Ec Theory

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When studying the mechanical properties of motor units, important parameters (among motor units of the EO system) are fusion frequency, fatigability and force output. By integrating the fusion frequency and fatigability of motor units, the twitch motor units can be divided into 4 subgroups: fast fatigable (FF), fast fatigue resistant (FR), slow fatigable (SF) and slow fatigue resistant (S). The fifth subgroup was comprised of nontwitch (NT) motor units, which constituted 10% of the total population (Shall & Goldberg, 1992).
EO muscles are the most complex voluntary striated muscles in vertebrates in that they exhibit a greater variation in structural, physiological and biochemical properties than any other skeletal muscles. The arrangement
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The SIFs respond to electrical excitation with an all-or-nothing response, which propagates along the whole length of the fiber. They are innervated by relatively large nerves (7–11 mm), which terminate as large en plaque motor endplates in an endplate zone occupying the central third of the muscle. MIFs are highly fatigue resistant and respond to electrical stimulation with a slow tonic contraction, which is not propagated along the muscle fiber (Barmack, Bell, & Rence, 1971; Bond & Chiarandini, 1983; Chiarandini & Stefani, 1979; a F. Fuchs & Luschei, 1971; Hess & Pilar, 1963; G Lennerstrand, 1974; Nelson, Goldberg, & McClung, 1986). They are innervated by a myelinated nerve fiber, which usually is of fine caliber (3–5 mm), and terminates as small motor endplates that are distributed along the whole length of the fiber, with a higher density in the distal half of the muscle. The location of motoneurons innervating MIF is unknown, but the EO motor nuclei are assumed to accommodate them (Shall & Goldberg, 1995). Importantly so far no one has recorded from MIF supplying
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