Sinusoidal current is an alternating current that produces smooth, rhythmic muscle contractions at 50 Hz. It is produced from mains electricity reduced to 60-80 volts using a step-down transformer. This current stimulates both motor and sensory nerves, causing tetanic muscle contraction and tingling sensation. It is often used over large areas to relieve pain through sensory stimulation and reduce edema through rhythmic muscle pumping. Sinusoidal current is similar to faradic current but provides deeper penetration and is less irritating, making it well-suited for nervous clients.

1. Sinusoidal current 2
DR RIAZ AHMED PT

2. Definition
• sinusoidal currents are evenly sine wave
alternating currents with a frequency of
50 Hz.
• The sine wave or sinusoid is a mathematical
curve that describes a smooth repetitive
oscillations.

4. • It is produced from the mains by reducing the
voltage to 60 to 80 volts with a step down
transformer.
• This gives 100 pulses or phases in each
second, 50 in one direction and 50 in other.
• It is usually surged to cause rhythmical muscle
contractions.
• It relieves pain and reduces edema.
• Because of its marked sensory stimulation
this current is often used over large areas and
rarely used for local muscle stimulation.

5. Sinusoidal current
• Similar to faradic current
• Alternating current that produces
mechanical contractions that tone the
muscles
• Produce impulses on muscles & force
them to contract;

6. Advantages
•Supplies greater stimulation,
deeper penetration, & is less
irritating than faradic current
•Soothes the nerves &
penetrates into deeper muscle
tissue
•Is best suited for the nervous
client

7. EFFECTS OF SINUSOIDAL CURRENT
• STIMULATION:-When it is applied continuously, it
causes a tetanic muscle contraction and tingling
sensation due to stimulation of motor and
sensory nerves.
• It is usually surged to cause a rhythmical muscle
contraction.
• The sensory stimulation help for pain relief by
the mechanism, same as that of TENS and the
rhythmic muscle contraction help in relief of
edema.

8. EFFECTS OF SINUSOIDAL CURRENT
• Metabolism:-It also helps for enhancing blood
flow and intramuscular metabolism.
• Reduction of edema: The unsurged sinusoidal
current also helps for reduction of edema
inflammatory exudates.

9. APPLICATION:
• Sinusoidal currents can be applied in the same
way as other low frequency currents by means
of Electrodes and pads.
• This current is applied to large areas due to
marked sensory stimulation.
• It is rarely used for local muscle stimulation.

10. Indications
• Pain:-For pain control continuous sinusoidal
current is applied at intensity close to patient
tolerance and applied for approx.. 5 min and
repeat if there is insufficient immediate side
effects.
• Edema:-For reduction of edema and to
increase the limb circulation surged sinusoidal
current is suggested; causing rhythmical
muscle pumping action.

11. Indications
• Used during scalp & facial
manipulations
• Sinusoidal current is rarely used in
modern Physiotherapy.

12. Contraindications:
• Skin lesions
• Unstable fracture.
• Impaired cognitive ability
• Pregnancy
• Over Carotid sinus
• Cancer.
• Cardiac pacemakers.
• Superficial metals