The relationship between force depression following shortening and mechanical work in skeletal muscle

Herzog, Walter; Leonard, Tim; Wu, Jianfeng

doi:10.1016/s0021-9290(00)00008-7

Cited by 98 publications

(119 citation statements)

References 19 publications

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“…8A) and decreased with increasing speeds of shortening (Fig. 8B) for each muscle, as shown previously (18).…”

Section: Resultssupporting

confidence: 89%

“…Our steady-state results support the findings of previous studies, showing that FD ss (ϭ F iso Ϫ F inf ) increased with shortening amplitude (1,6,15,28,30,32,34), decreased with larger shortening speeds (1,6,15,28,30,32,34), and increased with mechanical work done during shortening (6,18). An increase in shortening amplitude increases the distance over which the contractile force operates and thus, for a fixed speed Fig.…”

Section: Discussionsupporting

confidence: 91%

“…7, 13, 25, 34) preparations. It has been shown that FD ss increases with increasing amplitudes of shortening (1,6,15,28,30,32,34), with decreasing speeds of shortening (1,6,15,28,30,32,34), with increasing force during shortening (6,15), and with increasing mechanical work done by the muscle during shortening (18). Furthermore, Sugi and Tsuchiya (34) showed, in single muscle fibers of the frog, that force depression (FD) was accompanied by a proportional reduction in fiber stiffness.…”

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confidence: 99%

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Force recovery after activated shortening in whole skeletal muscle: transient and steady-state aspects of force depression

Corr

2005

Journal of Applied Physiology

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The depression of isometric force after active shortening is a wellaccepted characteristic of skeletal muscle, yet its mechanisms remain unknown. Although traditionally analyzed at steady state, transient phenomena caused, at least in part, by cross-bridge kinetics may provide novel insight into the mechanisms associated with force depression (FD). To identify the transient aspects of FD and its relation to shortening speed, shortening amplitude, and muscle mechanical work, in situ experiments were conducted in soleus muscletendon units of anesthetized cats. The period immediately after shortening, in which force recovers toward steady state, was fit by using an exponential recovery function (R 2 Ͼ 0.99). Statistical analyses revealed that steady-state FD (FD ss) increased with shortening amplitude and mechanical work. This FD ss increase was always accompanied by a significant decrease in force recovery rate. Furthermore, a significant reduction in stiffness was observed after all activated shortenings, presumably because of a reduced proportion of attached cross bridges. These results were interpreted with respect to the two most prominent proposed mechanisms of force depression: sarcomere length nonuniformity theory (7, 32) and a stress-induced inhibition of cross-bridge binding in the newly formed actin-myosin overlap zone (14, 28). We hypothesized that the latter could describe both steadystate and transient aspects of FD using a single scalar variable, the mechanical work done during shortening. As either excursion (overlap) or force (stress) is increased, mechanical work increases, and cross-bridge attachment would become more inhibited, as supported by this study in which an increase in mechanical work resulted in a slower recovery to a more depressed steady-state force.shortening-induced depression; mechanical work; stress-induced cross-bridge inhibition; sarcomere length nonuniformity; rate of force redevelopment STEADY-STATE FORCE DEPRESSION (FD ss ), the reduction of isometric force after active shortening compared with a purely isometric force at the corresponding final length, is a wellaccepted characteristic of skeletal muscle that has been demonstrated in both whole muscle (e.g., Refs. 1,15,28,30,32) and single-fiber (e.g., Refs. 7, 13, 25, 34) preparations. It has been shown that FD ss increases with increasing amplitudes of shortening (1,6,15,28,30,32,34), with decreasing speeds of shortening (1,6,15,28,30,32,34), with increasing force during shortening (6, 15), and with increasing mechanical work done by the muscle during shortening (18). Furthermore, Sugi and Tsuchiya (34) showed, in single muscle fibers of the frog, that force depression (FD) was accompanied by a proportional reduction in fiber stiffness. Despite this thorough characterization of the steady-state behavior, the underlying mechanisms of FD ss remain unknown.Our current understanding of FD ss is based almost exclusively on steady-state observations, whereas transient phenomena have not been considered. The behavior of muscle du...

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“…8A) and decreased with increasing speeds of shortening (Fig. 8B) for each muscle, as shown previously (18).…”

Section: Resultssupporting

confidence: 89%

Section: Discussionsupporting

confidence: 91%

mentioning

confidence: 99%

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Force recovery after activated shortening in whole skeletal muscle: transient and steady-state aspects of force depression

Corr

2005

Journal of Applied Physiology

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“…Segundo Ruiter e Haan (10) a diminuição da capacidade de produção de força aumenta linearmente com a magnitude do encurtamento durante activação voluntária máxima, quando imposta uma velocidade constante. Assim como eles, diversos estudos têm relatado que a capacidade de produção de força muscular é diminuída com o encurtamento muscular (1,7,9,11,18,20,21,41,42,46,48) . Existem três hipóteses para justificar a diminuição da capacidade de produção de força após o encurtamento do músculo: a não uniformidade dos sarcômeros, o aumento da concentração de prótons e fosfato inorgânico no músculo e a inibição das pontes cruzadas por estresse induzido (20) .…”

Section: Figura 3 Torque Estimado Dos Motores Secundários De Rotaçãounclassified

Modelo para estimativa de força e torque dos músculos rotadores externos do ombro no plano transverso

Castro¹,

Marques²,

Costa³

et al. 2008

RPCD

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RESUMOEstimar a força dos músculos do ombro e compreender o quanto cada músculo contribui para produção do torque em determinado movimento articular torna-se indispensável para a compreensão do movimento humano, bem como para o planejamento da reabilitação de pacientes com disfunções no ombro. Neste sentido, o presente estudo tem como principal objetivo estimar a força muscular e analisar a contribuição dos múscu-los Infra-espinhoso, Redondo Menor, Supra-espinhoso, Deltóide Posterior e Deltóide Médio no torque de rotação externa dinâmico do ombro no plano transverso. Para isso, um modelo de otimização gerado no software MATLAB‚ 7.0 (MathWork Inc, Massachusetts -USA), capaz de estimar a produção de força e torque de cada um dos músculos rotadores externos do ombro foi utilizado.Os músculos Infra-espinhoso e Redondo Menor apresentaram um pico de torque de 22Nm em 20º e 6Nm em 28º, respectivamente, quando o ombro encontrava-se em rotação interna. A magnitude máxima de força alcançada por estes músculos foi de 996N para o Infraespinhoso e 306N para o Redondo Menor. Os músculos Supra-espinhoso, Deltóide Posterior e Deltóide Médio praticamente não produziram torque e obtiveram magnitudes pequenas de força. Estes resultados apontam que os músculos Infraespinhoso e Redondo Menor são preferencialmente recrutados para o gesto de rotação externa do ombro.Palavras-chave: ombro, torque muscular, força muscular e modelo de otimização. ABSTRACT Model for force and moment prediction of shoulder external rotation muscles in the transverse plane Estimating shoulder muscle forces and understanding the contribution of each muscle to the torque generated during joint movement is indis-

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“…This phenomenon was reported in skeletal muscle by Jewell and Wilkie (Jewell and Wilkie, 1960) and later referred to by Edman (Edman, 1975) as shortening-induced deactivation. However, it has been shown in crab muscle (Josephson and Stokes, 1999b) and in whole cat soleus muscle (Herzog et al, 2000) that the observed deactivation is not dependent on the shortening alone but is proportional to the amount of work done by the shortening muscle. Josephson and Stokes thus referred to the phenomenon as WDD (Josephson and Stokes, 1999b).…”

Section: Introductionmentioning

confidence: 98%

A new model for force generation by skeletal muscle, incorporating work-dependent deactivation

Williams

2010

Journal of Experimental Biology

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SUMMARYA model is developed to predict the force generated by active skeletal muscle when subjected to imposed patterns of lengthening and shortening, such as those that occur during normal movements. The model is based on data from isolated lamprey muscle and can predict the forces developed during swimming. The model consists of a set of ordinary differential equations, which are solved numerically. The model's first part is a simplified description of the kinetics of Ca 2+ release from sarcoplasmic reticulum and binding to muscle protein filaments, in response to neural activation. The second part is based on A. V. Hill's mechanical model of muscle, consisting of elastic and contractile elements in series, the latter obeying known physiological properties. The parameters of the model are determined by fitting the appropriate mathematical solutions to data recorded from isolated lamprey muscle activated under conditions of constant length or rate of change of length. The model is then used to predict the forces developed under conditions of applied sinusoidal length changes, and the results compared with corresponding data. The most significant advance of this model is the incorporation of work-dependent deactivation, whereby a muscle that has been shortening under load generates less force after the shortening ceases than otherwise expected. In addition, the stiffness in this model is not constant but increases with increasing activation. The model yields a closer prediction to data than has been obtained before, and can thus prove an important component of investigations of the neural-mechanical-environmental interactions that occur during natural movements.

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The relationship between force depression following shortening and mechanical work in skeletal muscle

Cited by 98 publications

References 19 publications

Force recovery after activated shortening in whole skeletal muscle: transient and steady-state aspects of force depression

Force recovery after activated shortening in whole skeletal muscle: transient and steady-state aspects of force depression

Modelo para estimativa de força e torque dos músculos rotadores externos do ombro no plano transverso

A new model for force generation by skeletal muscle, incorporating work-dependent deactivation

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