Phototherapy is one among the physiotherapic modalities in which different sources of light are used for therapeutic purpose. These sources of light can be either laser, or infrared or even ultraviolet rays.

Infrared rays are electromagnetic waves with a wavelength of 750 to 4,00,000 nm. It is also called as thermiogenic rays since these rays produce heat when they are absorbed by the body tissue. Based on wavelength, the infrared rays are divided into 2 namely shortwave infrared (750 – 1,500 nm) and long wave infrared (above 1,500nm).

In physiotherapy several artificial generators are used for the production of infrared lights, and they can be classified into 2 – namely luminous and on luminous generators.

1. Luminous Generators – they are also called as high temperature generators and are in the form of incandescent bulbs. All luminous generators emit electromagnetic waves with a wavelength between 350 – 4000 nm, but the maximum emission of the rays is around 1,000 nm.
2. Nonluminous Generators – also called as low temperature generators. They produce only infrared rays and are not visible. These generators are heated by the passage of electric current through them. All non-luminous generators emit infrared rays in between 750 to 1,500 nm. The maximum emission of the rays is around 4,000 nm.

Depth of penetration:-

Maximum effective penetration of infrared rays is three centimeters; however it may vary from 0.1mm to a few centimeter.

Indications: –

1. Various subacute and chronic inflammatory conditions
2. Various arthritis such as osteoarthritis and rheumatoid arthritis
3. Skin conditions (furunculosis, folliculitis, etc.)
4. Bell’s palsy (mainly for pain relief)
5. Various muscle spasm

Contraindications:-

• Fever
• Pregnancy
• Malignant conditions
• Impaired sensations, anesthetic areas.
• Cardiac disorders
• Eczema, dermatitis,
• Impaired circulation, oedema                    
• Varicose veins, etc.

Short Wave diathermy is the most commonly used physiotherapeutic modality for deep heating. In simple words diathermy means heat given through an object and not confined to that object. In this process, high frequency current of 27.12MHz frequency and 11 meters wavelength is used.

Physiological Effects: –

1. Increased heat production
2. Temperature: – local temperature increases as there is an increase in heat. If given for a prolonged time, there will be a generalized increase in body temperature by a few degrees.
3. Metabolism: – When SWD is applied to bodily tissues, it produces heat, which in turn increases the metabolic rate of the body tissues.
4. Blood Supply: – SWD application increases local blood supply. Increase in blood supply may occur due to the direct effect of the heat on the vessels in terms of vasodilation. Due to increased vasodilation, there is an increase in the lumen of the vessels, which leads to increased blood supply.
5. Effect on nerves: – reduce the excitability of the nerves, especially sensory nerves.
6. Muscle relaxation: – rise in temperature induces relaxation of muscles and increases their efficacy of action.
7. Blood Pressure: -reduces blood pressure. This happens due to reduction in peripheral resistance to the flow of blood, which is due to generalized vasodilation and reduction in viscosity of the blood

Indications: –

Low back Pain, Osteoarthritis, rheumatoid arthritis, sprains, strains, muscle tear, tendon tear, capsulitis, frozen shoulder, myalgia, spondylitis, etc.

Contraindications: –

Pregnancy, Cardiac pacemaker, hemorrhage, thrombosis, peripheral vascular diseases, metal implants, impaired sensations, anesthetic areas, malignancy, epileptic and mentally retarded patients, fever, etc.

Duration: –

In Acute conditions: – 5 to 10 minutes (once or twice daily)

In Chronic conditions: – 20 to 30 minutes

This is a form of physiotherapy method in which ultrasound waves are used for therapeutic purpose. We humans can hear the sounds coming under the 20KHz. Therefore, all the sound waves coming beyond to the above frequency is told as ultrasounds and these are used for therapeutic purposes. For physiotherapeutic purposes, ultrasound with a frequency range of 0.5 to 5MHz is used. Most commonly used sound waves for physiotherapy are 1 MHz

Indications: –

1. Bursitis
2. Tendonitis
3. Plantar fasciitis
4. Warts, calcaneal spur
5. Tennis elbow, golfers’ elbow
6. Osteoarthritis, rheumatoid arthritis, fibrous nodules, rheumatic nodules.
7. Sports injury, capsulitis, joint contractures, dislocations, etc.

Contraindications: –

1. over metal implants, cardiac implants, plastic implants, acrylic implants, etc.
2. haemorrhage, hematoma, haemophilia, thrombosis, embolism, arteriosclerosis and ischemia.
3. tumour / neoplasm.
4. in conditions such as spina fidia.

Therapeutic Effects: –

1. Pain Relief – US therapy is used for the relief of acute, subacute and chronic musculoskeletal pain. Pain relief may occur due to the resolution of inflammation, removal of waste products or altered permeability of cell membrane to sodium, which may alter the electrical activity or pain threshold.
2. Inflammation – helps in the inflammation by increasing the blood supply, white blood cells and removal of waste products. Hence can be used in the treatment of inflammatory conditions and traumatic conditions.
3. Healing / Repair – Ultrasound facilitates the healing at all the three stages of repair. It acts on inflammatory phase proliferative phase and on remodelling phase. And thus, helps in the repair of damaged tissue.