Spatial differences in fatigue‐associated electromyographic behaviour of the human first dorsal interosseus muscle.

Zijdewind, Inge; Kernell, Daniel; Cg, Kukulka

doi:10.1113/jphysiol.1995.sp020601

Cited by 54 publications

(46 citation statements)

References 24 publications

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“…The time and frequency domain parameters of the EMG during test 1 showed a time course similar to that reported in the literature (Viitasalo and Komi 1977;De Luca 1985;Gamet and Maton 1989;Orizio et al 1989Krogh-Lund and Jorgensen 1991;Linssen et al 1993;West et al 1995;Zijdewind et al 1995). The linear increase in the EMG rms during the ®rst part of the exercise has been found to be mainly dependent on:…”

Section: Testsupporting

confidence: 68%

Electromyogram and mechanomyogram changes in fresh and fatigued muscle during sustained contraction in men

Esposito

Orizio

Veicsteinas

1998

European Journal of Applied Physiology

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In surface electromyogram (EMG) and mechanomyogram (MMG) the electrical and mechanical activities of recruited motor units (MU) are summated. Muscle fatigue influences the electrical and mechanical properties of the active MU. The aim of this study was to evaluate fatigue-induced changes in the electrical and mechanical properties of MU after a short recovery period, using an analysis of force, surface EMG and MMG. In seven subjects the EMG and MMG were recorded from the biceps brachii muscle during sustained isometric effort at 80% of the maximal voluntary contraction (MVC), before (test 1) and 10 min after (test 2) a fatiguing exercise. From the time and frequency domain analysis of the signals, the root mean square (rms) and the mean frequency (f) of the power spectrum were calculated. The results were that the mean MVC was 412 (SEM 90) N and 304 (SEM 85) N in fresh and fatigued muscle, respectively; during tests 1 and 2 the mean EMG rms increased from 0.403 (SEM 0.07) mV to 0.566 (SEM 0.09) mV and from 0.476 (SEM 0.07) mV to 0.63 (SEM 0.09) mV, respectively; during test 1 the mean MMG rms decreased from 9.4 (SEM 0.8) mV to 5.7 (SEM 0.9) mV; in contrast, during test 2 constantly lower values were observed throughout contraction; during tests 1 and 2 the EMG f declined from 122 (SEM 7) Hz to 74 (SEM 7) Hz and from 106 (SEM 8) Hz to 60 (SEM 7) Hz, respectively; during test 1 the MMG f increased in the first 6 s from 19.3 (SEM 1.4) Hz to 23.9 (SEM 2.9) Hz, falling to 13.9 (SEM 1.3) Hz at the end of contraction; in contrast, during test 2 the MMG f declined continuously from 18.7 (SEM 1) Hz to 12.4 (SEM 0.8) Hz. The lower MVC after the fatiguing exercise and the changes in the EMG parameters confirmed that 10 min after the fatiguing exercise, the mechanical and electrical activities of MU were altered. In addition, the MMG results suggested that after a 10-min recovery, some highly fatigable MU might not be recruitable.

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Section: Testsupporting

confidence: 68%

Electromyogram and mechanomyogram changes in fresh and fatigued muscle during sustained contraction in men

Esposito

Orizio

Veicsteinas

1998

European Journal of Applied Physiology

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“…The electrodes for first dorsal interosseus were placed parallel to the radial border of the second metacarpal, just proximal to the junction between the muscle and distal tendon (Zijdewind et al 1995). Electrodes were placed over accessory muscle groups (abductor pollicis brevis, biceps brachii, and extensor digitorum) according to previously published recommendations (Hermens et al 1999;Basmajian and Blusmenstein, 1983).…”

Section: Data Processing and Statistical Analysesmentioning

confidence: 99%

Reflex responsiveness of a human hand muscle when controlling isometric force and joint position

Maluf

Barry

Riley

et al. 2007

Clinical Neurophysiology

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Objective-This study compared reflex responsiveness of the first dorsal interosseus muscle during two tasks that employ different strategies to stabilize the finger while exerting the same net muscle torque.Methods-Healthy human subjects performed two motor tasks that involved either pushing up against a rigid restraint to exert a constant isometric force equal to 20% of maximum, or maintaining a constant angle at the metacarpophalangeal joint while supporting an equivalent inertial load. Each task consisted of six 40-s contractions during which electrical and mechanical stimuli were delivered.Results-The amplitude of short and long latency reflex responses to mechanical stretch did not differ significantly between tasks. In contrast, reflexes evoked by electrical stimulation were significantly greater when supporting the inertial load.Conclusions-Agonist motor neurons exhibited heightened reflex responsiveness to synaptic input from heteronymous afferents when controlling the position of an inertial load. Task differences in the reflex response to electrical stimulation were not reflected in the response to mechanical perturbation, indicating a difference in the efficacy of the pathways that mediate these effects.Significance-Results from this study suggest that modulation of spinal reflex pathways may contribute to differences in the control of force and position during isometric contractions of the first dorsal interosseus muscle.

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“…Similar problems develop when duration of the IAP and its velocity change with the muscle functional state in such a way that their product (the length of the depolarized zone) is also changed. The opposite changes in amplitude of the signals detected simultaneously by electrodes located at different distances from the active fibers (4,81,(83)(84)(85) is an indirect indication of the possible changes in the IAP profile length. The only case when the identical source can be moved along the fibers with different velocity is when the IAP duration is changed together with velocity in such a way that their product remains unchanged.…”

Section: Other Ways To Model Sfp and Mupmentioning

confidence: 99%

Electromyography (EMG) Modeling

Dimitrova

Dimitrov

2006

Wiley Encyclopedia of Biomedical Engineering

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Modeling is a measure of our understanding of processes and a tool for checking hypotheses and making prognoses. Any attempt to understand and explain electromyographic (EMG) signals, their characteristics, and changes is related to modeling. The authors’ aim is to present the main ideas of EMG modeling in terms understandable to people without special mathematical education. The main physical regularities that rule the formation of electrical potentials in a volume conductor (extracellular medium) are pictorially demonstrated and can be realized ignoring equations. Potentials produced by individual muscle fibers are the basis of EMG signals, which is why a more detailed picture of the physical basis for modeling single‐fiber potentials (SFPs) generated in a homogeneous volume conductor of infinite extent is presented. It is demonstrated why the shape of SFP changes with distance from the active fibers, why amplitude of EMG signal can be an unreliable characteristic, and why detection of EMG by needle and surface electrodes has different sensitivity to prolonged phase of repolarization or to after‐depolarization in intracellular action potential (IAP) and to IAP propagation velocity along the fiber. Description of some equations resulting in fast calculation of the motor unit potentials and interference EMG are presented. The latest papers on mathematical modeling that take into account inhomogeneous and restricted muscle tissue are discussed.

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Spatial differences in fatigue‐associated electromyographic behaviour of the human first dorsal interosseus muscle.

Cited by 54 publications

References 24 publications

Electromyogram and mechanomyogram changes in fresh and fatigued muscle during sustained contraction in men

Electromyogram and mechanomyogram changes in fresh and fatigued muscle during sustained contraction in men

Reflex responsiveness of a human hand muscle when controlling isometric force and joint position

Electromyography (EMG) Modeling

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