An automated method for the frequency analysis of myoelectric signals evaluated by an investigation of the spectral changes following strong sustained contractions

Johansson, Stefan; Larsson, Lars‐Erik; Örtengren, Roland

doi:10.1007/bf02477242

Cited by 24 publications

(11 citation statements)

References 7 publications

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“…These findings were reported by BiglandRitchie et al 7 The reason for this outcome was thought to be that as motoneuron firing rates decreased, muscle latency times lengthened. A decrease in conduction velocity, which has previously been shown to occur during fatiguing isometric contractions, 29 may also be the underlying mechanism for this increase in muscle latency times.…”

Section: Discussionmentioning

confidence: 80%

Scapular Muscle Recruitment Pattern: Electromyographic Response of the Trapezius Muscle to Sudden Shoulder Movement Before and After a Fatiguing Exercise

Cools¹,

Witvrouw²,

Clercq³

et al. 2002

J Orthop Sports Phys Ther

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4Study Design: Test-retest reliability study and single-group repeated measures design. Objectives: To evaluate the muscle latency times of the 3 portions of the trapezius muscle to a sudden arm movement in normal shoulders and to determine if this recruitment pattern is altered as a result of fatigue. Background: It has been suggested that shoulder impingement may be related to altered muscle activity and muscle fatigue in the scapular stabilizers. Fatigue-induced changes in latency times of the trapezius might influence scapular stability. Methods and Measures: Muscle latency times were investigated in 30 healthy shoulders with surface electromyography. Muscle activity was measured in all 3 sections of the trapezius and the middle deltoid muscle during a sudden downward falling movement of the arm. Subsequently the shoulder was fatigued on an isokinetic dynamometer, after which muscle latency time measurement was repeated. Results: ANOVA for repeated measures revealed significant differences in latency times (P Ͻ 0.05) among the 4 muscles of interest. Although there were no significant differences among the 3 sections of the trapezius muscle, they all were recruited after the initialization of the deltoid muscle. The recruitment order of the shoulder muscles did not change with muscle fatigue. However, after fatigue, muscle responses were significantly slower in all muscles except for the lower trapezius (P Ͻ 0.05). Sciences and Physiotherapy, De Pintelaan 185, 6K3, B9000 Ghent, Conclusions: There is a specific recruitment sequence in the shoulder muscles in response to a sudden arm movement characterized by initial activation of the middle deltoid muscle and followed by simultaneous contraction of all 3 sections of the trapezius. This muscle activation pattern is delayed but not altered with fatigue.

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Section: Discussionmentioning

confidence: 80%

Scapular Muscle Recruitment Pattern: Electromyographic Response of the Trapezius Muscle to Sudden Shoulder Movement Before and After a Fatiguing Exercise

Cools¹,

Witvrouw²,

Clercq³

et al. 2002

J Orthop Sports Phys Ther

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“…The muscles 14; other muscles of the lower extremity, 9. Broad-band frequency analysis of the EMG signal was performed in 42 muscles (9).…”

Section: Methodsmentioning

confidence: 99%

Primary Fibromyalgia:A Clinical and Laboratory Study of 55 Patients

Bengtsson

Henriksson²,

Jorfeldt

et al. 1986

Scandinavian Journal of Rheumatology

149

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The clinical symptoms of 55 patients with primary fibromyalgia (PF) were studied and compared with 30 patients with rheumatoid arthritis (RA). The PF patients expressed a more intense feeling of illness than did the RA patients. Stiffness occurred just as often in PF as in RA. Trigger points occurred less frequently in RA patients. Muscular fatigue appeared to be one of the most disabling symptoms in PF. Neurophysiological studies indicated that the fatigue was at least partly of central origin. Ischemic forearm exercise test gave no evidence of impaired glycogenolysis. Laboratory investigation revealed normal 25-hydroxyvitamin D, cobalamin, folate, estrogen, testosterone, and myoglobin in the PF patients.

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“…A pathologically increased ratio of highAow frequency components in the EMG signal on broad band frequency analysis (Johansson et al 1970, Larsson 1975, Sandstedt et al 1982 was further evidence of myopathy. The finding during the course of the disease of: 1) Bilateral muscular weakness.…”

Section: (Om) Used In the Present Investigationmentioning

confidence: 95%

Polymyositis - treatment and prognosis

Henriksson

Sandstedt

1982

Acta Neurologica Scandinavica

168

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One hundred and seven patients with polymyositis or dermatomyositis were followed for an average of 5 years. In 100 patients it was possible to evaluate the effect of treatment with steroids or a combination of steroids and immunosuppressive drugs. Fifty patients improved, 50 did not. Compared with the treatment-resistant group the treatment-responsive patients were of younger age, did not have an associated malignancy or cardiac disease and began treatment within 24 months after the onset of muscular weakness. In the treatment-responsive group the degree of improvement was correlated to the mean dose of steroids given during the first 3 months of treatment. Eighty-seven per cent of surviving responsive patients had no or slight disability at the end of the investigation. The mortality rate was 23% and was highest in the treatment-resistant group. Comparison between different treatment programs was possible and based on the results, a treatment schedule could be recommended. The principles of this schedule are: During the first month high doses of prednisone or prednisolone should be given daily. From the second month, an alternate-day administration can be employed. Tapering to maintenance dose should be gradual and slow. The treatment period should be long. The mean duration in the present series was 27 months.

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An automated method for the frequency analysis of myoelectric signals evaluated by an investigation of the spectral changes following strong sustained contractions

Cited by 24 publications

References 7 publications

Scapular Muscle Recruitment Pattern: Electromyographic Response of the Trapezius Muscle to Sudden Shoulder Movement Before and After a Fatiguing Exercise

Scapular Muscle Recruitment Pattern: Electromyographic Response of the Trapezius Muscle to Sudden Shoulder Movement Before and After a Fatiguing Exercise

Primary Fibromyalgia:A Clinical and Laboratory Study of 55 Patients

Polymyositis - treatment and prognosis

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