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5 Articles in Volume 0, Issue #1
Chronic Tension Headache
Corticosteroid Use in Pain Management
Fibromyalgia Syndrome & Surface Electromyography
Intraarticular Mechanisms for Pain Control
Pharmaceuticals in the Pipeline - Anti-rheumatic Drugs

Fibromyalgia Syndrome & Surface Electromyography

Dynamic functional capacity and movement assessment via sEMG is a viable tool in treating patients with FMS.

Fibromyalgia (FMS) was recognized as a true illness by the American Medical Association and as a major cause of disability in 1987. The American College of Rheumatology further clarified the illness in 1990 by identifying diagnostic criteria and stating "...the presence of unexplained widespread pain or aching, persistent fatigue, generalized morning stiffness, non-refreshing sleep, and multiple tender points."

FMS is defined as a painful, but not articular, condition predominantly involving muscles. It is known as the most common cause of chronic widespread musculoskeletal pain.1 Some of the more recent literature implies that FMS is a centrally mediated pain disorder and exists concurrently with Myofascial Pain (MFP). Patients with FMS/MFP are often incapable of performing even sedentary work in a vocational environment. In addition, key findings in patients with the medical diagnoses of FMS/MFP are the failure to recover from metabolic fatigue. This evidence substantiates the complex issues of physical dysfunction that is intrinsic to designing appropriate, safe and specific parameters of performing simple daily living tasks. Clearly FMS/MFP are debilitating syndromes.

There are numerous perpetuating factors of the concurrent FMS/MFP illnesses. There are three factors – behavioral, biomechanical and mechanical – that can be considered most common. Behavioral factors are those that include non-restorative (lack of stage IV phase) sleep, secondarily induced depression and anxiety, muscle abuse (from performance of actions beyond physiological ability) and repetitive motion. Biomechanical factors that are involved include vitamin inadequacy and other nutritional factors, hormonal dysfunctions, allergic conditions, impaired muscle metabolism and hypoglycemia. The third set of factors are those that are mechanical. These include asymmetrical use of body musculature, sensory changes, immobility (secondary to pain), prolonged inactivity, intrinsic chronic and persistent trigger points of MFP.

Assessment and Treatment with sEMG

Identifying and treating FMS/MFP can be accomplished through dy-namic functional movement assessment using Surface Electromyography (sEMG). It was first described in the mid-1800s and came into clinical use in the 1920s. However, many medical practitioners are still unfamiliar with this technology and its significance for soft tissue injury. Perpetuating factors in chronic pain through the appropriate quantification of muscle spasm and contracture, and the objective analysis of posture, movement and emotions, are strong considerations.

The assessment of functional movement potential not only aids in quantifying goals, it reflects and identifies spasm, hypertonicity, hypotonicity, protective guarding, somatic dysfunction, fasiculations, trigger points and contractures. Moreover, this objective measurement modality assists the rehabilitation practitioner in a patient's status and progress. SEMG has the ability, with Median Frequency Spectral Analysis (MFSA), to assess not only force fatigue but also metabolic fatigue and recovery time of the muscle, which is a critical component that relates to a variety of movement tasks. Dysfunctional movement patterns are also identified with sEMG, thus decreasing compensatory movement behaviors perpetuating pain.

SEMG is a primary complement to comprehensive medical and physical therapy evaluations. Given that it best records surface muscle groups, and can be correlated to needle EMG findings for trigger point activity, sEMG is valuable in the rehabilitation of patients with the following medical and physical therapy working diagnoses:

  • Muscle Injury or Spasm
  • Complicated Pain
  • Altered Motor Strategies
  • Myofascial Soft Tissue Restrictions
  • Incontinence Dysfunctions
  • General Decondition
The author checks the sEMG unit on physical therapy assistant, Bob Gilson.

Key Applications and Benefits of sEMG

  • The critical factors of muscle fatigue and recovery time in designing exercise programs are considered with sEMG MFSA.
  • Dysfunctional movement patterns from a variety of physiological causes can be assessed in viewing the firing patterns of muscles with trigger points. Asymmetrical utilization of muscle groups can be measured and treated appropriately.
  • Complicated musculoskeletal disorders have characteristic patterns of referred and compensatory muscle activity and trigger points. The negative impact on functional ability and outcomes can be adequately assessed, effectively and immediately treated, and often predicted with sEMG and MFSA.
  • The ability of a muscle to adequately contract is fundamental to any strengthening, endurance and skilled functional movement exercise program. SEMG can identify inappropriate responses to varying workloads, level of coordinated muscle skill and readiness to participate.
  • Repetitive motion and selective low frequency fatigue failure disorders have a pattern of onset, predictable course of compensation patterns and widespread muscular dysfunction with time. These patterns can be quantitatively documented with sEMG.
  • Muscles rated as normal strength in manual or isokinetic tests may not be recruited during movements in a variety of functional tasks. The resulting imbalances may perpetuate chronic dysfunction and pain. SEMG can document the physical therapy diagnosis and support the medical necessity for skilled intervention.
  • Patients respond positively to the feedback and resulting self efficacy in actively creating the changes that are possible and necessary in their functional daily activities.

Surface EMG also studies the energy of the soft tissue muscles and their related function. Studying the body's energy at this level, enables the practitioner to begin to see the contributions and perpetuating factors in chronic pain through objective quantification.2 Muscle function may be affected negatively by nociception and the response may be splinting rather than functional motion. Once the faulty muscle patterns have been identified via sEMG, it may be used as a measurement tool to track the effects of treatment or may be used as a tool itself with which to precipitate.3 Two major theses of sEMG biofeedback do exist; one is relaxation and the other is dynamic functional movement. SEMG can be enlisted periodically to reassess the status of the neuromuscular system following therapeutic endeavors including physical therapy or manipulations. Moreover, sEMG can quantify the functional capacity for an individual wishing to return to work.

Roland Staud, MD, of the Division of Rheumatology and Clinical Immunology, Department of Medicine, Gainseville, Florida, has studied the mechanisms of pain in patients with FMS. He particularly investigated the phenomena of "wind up." Wind up is the sensitization at the cord level via the NMDA receptors secondary to repetitive afferent impulse. Such sensitization is supposed to increase one's tolerance to pain. Dr. Staud noted through research that exercise does not desensitize FMS patients, and questions any substantial positive effect of aerobic exercise. Dr. Stoud's basic hypotheses are that abnormal central pain processing of pain in FMS subjects is one of the fundamental abnormalities in this syndrome. FMS patients showed only a 40 percent wind up effect. His study results indicate that FMS patients show abnormal central pain that can lead to central sensitization via the N-Methyl D-Aspartate (NMDA) re-ceptors. This is a very significant finding in the mechanism of chronic pain.

Trigger Points

My clinical experience overwhelmingly presents the objective findings of primary, secondary and satellite trigger points (neuromuscular points) that create referred pain throughout the musculoskeletal system. Trigger points (TP) of MFP are differentiated from tender points (Tp) of FMS. There is almost always a concurrent overlay of trigger points, MFP with FMS. It is indicated that a sEMG bilateral difference of more than 20 percent differentiated sufferers with trigger points from those without trigger points. A 45 percent asymmetry of right to left indicated clinical pathology in 80 percent of the cases. Unilateral trigger points corresponded 100 percent of the time to the higher sEMG readings. This is clinically significant indicating that sEMG is utilized to differentiate and identify trigger points.

Exercise and Precautions

Physical Therapy intervention for FMS patients is best directed toward attaining optimal functional motion, up to or under the limits of perceived pain, on an individual basis. FMS, MFP and most complicated pain syndromes most often include some type of muscular pain, which characteristically worsens with physical activity. Because exercise has been shown to activate endogenous opioid and noradrenergic pain inhibitory systems, it is hypothesized that this pain modulary system may be compromised in FMS patients. In addition, aerobic exercise is contraindicated due to the prevalence of "failure to recover from metabolic fatigue" which complicated pain patients usually experience.4

Protocols or recipes of rehabilitation and reconditioning for the complicated pain patient do not acknowledge the uniqueness of the complex patient. Drs. Wolfe, Simmons and Travell expressly caution against exercising a muscular region that has trigger points. Specific inhibition of the TPs and diminution of referred pain must precede any therapeutic exercise session within a program. Additionally, there is a group of FMS patients who cannot participate in any aerobic regimes due to metabolic, hormonal and vascular permanent inadequacies.

SEMG is a primary complement to comprehensive medical and physical therapy evaluations.

Another concern is lack of ability to perform any type of aerobic activity in the FMS/MFP patient. There is evidence that exercise exacerbates chest pains. Mark J. Pellegrino, MD, a FMS researcher at Ohio State University, indicates trigger point referred pain in the chest area is often a serious problem. Patients reporting perpetuating chest pain had quite a few unifying factors which included active Tp and TP in the chest area, costochondritis and referred pain to the level of pain in which the patient often thought they were having severe cardiac problems. The pain level experienced was noted as severe.5

While studies now indicate that aerobic exercise is injurious to FMS patients, gentle non-aerobic programs can be of benefit. Basic gentle stretching, self-management techniques of trigger point diminution precede and follow each patient's unique regime of "exercise." Slow paced walking, aquatic therapy or some home gym equipment use, such as recumbent bike or motorized treadmill, are examples of usually safe exercise. I do not suggest aerobic exercise utilizing isokinetic equipment typically found in an exercise gym. I do, however, support patients participating in a conservative movement program for 20 minutes, three times a week and a daily regime of periodic stretching with referred pain self management.


The complex interrelationship amongst the identifying components of FMS/MFP requires the intervention of practitioners experienced in complicated pain dysfunction and disability. Each of these noted diagnoses is, in and of itself, disabling. Moreover, the combination of diagnoses renders patients incapable of performing even sedentary work in a vocational environment. Physical therapy treatment priorities for a complicated pain patient emphasize only the diminution of symptoms to optimize basic functional ability in the domestic domain, which includes personal activities of daily living, structured physical intervention and involvement in the responsibilities of family care.

Diligent evaluation and plan of care for the complicated pain patient demands the attention of a well-educated and experienced practitioner. Too often patients are attended to by practitioners lacking the education to clearly identify the components of these syndromes versus other significant pathologies. It also demands patience and time. Too often managed care providers are constrained by the limitations of policy. Exceptions are medically indicated for complicated pain patient. Objective, quantified measurement of functional ability and disability require and demand, not only the subjectivity of the evaluator, but moreover the consistency and standardization of measurable data with surface electromyography.

Last updated on: May 16, 2011
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