Efficacy of spinal manipulation and mobilisation on trunk flexibility and stiffness in horses: a randomised clinical trial.

The research article undertook a clinical trial to assess the effects of spinal mobilisation and spinal manipulative therapy (SMT) on the flexibility and stiffness of the spines of actively ridden horses. The objective was to provide quantitative data on these techniques, hypothesizing that they would led to greater spinal mobility. The results indicated that the SMT group did exhibit significantly increased trunk displacement and applied force, indicating increased spinal flexibility.

Objective of the Research

• This research aimed to assess the impact of spinal manipulation and spinal mobilisation on horses, specifically in relation to spinal mobility and stiffness. The goal was to provide objective, measurable data on the effects of these therapies, given their increasing application to horses.

Methodology

• The experiment involved 24 actively ridden mature horses. Over a period of three weeks, passive spinal mobility was assessed in the horses.
• Parameters such as peak vertical displacement, loading and unloading velocities, applied force, stiffness, and the frequency of truncal oscillations were measured at five different locations in each horse’s spine.
• The horses were split into two groups: one that received manual high-velocity, low-amplitude (HVLA) thrusts and a control group that did not receive any additional intervention.
• Measurements were taken before and after the intervention, with a gap of 10 minutes, each week.
• Data analysis was conducted using a mixed-effects linear regression model to assess the interactive effects of treatment group, vertebral level, week and pre-/post intervention results.

Results

• Results indicated that post-intervention displacement amplitudes of the trunk and the applied forces were significantly higher in the SMT group compared to the control group, suggesting greater spinal flexibility.
• Similarly, an increase in spinal stiffness was found in the SMT group, indicating another impacting effect of the therapy.
• Across the vertebral levels, the SMT induced a 40% increase in displacement, a 20% increase in applied force, and a 7% increase in stiffness.

Conclusions

• The research concludes that spinal manipulative therapy (SMT) can increase the dorsoventral displacement of a horse’s trunk, suggesting increased spinal flexibility.
• However, the researchers recommend further clinical research is needed including objective measures of back pain, stiffness and performance to corroborate and expand on these insights.