IMS stands for intramuscular stimulation and is an anatomy specific form of acupuncture performed by specially trained physiotherapists and some doctors.  It has its roots in traditional Chinese acupuncture, but is fundamentally different in many ways.  IMS uses Western medicine's understanding of the neurophysiology of pain and Dr Chan Gunn's assessment techniques of identifying underlying nerve irritations to treat chronic pain issues.  The technique does use acupuncture needles, but not in the way someone practicing traditional acupuncture would.  Traditional acupuncture focuses on pre-mapped out points in the body that relate to different organs and meridians of energy running through the body.  Fine acupuncture needles are then inserted into a number of these points and the person rests with them in for 10-20 minutes.  It can be very useful for the right condition, but it is not as specific or as purposeful as IMS.

To understand why IMS is performed the way it is you should have a basic understanding of how your body experiences pain.  If you haven't already, please read the article titled Why Things Hurt: Explain Pain.

‍When a physiotherapist performs IMS he will first assess your basic posture and movement patterns to look for some common signs of underlying nerve irritation.  The most common one is to palpate for tender bands or knots in particular muscle groups.  He will look for restriction of movement in major joints such as your hips and shoulders and note the appearance of the skin and muscle tissue on either side of your spine.  When there is an underlying nerve irritation in an area, the skin can start to look like the rind of an orange peel, feel thickened and respond differently to light touch.  A person may develop goose bumps easily and/or have areas of coolness or hair loss.  The therapist will take all these things into account when determining where to treat you.

Can start to see all the pores in the skin around the spine on two finger test

IMS needles are typically slightly thicker than acupuncture needles, but to the lay person would look exactly the same.  Once the physiotherapist has determined all the troubled areas he will start using the needle to release them.  The needle comes in a small plastic tube that is just slightly shorter than the needle.  The plastic tube is pressed against the skin and the therapist quickly taps the end to push the fine needle through the skin with very minimal discomfort.  The plastic tube is pulled off and the practitioner will grab the end of the needle to push it further into the muscle.  Here is a big difference between IMS and acupuncture; in IMS the needle is inserted deeper into the muscle and moved in and out to hunt and peck for bands of tight muscle tissue.  The physiotherapist can feel the relative resistance to the movement of the needle and actively searches for the stiffer, thicker feeling areas; as the muscle releases, the relative resistance gets less and less.  Portions of the muscle can go from feeling like sticking a needle into a rubber eraser to more like a block of soft butter.  The needle becomes an extension of the practitioners hand to feel inside the muscle tissue.

Tube against skin, tap end of needle with finger

If you put an acupuncture needle into a happy, healthy, normal muscle, not much happens and the person doesn't feel very much at all.  On the other hand, if you put a needle into a muscle that is in a banded state, they are by nature hypersensitive , and the stimulus will cause the muscle to contract strongly and sometimes even twitch.  This contraction feels like a strong crampy ache to the person, but the good part is that it only lasts 5-10 seconds because once the cramp is achieved the needle is pulled back out and the therapist moves on to the next point.  The patient doesn't really feel the needle at all, it is their muscle cramping that can be the uncomfortable part.  The physiotherapist will likely treat you in areas that you were complaining hurt, but also a variety of other parts of your body that may not hurt, but are part of the root cause of your problem.  For example, most elbow problems are caused by an irritation of the C6 nerve root that extends out from the base of your neck so to fix your elbow you would likely be needled around your neck, shoulder and arm first, then the forearm muscles if the elbow still hurts.  Watch Why Elbows Hurt

‍IMS, compared to acupuncture, is a much more active process by the practitioner and requires a greater knowledge of anatomy, muscle balancing and biomechanics to release the right areas and restore optimal movement.  The ability to perform IMS gives a practitioner a powerful tool to help eliminate chronic pain issues, but it is the physiotherapist's ability to assess and release things in the right order and start to reintegrate proper movement patterns in the client that make the real difference.  In other words, a client may find success with IMS with one practitioner and simply find it painful and not productive with another.  There is an art and a science to it, the practitioner has been trained to use the science, but has to develop the art with experience and the integration into rehabilitation and movement principle.

Many people either haven't heard about IMS, or have just been told it is really painful, but works really well.  What I tell people is that everyone's experience with IMS is different; some people do find it quite uncomfortable while others don't mind it at all.  The difference seems to be related to both the person's body type and his/her personality.  People that are very muscular, tight and compressed tend to find IMS the most painful (but still very effective).  People that have lower muscle tone don't seem to be bothered by the treatment at all.  On the personality side, high strung, type A people have trouble with it because they are in a vulnerable position with involuntary muscle contraction and the lack of control stresses them out.  That being said they come back every time they hurt themselves asking for IMS even though they hate every minute of it because it works so well and they value the result over the temporary discomfort.  I find people that are scared of needles tend to do better with IMS than acupuncture because they only actually have one needle in them at a time and only for 10 seconds instead of 10 minutes.

So how does it work?

Nerves are the electrical wiring to muscles.  Muscles are a stringy, elastic tissue strung between two bones by tendons.  In a normal resting state, the nerve supplies a steady signal to the muscle to create a normal resting tone in the muscle; it is not overly contracted or totally flaccid.  When the nerve is irritated it sends an altered signal to the muscle making the muscle hyper-reactive and the result is usually bands of tension and muscle knots that are sore to the touch.  These taut muscle bands don't allow the muscle to function properly and put way more stress on the tendons and joints when used.  If you stick a fine needle into a muscle in its normal healthy state, not much happens and the client doesn't feel much, but if you stick a needle into a hypersensitive taut band the muscle will reflexively contract strongly or even twitch; this feels like a deep, crampy achy pressure to the client.

Normal state muscle                                                         Banded, hyper-reactive muscle

So why do you want to make a tight, sore muscle contract more?

When the muscle contracts strongly it stretches the tendons on either end that attach it to the bone.  Your tendons have little stretch receptors embedded in them called golgi tendon organs (GTO), their job is to sense stretch and protect the muscle from contracting too strongly. When they get triggered they reflexively send a signal to your spinal cord that immediately comes back saying relax, relax, relax to the muscle.  IMS effectively takes advantage of your body's own protective feedback loops and tricks your nervous system into dampening down the tone in specific muscle groups.  People develop a love/hate relationship with it because the crampy, achy feeling can be unpleasant, but it can literally produce immediate and lasting relief from pain.

‍Click here for a FAQ list related to IMS provided by iSTOP the regulatory body of IMS

You will find more information about the use of IMS as it relates to specific conditions in other posts and videos on this site, but it is particularly useful in treating the following areas and conditions:

Tennis elbow, low back pain, rotator cuffs, stiff necks, headaches, TMJ issues, sprained ankles, alignment issues, IT band syndrome, patellofemoral syndrome, plantar fasciitis, Achilles tendonitis, thoracic outlet syndrome, carpal tunnel syndrome…..and many others

The above information is referencing the work of Dr. Chan Gunn.  I have integrated his work into my own clinical practice to use IMS as a part of the treatment of sub-acute to chronic pain