By Jec A. Ballou

I call it the lameness that is not really lameness. Sometimes, a horse develops an unexplainable hitch in his movement that leads to much head scratching from vets who, after an array of diagnostics, find no clear answers. The horse is described as being “not quite right,” but beyond that, there is no reason or treatment.

This mystery lameness that produces an inconsistent limp during one or more gaits is often what we call “rein lameness.” It is a disrupted gait pattern owing to muscular tension or imbalances that have reached a point of negatively affecting motion through the spine. The term “rein lameness” originated from the frequent occurrence of horses made sore from riders with too much rein pressure. It does not, however, only originate from tight reins. In fact, I observe it most often in recreational riders’ horses ridden on loose or inconsistent rein contact.

The following is a simplified description of the development of this condition. In good healthy movement, the horse’s torso channels energy forward from the hind legs. It both creates and stabilizes the force of the hind limbs swinging forward each stride. Tension in the back or abdominals disrupts the synergy needed between these two muscle groups in order to play this role. The disruption in their interplay due to this tension and imbalance causes the horse to short-stride with one hind leg. This causes his trot rhythm to be noticeably uneven, or it may cause an actual limp. While it can sometimes be observed in other gaits, rein lameness is usually most notable when trotting.

Rein lame horses rarely show gait patterns that are explained through the typical diagnostic veterinary exam. They can be intermittent, or the soreness might appear in the front limbs one day but the hind limbs the following day. Sometimes they appear sound on the longe line but start limping when a rider gets on.

In the past year, I have become increasingly vocal about drawing riders’ attention to the fact that muscle tension patterns can indeed be the source of “lameness.” Initially, this can sound too simplistic; riders assume that something on their horse must be broken, pulled, or otherwise very wrong if the horse is moving “not quite right.” But let’s stop and think about this.

To make a human comparison, consider how altered your own gait becomes following even a mild exertion. If you have ever used your body in an asymmetrical fashion (worn shoes with uneven soles, for example, or sat in a twisted position on an airplane), you have experienced a mild lameness without breaking or tearing anything. In order to resolve your disrupted gait, you must loosen up your muscles and rid them of the tension that is causing the limp. These occurrences are quite frequent over the course of our lives. For many horses, it is the same.

Of course, plenty of horses can be exercised in all manner of incorrect postures and states of tension, and yet they do not develop rein lameness. Others, however, are very susceptible. In my own experience, I believe some horses are just naturally more negatively affected by muscle tension and imbalance. Perhaps it is because of a less than ideal conformation or metabolism, or a delicate constitution. The good news is that despite having a slight limp in their gait, many rein lame horses are not in pain. Remember, the limp comes from a mechanical glitch, not necessarily from a glaring soreness.

The answer that many vets do not provide is that the problem must be fixed with good, correct gymnastic exercise. The horse must be ridden in a basic dressage balance and required to stabilize his core for short, rhythmic bouts of exercise.

Resting a rein lame horse does not usually resolve the problem. Chances are high that once he is put back in a training routine the underlying gait patterns will show up again after a week or two. In order to resolve the problem, the horse must be exercised with his body in an ideal balance and engagement. On several occasions, I have seen the disrupted gait pattern disappear immediately once a skilled rider gets on and asks the horse to carry his body with correct posture. Other times, it might take a day or two, but it rarely takes longer than one week.

It is too tempting for modern riders to think they can resolve any abnormality in their horse’s movement with an injection or medicines or costly layups. My plea is to do our horses well by treating dysfunctional movement with a protocol of good, functional movement. This should be our first plan before taking more drastic actions. 

Related: Training Horses to Improve Fitness

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