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Momentary reductions in the electrical activity of working muscles (EMG gaps) contribute to the explanation for the relationship between psychosocial stress and musculoskeletal problems in computer work. EMG activity and gaps in the left and right trapezii were monitored in 23 participants under low and high mental workload (LMW and HMW) demands during computer data entry. Increases in EMG activity and decreases in EMG-gap frequencies in both left and right trapezius muscles were greater during HMW than LMW. In addition, heart period and end-tidal CO2 were lower during HMW, whereas self-reported mood states were higher during HMW. The correspondence between lower end-tidal CO2 and lower EMG-gap frequencies suggests that hyperventilation (overbreathing) may mediate trapezius muscle activation. The reduction of EMG gaps suggests that the salutary benefits of momentary rest from musculoskeletal work are diminished during mental stress.

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 surface electromyography are reviewed.

A comparative analysis was conducted on a series of three experimental studies that examined the effect of various local and nonlocal (distant) complementary healing methods on multisite surface electromyographic (sEMG) and autonomic measures. The series concentrated sEMG electrode placement on specific neuromuscular paraspinal centers (cervical [C4], thoracic [T6], and lumbar [L3]), along with the frontalis region, due to the fact that these sites corresponded to the location of individual chakra centers as delineated in ancient Eastern medical and philosophical texts. It was hypothesized that the sEMG assessment procedure had the potential to provide objective, quantifiable correlates for complementary healing treatment effects, as well as assess the energy flow through the chakras during a healing treatment. The studies were the first of their kind to incorporate randomized, double-blind, placebo-controlled protocols in order to evaluate correlative neuromuscular multisite sEMG paraspinal measures with different complementary healing treatment interventions. Although the measurement protocols were similar between experiments, the results, demonstrated by the individual studies, varied. Whereas the overall findings of the series are encouraging because they indicate a potential objective scientific correlate to complementary healing treatment intervention, the results are considered preliminary in nature and appear to be linked to either the meditational experience of the subjects or dependent on the particular healer(s) used. Additional research is needed in order to establish the multisite sEMG assessment procedure as a reliable correlative measure for complementary healing treatment effects and to determine whether a consistent replicative treatment effect can be demonstrated independent of the specific subject population or practitioner(s) used.

The influence of complementary healing treatment on paraspinal electromagnetic activity at specific neuromuscular sites was examined in an exploratory pilot study that used a multisite surface electromyographic (sEMG) assessment procedure. The study was a replication and extension of previous research that indicated that complementary healing had a significant effect in normalizing the activity of the "end organ" for the central nervous system (CNS). Multisite sEMG electrodes were placed on the frontalis, cervical (C4), thoracic (T6), and lumbosacral (L3) paraspinals of 44 subjects who were divided into three groups: (1) students/patients of a Qigong practitioner (n = 16); (2) students/patients of a therapeutic touch (TT) practitioner (n = 14); and (3) nonbelievers in complementary healing (n = 14). A traditional ABAC experimental design was used with each subject evaluated for one 20-minute session that included four 5-minute segments. The purpose of this study was to measure the variable energizing effect of Qigong therapy along with the anecdotally and experimentally established relaxation effect of TT therapy relative to patient belief and expectancy. Treatment sessions consisted of Qigong and a modified form of TT intervention for all three groups. Due to the double-blind nature of the study, however, group 1 subjects were aware of only the Qigong intervention; group 2 subjects were aware of only the TT intervention, and group 3 subjects were informed that the study was designed to assess the neuromuscular activity of individuals in a seated position. The results indicated a statistically significant rise in electromagnetic activity for group 1 during the Qigong intervention segment (p < .024). Group 2 demonstrated a modest although overall nonsignificant decrease in multisite sEMG levels for both treatment protocols, whereas group 3 exhibited relatively consistent neuromuscular activity for both control and treatment segments. The results of this study are considered preliminary in nature, however, due to the potential influence of several confounds including psychophysiological factors, established behavior patterns, and the possibility for information transfer due to sensory cues.

The reliability of a surface EMG scanning procedure was investigated for the right and left aspects of 10 muscle sites using a large clinical sample of 102 chronic pain patients. Two neutral postures (sitting/standing) were systematically studied on three occasions approximately one hour apart on the same day. The multivariate analysis of RMS microvolts indicated no significant effects for Age, Gender, Muscle site, Aspect or Period. The range of the Pearson correlations was 0.41 to 0.94 when all muscle sites, aspects, postures, and periods were considered. The median correlation was found to be 0.64. The pattern of reliability was seen to be slightly higher in the upper back while sitting, and slightly higher in the lower back while standing. The results indicate that with adequate attention to skin preparation, EMG sensors held in place by hand with a light pressure produce reliable results.

Therapeutic Touch (TT) has been an active change agent within the field of medicine since its introduction as a nursing intervention in 1975. A critical factor which has been missing from the research conducted in this area, however, is definitive scientific evidence or documentation that TT has an objective quantifiable impact upon the physiology of the subject. This study utilized a randomized ABAC methodological design to investigate the effect of TT without contact (NCTT) upon autonomic and CNS parameters. The subjects were blinded to the true nature of the experimental protocol as well as the fact that a healing study was being conducted in order to control for placebo and expectation effects. The impact of NCTT was assessed by multi-site surface EMG recordings located at the Frontalis, Cervical 4 paraspinals, Thoracic 6 paraspinals, and Lumbosacral 3 paraspinals. Autonomic indicators of physiological activity were also monitored and included hand and head temperature, heart rate, and end tidal CO2 levels. The results demonstrated that all of the autonomic indicators showed a general trend towards lower levels of arousal over time. The data also showed that three of the four muscle regions monitored--C4, T6, and L3 paraspinals--indicated a significant reduction in energy during and following the NCTT treatment sessions for a majority of the subjects. For example, the C4 EMG showed a significant NCTT treatment effect (F = 10.31; df = 1; p < .009 level), while the T6 EMG (F = 13.49; df = 1; p < .004) and L3 EMG (F = 4.74; df = 1; p < .05) also demonstrated significance. In addition to the habituation effects seen in the autonomic variables, the implications of neutralization of postural homeostasis and lowering of emotional arousal are discussed along with consideration of the Eastern concept of "nadis."

The relationship between surface EMG recordings from paraspinalis recording sites and subjective pain ratings were examined in a group of pre-chronic back pain patients. thirty-eight back pain patients without major orthopedic diagnosis and a pain duration between 2 to 6 months participated in a three week long subjective pain rating. Following the completion of their pain diary, the paraspinal sites were assessed under the "static" postural conditions of sitting and standing using an EMG scanning procedure. Results of the correlational analysis revealed significant and positive relationships between pain and muscle activity in the upper back (Trapezius, T1 paraspinalis sites) and significant but negative relationships between erector spinae activity (L3 paraspinalis site) and pain. When considering etiological factors of pre-chronic back pain, the results support both the organicity model for upper back, as well as the biomechanical model for the lower back.

The reliability of a surface EMG scanning procedure was investigated for the right and left aspects of ten muscle sites using a large clinical sample of 102 chronic patients. Two neutral postures (sitting/standing) were systematically studied on three occasions approximately one hour apart on the same day. The multivariate analysis of RMS microvolts indicated no significant effects for Age, Gender, Muscle Site, Aspect, or Period. The range of the Pearson correlations was 0.41 to 0.94 when all muscle sites, aspects, postures, and periods were considered. The median correlation was found to be 0.64. The pattern of reliability was seen to be slightly higher in the lower back while standing. The results indicate that with adequate attention to skin preparation, EMG sensors held in place by hand with a light pressure produced reliable results.

A surface EMG diagnostic protocol was developed to assess the neuromuscular/postural contributions to pain states. The EMG activity of the right and left aspects of 11 muscle groups were monitored while the patient was in the sitting and standing positions. The diagnostic protocol was evaluated by comparing the patterns of EMG activity in four diagnostic groups: headache only, neck/shoulder/upper back pain only, low back pain only, and mixed pain states. The results suggest that (1) bilateral levels of EMG activity in the frontalis and masseter groups are of primary importance for the headache patients, (2) the discrepancy between the right and left EMG activity in the lumbar and cervical paraspinal muscle groups are of primary importance for low back pain patients, (3) position (sit/stand) may provide important diagnostic information, and (4) the data appear to support the notion of a postural disturbance as a contributing factor in low back pain.

This study examined the correlation between EMG values measured with wide (25-1000 Hz) and narrow (100-200 Hz) band-width filters. An EMG diagnostic scan was conducted on 32 chronic pain patients admitted to an inpatient treatment unit. EMG readings were taken from a total of 44 sites (11 sites X 2 sides X 2 postures). Each EMG measure was passed in parallel through a narrow and wide band-pass filter and the stable readings were recorded. Correlated t tests and Pearson correlations were used to compare the data from the narrow and wide filter settings. The measures from the wide filter were significantly higher than the measures from the narrow filter. In addition, 61% of the correlations were greater than .90. The majority of the correlations below the median (.93) occurred in the neck region and the abdomen. The implications of the findings are discussed.

Surface electromyography provides a very valuable set of information when used diagnostically with pain-related disorders. Unfortunately, most researchers and clinicians limit their investigation to only one level of diagnostic information available concerning the neuromuscular system. This article develops and encourages the clinician/researcher to consider three levels of diagnostic information: emotional, organ-related, and postural aspects. The theoretical background and diagnostic procedures used to investigate each is presented. Differential treatment considerations, given differential diagnostic findings, are discussed.