A Bridle Designed to Avoid Peak Pressure Locations Under the Headpiece and Noseband Is Associated With More Uniform Pressure and Increased Carpal and Tarsal Flexion, Compared With the Horse's Usual Bridle

Bits are frequently blamed for veterinary and performance problems, but there is minimal other research into bridle and horse interaction. Study objectives were to (1) determine sites of maximum pressure under a double bridle headpiece, and under a crank cavesson noseband in trot using a pressure mat; (2) design a headpiece and crank cavesson noseband combination that avoids maximal pressure locations during movement; and (3) compare maximum pressure and gait characteristics of horses wearing the designed bridle (bridle F) with their usual bridle (bridle S). In part 1, peak pressure locations were determined using calibrated pressure mats under the headpiece (n = 8 horses) and noseband (n = 10). In part 2, 12 elite horses and riders with no lameness or performance problem were ridden in bridle F and bridle S in a double blind crossover design. Pressure mat data was acquired from under the headpiece and noseband. High speed motion capture in trot was used to determine forelimb and hind limb protraction, and maximal carpal and tarsal flexion during flight. Under the headpiece, bridle S peak pressure was 106.7% (mean) greater than that of bridle F, and bridle S maximum force was 59.7% greater than that of bridle F. Under the noseband, bridle S peak pressure was 47.8% greater than that of bridle F, and bridle S maximum force was 41.2% greater than that of Bridle F. On gait evaluation, bridle F had 4.1%, 3.5%, and 4.2% greater carpal flexion, tarsal flexion, and forelimb protraction than those of bridle S. These findings suggest an association between reduced peak pressures and improved gait, which may indicate improved comfort for the horse.