Erm�dung und Aktionsstromspannung bei der isometrischen Muskelkontraktion des Menschen

Bayer, Hans; Flechtenmacher, Carl

doi:10.1007/bf00933844

Cited by 7 publications

(4 citation statements)

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“…The mathematical basis of frequency analysis is the Fourier transform which takes different forms depending on the type of signal analysed. The mathematical basis of this procedure is described by Bendat and Piersol (1971) and Fourier (1822). Analysis of simulated and recorded muscle action potentials showed that the frequency distribution was not changed by the repetition rate and the amplitude of discharge.…”

Section: Frequency Spectrummentioning

confidence: 99%

Electrical Activity and Force During Voluntary Contraction of Normal and Diseased Muscle

Frederiksen

1981

Acta Neurologica Scandinavica

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Section: Frequency Spectrummentioning

confidence: 99%

Electrical Activity and Force During Voluntary Contraction of Normal and Diseased Muscle

Frederiksen

1981

Acta Neurologica Scandinavica

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“…However, the surface electromyogram (e.m.g.) has the advantage that the mean signal recorded (measured after rectification and smoothing) varies linearly with the force generated at constant length (Bayer & Flechtenmayer, 1950;Lippold, 1952;Inman, Ralston, Saunders, Feinstein & Wright, 1952), or during contractions with constant velocity (Bigland & Lippold, 1954a). A linear relation, though with increased slope, is still found in fatigued muscle (Edwards & Lippold, 1956) or in muscular diseases which produce weakness (Lenman, 1959).…”

Section: Introductionmentioning

confidence: 99%

The relation between the surface electromyogram and muscular force.

Milner-Brown¹,

Stein²

1975

The Journal of Physiology

571

219

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SUMMARY1. Motor units in the first dorsal interosseus muscle of normal human subjects were recorded by needle electrodes, together with the surface electromyogram (e.m.g.). The wave form contributed by each motor unit to the surface e.m.g. was determined by signal averaging.2. The peak-to-peak amplitude of the wave form contributed to the surface e.m.g. by a motor unit increased approximately as the square root of the threshold force at which the unit was recruited. The peak-to-peak duration of the wave form was independent of the threshold force.3. Large and small motor units are uniformly distributed throughout this muscle, and the muscle fibres making up a motor unit may be widely dispersed.4. The rectified surface e.m.g. was computed as a function of force, based on the sample of motor units recorded. The largest contribution of motor unit recruitment occurs at low force levels, while the contribution of increased firing rate becomes more important at higher force levels.5. Possible bases for the common experimental observation that the mean rectified surface e.m.g. varies linearly with the force generated by a muscle are discussed. E.m.g. potentials and contractile responses may both sum non-linearly at moderate to high force levels, but in such a way that the rectified surface e.m.g. is still approximately linearly related to the force produced by the muscle.

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“…Electrode positions were kept constant during experimentation on the single subject. The myoelectrical activity was expressed by the cumulative signals in /u.V.s, while the myomechanical activity was approximated by the cumulative mean voltage in x IJLV (Bayer & Flechtenmacher, 1950;Lippold, 1952). A cumulative fatigue index, modified after Kernell & Monster (1982), was calculated as the summed mean voltage of 30-40 s of clenching divided by the summed mean voltage of 10-20 s of clenching.…”

Section: Methodsmentioning

confidence: 99%

Cumulative electromyography of the human masseter muscle during fatiguing isometric contractions

Christensen

1984

J of Oral Rehabilitation

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Six adult males performed maximum voluntary tooth clenching (MVC) for 10, 20, 30, 40 s and, after 15 min, for 40, 30, 20, 10 s. During the isometric exercises the electrical currents of the masseter muscle were sampled by integrated and cumulative surface electromyography. Subjective masseter fatigue was present after 30 and 40 s of MVC clenching, accompanied by changes in myoelectrical activity. Strength testing of the masseter muscle, before and after endurance testing, showed that the strength increased by a significant 16% following two endurance tests. This observation was explained by a post-tetanic potentiation and/or a differentiated use of motor units in the fatigued muscle. It is concluded that brief MVC isometric activity, or strength testing, is not a reliable measure of fatigue in the masseter muscle when cumulative electromyography is used. Prolonged MVC isometric activity, or progressive endurance testing, monitors reliably the onset and progression of masseter fatigue.

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Erm�dung und Aktionsstromspannung bei der isometrischen Muskelkontraktion des Menschen

Cited by 7 publications

References 0 publications

Electrical Activity and Force During Voluntary Contraction of Normal and Diseased Muscle

Electrical Activity and Force During Voluntary Contraction of Normal and Diseased Muscle

The relation between the surface electromyogram and muscular force.

Cumulative electromyography of the human masseter muscle during fatiguing isometric contractions

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