Evaluation of neuromuscular electrical stimulation on fibre characteristics and oxidative capacity in equine skeletal muscles.

The research study investigates the effects of Neuromuscular Electrical Stimulation (NMES) on the muscle fibre characteristics and oxidative capacity in horses, concluding that the protocol used did not lead to significant muscle adaptations.

Research Goals and Methods

• The primary objective of this study was to assess the impact of NMES on specific aspects of equine muscle. The focus was on changes in muscle fibre types and areas, glycogen concentrations and enzyme activities.
• NMES was applied to two muscles – m. gluteus medius and m. longissimus dorsi – on one side of six healthy Standardbred horses. The other, untreated side, served as a control for comparison.
• The NMES treatment consisted of daily stimulation at 50 Hz, with an intensity of 21-39 mA, for durations between 45-60 minutes, implemented five days per week for four weeks.
• The researchers opted for a noninvasive method to gather data, involving extracting needle biopsies from both the treated and untreated muscles before and after the experimental period.
• These muscle samples were then subjected to histochemical and biochemical analyses to measure various parameters such as fibre type proportions and area, glycogen concentrations, and enzyme activities.
• Diagnostic ultrasound was used to confirm muscle contractions at the exact location and depth of the muscle biopsy.
• A set of nonparametric tests including Mann-Whitney and Wilcoxon sign-rank were employed for statistical analysis of this data.

Findings and Conclusion

• The results showed that no significant differences were observed in terms of type I, IIA or IIX fibres, fibre areas, glycogen levels or enzyme activities.
• These observations remained consistent while comparing stimulated and non-stimulated muscles before and after the NMES treatment, and while comparing the left and right muscle samples.
• While the horses well-tolerated the NMES treatment, it did not bring about any notable adaptations in their muscles as per the specific protocol used in this study.
• The study concludes by suggesting the necessity for further studies in this area to determine the potential impacts of more intensive and/or prolonged NMES treatment protocols on the muscles of healthy horses, as well as to ascertain if such protocols could induce beneficial changes in muscles that have atrophied.