What Is IFT (Interferential Therapy) in Physiotherapy?
Interferential Therapy (IFT) is one of the most widely used electrotherapy modalities in physiotherapy clinics across India. When looking for IFT physiotherapy near me, understanding the underlying mechanism and clinical application helps set realistic expectations for treatment.
The Physics Behind IFT
IFT uses two medium-frequency alternating electrical currents, each at approximately 4,000 Hz but with a slight frequency difference (e.g., 4,000 Hz and 4,100 Hz). When applied through four electrodes placed on the skin, these currents travel through the tissues and interfere with each other at the target site, creating a resultant frequency of 100 Hz (4,100 – 4,000).
This interference frequency — ranging from 1 to 150 Hz depending on settings — is the therapeutic frequency that stimulates nerve fibres, reduces pain, and promotes tissue healing.
Why IFT Penetrates Deeper Than TENS
Skin impedance to electrical current is inversely proportional to frequency. At 4,000 Hz, skin resistance is significantly lower than at TENS frequencies (1 to 150 Hz), allowing IFT currents to penetrate deeply into joints, muscles, and ligaments before interfering to produce the therapeutic effect.
What Happens During an IFT Session?
- Assessment — physiotherapist confirms the target area, checks for contraindications
- Electrode placement — four suction cup electrodes are applied around the painful region in a cross pattern
- Parameter setting — frequency sweep (e.g., 80 to 120 Hz for pain), intensity adjusted to comfort
- Treatment duration — 15 to 20 minutes
- Post-session — electrodes removed, brief manual therapy or exercise follows
Clinical Applications of IFT
| Condition | Therapeutic Effect of IFT |
|---|---|
| [Knee Osteoarthritis](/conditions/knee-osteoarthritis) | Pain relief, reduction of joint effusion |
| Acute Low Back Pain | Analgesic effect, muscle relaxation |
| Post-Surgical Swelling | Improved lymphatic drainage, oedema reduction |
| Rotator Cuff Tendinopathy | Deep tissue stimulation, pain modulation |
| [Cervical Spondylosis](/conditions/cervical-spondylosis) | Nerve root pain relief |
| [Urinary Incontinence](/conditions/urinary-incontinence) | Pelvic floor muscle stimulation |
| Sports Injuries | Accelerated tissue repair in acute phase |
IFT Contraindications
IFT is contraindicated in:
- Pregnancy (over the abdomen or lumbar region)
- Active malignancy over the treatment area
- Deep vein thrombosis (DVT)
- Cardiac pacemakers
- Open wounds or active skin infections
- Febrile conditions
- Over the eyes, heart, or carotid sinus
IFT vs TENS: Which Should You Choose?
| Feature | IFT | TENS |
|---|---|---|
| Frequency | 4,000 Hz carrier | 1 – 150 Hz |
| Penetration depth | Deep (joints, muscles) | Superficial |
| Sensation | Internal buzz | Surface tingling |
| Electrode count | 4 | 2 |
| Best for | Deep joint/muscle conditions | Surface nerve pain |
For a full explanation of how IFT works and its evidence base, see our guide: IFT (Interferential Therapy): What It Is & How It Works.
Cost of IFT in India
IFT sessions in Indian physiotherapy clinics typically cost INR 300 to INR 800 per session when combined with other treatments. Standalone IFT-focused sessions range from INR 500 to INR 1,200.
References
- Goats GC. Interferential current therapy. British Journal of Sports Medicine. 1990.
- Brosseau L et al. Interferential current for shoulder pain. Physiotherapy. 2002.
- Physiopedia. Interferential Therapy. physio-pedia.com. 2024.