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Why Do I Get ‘Stimulated’ During Physical Therapy?

by Danielle Clark-Fox, DPT

TENSPhysical Therapists often use electrical stimulation during treatments, which may initially be a bit scary or unknown for patients. We were always told to avoid sticking our fingers in the socket, right? So I wanted to break therapeutic electrical stimulation down to its simplest form and talk about when and why it’s a useful tool in physical therapy.

During the 1800’s and into the early 1900’s medical researchers first realized the human body and its muscles operate from electrical impulses and properties. Every beat of your heart happens because your body responds to electrical impulses. Every time you move your arm several muscles generated their contribution to that movement based on an electrical impulse. We really are electric! Further studies of our electric abilities revealed that functions induced by electrical stimulation caused long term changes in the muscles involved. Since that time electrical effect on the body has been one of the most studied aspects of our being, as well as one of the most documented modalities used to assist the human body.

To put it most simply, there are 4 main methods physical therapists use electrical stimulation for during a rehabilitation process. One is to assist in reducing pain, inflammation and swelling around a joint. This is called interferential stimulation. It works just like the name infers, there are 2 channels of current at a sensory level to ‘interfere’ with the pain signals that particular part of your body is trying to send up the chain so you are aware you are in pain. The textbook name for this is the gate control theory of pain, formally introduced around 1965. Physical therapists will typically use this type of stimulation after an ankle sprain causes swelling, meniscus repair to the knee, rotator cuff surgery and other injuries involving a joint such as the knee, ankle, shoulder or low back.

The second method of electrical stimulation is called pre-mod. This is used for soft and connective tissues to decrease pain or reinforce a change in the tissue after manual therapy such as Graston, trigger point release or other manual tissue techniques. A pre-mod stimulation involves two pads so the electrical stimulation runs in the area between the two pads. Physical therapists will typically use this type of stimulation along a ligament or tendon such as your achilles tendon or along a muscle such as one of your quadriceps muscles.

The third type of electrical stimulation is called Russian, aptly named for Dr. Kots of Russia who pioneered studies showing his type of current was helpful in strengthening muscles. This type of stimulation is motor versus sensory because it will cause your muscle to contract. It is commonly used to assist a muscle in strengthening more quickly following injury or surgery, such as a quadricep muscle known as the VMO which is often weakened during knee surgery. While this type of stimulation is uncomfortable, it is not adjusted to a painful setting and will not contract your muscle continuously but rather cycle on and off for a period of time, for example your therapist may set it to be on for 4 seconds, off for 12 and run for a few minutes. There is one stimulation pad on the muscle’s insertion into the bone and another on the muscle belly. This is the only type of stimulation where a strong muscle contraction is the goal.

The fourth type of stimulation is called hi-volt, it uses polarity (positive or negative) to stimulate the tissue. This type of stimulation is typically used to decrease pain, swelling or assist in wound healing. It has been proven very effective in healing wounds in patients with circulatory issues such as diabetes. There are specialized pads that will fit inside the wound bed to stimulate new tissue production. Polarity for swelling reduction is usually negative and the pads will be placed on either side of the affected area such as the ankle or shoulder.

Most of these types of stimulation will run 5-10 minutes in duration and may be coupled with ice or heat. Russian stimulation and wound healing stimulation are not performed with heat or ice. Coupled with other therapies such as laser, ultrasound, manual treatment, exercises and range of motion electrical stimulation is an integral part of rehabilitation and healing for many patients. Now after reading a bit more about ‘e-stim’ hopefully you won’t see flashes of Frankenstein if your therapist suggests electrical stimulation as part of your treatment!

Dr. Fox is a Physical Therapist at Boston Sports Medicine

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