Dependence of conduction velocity on spike interval during voluntary muscular contraction in human motor units

  • S. Morimoto
  • M. Masuda
Article

Summary

The dependence of the conduction velocity of the action potential on the spike interval from a preceding potential was studied using human single motor units during voluntary muscle contraction. The spike potential was recorded from the surface of the skin overlyingM. vastus medialis by use of surface electrodes (Ø 5 mm).

The results were as follows: 1) Conduction velocity increased with a decrease in spike interval. The relation between conduction velocity and spike interval can be expressed as logv=kt+a, wherev is conduction velocity (m·s−1),t is spike interval (ms) andk anda are constants. All data can be expressed by the above formula with a highly significant correlation. 2) After arterial occlusion, there was little or no relation between conduction velocity and spike interval. This lack of correlation between these parameters was not restored to the initial correlation within a period of 15 min. 3) Effects similar to occlusion could be seen in the result of prolonged isometric contraction. However the lack of correlation between these parameters was restored to the initial correlation within a 15 min recovery period. 4) At low muscular temperature, the relation could not be described by a logarithmic regression. As the spike interval became shorter, the conduction velocity decreased. After cessation of cooling, the relation was restored to the initial correlation within 30 min.

The mechanisms of these changes are still uncertain but some possible factors can be considered, for example, composition of the extracellular fluid, pH, temperature and permiability of the excitable membranes of the muscle.

Key words

Motor unit Conduction velocity Spike interval Muscular temperature Arterial occlusion 

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References

  1. Bezanilla F, Caputo C, Gonzalez-Serratos H, Venosa RA (1972) Sodium dependence of the inward spread of activation in isolated twitch muscle fibers of the frog. J Physiol 223: 507–523Google Scholar
  2. Farmer TW, Buchtal F, Rosenfalck P (1960) Refractory period of human muscle after the passage of a propagated action potential. EEG Clin Neurophysiol 12: 455–466Google Scholar
  3. Grabowski W, Lobsiger EA, Lüttgau H (1972) The effect of repetitive stimulation at low frequencies upon the electrical and mechanical activity of single muscle fibers. Pflügers Arch 334: 222–239Google Scholar
  4. Graham HT (1934) Supernormality, a modification of the recovery process in nerve. Am J Physiol 110: 225–242Google Scholar
  5. Graham HT, Lorente de Nó R (1938) Recovery of blood perfused mammalian nerves. Am J Physiol 123: 326–340Google Scholar
  6. Jorfeldt L, Juhlin-Dannfelt A, Karlsson J (1978) Lactate release in relation to tissue lactate in human skeletal muscle during exercise. J Appl Physiol 44: 350–352Google Scholar
  7. Lindström L, Magnusson R, Petersen I (1970) Muscle fatigue and action potential conduction velocity changes studies with frequency analysis of EMG signal. Electromyography 4: 341–353Google Scholar
  8. Lynn P (1979) Direct on-line estimation of muscle fiber conduction velocity by surface electromyography. IEEE Trans Biomed Eng 26: 564–571Google Scholar
  9. Macfarlane WV, Meares JD (1958a) Chemical modification of intracellularly recorded after-potentials of frog skeletal muscle. J Physiol 142: 78–96Google Scholar
  10. Macfarlane WV, Meares JD (1958b) Intracellular recording of action potentials of frog muscle between 0 and 45‡ C. J Physiol 142: 97–109Google Scholar
  11. Masuda T, Mizuno H, Sadoyama T (1982) The measurement of muscle fiber conduction velocity using a gradient threshold zero-crossing method. IEEE Trans Biomed Eng 10: 673–678Google Scholar
  12. Morimoto S, Umazume Y, Masuda M (1980) Properties of spike potentials detected by a surface electrode in intact human muscle. Jpn J Physiol 30: 71–80Google Scholar
  13. Morimoto S (1983) Discharge and conduction velocity of a human single motor unit during voluntary prolonged activity. Jikeikai Med J 30: 111–122Google Scholar
  14. Petrofsky JS, Lind AR (1980a) Frequency analysis of surface electromyograms during sustained isometric contractions. Eur J Appl Physiol 43: 173–182Google Scholar
  15. Petrofsky JS, Lind AR (1980b) The influence of temperature on the amplitude and frequency components of the EMG during brief and sustained isometric contractions. Eur J Appl Physiol 44: 189–200Google Scholar
  16. Pillat B, Heistracher P (1960) VerÄnderungen von Leitungsgeschwindigkeit und Latenz am Papillarmuskel der Katze wÄhrend des RefraktÄrstadiums. Pflügers Arch 271: 564–582Google Scholar
  17. Sadoyama T, Masuda T, Miyano H (1983) Relation between muscle fiber conduction velocity and frequency parameters of surface EMG during sustained contraction. Eur J Appl Physiol 51: 247–256Google Scholar
  18. Stålberg E (1966) Propagation velocity in human muscle fibers in situ. Acta Physiol Scand [Suppl] 70: 287Google Scholar
  19. Tasaki I (1949) The excitatory and recovery process in the fiber as modified by temperature changes. Biochim Biophys Acta 3: 498–509Google Scholar

Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • S. Morimoto
    • 1
  • M. Masuda
    • 1
  1. 1.Department of PhysiologyThe Jikei University, School of MedicineTokyoJapan

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