Initial conditions influence the characteristics of ballistic contractions in the ankle dorsiflexors

Richartz, Christophe; Lévénez, Morgan; Boucart, J.; Duchateau, Jacques

doi:10.1007/s00421-010-1564-x

Cited by 4 publications

(13 citation statements)

References 44 publications

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“…The current results may be construed as reflecting a type of preparatory inhibition in relation to elicited speech (Conrad, Benecke, and Goehmann, 1983;Richartz et al, 2010;Kolářová et al, 2016;Lebon et al, 2016;Doque et al, 2017). However, there is a difference in the time scales; in Lebon et al's study, inhibitory preparatory processes were found only 200 ms (but not 500 ms or 900 ms) prior to an imperative signal to move.…”

mentioning

confidence: 73%

“…Lip muscles activation, as recorded in sEMG, was higher during covert speech, compared to activation in a silent visualization task (Livesay et al, 1996). However, studies that have examined EMG muscle activity of peripheral musculature in tasks unrelated to language (Conrad, Benecke, and Goehmann, 1983;Richartz, Lévénez, Boucart, & Duchateau, 2010;Kolářová, Krobo, Kolář, Hluštík, & Polehlová, 2016), using both real and imagined movements, reported a 'premotor silent period' that is, an inhibition relative to baseline. Thus, the approach to data analysis in the current study was to compare the relative activation of articulatory muscles before (baseline) and during stimulus presentation (up to the 'go' cue for snetence repetition) in the different input and intended response conditions.…”

Section: Introductionmentioning

confidence: 98%

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Modulation of articulation muscles during listening and reading: a matter of intention to speak out loud

Zur

Eviatar

Karni

2019

Preprint

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Articulation of a given speech sound is often contingent on the intention to produce subsequent sounds (co-articulation). Thus, intended acts affect the way current acts are executed. Here we show that the intention to subsequently repeat a short sentence, overtly or covertly, significantly modulated the articulatory musculature already during listening or reading (i.e., during the input phase). Young adults were instructed to read (whole sentences or word-by-word) or listen to recordings of sentences to be repeated afterwards. Surface electromyography (sEMG) recordings showed significant reductions in articulatory muscle activity, above the orbicularis-oris and the sternohyoid muscles, compared to baseline, during the input phase. These temporary reductions in EMG activity were contingent on the intention to subsequently repeat the input overtly or covertly, as well as on the input modality. Inhibition was stronger when an overt response was intended. When participants intended to repeat the sentences covertly, only auditory input but not reading resulted in significant reductions in sEMG activities during the input phase. Higher temporal resolution analyses also showed different patterns of activity modulations before the cue to respond, depending on the input modality and the intended response. Only when repetition was to be overt, a significant build-up of activity occurred after sentence presentation, before the cue to respond; this build-up was most pronounced when the sentence was heard or read wordby-word. Neurolinguistic models suggest that language perception and articulation interact; the current results suggest that the interaction begins already during the input phase, listening or reading, and reflects the intended responses.

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mentioning

confidence: 73%

Section: Introductionmentioning

confidence: 98%

Modulation of articulation muscles during listening and reading: a matter of intention to speak out loud

Zur

Eviatar

Karni

2019

Preprint

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“…The lack of increase in sEMG magnitude, led the authors to suggest that the facilitated contractions may be due to musculoskeletal biomechanics: that is, during the flexion-to-extension sequence, the contracting flexors lengthen the extensors while coactive as antagonists, placing them at optimal muscle length immediately prior to their voluntary activation as an agonist (Gabriel et al, 2001a). Unfortunately, coactivation was not assessed as a probable mechanism in this particular study, but was later identified as a torque contributor by Richartz et al (2010). Richartz et al (2010) studied the maximal rate of isometric dorsiflexion torque development in response to the following conditions: (1) relaxation of the dorsiflexors; (2) pre-activation of the dorsiflexors at 20% MVC; and (3) a rapid reversal contraction of the plantar flexors at 25, 50, and 75% of MVC.…”

Section: Introductionmentioning

confidence: 86%

“…Unfortunately, coactivation was not assessed as a probable mechanism in this particular study, but was later identified as a torque contributor by Richartz et al (2010). Richartz et al (2010) studied the maximal rate of isometric dorsiflexion torque development in response to the following conditions: (1) relaxation of the dorsiflexors; (2) pre-activation of the dorsiflexors at 20% MVC; and (3) a rapid reversal contraction of the plantar flexors at 25, 50, and 75% of MVC. The average sEMG amplitude was calculated from its onset to 25 ms, 50 ms, and to the time point where dτ/dt max occurred.…”

Section: Introductionmentioning

confidence: 99%

Effects of the Proprioceptive Neuromuscular Facilitation Contraction Sequence on Motor Skill Learning-Related Increases in the Maximal Rate of Wrist Flexion Torque Development

Green

McGuire

Gabriel

2021

Front. Hum. Neurosci.

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Background: The proprioceptive neuromuscular facilitation (PNF) reciprocal contraction pattern has the potential to increase the maximum rate of torque development. However, it is a more complex resistive exercise task and may interfere with improvements in the maximum rate of torque development due to motor skill learning, as observed for unidirectional contractions. The purpose of this study was to examine the cost-benefit of using the PNF exercise technique to increase the maximum rate of torque development.Methods: Twenty-six participants completed isometric maximal extension-to-flexion (experimental PNF group) or flexion-only (control group) contractions at the wrist. Ten of the assigned contractions were performed on each of three sessions separated by 48-h for skill acquisition. Retention was assessed with 5 contractions performed 2-weeks after acquisition. Torque and surface electromyographic (sEMG) activity were analyzed for evidence of facilitated contractions between groups, as well as alterations in muscle coordination assessed across test sessions. The criterion measures were: mean maximal isometric wrist flexion toque; the maximal rate of torque development (dτ/dtmax); root-mean-square error (RMSE) variability of the rate of torque versus torque phase-plane; the rate of wrist flexion muscle activation (Q30); a coactivation ratio for wrist flexor and extensor sEMG activity; and wrist flexor electromechanical delay (EMD).Results: There were no significant differences between groups with respect to maximal wrist flexion torque, dτ/dtmax or RMSE variability of torque trajectories. Both groups exhibited a progressive increase in maximal strength (+23.35% p < 0.01, η2 = 0.655) and in dτ/dtmax (+19.84% p = 0.08, η2 = 0.150) from the start of acquisition to retention. RMSE was lowest after a 2-week rest interval (−18.2% p = 0.04, η2 = 0.198). There were no significant differences between groups in the rate of muscle activation or the coactivation ratio. There was a reduction in coactivation that was retained after a 2-week rest interval (−32.60%, p = 0.02, η2 = 0.266). Alternatively, EMD was significantly greater in the experimental group (Δ 77.43%, p < 0.01, η2 = 0.809) across all sessions. However, both groups had a similar pattern of improvement to the third consecutive day of testing (−16.82%, p = 0.049, η2 = 0.189), but returned close to baseline value after the 2-week rest interval.Discussion: The wrist extension-to-flexion contraction pattern did not result in a greater maximal rate of torque development than simple contractions of the wrist flexors. There was no difference between groups with respect to motor skill learning. The main adaptation in neuromotor control was a decrease in coactivation, not the maximal rate of muscle activation.

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“…The breakpoint for this interrupted regression was calculated ( Linden, 2015 ) and the coefficients for the first part of linear regression, i.e., up to the breakpoint, was reported. To compare the absolute values of RFD between subjects, the peak force and the peak RFD were then normalized to the MVCF ( Richartz et al, 2010 ) obtained at PRE. Notably, the RFD data at POST were normalized with respect to the MVCF at PRE as well.…”

Section: Methodsmentioning

confidence: 99%

Neuromuscular Fatigue Does Not Impair the Rate of Force Development in Ballistic Contractions of Submaximal Amplitudes

et al. 2018

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The effect of muscle fatigue on rate of force development (RFD) is usually assessed during tasks that require participants to reach as quickly as possible maximal or near-maximal force. However, endurance sports require athletes to quickly produce force of submaximal, rather than maximal, amplitudes. Thus, this study investigated the effect of muscle fatigue induced by long-distance running on the capacity to quickly produce submaximal levels of force. Twenty-one male amateur runners were evaluated before and shortly after a half-marathon race. Knee extensors force was recorded under maximal voluntary and electrically evoked contractions. Moreover, a series of ballistic contractions at different submaximal amplitudes (from 20 to 100% of maximal voluntary force) was obtained, by asking the participants to reach submaximal forces as fast as possible. The RFD was calculated for each contraction. After the race, maximal voluntary activation, resting doublet twitch, maximal force, and RFD during maximal contraction decreased (-12, -12, -21, and -19%, respectively, all P-values < 0.0001). Nevertheless, the RFD values measured during ballistic contractions up to 60% of maximal force were unaffected (all P-values > 0.4). Long-distance running impaired the capacity to quickly produce force in ballistic contractions of maximal, but not of submaximal, amplitudes. Overall, these findings suggest that central and peripheral fatigue do not affect the quickness to which muscle contracts across a wide range of submaximal forces. This is a relevant finding for running and other daily life activities that rely on the production of rapid submaximal contractions rather than maximal force levels.

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Initial conditions influence the characteristics of ballistic contractions in the ankle dorsiflexors

Cited by 4 publications

References 44 publications

Modulation of articulation muscles during listening and reading: a matter of intention to speak out loud

Modulation of articulation muscles during listening and reading: a matter of intention to speak out loud

Effects of the Proprioceptive Neuromuscular Facilitation Contraction Sequence on Motor Skill Learning-Related Increases in the Maximal Rate of Wrist Flexion Torque Development

Neuromuscular Fatigue Does Not Impair the Rate of Force Development in Ballistic Contractions of Submaximal Amplitudes

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