The effect of spinal skin cooling with topical ointment on the recruitment curve parameters of soleus H-reflex

Introduction : There are different applications for cooling in rehabilitation and there is also a controversy in results of applying ice on limb and its effects on motorneurons excitability. Methods : This study was done to determine the effect of applying controlled cooling (rubbing cold ointment with 3°C temperature) on the spinal skin (around T place of S root nerve) on the excitability of soleus 11, 11 motorneurons in ten healthy, non-athletic men. Each volunteer was tested in two [control (vazeline ointment with - environment temperature) and examination (cold vazeline)] separate sessions. We used soleus H-reflex and M h wave recruitment curve parameters for evaluation. Stimulation current was a square pulse with 700 microsecond duration and 0.2 Hz frequency. H-reflex was recorded with 9 different amplitudes. Results: Fit L slope, fit L slope and peak to peak amplitude of H-reflex decreased immediately and 30 3 5 minutes after the application of cold ointment. Conclusion: Cold by stimulating the thermoreceptors and reducing the firing rate of surface mechanoreceptors can decrease the excitability of motoneurons and this effect may be long lasting.