Extent of motor unit activation during effort.

BELANGER, A. Y., AND A. J. NICCOMAS. Extent of motor unit activation during effort. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 51(5): 1131-1135, 1981.-The technique of twitch interpolation has been used to study the degree of motor unit activation during voluntary effort. In nearly all subjects complete activation of the tibialis anterior was easily achieved during strong dorsiflexion of the ankle; in contrast, it was more difficult to drive plantar-flexor motor units fully. The findings of other studies have been reviewed, and an explanation has been advanced to account for the differences between the tibialis anterior and plank-flexor muscles.

[1]  A. McComas,et al.  Influence of joint position on ankle dorsiflexion in humans. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[2]  F. Zajac,et al.  The effect of activation history on tension production by individual muscle units , 1976, Brain Research.

[3]  D. Jones,et al.  Heat production and chemical changes during isometric contractions of the human quadriceps muscle. , 1975, The Journal of physiology.

[4]  P D Gollnick,et al.  Selective glycogen depletion in skeletal muscle fibres of man following sustained contractions , 1974, The Journal of physiology.

[5]  R B Stein,et al.  The orderly recruitment of human motor units during voluntary isometric contractions , 1973, The Journal of physiology.

[6]  E Jankowska,et al.  A comparison of peripheral and rubrospinal synaptic input to slow and fast twitch motor units of triceps surae , 1970, The Journal of physiology.

[7]  P. Matthews,et al.  The effect on a muscle twitch of the back‐response of its motor nerve fibres , 1960, The Journal of physiology.

[8]  J. Joseph,et al.  Electromyography of muscles of posture: leg and thigh muscles in women, including the effects of high heels , 1956, The Journal of physiology.

[9]  P. Merton.  Voluntary strength and fatigue , 1954, The Journal of physiology.

[10]  D. Denny-Brown.  On Inhibition as a Reflex Accompaniment of the Tendon Jerk and of other Forms of Active Muscular Response , 1928 .

[11]  R. Burke.  Motor Units: Anatomy, Physiology, and Functional Organization , 1981 .

[12]  F Buchthal,et al.  Motor unit of mammalian muscle. , 1980, Physiological reviews.

[13]  M. Johnson,et al.  Data on the distribution of fibre types in thirty-six human muscles. An autopsy study. , 1973, Journal of the neurological sciences.