ELECTRICAL STIMULATION PROTOCOL
This will be the procedures used by the trainer and the training staff at Palo Verde Magnet High School while administering Electrical Stimulation to an athlete or student at the district.
The following explanation of the uses, contraindications, and other information was taken form Therapeutic Modalities in Sports Medicine by W. Prentice, 1986.
Electrotherapeutic devices are usually classified as being either high-voltage generators or low-voltage generators. High voltage devices produce waveforms with an amplitude of 150 volts or greater and a relatively short pulse duration or less than 100 msec. Most high-voltage devices produce direct current, but some alternating current generators are also available. The unit owned by the School District is a direct current high voltage generator. The amplitude of high voltage currents is greater that of low voltage currents and this factor combined with a short pulse duration enables high-voltage currents to produce a muscle contraction, as well as selectively stimulating sensory nerves. most modern high-voltage generators produce twin pulses of high amplitude and short pulse width, thus allowing for nonirritating stimulation of nerve and muscle tissue.
CURRENT FLOW THROUGH BIOLOGIC TISSUES
Electrical current tends to choose the path that offers the least resistance to flow or, stated differently, the material that is the best conductor. The conductivity of the different types of tissues in the body is variable. Typically tissue that is best highest in water content and consequently highest in ion content is the best conductor of electricity.
The skin has different layers that vary in water content, but generally the skin offers the primary resistance to current flow and is considered an insulator. Skin preparation for the purpose of reducing electrical impedance is of primary concern with electrodiagnostic apparatus, but it is also important with electrotherapeutic devices. The greater the impedance of the skin, the higher the voltage of the electrical current must be to stimulate underlying nerve and muscle. Chemical changes in the skin can make it more resistant to certain types of current. Thus skin impedance is generally higher with direct current that with alternating current.
Blood is a biologic tissue that is composed largely of water and ions and is consequently the best electrical conductor of all the tissues. Muscle is composed of about 75% water and depends on the movement of ions for contraction. Muscle tends to propagate an electrical impulse much more effectively in a longitudinal direction than transversely. Muscle tendons are considerably more dense than muscle, contain relatively little water, and are considered poor conductors. Fat contains only about 14% water and is thought to be a poor conductor. Peripheral nerve conductivity is approximately 6 times that of muscle. However, the nerve is generally surrounded by fat and a fibrous sheath, both of which are considered to be poor conductors. Bone is extremely dense, contains only about 5% water, and is considered to be the poorest biologic conductor of electrical current. It is essential for the athletic trainer to understand that may biologic tissues will be stimulated by an electrical current. Selecting the appropriate treatment parameters is critical if the desired tissue response is to be attained.
MUSCULAR RESPONSES TO ELECTRICAL CURRENT
Stimulation of the motor nerve is the method used in most clinical applications of electrical muscular contraction. In the absence of innervation, of nerve supply, such as after injury or surgery, muscle contraction can be stimulated by an electrical current by causing the muscle membrane to depolarize. This will create the same muscle contraction as a natural stimuli.
The all or none response is another important concept in applying electrical current to nerve or muscle tissue. Once a stimulus reaches a depolarizing threshold, the nerve or muscle membrane depolarizes and propagation of the impulse or muscle contraction occurs. This reaction remains the same regardless of increases in the strength of the stimulus used. Either the stimulus will cause depolarization, the all, or the stimulus will not cause depolarization, the none, There is non gradation of response other than by recruiting more nerve fibers by stimulation. The response of the single nerve or muscle is maximal or none at all.
This all or none phenomenon does not mean that muscle fiber contraction and overall muscle activity cannot be influenced by changing the intensity, pulses per second, of duration of the stimulating current. Adjustments in current parameters can cause muscle fiber contraction.
THERAPEUTIC USES OF ELECTRICALLY INDUCED MUSCLE CONTRACTION
A variety of therapeutic gains can be made by electrically stimulating a muscle contraction:
1. Muscle Reeducation
2. Muscle Pump Contractions
3. Retardation of Atrophy
4. Muscle Strengthening
5. Increasing Range of Motion
6. Decreasing Muscle Spasm
7. Chronic Pain Control
8. Acute Pain Control
Any electrical stimulator-high voltage, low voltage, alternating current, or transcutaneous electrical nerve stimulating (TENS) units-may be used to cause muscle contraction. The efficiency and effectiveness of the treatment can be increased by following the protocols as closely as possible.
Muscular inhibition after surgery or injury is the primary indication for muscle reeducation. If the neuromuscular mechanisms as a muscle have not been damaged, then the central nervous system inhibition of this muscle is usually a factor in loss of control. A muscle contraction can usually be caused by electrically stimulating the muscle. Forcing the muscle to contract causes an increase in the sensory input from that muscle. The patient feels the muscle contract, sees the muscle contract, and can attempt to duplicate this muscular response.
1)Intensity- High enough for contraction and low enough to be comfortable.
2)Pulses per second- 35-50 pps.
3)Interrupted or surge mode.
4)On time- 1 to 2 sec.
5)Off time- 2 to 4 sec.
6)Patient should help the contraction occur.
7)Treatment time- 15 to twenty minutes.
CHRONIC EDEMA CONTROL
Muscle Pump Contractions
Electrically induced muscle contraction ca be used to duplicate the regular contractions that help stimulate circulation by pumping fluid and blood through venous and lymphatic channels back into the heart. In most traumatic injuries and surgical interventions, one of the major problems is excessive accumulation of fluid. This edema is the result of damage to the vascular structures, loss of normal muscular activity, and dependency of the extremity. Electrical stimulation of muscle contraction in the affected extremity can help in reestablishing the proper circulatory pattern while keeping the injured part protected. The following protocol will be followed when working to produce a muscle pump contraction.
1)Intensity should be high enough for a contraction and low enough to be comfortable.
2)Pulses per second- 10 pps.
4)On time- N/A
5)Off time- N/A
7)Active Range of motion encouraged of not contraindicated by injury.
8)Treatment time- 20-30 min. 3x daily.
ACUTE EDEMA CONTROL
1)Intensity high enough to be felt by the athlete.
2)Pulses per second- 80-120
6)Treatment time- 20-30 min. 3x daily.
Prevention or retardation of atrophy has traditionally been the reason for treating patients with electrically stimulated muscle contraction. The maintenance of muscle tissue, after an injury that eliminates normal muscular exercise, can be accomplished by substituting an electrically stimulated muscle contraction. The electrical stimulation reproduces many of the physical and chemical events associated with normal voluntary muscle contraction.
Again, the following protocol will be followed by the training staff when administering the Electrical Stimulator.
2)Pulses per second- 30 to 60 pps.
3)Interrupted or surge mode.
4)On time- 6 to 15 seconds.
5)Off time- 2x the on time.
6)The muscle should be given resistance, ie, gravity, sandbags, manual etc.
7)Treatment time- 15 to 20 minutes.
8)High frequency AC setting.
Muscle strengthening from electrical Stimulation has been used with some good results in patients with weakness or denervation of a muscle group. Several studies also indicate that strength gain can be achieved. The Protocol is better established for this use, but more research is needed to clarify the procedures and allow us to generalize the results to other electrical stimulators. The following are the protocols used successfully for Muscle strengthening.
1)Intensity- should be high enough to make the muscle develop a contraction equaling 60 % of the torque produced in a maximal voluntary contraction.
2)Pulses per Second- 50 to 60 pps.
3)Surged or interrupted with 10 msec on/off cycle of 2500 cps. and gradual current increase.
4)On time- 15 sec.
5)Off time- 50 sec.
6)Apply resistance by immobilizing limb, see #1.
7)Treatment time= 10 reps 3x week.
INCREASING RANGE OF MOTION
Increasing Range of Motion
Increasing the range of motion in contracted joints is also a possible and documented use of electrical muscle stimulation. Electrically stimulating a muscle pulls the joint through the limited range. The continued contraction of this muscle group over an extended period of time appears to make the contracted joint and muscle tissue modify and lengthen. The procedures needed to achieve a range of motion increase are as follows:
1)Intensity- Strong enough to move the extremity through the anti-gravity range of motion. Intensity should be increased throughout the treatment.
2)Pulses per Second- 20 to 30 pulses per second.
3)Interrupted or surge mode.
4)On time- 15 to 20 sec.
5)Off time- 15 to 20 sec.
6)Stimulate the antagonist group to the group that has the contracture.
7)The patient need not work with the stimulator.
8)Treatment time is 90 minutes daily, 3x 30 minutes.
Reducing Acute and Chronic Muscle Spasm
Stimulation of the muscle fiber at a certain intensity and for a long duration will render that muscle unable to contract. This allows for a decrease in pain that the athlete feels and allows other tissues surrounding the area to recuperate without the muscle spasm hindering healing.
1)Intensity- Strong enough to see a visible contraction of the affected muscle.
2)Pulses per Second- 100 to 125 pps.
4)Pad placement should allow for complete contraction of the affected muscle. A surrounding technique is usually the most accurate.
5)Treatment Time- 20 minutes or until the spasm is broken.
THERAPEUTIC USES OF ELECTRICAL STIMULATION OF SENSORY NERVES
Clinically, efforts are made to stimulate the sensory nerves to change the patient's perception of a painful stimulus coming from the injured area. To understand how to maximally affect the perception of pain through electrical stimulation, it is necessary to understand pain perception. There are several theoretical bases for pain reduction phenomena.
We will use several different programs for the various types of pain such as Acute pain, Chronic Pain, localized pain, and general area pain.
ACUTE PAIN CONTROL
1)Intensity- should be high enough to be tolerable without causing discomfort.
2)Pulses per second- 80-120 pps.
4)Stimulation should be applied over trigger or acupuncture points.
5)Treatment should last as long as pain is perceived and then turned off.
CHRONIC PAIN CONTROL
1)Intensity- High enough to cause a twitch contraction in the affected area.
2)Pulses per second- 2-5 pps
4)Treatment should be applied over area of pain as well as at the site where the affected nerve root enters the spine.
5)Treatment time - 20-40 minutes.
The program for localized pain will be the Acute settings with the pad placement for the Chronic control program.
The program for generalized pain will be the Chronic settings with the pad placement for the Acute control program.
When using any of the treatment protocols aimed at the electrical stimulation of sensory nerves for pain suppression, there are several guidelines that will help select the appropriate sites for electrode placement. Transcutaneous electrical nerve stimulation (TENS) uses similar sized electrodes placed according to a pattern and moved in a trial and error pattern until pain is decreased. The following patterns may be used:
1. Electrodes may be placed on or around the painful area.
2. Electrodes may be placed over specific dermatomes, myotomes, or sclerotomes that correspond to the painful area.
3. Electrodes may be placed close to the spinal cord segment that innervates an area that is painful.
4. Peripheral nerves that innervate the painful area may be stimulated by placing electrodes over sites where the nerve becomes superficial and can be easily stimulated.
5. Both acupuncture and trigger points have been conveniently mapped out and illustrated. A reference on acupuncture or trigger areas should be consulted and the trainer should systematically attempt to stimulate the points listed as successful for certain areas and types of pain. If they prove effective, the athlete will have decreased pain. These can also be identified using an ohm meter point locator to determine areas of decreased skin resistance.
6. Combinations of any of the above systems and bilateral electrode placement can also be effective.
7. Crossing patterns, also referred to as an interferential technique, involve electrode application so that the electrical signals from each set of electrodes add together at some point in the body and the intensity summates. The pulses must arrive at the point to be stimulated at the same time and with the same wave form and frequency. The electrodes are usually arranged in a crisscross pattern around the point to be stimulated.
CONTRAINDICATIONS TO ELECTRICAL STIMULATION
Skin burns are one of the hazards of using any uninterrupted direct current technique. These burns result form excessive current density in any area, usually from direct metal contact with skin or from having the intensity to high for the size of the electrode. Both of these problems cause a very high density of current in the area of contact.
Pain should not be felt by the patient while being treated with electrical stimulation.