stilted motion, is not merely an oddity for spectators but a critical indicator of the animal's physical health and soundness. Understanding the mechanics behind this gait is essential for anyone involved with equines, from the casual observer to the seasoned veterinarian, as it often signals underlying orthopedic issues that require attention.
The Biomechanics of a Post Legged Stance
To grasp the implications of the movement, one must first understand the static posture that often precedes it. A post legged horse typically stands with an excessively straight angle in its hind limbs when viewed from the side. Instead of the standard configuration where the hock joint forms a distinct, slightly obtuse angle, the angle becomes nearly linear, placing the cannon bone almost directly behind the point of the buttock. This structural alignment removes the natural shock-absorbing suspension system provided by the lower leg, forcing the joints to bear weight in a less efficient and more rigid manner.
How the Gait Manifests
When the horse transitions into motion, the effects of this straightness become pronounced. Rather than bending the hock to absorb impact and propel the body forward, the leg extends rigidly. This results in a gait where the hind limb appears to slam into the ground and then kick slightly forward in a sweeping motion. The lack of flexion means the horse loses the elastic energy storage and release typical of a sound stride, leading to a choppier, more abrupt movement that lacks the usual spring and flow.
Identifying the Cause: Common Origins of the Gait
The development of a post legged movement is rarely random; it is usually a response to pain, discomfort, or a congenital defect. One of the most common culprits is osteoarthritis within the hock joint. The constant stress on a misaligned joint wears down the cartilage, leading to inflammation and bone spurs. As the horse attempts to move, the resulting pain causes it to alter its mechanics, locking the joint in a straighter position to minimize the range of motion that triggers the discomfort. Other potential causes include previous trauma to the limb, congenital angular limb deformities, or chronic inflammation from strenuous work without adequate recovery.
Differentiating from Other Gait Abnormalities
It is crucial to distinguish a post legged gait from other hind limb abnormalities, such as cow hocks or sickle hocks. While these conditions also involve misalignment, the resulting movement patterns differ. A horse with cow hocks will often exhibit a paddling motion, while a sickle hocked horse may interfere or cross over. The post legged horse, conversely, displays a more linear, pushing motion where the limb does not bend adequately, making the movement appear stiff and mechanical rather than swinging or crossing.
The Impact on Long-Term Health and Performance
Ignoring this gait anomaly can have serious consequences for the horse's career and quality of life. The rigid mechanics place excessive strain on the hock joints, the stifles, and even the lower back. Over time, this abnormal stress accelerates degenerative changes, leading to chronic lameness and a significant reduction in the horse's ability to perform. What might begin as a subtle stiffness can progress to a pronounced limp, rendering the animal unable to jump, cut, or engage effectively, depending on its discipline.
Management and Veterinary Intervention
Addressing the issue requires a multi-faceted approach initiated by a veterinary professional. Diagnosis typically involves a thorough physical examination, flexion tests, and diagnostic imaging such as radiographs or ultrasound to assess the internal structures of the hock. Treatment may include a combination of rest, anti-inflammatory medications to manage pain and swelling, and targeted joint injections. In severe cases, surgical intervention may be necessary to correct the alignment or address advanced joint degeneration.
