rein tension

Which setup results in the least rein tension: Western curb bits or English snaffle bits?

The answer might surprise you.

In a recent study, researchers in Germany determined that Western curb bits caused less rein tension than did English snaffles. They also found that one-handed riding is associated with more stable rein tension.

“We furthermore determined that rein tension was actually higher with bridles that prohibit jaw-opening, indicating possible welfare issues,” said Sandra Kuhnke, PhD candidate at the University of Kassel, on behalf of herself and Uta König von Borstel, PhD, also of the University of Kassel. Kuhnke presented their study at the 2017 International Society for Equitation Science conference, held Nov. 22-26 in Wagga Wagga, Australia.

Kuhnke and von Borstel investigated the effects of various bridles, bits, riding styles, and horses’ muscle trigger points on rein tension. Muscle trigger points are “irritable” spots on the horse’s body within the fascia (connective tissue that surrounds muscles and muscle groups), Kuhnke said. The researchers measured study horses’ reactions to them touching about 25 trigger points on both sides of the body, scoring horses’ reactivity levels at each point. The results give a reliable gauge of muscle condition, she said.

To test rein tension and stability, they used rein tension meters on nearly 100 horses ridden in curb bits or snaffle bits, two-handed or one-handed, Western or English.

They found that, generally, snaffle bits were associated with higher rein tension than curb bits. However, the bit-bridle combination had a significant effect on the tension. For example, a bridle with a plain noseband and curb bit resulted in the lowest average rein tension in the whole study.

As far as snaffle bits go, rein tension was lowest when combined with a figure-eight noseband. It was highest with a flash noseband—nearly three times as high as with a figure-eight, Kuhnke said. Still, the lowest average snaffle bit rein tension was almost twice as high as it was for the lowest average curb bit tension.

When riders rode one-handed, their rein tension was more stable than when riding double-handed, she said. And it was even more stable when right-handed riders rode with their left hand only.

Meanwhile, riders with better rein tension stability had horses with more symmetric trigger point reactions (similar on both sides), Kuhnke said. It could be that the horse’s muscular condition affected the rein tension, as well as the other way around, she added.

“Considering relationships between horses’ muscular condition and rein tension appears important for equine welfare and has the potential to add further knowledge to investigations of horse-rider interactions,” Kuhnke said.