Model-generated decomposition of unfused tetani of motor units evoked by random stimulation

Celichowski, Jan; Raikova, Rositsa; Drzymała‐Celichowska, Hanna; Ciechanowicz-Kowalczyk, I.; Krutki, Piotr; Rusev, Rostislav

doi:10.1016/j.jbiomech.2008.09.013

Cited by 15 publications

(13 citation statements)

References 43 publications

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“…Each of the chosen 30 tetanic curves was decomposed into 41 successive contractions (twitches). The algorithm for decomposition was described in detail by Raikova et al (2007a) and Celichowski et al (2008). In general, it is supposed that a tetanic force curve developed as a result from n pulses is constituted from n contractions with twitchlike forms with different parameters (maximal force amplitude, lead time, contraction and half-relaxation times).…”

Section: Methodsmentioning

confidence: 99%

Dynamic changes of twitchlike responses to successive stimuli studied by decomposition of motor unit tetanic contractions in rat medial gastrocnemius

Celichowski

Raikova

Aladjov

et al. 2014

Journal of Neurophysiology

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Celichowski J, Raikova R, Aladjov H, Krutki P. Dynamic changes of twitchlike responses to successive stimuli studied by decomposition of motor unit tetanic contractions in rat medial gastrocnemius. J Neurophysiol 112: 3116 -3124, 2014. First published September 24, 2014 doi:10.1152/jn.00895.2013.-Unfused tetanic contractions evoked by trains of stimuli at variable interpulse intervals (IPIs) were recorded for 10 fast fatigable (FF), 10 fast resistant (FR), and 10 slow (S) motor units (MUs) and subsequently decomposed with a mathematical algorithm into trains of twitch-shape responses to successive stimuli. The mean stimulation frequencies were matched for each MU to evoke tetani of similar fusion degrees, whereas the variability range of IPIs was in each case 50 -150% of the mean IPI. Force and time parameters of decomposed twitches were analyzed and related to the first response. Considerable variability of the analyzed twitch parameters was observed in each MU, although the largest range of variability occurred in slow MUs. In general, the decomposed twitch responses had longer duration and higher force than single-twitch contractions, although for nine FF and six FR MUs some of the decomposed responses were slightly weaker (but not faster) than the first twitches of these MUs. Comparison of the strongest decomposed twitch to the first decomposed twitch revealed ratios of forces up to 2.35, 3.33, and 6.89 for FF, FR, and S MUs and ratios of force-time areas up to 3.54, 4.67, and 14.26 for FF, FR, and S MUs, whereas for the contraction times the ratios of the longest decomposed twitch to the first twitch amounted to 2.46, 2.07, and 3.52 for FF, FR, and S MUs, respectively. The results indicate that contractile responses to successive action potentials are considerably variable, especially for slow MUs. motor unit; force development; random stimulation pattern; twitch THE FORCE OF A SKELETAL MUSCLE is a result of summation of forces generated by numerous coactive motor units (MUs) and mechanical activity of each MU evoked by trains of action potentials generated by a motoneuron at variable time intervals (Adam et al. 1998;Boe et al. 2005;Masuda and De Luca 1991;Moritz et al. 2005;Westergaard and De Luca 2011). In general, successive MU action potentials recorded in a muscle are quite stable in amplitude and shape (Mambrito and De Luca 1983;Stålberg 2003), although small changes in duration and amplitude of MU action potentials, related to a decrease in muscle fiber conduction velocity, were also reported during 30 s of voluntary activity (Farina and Falla 2007). Contrary to this, the twitchlike responses to successive motoneuronal action potentials within a tetanic contraction are highly variable, as reported in several studies on cat Parmiggiani 1979, 1981) and rat (MacIntosh et al. 2007) muscles. These studies have shown that the amplitude of a single muscle twitch may be significantly smaller than a twitchlike response to one of the stimuli within a train. When the same method was used for tetanic contrac...

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Section: Methodsmentioning

confidence: 99%

Dynamic changes of twitchlike responses to successive stimuli studied by decomposition of motor unit tetanic contractions in rat medial gastrocnemius

Celichowski

Raikova

Aladjov

et al. 2014

Journal of Neurophysiology

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“…It was hypothesised that the different effect of the same given frequency along the two limbs of FT is based on the influence of the time elapsed from the previous frequency on Ca ++ transient which in turn affects the tension due to cross-bridge interaction (Celichowski, 2001;Łochyń ski and Celichowski, 2009). Finally, it has to be considered that at the end of the UGR a nearly fused tetanic stimulation is reached and, according to Celichowski et al (2006), the active MUs can switch to the biphasic longer relaxation changing the shape of the elicited twitch (Celichowski et al, 2008). This leads to an increase in the tension at the tendon on which the next delivered stimulus will add its mechanical output, with larger torque values during DGR.…”

Section: Extra Torque During Ftmentioning

confidence: 99%

Extra-torque of human tibialis anterior during electrical stimulation with linearly varying frequency and amplitude trains

Orizio

Celichowski

Toscani

et al. 2013

Journal of Electromyography and Kinesiology

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“…This is in contrast to the few previous studies that have been done on decomposing muscle force into contributions from individual stimuli (Bobet et al 1993;Raikova et al 2007Raikova et al , 2008Celichowski et al 2008). In these, where models were developed, a general model was fitted to each contraction, with no attempt made to minimise model order or investigate how the model may change over the course of the CFT.…”

Section: Modellingmentioning

confidence: 99%

“…Although Bobet et al (1993) show some trends in how parameters change, a detailed analysis of how the pulse shape changes with input conditions is not provided. Raikova et al (2007Raikova et al ( , 2008 and Celichowski et al (2008) model the summation of twitches for various types of motor units by describing the response to CFTs in terms of the response to each individual stimulus. In their study an analytical function is used which describes the twitch shape using six parameters .…”

Section: Introductionmentioning

confidence: 99%

Modelling the isometric force response to multiple pulse stimuli in locust skeletal muscle

et al. 2011

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An improved model of locust skeletal muscle will inform on the general behaviour of invertebrate and mammalian muscle with the eventual aim of improving biomedical models of human muscles, embracing prosthetic construction and muscle therapy. In this article, the isometric response of the locust hind leg extensor muscle to input pulse trains is investigated. Experimental data was collected by stimulating the muscle directly and measuring the force at the tibia. The responses to constant frequency stimulus trains of various frequencies and number of pulses were decomposed into the response to each individual stimulus. Each individual pulse response was then fitted to a model, it being assumed that the response to each pulse could be approximated as an impulse response and was linear, no assumption were made about the model order. When the interpulse frequency (IPF) was low and the number of pulses in the train small, a second-order model provided a good fit to each pulse. For moderate IPF or for long pulse trains a linear third-order model provided a better fit to the response to each pulse. The fit using a second-order model deteriorated with increasing IPF. When the input comprised higher IPFs with a large number of pulses the assumptions that the response was linear could not be confirmed. A generalised model is also presented. This model is second-order, and contains two nonlinear terms. The model is able to capture the force response to a range of inputs. This includes cases where the input comprised of higher frequency pulse trains and the assumption of quasi-linear behaviour could not be confirmed.

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Model-generated decomposition of unfused tetani of motor units evoked by random stimulation

Cited by 15 publications

References 43 publications

Dynamic changes of twitchlike responses to successive stimuli studied by decomposition of motor unit tetanic contractions in rat medial gastrocnemius

Dynamic changes of twitchlike responses to successive stimuli studied by decomposition of motor unit tetanic contractions in rat medial gastrocnemius

Extra-torque of human tibialis anterior during electrical stimulation with linearly varying frequency and amplitude trains

Modelling the isometric force response to multiple pulse stimuli in locust skeletal muscle

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