There are different types of ultrasound. In sports therapy, we use therapeutic ultrasound, which creates sound waves to produce an effect within the tissue it is applied to.
How does therapeutic ultrasound work?
The ultrasound waves are generated by a piezoelectric effect caused by the vibration of crystals within the head of the probe. The ultrasound waves that pass through the skin cause a vibration of the local soft tissues. Gel is used to transmit this delivery and based on a range of application settings, the ultrasound will have different effects.
What are the different settings used for?
Different settings that can be adjusted:
Frequency: This determines the depth of penetration of the waves.
1MHz is a deeper application reaching 5cm into the tissue; this would be used on a large muscle.
3MHz is for superficial areas reaching a depth of 2 cm; this depth would be appropriate for a tendon in the hand.
Continuous or pulsed
The continuous setting refers to the sound waves continually being transferred into the treatment area. This is applied to chronic injuries.
The pulsed setting results in a fluctuation of the output. This is applied to acute injuries.
Intensity: The intensity used is determined by the current state of the tissue, whether it is acute (new injury), sub-acute or chronic (old injury).
Treatment time is dependent on the size of the area being treated, the frequency and intensity being used (5-15 minutes).
A therapist will determine the settings based on an assessment of the injury noting the stage of healing, inflammatory state, size of the area and the goals for the treatment.
How does ultrasound help?
Depending on the type of setting the sports therapist uses, the following effects can take place:
Decreases pain e.g. sprained/torn ligaments
Reduces inflammation of tendons & sheaths e.g. tendonitis, fasciitis
Aids in tissue healing, for example calf muscle strain
Helps increase joint motion and tissue flexibility e.g. scar tissue
Aids in reducing swelling & tissue relaxation e.g. muscle spasm
When should you avoid using ultrasound?
As with all treatment options, there are contra-indications to using ultrasound and application should not be used:
metal, surgical or cosmetic implants (screws, rods, pacemakers, etc)
major artery, nerve or regenerating nerve
deep vein thrombosis
cancer or undiagnosed lumps/ bumps
circulatory or sensation impairments
pregnancy – don’t use around torso or reproductive organ – extremities are okay with no other contra-indications present.