Graphical Analysis and Experimental Determination of the Active State in Frog Skeletal Muscle

Mashima, Hidenobu; Akazawa, Kenzo; Kushima, Hiroki; Fujii, Katsuhiko

doi:10.2170/jjphysiol.23.217

Cited by 8 publications

(3 citation statements)

References 21 publications

(19 reference statements)

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“…According to HILL(1949b),the active state of muscle is defined as the force developed when the contractile component is neither lengthening nor shortening. Recently,BAHLER et al(1967)and MASHIMA et al(1973 Recently, HUXLEY and SIMMONS(1971)and HUXLEY(1974)have done hightime-resolution mechanical experiments and concluded that the instantaneous elasticity of muscle or at least the greater part of it resides in the cross-bridges them-lves. BRESSLER and CLINCH(1974)have also confirmed this evidence from the analysis of the compliance of contracting muscle.…”

Section: Discussionmentioning

confidence: 99%

“…Since the study of HILL(1938)skeletal muscle has been considered to contain a contractile component capable of generating force, which is mechanically linked to a noncontractile series elastic component (WILKIE, 1950;BAHLER, 1968;MASHIMA et al, 1973). Since 1957, however, the sliding filament idea has been developed by A. F. HUXLEY and his co-workers (A. F. HUXLEY, 1957;GORDON et al, 1966)in parallel with the electron-microscopic findings made by H. E. HUXLEY (1957).…”

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confidence: 99%

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A Mechanochemical Model for the Steady and Transient Contractions of the Skeletal Muscle

et al. 1976

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A mechanochemical model for muscle contraction was presented which consisted of three subsystems: the regulatory mechanism of contraction by Ca ion, the cross-bridge cycle coupled with actin-myosin interaction and the dynamics of contraction with an external load. It was assumed that both the rate constant of the cross-bridge cycle and the net force of the cross-bridge were linear functions of the sliding velocity. Most parameters in the model were determined from the experimental data, but several were estimated by simulation techniques. The model adequately described the force-load-velocity relation, the rates of energy and heat output as well as some basic mechanical properties of muscle. Not only the steady-state contraction but also the twitch response could be explained by the model. Time courses of tension and shortening during isometric and isotonic twitches were calculated by the model on a digital computer. The calculated curves agreed satisfactorily with the experimental ones obtained from the frog semitendinosus muscle. The rate of tension rise of the isometric twitch was shown to attain the peak at nearly the same time as does the calculated Ca concentration curve.

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Section: Discussionmentioning

confidence: 99%

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A Mechanochemical Model for the Steady and Transient Contractions of the Skeletal Muscle

et al. 1976

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“…BAHLER et al [5] defined the active state as a force-generating capability of the CC and determined the whole course of the active state during isometric twitch and found that the active state did not reach maximum a value but only 92% of it at 17.5°C, in rat gracilis anticus muscle. MASHIMA et al [38] also determined the time-course of the active state by both analytical and experimental methods in frog semitendinosus muscle and comfirmed that the active state never reached its full extent in a single twitch but only 70-80% of it at 15°C and that two or three stimuli were necessary for the active state to fully develop and form a plateau. b) Method of velocity measurement.…”

Section: Hill's Characteristic Equationmentioning

confidence: 96%

Force-velocity relation and contractility in striated muscles.

Mashima

1984

Jpn.J.Physiol

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This review deals with the contractility of striated muscles as made evident in the force and the shortening velocities in various contractions. The contractility, that is, the capability of contraction, can be expressed using two parameters. One is the maximum tension during isometric contraction and the other, the maximum shortening velocity during isotonic contraction under zero load.Shortening velocity is a function of load, which is equal to the muscle tension during isotonic contraction, and the maximum tension, Tm, can be obtained from the full isometric tetanic contraction at the optimal muscle length, Lm. Therefore, the most important way of ascertaining contractility is to determine the relation between tension and velocity, i.e., the force-velocity relation, at the initial length of Lm. Figure 1 is a three-dimensional illustration of contractility, in which force-velocity curves (a, b, and c) are depicted on the T -v plane and a tension-length curve (dl, descending limb; d2, ascending limb) is on the T -L plane. The curve a is a typical force-velocity curve obtained at Lm where the isometric tension, Tm, is true maximum tension, and the shortening velocity under zero load, vm, is true maximum velocity. In the curve b the isometric tension, Tb, is smaller than Tm, because the muscle is not fully but partially activated. In the curve c, the muscle is fully activated, but the isometric tension, To, is also smaller than Tm, because the initial length, Lo, is different from Lm. Whether the maximum shortening velocities obtained under various conditions, such as represented by curves b and c, are equal or not and the nature of the theoretical explanation of the force-velocity curve from the viewpoint of the recently constructed crossbridge model are the main concerns of this review. A. FORCE-VELOCITY RELATION OF SKELETAL MUSCLES Hill's characteristic equationThe force-velocity relation of skeletal muscle at Lm was described by HILL [22] for the isotonic shortening of the frog sartorius muscle in terms of a simple hyperbolic "characteristic equation," (T+a)(v+b)=b(Tm+a)=const.,where T is the load equal to the tension during isotonic shortening, v is the shorten-1

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Data compression of myoelectric signal—estimation of force and its long‐term monitoring

Akazawa

Nire

Fujii

1989

Systems & Computers in Japan

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It is desired in medicine and sport science to develop a lightweight and small‐sized measuring device which can estimate the generated force of muscle from a myo‐electric signal and monitor that signal for a long time. The purpose of this study is to develop a data compression method for the myoelectric signal. First, the myoelectric signal is full‐wave rectified and smoothed to extract the generated force (equivalent isometric tension) of the muscle. The smoothing filter was designed based on the measurements of the myoelectric signal and the force in the isometric contraction. Next, the waveform of the signal (FEMG) after a full‐wave rectification and smoothing is encoded by the adaptive delta modulation (ADM), and the result is stored in the memory. The parameters of ADM were determined in the optimal way for the myoelectric signal. FEMG signals were constructed from fast motion such as occurs in sports, usual motion such as walking, and the delay motion of a neural‐diseased patient, at sampling intervals of 24, 48 and 100 ms. The S/N ratios of ADM data were calculated as above 37, 45 and 52 dB, respectively. A portable computer (8‐bit CPU and 64‐kB memory) with the data compression program was constructed which can measure continuously the myoelectric signal of a normal subject for up to 12 hours. The decoded signal agreed well with the original FEMG, indicating the usefulness of the developed data compression method and the measuring system.

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Graphical Analysis and Experimental Determination of the Active State in Frog Skeletal Muscle

Cited by 8 publications

References 21 publications

A Mechanochemical Model for the Steady and Transient Contractions of the Skeletal Muscle

A Mechanochemical Model for the Steady and Transient Contractions of the Skeletal Muscle

Force-velocity relation and contractility in striated muscles.

Data compression of myoelectric signal—estimation of force and its long‐term monitoring

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