Summary
The study of the relations between the electrical activity of a group of synergistic muscles and the biomechanical parameters characterizing the resultant movement is generally reduced to one of the muscles of this group, this muscle being considered as “equivalent”. This is in particular the case for the biceps brachii in the group of elbow flexor muscles. The validity of this concept in the case of isometric, isotonic contraction can be tested by the simultaneous utilization of surface-electrode and wire-electrode detection techniques.
It has been shown 1. that the quadratic relation between the global integrated EMG of the biceps brachii and the external force resulting from the action of the group of flexors can be extended to each of the muscles of this group (brachialis, brachioradialis, pronator teres); 2. that the slope of the relation between the integrated EMG of the biceps brachii and the force differs according to whether the hand is supine or prone. An explanation of a mechanical nature has been proposed for this phenomenon; 3. that in a given situation the relations between the different integrated EMG's remain constant whatever the value of the force.
It follows that 1. each value of the integrated EMG of a muscle equals a coefficient times the value of the force exerted by this muscle; 2. the notion of muscle equivalent is justified for a given situation.
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References
Bankov, J., Jorgensen, K.: Maximum strength of elbow flexors with pronated and supinated forearm. Dan. Nat. Ass. Inf. Paralysis 29, 3–11 (1969)
Basmajian, J. V., Latif, A.: Integrated actions and functions of the chief flexors of the elbow. (A detailed electromyographic analysis.) J. Bone Joint Surg. 39-A(5) 1106–1118 (1957)
Bierman, W., Yamshon, L. J.: Electromyography in kinesiologic evaluations. Arch. Phys. Med. 29, 206–211 (1948)
Bouisset, S., Maton, B.: The quantitative relation between surface and intramuscular electromyographic activities for voluntary movement. Amer. J. Phys. Med. 51, 285–295 (1972)
Bouisset, S.: EMG and muscle force in normal motor activities. In: New developments in electromyography and clinical neurophysiology. (J. E. Desmedt, ed.), Vol. I, pp. 547–583. Basel: Karger 1973
Bouisset, S., Lestienne, F., Maton, B.: The stability of synergy in agonists during the execution of a simple voluntary movement. E.E.G. Clin. Neurophysiol. 42, 543–551 (1977)
Buchthal, F., Schmalbruch, H.: Contraction times and fibre types in intact human muscle. Acta Physiol. Scand. 79, 435–452 (1970)
Cnockaert, J. C., Lensel, G., Pertuzon, E.: Relative contribution of individual muscle to the isometric contraction of a muscular group. J. Biomech. 8, 191–197 (1975)
Feuer, D.: Integrateur convertisseur (analogique-numérique). Application à l'évaluation de l'activité électrique cellulaire. J. Physiol. (Paris) 59, 319–321 (1967)
Goss, C. M.: American edition of gray's anatomy, pp. 498–506. Philadelphia: Lea and Febiger 1965
Ip, M. C., Chang, K. J. F.: A study on the radial supply of the human brachialis muscle. Anat. Rec. 162, 363–372 (1968)
Lippold, O. C. J.: The relation between integrated action potentials in a human muscle and its isometric tension. J. Physiol. (Lond.) 117, 492–499 (1952)
Maton, B.: Etude périphérique de l'organisation du mouvement volontaire, 214 p. Thèse Doct. Etat, Lille 1975
Maton, B., Bouisset, S., Metral, S.: Comparaison des activités éléctromyographiques globale et élémentaire au cours de la contraction statique volontaire. Electromyography 9, 311–323 (1969)
MØller, E.: The chewing apparatus. (An electromyographic study of the action of the muscles of mastication and its correlation to facial morphology.) Acta Physiol. Scand. 69, Suppl. 280, 1–229 (1966)
Rouviere, H.: Anatomie humaine descriptive et topographique, Vol. 2, pp. 112–113. Paris: Masson 1948
Scherrer, J., Monod, H.: Le travail musculaire local et la fatigue chez l'homme. J. Physiol. (Paris) 52, 419–501 (1960)
Simons, D. G., Zuniga, E. N.: Effect of wrist rotation on the XY plot of averaged biceps EMG and isometric tension. Amer. J. Phys. Med. 49, 253–256 (1970)
Sullivan, W. E., Mortensen, O. A., Miles, M., Greene, L. S.: Electromyographic studies of m. biceps brachii during normal voluntary movement at the elbow. Anat. Rec. 107, 243–251 (1950)
Tokizane, T., Shimazu, H.: Functional differentiation of human skeletal muscle, Vol. I, 62 p. University of Tokyo Press 1964
Vredenbregt, J., Koster, W. G.: Some aspects of muscle mechanic in vivo. I.P.O. Ann. Progr. Rep. 1, 94–99 (1966)
Wacholder, K., Altenburger, H.: BeitrÄge zur Physiologie der willkürlichen Bewegung. VII. Mitteilung: Willkürliche Haltungen. Pflüger's Arch. ges. Physiol. 210, 657–665 (1926)
Zuniga, E. H., Simons, D. G.: Non linear relationship between averaged electromyogram potential and muscle tension in normal subjects. Arch. Phys. Med. 50, 613–620 (1969)
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Maton, B., Bouisset, S. The distribution of activity among the muscles of a single group during isometric contraction. Europ. J. Appl. Physiol. 37, 101–109 (1977). https://doi.org/10.1007/BF00421696
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DOI: https://doi.org/10.1007/BF00421696