1. Stimulation of sensory nerves:
Applying the faradic current, there is having a mild pricking sensation. And there is also leading mild erythema(redness)of the skin due to vasodilation of superficial vessel. This vasodilation will only occur in superficial tissue.
2. Stimulation of the motor nerves:
Faradic current stimulate motor nerve if the sufficient intensity there will occur muscle contraction. As stimulation and thereby contraction repeated 50 times per second there occurs a tetanic type of contraction. If it is continued more than a short period of time , the concerned muscle will be fatigued. That is why the current is surged or interrupted give rest or relaxation to the muscle.
3. Effect on muscle contraction
When muscle contact, result of electrical stimulation. The changes taking place within the muscle are similar to those asociated with voluntary contraction. There occurs increased metabolism with consequence increase the demand for O2 and foodstuff associated with increased output of waste materials. As the muscle contract and relax, it exerts a pumping action on vein and lymphatic vessel lying within and around them.
4. Stimulation of the nerve is due to producing a change in the semi-permeability of the cell membrane:
This is achieved by altering the resting membrane potential. When it reaches a critical excitatory level, the muscle supplied by this nerve is activated to contract.
5. Effect on denervated muscles
For the stimulation of denervated muscles, the impulse required is more than 1 ms. So, faradic current is short duration current which cannot stimulate the denervated muscles.
6. Reduce swelling and pain:
Due to alteration of the permeability of the cell membrane, leading to acceleration of fluid movement in the swollen tissue and arterial dilatation. So, it leads to increase metabolism and get rid of waste products.
7. Chemical changes:
The ions move one way during one phase of the current; and in the reverse direction during the other phase of the current if it is alternating. If the two phases are equal, the chemicals formed during one phase are neutralized during the next phase. In faradic current, chemical formation should not be great enough to give rise to a serious danger of burns because of the short duration of impulses.