Effects of transcutaneous electrical nerve stimulation on the H-reflex of muscles of different fibre type composition.
Differential effects of repetitive stimulation of low threshold afferents on both the recruitment threshold and motoneuronal excitability of type I and type II motor units have been demonstrated. The present study was aimed at further investigating the differential effects of 30 minutes of transcutaneous electrical nerve stimulation (TENS) on the H-reflex amplitude (Hmax/2) of the Soleus (SO), gastrocnemius lateralis (GL) and medialis (GM) muscles. Eleven healthy subjects were tested in order to evaluate the effects of TENS on either the common peroneal (CPN), saphenous or sural nerve. The experimental session consisted of three consecutive 45 min periods. Within each of these periods, H-reflexes were recorded before, during and after the TENS was applied. It was hypothesized that repetitive low threshold afferent stimulation would either have inhibitory or facilitatory effects on the H-reflex amplitude of the SO or gastrocnemii muscles respectively. Non-parametric Friedman ANOVAs revealed a significant tendency (p < 0.05) toward inhibition of the H-reflex amplitude of the SO and GL muscle during TENS applied over either the CPN or sural nerve, as well as that of the GM during repetitive stimulation of the saphenous nerve. Although the present study failed to reveal any differential effects of TENS on the H-reflex amplitude of muscle on different fibre type content, the significant decrease in H-reflex observed on the triceps surae muscles during TENS applied over the CPN might have promising clinical outcomes for hyperreflexive subjects.
Goulet
C G
CG
Physiotherapy, Program, Faculty of Health Sciences, University of Ottawa.
Arsenault
A B
AB
Bourbonnais
D
D
Levin
M F
MF
D000328:Adult; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D009412:Nerve Fibers / Q000502:physiology*; D004561:Transcutaneous Electric Nerve Stimulation