Abstract
Most of the theoretical studies relating the surface electromyogram (s.e.m.g.) to muscular force suggest that the amplitude of the e.m.g. should increase proportionately with the square root of the tension. However, direct experiments have shown a linear relationship. The reasons for this difference are the oversimplified assumptions adopted in the various models. These models assume that all the motor units are the same size. Also, variations in action potential magnitudes and firing frequency have not been taken into account. Recent physiological experiments have contradicted these assumptions and the various parameters have now been mathematically correlated. If these mathematical correlations are incorporated in a model, the linearity between the s.e.m.g. and the muscular force is greatly imporved.
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References
Clamann, H. P. (1967) A quantitative analysis of firing pattern of single motor units of skeletal muscle of man and their utilization on isometric contractions. Ph.D. Thesis, John Hopkins University, Baltimore, Maryland, USA.
Desmedt, J. E. andGodaus, E. (1977) Ballistic contractions in man: characteristic recruitment pattern of single motorunits of the tibialis enterior muscle.J. Physiol.,264, 673–693.
Freund, H. J., Budingen, H. J. andDietz, V. (1975) Activity of single motor units from human forearm muscles during voluntary isometric contractions.J. Neurophysiol.,38, 933–946.
Grimby, L. andHannerz, S. (1977) Firing rate and recruitment order of toe extensor motor units in different modes of voluntary contraction.J. Physiol.,264, 865–879.
Libkind, M. S. (1968) Modelling of interference bioelectrical activity II.Biophysics,13, 811–821.
Libkind, M. S. (1972) Modelling of interference bioelectrical activity V.,17, 130–137.
Milner-Brown, H. S., Stein, R. B. andYemm, R. (1973a) The orderly recruitment of human motor units during voluntary isometric contraction.J. Physiol.,230, 359–370.
Milner-Brown, H. S., Stein, R. B. andYemm, R. (1973b) Changes in firing rate of human motor units during linearly changing voluntary contractions.,230, 371–390.
Milner-Brown, H. S. andStein, R. B. (1975) The relation between the surface-electromyogram and muscular force.,246, 549–569.
Moller, E. (1966) The chewing apparatus.Acta Physiol. Scand.,69, Suppl. 280.
Person, R. S. andLibkind, M. S. (1969) Simulation of electromyograms showing interference patterns.Electroencep. & Clin. Neurophysiol.,28, 625–636.
Shwedyk, E., Balasubramanian, R. andScott, R. N. (1977) A non-stationary model for the electromyogram.IEEE Trans.,BME 24, (5).
Wilks, S. S. (1962)Mathematical statistics. John Willey & Sons, 256–257.
Yemm, R. (1977) The orderly recruitments of motor units of masseter and temporal muscles during voluntary isometric contraction in man.J. Physiol.,265, 163–174.
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Ray, G.C., Guha, S.K. Relationship between the surface e.m.g. and muscular force. Med. Biol. Eng. Comput. 21, 579–586 (1983). https://doi.org/10.1007/BF02442383
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DOI: https://doi.org/10.1007/BF02442383