A Preliminary Study of the Effect of Manual Chiropractic Treatment on the Splenius Muscle in Horses When Measured by Surface Electromyography

Reasons for performing study A quantifiable measure of muscle activity related to the cervical spine may provide further understanding and evidence based support for chiropractic techniques. Surface electromyography (s EMG ) is a noninvasive method of measuring muscle activity of the splenius muscle when the horse is at rest. Objectives To determine if there is a relationship between objective measurable muscle parameters and misalignments and muscle tension in the equine cervical spine. Study design Controlled paired randomised study. Methods Privately owned horses (n = 14), of mixed sex, age and mean height 157.8 cm were selected and assigned a group by matching work, management regime, age, sex and breed. The treatment group (n = 7) underwent manual chiropractic treatment following palpation. The control group underwent palpation only. A Delsys 4 sensor system was used for data collection. Probes were positioned on the muscle halfway between C1/C2 joint and the crest on the left and right sides, between the tendon insertion and the motor point to maximise signals. s EMG readings were taken at immediately before (0) and after palpation ( PP ) and 30 min later (30). Data were tested for normality and variance by one‐way ANOVA and paired t test. Results P ost treatment, there was a significant decrease (P<0.01) in s EMG activity for treatment group at 0 to 30 and PP to 30. There was a significant decrease (P<0.05) in sEMG for right side for treatment group at 0 to 30 and PP to 30. There were no such significant effects for the control group. The majority (83%) of horses had atlas rotation and tilt to the right. Conclusions This preliminary study supports use of s EMG as a means of assessing muscle activity of equines and suggests a statistically significant reduction in splenius muscle activity is observed following manual chiropractic treatment although the benefit to the horse is unknown. Ethical animal research:  The study protocol was reviewed by the College Research Ethics Committee before commencement of the study. Owners gave informed consent for their horses' inclusion in the study. Source of funding:  McTimoney College of Chiropractic assisted with the hiring of the equipment. Competing interests:  None declared.