What's the story with hind limb rotation?
Rotation of the hind limb in walk is a very common sight in horses. There are many factors that contribute to it, and if we want to address the issue properly, we need to take a multi – pronged approach.
The rotation that occurs in the hind leg can be easily observed when the horse is walking away from us. The hoof rotates inwards and the hock deviates outwards.
If you observe horses walking away from you, you might notice a very common pattern in some of them. As they land, their foot rotates inward, causing their hocks to shift to the outside. It might be bilateral or more obvious on one side than the other. And while it's easy to say, oh that's just the way he's always walked, it's probably a better idea to explore why it's happening. This kind of gait pattern is detrimental in the long run for pretty much every structure in the leg, so it makes sense to address it as soon as we notice it.
If you ask different professionals why this pattern occurs, you might be surprised to get a lot of different answers. A trainer might tell you that he needs more strength in the hind legs, a hoof care provider might say that it's due to an imbalance in the hind feet, a bodyworker might point to issues in the pelvis and back. While it might be frustrating to get a bunch of different answers, the thing is, all of them are probably right. This pattern of movement is rarely just one thing. Trying to figure out exactly where it started might be a bit of a chicken and egg situation, but at the end of the day what matters more than figuring out the exact pathway, is to address all the structure this pattern is influencing. And the list is long.
In most cases of hind limb rotation, there will be some degree of dysfunction in the pelvis.
Let's say it started years ago when the horse had a particularly eventful afternoon in a muddy turnout. While running around, he slipped and injured his hip flexor. He was stiff for a few days, then seemed to be ok. Except he wasn't. The pain in his hip flexor made him change the way he moved and the way he placed his affected hindlimb. This involved changing the position of his pelvis and stabilizing the affected area using more muscular effort. Eventually, connective tissue formed adhesions around it to protect it. Now his pelvis was stuck in the same position, making is difficult to return to a normal way of moving. His nervous system got used to the changes and set it as a »default« way of moving. The altered position of the pelvis made a full range of motion impossible to access, which means the muscles of the hind end were not being used in their full capacity. The hamstrings developed more, the quadriceps atrophied. This reduced stability around the knee, setting the leg up for rotation. Pretty soon the hooves adapted to this new way of moving, changing shape and becoming imbalanced. This then starts to negatively impact the structures above and the vicious cycle is complete.
Resolving the issue will take a multi-pronged approach with several professionals working together.
So, if we want to resolve the problem, we need to address a lot of things. We need to make sure the horse's back is free and mobile. We need to address the hip flexors and release the structures limiting the range of motion of the pelvis. We need to restore muscular balance in the hind end musculature by releasing some muscles and strengthening others. We need to deal with hoof imbalances and restore function of the foot. And of course, we also need to talk to the nervous system to teach it to change its default way of moving. It's a big job. It will take time. And it will take a team of experts to each provide their piece of the puzzle. But in the long run, by addressing this problem thoroughly, you are setting your horse up for a longer, healthier career.