The effect percussive therapy on equine thoracic profile, mechanical nociceptive thresholds, spinal and limb kinematics and gait symmetry.

Therapeutic devices are increasingly used by therapists and horse owners. Percussive therapy (PCT) has been shown to effect blood flow, tissue oxygenation, increase range of motion (ROM) and improve recovery in humans. The aims of this study were to investigate the immediate effects of PCT on horses. Using a within-subjects randomised blinded cross-over design, twelve polo horses in training received two 12-minute PCT sessions to the major muscle groups, with the device on or off, 24-hours apart.
Pre- and post-intervention or sham sessions epaxial muscle mechanical nociceptive thresholds (MNT) and thoracic (T) profile dimensions were measured. Each horse performed four in-hand trot passes where spinal kinematics and gait symmetry were measured with inertial measurement units, plus stride length was analysed via 2D video recordings.
There were no significant differences between MNT measures. Within the sham group, thoracic profile was significantly different pre and post at T18 (mean change -0.48 cm ± 1.03; p = 0.003) and in the intervention group, there was a significant difference between the pre and post at T13 (mean change = -0.76cm ± 1.35). There was no significant difference in stride length or gait symmetry at the poll, withers, and pelvis but differences in T6, T13, L3 and sacrum ROM in the sham group and T6 and T18 in the intervention group were seen.
Overall, the application of PCT did not result in MNT or stride length changes in the intervention group when compared to the sham scenario although there were minor changes to thoracolumbar profile and spinal ROM. Further research assessing walk kinematics, ridden horse performance are recommended, along with assessing different PCT applications and other variables such as blood flow and neurophysiological responses that affect behaviour.