Manchester's first video
The following video was recorded in 2006. Lameness of the right hind leg is apparent. When I rode the horse a few months ago, Manchester was not in training, yet the lameness was worse. This might be an indication that the source of the problem is muscular rather than neurological.
Morphologically, you can observe that Manchester has sickle hocks. According to James Rooney, sickle hocks tend to put more strain on the hock joint referred to as TC, T3.
The pathologist explains that the maximum stress on the joint occurs toward the end of the stride. "If, on the other hand, the animal tends to be sickle hocked, the limb below the hock will be too far forward. The pastern would not be elevating as the stifle flexed toward the end of the stride and asynchrony between TC and T3 would occur." (James R. Rooney, Biomechanics of Lameness in Horses, 1969)
Most of the time, the right hind-leg abnormality is apparent at the end of the stride, just before the push-off. This could suggest that the hocks might bother the horse at the time of this video recording. The vet report discussed fusion of the hocks' joints. However, when Manchester is turning left, there is also a brief protective reflex at impact of the right hind leg. As he turns right after the left turn the lameness is greater. Either the joints need a few steps to adjust to the new direction, or perhaps the back-muscle imbalance is causing the discomfort. The horse adjusts after a few strides. and the lameness is less visible.
When I rode him, the feeling of a muscle imbalance was perceptible on the right side in the area marked here with an arrow. My hope is that this muscle imbalance might be the root cause of the right hind leg's issue.
Manchester is scheduled to depart from Canada on February first and therefore, will arrive in Florida on February the third. You will witness his arrival and first steps in his new home