An Investigation Into the Short-Term Effects of Photobiomodulation on the Mechanical Nociceptive Thresholds of M. Longissimus and M. Gluteus Medius, in Relation to Muscle Firing Rate in Horses at Three Different Gaits.

This study investigates the effect of a laser treatment on the pain sensitivity and muscle contractions of horses, finding that while there was no noticeable impact on sensitivity, there were significant improvements in muscle function.

Research Context

• The focus of this study concerns back pain in horses, which is common yet lacking in concrete data to determine the success rate of treatments.
• A key point to consider is that the authors aim to quantify the effectiveness of laser treatments by observing changes in horses’ sensitivity to pain (measured by Mechanical nociceptive thresholds or MNTs) and muscle function (acoustic myography or AMG), specifically in the M. longissimus and M. gluteus medius muscles.

Methodology

• To carry out the experiment, the researches used eight healthy horses, and measured their MNTs and AMG before and after applying a class 1 laser treatment.
• The lasers were applied directly to the previously selected points from which MNT measurements were taken at a frequency of 1000 Hz for one minute.
• The intervention took place in a controlled environment: an indoor arena with a waxed sand surface, and the horses were observed at different movement speeds (walking, trotting, and cantering).
• The AMG and MNT measurements were then taken one hour and 24 hours after the treatment respectively to examine any short-term effects.

Results

• The researchers found that, contrary to their expectations, the MNTs did not show any significant changes following the treatment, which means the horses’ sensitivity to pain remained unaffected.
• However, the AMG measurements exhibited significant improvements, suggesting the laser therapy had a positive impact on the horses’ muscle operations.
• These improvements were noted in relation to the different gaits of the horses, indicating that the treatment may be beneficial in easing muscle stiffness or improving functionality during movement.

Conclusion

• The study ultimately concludes that class 1 laser therapy can positively influence horse muscles, manifesting as changes in their firing frequency that correlate with pain relief in subjects experiencing pain.
• Although the research didn’t show a substantial effect on pain sensitivity, the notable effects on muscle function suggest possible applications of laser therapy in the management of muscle-related health conditions in horses.