Pilot study: Effects of whole-body vibrational therapy on equine thoracolumbar epaxial muscle response to pressure algometry.

Abstract: Whole-body vibrational therapy (WBV) is well-studied in people, but there is a paucity of research regarding its effect on horses. It is suggested that the use of WBV in horses increases performance, aids in recovery, and stimulates nerves, bones, and muscles in ways that normal exercise does not. Objective: The purpose of this pilot study was to determine if frequent WBV therapy sessions affect mechanical nociceptive thresholds based on pressure algometry in horses without clinical signs of lameness or back pain. Methods: The mechanical nociceptive thresholds (MNTs) were measured for 5 horses at 8 points along their thoracolumbar epaxial muscles once every 7 days for 8 weeks. Baseline MNT scores were established during a control period with no vibration therapy treatment over the first 4 weeks. During the second 4-week period, horses received 5, 30-min vibration therapy sessions per week. Results: Despite previous research indicating that WBV increases epaxial muscle symmetry in horses, no significant difference was noted between the horses' mean MNTs across all 8 sites during the baseline and treatment periods. Upon further investigation of the change in sensitivity at the individual sites across all subjects, a statistically significant (p < 0.05) increase in MNT (0.49-0.62 kgf) was observed at 4 out of the 8 sites. Conclusions: While an increase in mean MNTs was not observed, this study found that WBV may increase MNTs at individual sites along the thoracolumbar epaxial musculature in horses. Further investigation is required to assess whether this difference is biologically meaningful and repeatable.