Soft tissue manipulation: neuromuscular and muscle energy techniques.
Soft tissue manipulation includes several techniques; some involve pressure or stretching of muscle fibers and others involve range of motion against resistance. Two of these are the neuromuscular technique (NMT) and the muscle-energy technique (MET). These techniques lengthen muscle fibers and either relax or increase the tension of muscle fibers while the MET can also be used to increase muscle strength. Their mechanisms of action are dependent on spinal reflexes that control the baseline tension of muscle fibers.
The Golgi tendon receptors play an important role in both of these techniques. Stretching of the muscle fibers stimulates these receptors, which have an inhibitory influence on muscle tension, leading to muscle relaxation. The Golgi tendon receptors can be activated by either active or passive contraction of the muscle. The degree of stretch must be great before a significant amount of muscle relaxation is noted. Hagbarth has demonstrated that cutaneous stimulation of certain areas of the body produces inhibition or excitation of specific motor neuron pools.
Application of both of these methods to muscles surrounding a joint allows the muscles to work in a balanced fashion throughout the range of motion of the joint. Muscles function as pairs, referred to as agonists and antagonists to a particular joint motion. The agonist muscle contracts for the desired movement. The antagonist muscle opposes the desired movement and relaxes in a gradual manner to ensure that the motion is coordinated and occurs at the desired speed. The contraction of the agonist muscle is in the direction of the movement and is termed concentric contraction. For example, in knee flexion, the hamstrings are the agonist muscle that is in concentric contraction. The opposing antagonist muscle is not idle, however. It is slowly releasing tension, which is termed eccentric contraction. For knee flexion, the quadriceps muscles are antagonist muscles that are in eccentric contraction. For knee extension, the quadriceps muscles are the agonists, and the hamstring muscles are the antagonists. See Figure 1 for an example of the functions of pairs of muscles during knee extension and flexion.
[Figure 1 ILLUSTRATION OMITTED]
To achieve muscle relaxation with the NMT, the muscle is slightly stretched by applying pressure over the insertion or origins of the muscle involved or by applying pressure over the muscle to stretch it in the direction of its longitudinal axis. This stimulates the stretch Golgi tendon receptors, which detect the tension in the muscle fiber. Thus, receptors perceive more tension in the muscle. Consequently, this stimulus initiates a reflex arc that relaxes the muscle fibers. The NMT can be used when muscle spasms cause pain or restrict range of motion of joints whose movement is dependent upon the function of the involved muscles. Moreover, the NMT can be used during active and passive range of motion to increase joint movement by applying pressure over the tendons or muscles opposing the motion (antagonist muscle). For limitations in range of motion for knee extension, pressure is applied to the tendons or the surface of the hamstrings that must relax for this motion to occur.
The MET can be used in conjunction with the NMT to enhance the relaxation of muscle fibers. The MET works through the Golgi tendon receptors to either increase or decrease muscle tone. By using resistance to muscle contraction, the MET can increase muscle tone and strength as well as coordination of movement among the antagonist and agonist muscles surrounding the joint. With the MET, resistance is applied against the patient's efforts to complete full active range of motion of a joint. This resistance against the contraction of the agonist muscle is associated with reflex inhibition of the antagonist muscle, that is, relaxation. This process is termed reciprocal inhibition of the antagonist. For example, flexion of the elbow requires contraction of the biceps (agonist) and relaxation of the triceps (antagonist).
The resistance applied can be less than, equal to or greater than the force generated by the patient. Resistance equal to that of the patient is an isometric contraction and increases tension in the agonist muscle but without movement; this is associated with increased strength or tone of this muscle. If the resistance applied is less than that of the patient, the movement will be completed but with greater effort. This is concentric isotonic contraction because the agonist muscle is still contracting and the joint is moving in the desired direction. If the resistance overcomes the patient's effort, this is eccentric isotonic contraction because the agonist is still in contraction but is lengthening at the same time.
For both the NMT and MET, assessment must focus on the joints, muscles and desired motor behavior. With passive range of motion, it is crucial to identify those joints where movement is restricted. For example, the knee may have normal range of motion for flexion but may not be able to fully extend. Thus, the knee has limited range of motion for extension. Using techniques described below, assess the muscles for increased tension and spasm as well as inadequate tone. If the knee cannot fully extend, the knee extensors may have poor tone; this may be the cause or consequence of the limited range of motion. At the same time, the knee flexors may have increased tension. When there is limited range of motion and increased muscle tension, assess whether the associated tendons are also shortened by manually stretching the tendon along its longitudinal axis. This information is used to determine the degree to which the joint can be moved during NMT and MET. For example, if the tendons are shortened, they will limit the extent of movement during these interventions and will require treatment over time to lengthen them. Lastly, evaluate body movement. If abnormal, evaluate the joints and muscles used. For example, ability to raise the toe off the floor during the swing phase of gait is dependent upon ankle dorsal flexion and knee and hip flexion. Thus, the ankle, knee and hip joints and surrounding muscles must be evaluated to identify limitations in range of motion, increased muscle tension and decreased strength that impair normal gait.
Procedures for Assessment of Muscles Identify the Muscles Involved
For severe spasms or muscle tension, observation will reveal raised muscles, and light palpation with the finger tips (the area of the body most sensitive to touch) will provide information about tension. Muscles with more tension than normal will feel hard and may stand out from nearby muscles. Using passive range of motion, determine the joints that have restricted range of motion. Although limited range of motion may indicate contractures, some limitation may be due to or exacerbated by excessive tension in the agonist muscles controlling the movement of the joint.
For example, restriction in elbow extension may be due to tension in the biceps, while restricted rotation of the head may be attributed to tension in the muscles in the neck (sternocleidomastoid and trapezius). Restricted dorsal flexion (foot drop) is affected by tension in the muscles of the calf (gastrocnemius and soleus).
Knowing the names of muscles and their insertion points on bones is not necessary. Observation and palpation can provide information about the muscles involved.
Identify Direction of the Muscle Fibers
To stretch a muscle appropriately, tension must be applied parallel to the muscle fibers. Those in the arm and leg run parallel to the bones of these extremities. If uncertain, lightly palpate the area and note where the muscle begins and ends, or inspect and palpate for the rope-like longitudinal axis.
For example, the fibers of the biceps run parallel to the humerus, the bone of the upper arm. The one section of the sternocleidomastoid muscle of the neck runs from behind the ear to underneath the collar bone.
Implementation of the NMT and MET requires knowledge of the range of motion of joints, muscles surrounding them and motor behavior dependent on these structures. However, the procedures themselves are not complex. The position of the person carrying out the procedure must allow easy access to the structures involved and application of pressure or resistance while maintaining proper body mechanics. Since each person, joint and muscle are different, the positions used for the techniques may not be identical. The NMT is used to reduce muscle spasms that interfere with the range of motion while the MET is used to increase muscle strength.
Neuromuscular Technique Procedure
Approximately 1/4 from one insertion point of the muscle to a bony prominence, apply slight pressure to stretch the skin and underlying muscle in the direction of the muscle fibers. The goal is to apply the stretch to all muscle fibers; therefore, muscle size determines the amount of pressure applied. For small muscles, the thumb or fingers can be used. For larger muscles, the hand is used.
Maintain the stretch and pressure while using your sense of touch to identify when the muscle relaxes slightly. Do NOT release the tension on the muscle, but gently apply slightly more pressure to stretch the muscle. You may feel the muscle relax several times before maximum relaxation is achieved. The purpose of this procedure is to get the maximum relaxation possible, which can take several minutes.
When maximum relaxation is achieved, SLOWLY release the pressure. If tension or spasm continues while releasing, reapply the pressure. Do NOT suddenly release pressure because the muscle can quickly go into a spasm and cause pain, sometimes severe. For muscles that continue to have excessive tension, this technique can be used 4 or more times a day.
Range of Motion Procedure
The technique for stretching the muscle is the same as that above, but pressure is applied to a tendon, although it can be also be applied to the body of the muscle. For example, to increase dorsal flexion of the ankle (to reduce foot drop), apply pressure on the Achilles tendon such that the muscles of the calf are slightly stretched along their longitudinal axis.
Start with the joint in the maximum range of motion where resistance first appears. For example, passively extend the knee until more than minimal pressure is needed to extend it further.
Once the joint is positioned as described above, apply pressure along the longitudinal axis of the tendon associated with the muscle group involved. When muscle relaxation is noted, CONTINUE the pressure and move the joint further into its range of motion until resistance is encountered. Continue applying more pressure until no more relaxation and joint movement can be achieved. Progress may be slow if the tendon has shortened, and achieving the maximum range of motion of one joint may take a minute or more.
Muscle Energy Technique
The MET is used to increase muscle strength using isometric and isokinetic contractions. Isometric contractions involve applying resistance to joint movement such that no movement occurs. Isokinetic contractions involve applying slightly less resistance so that the joint movement is allowed; resistance is applied to eccentric or concentric muscle contractions.
Isometric Contraction Procedure
For 30 to 60 seconds, apply resistance to joint motion that is equal to the patient's such that no movement takes place. This will increase strength and tone of agonist muscles.
As an example, for isometric contraction of the triceps, the patient flexes the elbow until half of the available range of motion is achieved. With your hand on dorsal surface of the wrist, and while the patient is attempting to extend the elbow, apply resistance with the hand on the wrist opposite to that of the patient such that no movement occurs in the elbow. Maintain resistance for 30 to 60 seconds. This will increase the strength and tone of the triceps.
Concentric Contraction Procedure
Apply resistance to the joint motion such that it is less than that of the patient. Thus, the patient can slowly moves the joint in the desired direction. Repeat 5 times. This will increase the concentric strength of the agonist muscles and relaxation of the antagonists.
As an example, for concentric contraction of the dorsal flexors, have the patient place the ankle joint in a neutral position (foot at a 90 [degrees] angle to the leg). Place your hand on the dorsal surface of the foot. While the patient is dorsal flexing the ankle, apply resistance opposite the movement but allow the patient to slowly dorsal flex against the resistance.
Eccentric Contraction Procedure
Apply resistance to joint motion such that it is greater than that of the patient. Thus, the patient is not only unable to move the joint in the desired direction but is unable to resist that of the person applying resistance. Consequently, even with maximum effort, the joint moves in the opposite direction of the desired movement. Repeat 5 times. This will increase eccentric strength and length of the agonist muscles.
As an example, for eccentric contraction of the hamstrings, have the patient flex the knee approximately 90 [degrees]. Place your hand at the back of the ankle and instruct the patient to try to flex the knee against your resistance. Apply resistance opposite to knee flexion such that the knee slowly extends. Do this until maximum knee extension is achieved. This will increase the eccentric strength of the hamstrings as well as lengthen them.
Other muscle relaxation techniques can be used with the NMT and MET to enhance their muscle relaxing effects. Heat or cold can be applied for 5 or 10 minutes prior to the NMT and MET. Music, progressive muscle relaxation, self hypnosis or imagery also may be used prior to or during the NMT and MET to increase muscle relaxation.
The short-term effects of the NMT and MET include decreased pain and increased range of motion of a joint, reduced muscle tension and spasm and increased muscle strength for both eccentric and concentric muscle contractions. These effects may last a few seconds or several minutes. Thus, the techniques may need to be repeated several times a day. Long-term effects may require several treatments, and significant improvements in motor behavior may depend on increased range of motion of involved joints and in the relaxation and improved strength of involved muscles. The case study that follows demonstrates that progress can be achieved with a program of soft tissue manipulation.
Mr. H is a 74 year old man with supranuclear palsy who was experiencing severe generalized muscle rigidity. A foot drop on his left significantly impaired his gait, such that he had great difficulty raising the left foot from the floor during the swing phase of the gait cycle. Limited range of motion for knee and hip flexion reduced his capacity to compensate for the foot drop during ambulation. He also indicated that the tension in his neck caused pain that was poorly relieved by analgesics. The goals of nursing care for this man were to: 1) increase dorsal flexion of the left ankle and knee and hip flexion of both extremities, 2) increase the distance the toe of the left foot was raised from the floor during the swing phase of gait and 3) reduce the pain in the neck from increased muscle tension.
All muscles exhibited increased tension, but only those that were associated with pain in the head and neck and those involved in raising the leg and foot during gait were initially the focus of the NMT and MET. Prior to initiating these techniques, Mr. H was evaluated for his relaxation response to heat and cold. Since he achieved the greatest muscle relaxation with heat, it was applied ten minutes prior to the NMT and MET. To relieve the pain, the NMT was applied to stretch the trapezius and sternocleidomastoid muscles. For the first few treatments, pressure and stretching of these muscles had to be maintained for about 30 seconds before relaxation was noticed. The stretching and pressure were then maintained and increased slightly until muscle relaxation occurred. Approximately 2 minutes were required to achieve maximum relaxation. Pain relief with these initial treatments was brief but lasted longer as treatment progressed. NMT was so successful that Mr. H asked for this intervention when pain was difficult to manage. In addition, the range of motion for head rotation, flexion and extension increased and enabled him to view more of the environment around him.
The NMT was used during passive range of motion of the left ankle for severe planter flexion contracture. With each relaxation of the planter flexors, the foot was moved into greater flexion while pressure was maintained on the Achilles tendon or the insertion points of the dorsal flexors. Again, approximately 2 minutes of stretching of the muscles was required to achieve maximum dorsal flexion without discomfort. After approximately 2 months of therapy, the contracture was significantly reduced. When Mr. H was able to actively planter flex his left foot, the MET was used to strengthen the muscles surrounding the ankle. With these interventions to the left ankle and similar interventions to the hips and knees of both limbs, Mr. H was able to raise his left foot off the floor during the swing phase of gait, his stride length increased and postural sway during ambulation decreased.
Maintenance of independence in activities of daily living and mobility require coordinated and functional motor behaviors. The NMT and MET have the potential to increase independence in these activities by improving range of motion, muscle strength and motor coordination, and by reducing muscle tension, spasm and pain. As with most interventions, the short-term effects may be small, but continued use of these techniques has the potential to improve the quality of motor behavior. These simple and noninvasive techniques have no untoward effects as long as resistance and pressures applied to muscles and tendons do not elicit severe discomfort. The NMT and MET are directed at some of the important factors that contribute to dependence in activities of daily living and are important nursing interventions to help maintain or improve the quality of motor behavior.
[1.] Chaitow L: Soft-tissue Manipulation: A Practitioner's Guide to the Diagnosis and Treatment of Soft Tissue Dysfunction and Reflex Activity. Healing Arts Press, 1988.
[2.] Hagbarth K: Excitatory inhibitory skin areas for flexor and extensor motoneurons. Acta Physiologica Scandi 1952; 94(suppl):1-58.
Questions or comments about this article may be directed to: Beverly L. Roberts, PhD, FAAN, FPB School of Nursing, Case Western Reserve University, Cleveland, Ohio 44106-4904. She is an associate professor and senior faculty associate of the University Center of Aging and Health.
Copyright [C] American Association of Neuroscience Nurses 0047-2603/96/2902/00123$1.25
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|Author:||Roberts, Beverly L.|
|Publication:||Journal of Neuroscience Nursing|
|Date:||Apr 1, 1997|
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