The History of Muscle Dysfunction and SEMG

 

Jeffrey R. Cram, PhD and Maya Durie, MEd, CMT

Abstract

The history of muscle pain and dysfunction is viewed through the lens of a four factor theory of histologic (tissue related) issues, psychologic (emotional) issues, sensory motor (movement) issues and biomechanical (postural) issues. The historical antecedents of both bodywork and surface electromyography are reviewed.

Key words: Surface EMG, SEMG, bodywork, trigger points, posture, emotions, movement.

Note: Parts of this article have appeared in The History of SEMG, Jour App Psychophys and Biof, In Press.

Humans have had to deal with sore muscles since the beginning of time. Initially, muscle assessments and treatments were conducted by hand and during the last century, the use of electronic instruments came into play.

To put muscle function and the clinical use of Surface electromyography (SEMG) into a perspective of history, is seems prudent to utilize a broad nomothetic net or conceptual framework. In Clinical Applications for Surface Electromyography, Kasman, Cram and Wolf (1998) consider chronic muscle dysfunction from a four fold perspective: Histologic (Tissue related issues); Psychologic (Psychophysiology and Emotions), Sensorimotor (Movement) and Mechanical Dysfunction (Cumulative Trauma, Posture etc). In this article we will provide a brief historical overview related to each of these four areas. This will provide a deep background for the emergence of the clinical use of SEMG, including information on the history of body work, psychophysiology, rehabilitation and the emergence of electricity and SEMG instrumentation.

We will begin with issues pertaining to the tissues of the body. The muscle, as an organ system, contains many sensory mechanisms. The muscle spindles tell the nervous system about the instantaneous length and force of contraction of segments of muscle tissue. The golgi tendon organ measures the actual force which the muscle is exerting and the rufini nucleus of the joints informs the nervous system of the relationship of angles of the bones. However, it is the free nerve ending within the muscle that senses local pain. And it is metabolic disturbances such as too much (lactic) acid or too much internal pressure due to swelling, congestion or edema, which activate the free nerve ending.

From a clinical point of view, up until the last two centuries, palpation and observations about movement and posture were the only tools available for assessing muscle oriented pain. Through the manual sense of touch, the practitioner can learn to feel many things. Is the muscle tissue hard to the touch? Does it feel stiff? Does it have lumps, tough fibers, etc. or is it soft, supple and relaxed? What does the fascia feel like? Is there a normal cranial-sacral rhythm? As you move the body passively through its range of motion, does it seem restricted suggesting a shortened muscle resting length? During active movement, does it appear that the body is using the correct muscles for the movement or is there a substitution pattern? Is the patient afraid of movement due to pain? Has a trauma become lodged in the nervous system or even the muscle tissue itself? Can one see or feel problems with ligament laxities or joint fixations? These are just some of the examples of questions we want to address, both by hand and by instrument. . Thus, one could think of body work as a means to help normalize the disturbance of tissue that might foster and create muscle pain and SEMG as an instrumented way of assessing some of these conditions.

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