Nature and Effects of Therapeutic Ultrasound


Ultrasound therapy as the name suggests works in connection with sound waves that are above the range of human hearing. These sound waves are used to treat various injuries and problems of human body. Although much research needs to be done and this technological medicine still lacks research in the field of physiotherapy. But the flavors and features of this therapy when used at varied intensities have given useful results for treatment of injuries especially those linked with muscles.

How Ultrasound therapy works?

Ultrasound machines are available in varied sizes and popular ones are the portable small size machine. These machines have metal treatment with mechanical vibration on top of it that vibrations produces high frequency sound waves above the range of human hearing. This head with vibrations is moved over a human body on area where it needs treatment. As the head is moved over skin, the energy from these sound waves is transmitted in tissues of human body.

The energy causes vibration in surrounding tissues especially those that have collagen. With vibration, further heat is produced within tissue that raises the inside temperature resulting in extensibility of tissues, ligaments and tendons. The process that activates function within human body through heating also reduces muscle tightness and pain thus promoting the process of healing. A special ultrasound gel is used on skin surface in order to create a medium for maximum contact and travelling of sound waves through skin. This gel keeps the waves from dissipating.

Application of Ultrasound Therapy:

This ultrasound machine can be used over skin for around 3-5 minutes and frequency of this treatment depends upon severity of injury or condition. Usually the treatment is repeated twice a day. Moreover frequency of beam (dosage) is controlled. When you need a deeper penetration for injuries or problems that are related to deeply situated tissues, lower frequency is applied. Whereas when the point of injury is closer to the skin surface, high frequency doses can be used.

Therapeutic Ultrasound Effects:

This therapeutic ultrasound technique is widely used around all the parts of the world however there are still questions and disputes related to the successfulness of these therapies. The treatment is more based on experiences than research and evidence from science. Different therapeutic effects are witnessed from this technique including:

  • Thermal effect
  • Non-thermal effect

Thermal Effect:

High intensity sound waves in continuous form are used for thermal effect that gives effective heating influence to your affected tissues and muscles. The thermal effect of therapeutic ultrasound can be effectively used as a simple treatment application for useful results although treatment parameters would vary depending upon particular condition or injury. This therapy when worked on some muscles, raises the temperature of tissues surrounding that muscle for healing and recovery. As the temperature of a particular ligament, tendon or muscle is raised to 40 to 45 degrees centigrade, it results in hyperaemia that gives therapeutic healing to your body. This body temperature is also known to initiate recovery from acute inflammatory conditions.

Non-Thermal Effect:

Non-thermal effects from a therapeutic ultrasound are contributed to a combination of Cavitation, Acoustic Streaming and Micro Massage. The concept of first two terms has proved to be rather more convincing than the third one but all of these concepts are quite appealing.


This concept involves formation of gas filled voids around your body tissues and within the fluids. Cavitation can be explained in two ways stable and unstable. Both of these types of cavitation has varied effects on a human body.

  • Stable: With stable cavitation type, formation and growth of bubbles of gas occurs at the Ultrasound therapeutic level of doses. These bubbles are formed by accumulation of gas (dissolved) within the medium. They grow and reach at their maximum size through around 1000 cycles. The cavity process enhances the function of acoustic streaming that further proves beneficial to human body.
  • Unstable:With unstable cavitation type, formation of bubbles of gas occurs at the low pressure area of ultrasound cycle. As these bubbles are formed at low pressure, they collapse really quickly which results in large energy release that could be unfavorable for sustainability of tissues. Although much evidence is not there for whether with a good technique, this process can be performed at therapeutic levels. But in many situations unstable method is used which is a high intensity focused ultrasound.

Acoustic Streaming:

This phenomenon involves small scale fluids eddying close to a vibrating structure and that could be cell membranes and the stable cavitation surface where there would be gas bubbles. With this process, penetrability of membrane and diffusion rate is affected. With some alteration of Sodium ion permeability, potential of cell membrane is improved. Sound waves drives a force that works for displacing ions and molecules to further cause an alteration and improvement in various mechanisms including metabolic processes, cellular secretions etc.

Both stable cavitation and acoustic streaming together can give effects that would regulate and enhance functions of your cell membrane thus activating and triggering the entire cellular activity. This results in offering therapeutic benefits for a human body.

Micro Massage:

The process although is not well-researched and is not considered as important as the other non-thermal methods of ultrasound but it offers a mechanical effect involving travelling of sound waves through a medium that enhances vibration in molecules. This vibration can probably increase interchange of tissue fluid thus affecting tissue flexibility and movement.

Benefits of Therapeutic Ultrasound:

This process works wonders for recovery and repair function within human body. It actually reduces the recovery and repair time of injuries within soft tissues of your body. When working for resolution of inflammation with this process, you don’t only work on that particular muscle or tissue but therapeutic ultrasound process tends to attract more cells to the area worked upon causing an increased flow of blood and quick recovery of tissue injury. This process even enhances the production of collagen (protein compartment) in soft tissues thus enhancing tissue healing process.  It also improves extensibility of collagen that proves beneficial with fibrous scar tissue.

Conditions Not Suitable for Therapeutic Ultrasound:

This therapy is proposed to aid in the process of tissue repair and thus there is possibility that affected tissue that is worked upon may behave abnormally. Moreover therapeutic ultrasound enhances flow of blood in your body and it can result in spreading malignancies in different parts of your body. There are some conditions where patients are strictly advised not to opt for this therapy which includes people suffering from:

  • Chronic infections
  • Cancerous tissues (risk of spreading)
  • Acute ischeamic tissue
  • Exposed neural tissue.
  • Hemorrhage risk
  • Bone fracture
  • Pregnancy and others.

Before opting for any such therapy, it is extremely important to consult your physician to see if this therapy would be beneficial and risk-free for your condition.


Therapeutic Ultrasound could treat injuries like runner’s knee, muscle strain, tightness, frozen shoulder, bursitis and others. This method has been here for years and is a proven method but there is still lack of evidence and research in this field. Although there is scope for growth. Ultrasound therapy in general would not feel like anything happening to your body but you would just feel your body slightly warming up or an effect of tingling but its affects are proven to be beneficial.

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