Riding instructors and trainers have long preached symmetry and balance when riding horses. But as symmetrical as you might feel in the saddle, have you ever considered that your dominant hand might be pulling a bit harder on your horse’s mouth than your less-dominant hand?

Because of the lack of research into human handedness’ effects on rein tension, Jenni Douglas, MSc, visiting associate principal lecturer in higher education equine, at Hartpury College, in Gloucester, United Kingdom, recently studied whether and how handedness factors in. She shared her findings at the 11th International Society of Equitation Science Conference, held Aug. 6-9 in Vancouver, British Columbia.

The study involved 23 female, right-hand-dominant riders ages 14 through 34. Each one completed a five-minute test on a mechanical horse: one minute at the walk, sitting trot, rising trot, seated canter, and two-point canter.

“The mechanical horse was chosen for this preliminary study as opposed to a live horse as it would eliminate all horse-related variables and be a true indicator of tension that the rider was emitting through the reins related to handedness and not as a result of horse-sidedness, aid application, etc.,” said Douglas.

Based on data collected by rein tensiometers during the riders’ tests, “the right rein reports greater mean (average) and peak tensions compared to mean and peak tensions in the left rein,” Douglas explained. Overall, average rein tensions in the dominant hand were 34-45% greater than in the nondominant hand.

She said there was no statistical difference between riders’ average