EDITOR’S NOTE: The information, ideas and opinions expressed are those of the author and do not necessarily represent those of the United States Department of Agriculture.

In a collaborative effort, Swedish, Dutch, Swiss and American researchers conducted an experiment with seven clinically normal upper-level dressage horses to examine movement asymmetry on a treadmill at walking and sitting trot speeds. After being acclimated to the treadmill, left-right comparisons were made with the horses’ regular riders sitting the horse in a dressage frame and without a rider.

Increased asymmetry was detected at both speeds with the horses under saddle compared with moving in hand. This included forelimb stance duration and protraction and hind limb stance protraction and retraction, as well as force peak and vertebral movements. Although movement asymmetries often indicate lameness, the horses in this study were sound when examined.

The authors speculate the increased asymmetry while under saddle could be attributable to the natural laterality of the horses themselves while being ridden or asymmetries of the riders in their use of aides or weight distribution. The degree of asymmetry observed in this study was considered close to or just below that sometimes associated with lameness, but also likely to be less than that generally detectable by humans without a rider.

— Bystrom A et al. EVJ 2020; in press

For more insights from Dr. Albert Kane, read Research Journal in the July/August 2020 issue of American Farriers Journal.