Summary
The contracting muscle generates a low frequency sound detectable at the belly surface, ranging from 11 to 40 Hz. To study the relationship between the muscular sound and the intensity of the contraction a sound myogram (SMG) was recorded by a contact sensor from the biceps brachii of seven young healthy males performing 4-s isometric contractions from 10% to 100% of the maximal voluntary contraction (MVC), in 10% steps. Simultaneously, the electromyogram (EMG) was recorded as an index of muscle activity. SMG and EMG were integrated by conventional methods (iSMG and iEMG). The relationship between iSMG and iEMG vs MVC% is described by parabolic functions up to 80% and 100% MVC respectively. Beyond 80% MVC the iSMG decreases, being about half of its maximal value at 100% MVC. Our results indicate that the motor unit recruitment and firing rate affect the iSMG and iEMG in the same way up to 80% MVC. From 80% to 100% MVC the high motor units' discharge rate and the muscular stiffness together limit the pressure waves generated by the dimensional changes of the active fibres. The muscular sound seems to reflect the intramuscular visco-elastic characteristics and the motor unit activation pattern of a contracting muscle.
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References
Barry DT (1987) Acoustic signals from frog skeletal muscle. Biophys J 51:769–773
Barry DT, Geiringer SR, Ball RD (1985) Acoustic myography: a non invasive monitor of motor unit fatigue. Muscle Nerve 8:189–194
Bergstrom RM (1959) The relation between the number of impulse and the integrated electric activity in electromyogram. Acta Physiol Scand 45:97–101
Brozovich FV, Pollack GH (1983) Muscle contraction generates discrete sound bursts. Biophys J 41:35–40
Burke RE (1981) Motor units: anatomy, physiology and functional organization. In: Brooks VB (ed) Handbook of physiology, sect I, vol 2: The nervous system: motor control, part 1. Am Physiol Soc, Bethesda, pp 345–422
Clamann HP (1970) Activity of single motor units during isometric tension. Neurology 20:256–260
Diemont B, Maranzana Figini M, Orizio C, Perini R, Veicsteinas A (1987a) Testing algorithms for appropriate spectral analysis of muscular sound. Proceedings of the 7th Nordic Meeting on Medical and Biological Engeneering, Trondheim, Norway. Institute of Biomedical Engineering, Trondheim, pp 147–148
Diemont B, Maranzana Figini M, Orizio C, Perini R, Veicsteinas A (1987b) Correlated spectral analysis of EMG and muscular sound (SMG) for the study of motor firing pattern. Proceedings of the IEEE/EMBS 9th Annual Conference, Boston, USA, vol 1. IEEE Publisher, New York, pp 341–342
Dixon WJ (1983) BMPD Statistical software. University of California Press, Berkeley
Edwards RHT (1981) Human muscle function and fatigue. In: Porter R, Whelan J (eds) Human muscle fatigue: physiological mechanisms. Pitman, London, p 10
Enoka RM, Stuart DG (1985) The contribution of neuroscience to exercise studies. Fed Proc 44:2279–2285
Frangioni JV, Kwan-Gett TS, Dobrunz LE, McMahon TA (1987) The mechanism of low-frequency sound production in muscle. Biophys J 51:775–783
Freund HJ (1983) Motor unit and muscle activity in voluntary motor control. Physiol Rev 63:387–436
Gordon G, Holbourn AHS (1948) The sounds from single motor units in a contracting muscle. J Physiol 107:456–464
Gydikov A, Kosarov D (1974) Some features of different motor units in human biceps brachii. Pflügers Arch 347:75–88
Helmholtz HLF (1864) Ueber den Muskelton. Monatsber Akad Wiss Berl 5:307–310
Kuroda E, Klissouras V, Milsum JH (1970) Electrical and metabolic activities and fatigue in human isometric contraction. J Appl Physiol 29:358–367
Moritani T, Muro M (1987) Motor unit activity and surface electromyogram power spectrum during increasing force of contraction. Eur J Appl Physiol 56:260–265
Oster G (1984) Muscle sounds. Sci Am 250:108–114
Oster G, Jaffe JS (1980) Low frequency sounds from sustained contraction of human skeletal muscle. Biophys J 30:119–128
Rhatigan BA, Mylrea KC, Lonsdale E, Stern LZ (1986) Investigation of sounds produced by healthy and diseased human muscular contraction. IEEE Trans Biomed Eng BME 33:967–971
Sadamoto T, Bonde-Petersen F, Suzuki Y (1983) Skeletal muscle tension, flow, pressure, and EMG during sustained isometric contractions in humans. Eur J Appl Physiol 51:395–408
Sejersted OM, Hargens AR, Kardel KR, Blom P, Jensen O, Hermansen L (1984) Intramuscular fluid pressure during isometric contraction of human skeletal muscle. J Appl Physiol 56:287–295
Wollaston WH (1810) On the duration of muscle action. Philos Trans R Soc Lond B Biol Sci 1–5
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Orizio, C., Perini, R. & Veicsteinas, A. Muscular sound and force relationship during isometric contraction in man. Europ. J. Appl. Physiol. 58, 528–533 (1989). https://doi.org/10.1007/BF02330708
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DOI: https://doi.org/10.1007/BF02330708