Like many riders, I enjoy having a wearable that lets me track how far I’ve ridden, where I’ve gone and how long I’ve spent at different gaits. I use the free version of Equilab, and find it very accurately depicts what my horses and I have accomplished in a work out. Not to mention, it’s very helpful to see where you’ve ridden when all the trails suddenly look the same and you’re lost! Even better, I sometimes use Equilab when I’m out walking, to track my miles. Did you know if you swing your arm while carrying your phone it records as cantering?

However, there are wearables now that purport to monitor the symmetry of your horse’s gaits, offering you insights into soundness and potentially alerting you to issues before they become serious. Several years ago, I was involved in the launch of the Equisense Motion, which in addition to reporting your time in each direction (helpful to know what lead or diagonal you favor) also monitors symmetry and cadence.

At the time, I spoke to a veterinarian who evaluates a lot of horses for lameness. He uses the Lameness Locator which was developed by Dr. Kevin Keegan, a professor of surgery and lameness at the University of Missouri, in Columbia, MO. He was suspicious of anything that purports to pick up asymmetries under saddle because the rider can cause a horse to move asymmetrically.

Now researchers have completed a study that shows that using horse-mounted sensors to detect uneven movement suggestive of lameness may be subject to error if the horse is asymmetric to begin with.  In theory, the rise and fall of the equine pelvis should be the same between the right and left side when no lameness is present. When horse are in pain, the pelvic rise on the lame side decreases.

The study comprised 16 sound horses that were being ridden daily. They were assessed as showing no asymmetry when standing squarely. They were fitted with sensors and then trotted in a straight line and on a lunge, on both hard and soft surfaces. They introduced a hind-limb length difference by attaching a single, rear 12.5mm glue-on shoe and the horses were reassessed.

All horses showed significant changes, with the pelvic minimum (which measures impact-type lameness) more consistently affected that the pelvic maximum (which measures push off-type lameness). The results of the study suggest that lameness associated with push off is more likely to be a result of differences in the push-off force between the hind limbs rather than limb length asymmetry.

However, this assumes that the hindlimb length between the right and left sides is the same. According to researcher Jael Pitts and her colleagues,

“Hindlimb length difference can result from growth discrepancies of the hooves or long bones between the right and left limbs.

“These discrepancies may have been caused by injuries that are healed and no longer painful, or differences in functional demand from specialized training or repetitive movement, leading to the development of a type of ‘leggedness’ similar to ‘handedness’ in humans.” (from HorseTalk.co.nz)

I’ve known several horses that had a permanent hitch in their step but didn’t appear to be in pain. Perhaps they also had hind limb length differences?

I suppose that the wearable sensors might sense a change in the gait of a horse over time, but given that just a half inch difference (12.5 mm) can have such a big impact on a horse’s gait, it makes me wonder what else could be going on. For the time being I’ll keep using my Equilab app and depend on the vet to bring out the big guns (Lameness Locator) if needed.

The other thing this study drove home is that even riding a horse without a shoe for a period of time could impact it’s gait and soundness. Now, since Freedom is unrideable without a shoe and Zelda is barefoot already, it’s not something I need to worry about, but in the past there have been times when I’ve certainly ridden a horse on soft ground when waiting for a farrier to come and replace a lost shoe. I might not do that again.