What do those machines actually do?!
Put your hand up
if you have been hooked up to a complicated-looking machine at the end of your
physio session!
Put your hand up
if you stared at your leg twitching, bemused, or contentedly laid back enjoying
that pleasant ‘pins and needles’ feeling!
Put your hand up
if you know what that machine was actually doing!
....If your hand
shot up for the first two questions, but stayed firmly glued to your side for
the third one; don’t worry you’re not alone! That’s where this article comes in
– hopefully by the end it will be an emphatic 3-hands-up.
Physiotherapists
use the collective term ‘modalities’ when referring to the various types of
machine that they use in the clinic. Two common types of modality are electrotherapy
(with the sticky electrodes or damp sponges) and ultrasound (with the wand that
is moved over your skin).
Electrotherapy
really does what it says in the tin: it delivers an electric current through the skin, causing physiological changes in
the injured tissues, with the aim of bringing about therapeutic effects. How does it do that? Well, it all starts with
the fact that all cells in our bodies have their own electrical charge, meaning
that they can conduct electricity. We also know that our nervous systems run on
electricity! It is the body’s internal electricity that keeps our heart beating
and makes our muscles contract when we ask them to. So electrotherapy works
because it takes advantage of the natural paths of communication in the body.
Your physiotherapist
will choose different electrotherapy settings depending on the nature of your
injury. At a lower intensity, electrotherapy is good for pain relief, for
example, low back pain or knee pain. It works by sending messages from the
sensory nerves to the brain which block the pain signals coming from the injured
area. It also causes endorphins to be released, which bring about a temporary
feeling of well-being and reduce the perception of pain. By setting a higher
intensity, your physiotherapist may also use electrotherapy to fire the muscles
in the affected area. This will cause more blood to flow, helping to speed up
the disposal of waste products and the synthesis of new healthy tissue at the
site of injury. Muscle stimulation can be particularly helpful if it is
difficult for you to work a specific muscle group the normal way, for example
for the quadriceps if you have just had knee surgery.
Different types of
electrotherapy that you may have heard of are TENS (Transcutaneous Electrical
Nerve Stimulation); EMS (Electrical Muscle Stimulation); and IFC
(Interferential Current). They all involve the delivery of an electric current
to your tissues but the settings are different in order to achieve different
therapeutic results. TENS machines are used for pain relief whereas EMS units
are used for muscle stimulation and IFC can be used for both.
Ultrasound is
different to electrotherapy in that it involves the delivery of vibrations (sound energy) into the
tissues, rather than electricity. We cannot hear it because the vibrations are
too fast; the frequency is too high. The vibrations pass from the steel
soundhead to our skin and then from molecule to molecule, cell to cell, through
our tissues. The vibrations cause little bubbles and eddies (whirlpools) to
form in and around cells. The swirling bubbles excite the cells and cause them
to speed up their activity. On a larger scale, this nudges along the natural
healing process in injured body tissues. Ultrasound also heats up the body
tissues, which increases blood flow in the area. As explained above, increased blood
flow helps to speed up the disposal of waste products and the synthesis of new
healthy tissue at the site of injury. Ultrasound energy is absorbed best by fibrous
tissues which contain a large amount of collagen, such as ligaments and
tendons. Physiotherapists therefore use ultrasound to treat injuries such as
sprained ankle ligaments, or rotator cuff tendon problems in the shoulder.
You may be
wondering now, “Do modalities really work? Many studies have been carried out
to answer this question. When all of the available evidence is considered
together, most authors conclude that electrotherapy and therapeutic ultrasound can be effective in combination with other physiotherapy treatments such as manual
therapy and exercise. However, they are not effective when used alone.
You may also be
wondering “are there any side-effects?” The good news is that if used properly,
you should not experience any side-effects from electrotherapy or ultrasound
treatment. There are some circumstances when they should be used with caution
for example if you are pregnant or have altered sensation. If you would like to
know whether electrotherapy or ultrasound may be helpful for your condition,
don’t hesitate to ask your physiotherapist for more information. Hopefully you
will be able to impress them with your knowledge of how the modalities work!
Kate Josling MSc
(PT)
t knee bend (flexion of approximately 20 degrees), as demonstrated by James Young in the picture ( His foot is another issue which he is working on, so watch out anyone in his age group). This knee flexion allows the impact forces to be dissipated through the knee and hip before they reach his lower back. Landing with your forward leg fully extended at impact means that most of the impact forces (which have been measured to be between 5-8 times body weight) need to be dissipated by the athletes’ lower back and the lion’s share of the work is done by the L4/L5 disc.