Horses were most likely to swish their tails and toss their heads when cued by the rider, Wilkinson said. | Photo: iStock

Under the direction of Carol Hall, PhD, Rachel Wilkinson, BSc, researcher at Nottingham Trent University, in the U.K., and colleagues compared heart rates and behaviors of horses longed with and without riders. The nine riding school horses were divided into three study groups:

• Longed with a rider giving signals;
• Longed with a rider, but with the longer giving signals; and
• Longed without a rider with the longer giving signals.

Heart rate analyses revealed no significant differences between the horses in the three groups, Wilkinson said, which suggests that the horses experienced no added physical stress when ridden and longed compared to when they were longed alone.

However, the horses’ behavior indicated they felt mental stress when the rider was present, and this stress was greatest when the rider gave cues. Horses were most likely to swish their tails and toss their heads when cued by the rider, Wilkinson said. They showed these behaviors to a lesser extent with a rider who didn’t give cues, and without a rider the behaviors were relatively uncommon