Comparison of techniques to determine human skeletal muscle voluntary activation

Zarkou, Anastasia; Stackhouse, Scott K.; Binder‐Macleod, Stuart A.; Lee, Samuel C. K.

doi:10.1016/j.jelekin.2017.05.011

Cited by 14 publications

(13 citation statements)

References 25 publications

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“…Moreover, the combination of the proposed technique with high-density sEMG recordings can provide the possibility to track the twitch properties of the same motor units across several recording sessions (E. Eduardo Martinez-Valdes et al, 2017) and/or compare them with other peripheral characteristics (Del Vecchio et al, 2017a, 2017b. Finally, the proposed methodology can be usefully applied together with the maximal twitch scan suggested by Orizio et al (Orizio et al, 2016) to evaluate the prevalence of fast or slow contribution to the mechanical output of a specific muscle during stimulated contraction and the interpolated twitch technique (Maffiuletti et al, 2016;Zarkou et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Robust estimation of average twitch contraction forces of populations of motor units in humans

Negro

Orizio

2017

Journal of Electromyography and Kinesiology

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The characteristics of motor unit force twitch profiles provide important information for the understanding of the muscle force generation. The twitch force is commonly estimated with the spike-triggered averaging technique, which, despite the many limitations, has been important for clarifying central issues in force generation. In this study, we propose a new technique for the estimation of the average twitch profile of populations of motor units with uniform contractile properties. The method encompasses a model-based deconvolution of the force signal using the identified discharge times of a population of motor units. The proposed technique was validated using simulations and tested on signals recorded during voluntary activation. The results of the simulations showed that the proposed method provides accurate estimates (relative error <25%) of the main parameters of the average twitch force when the number of identified motor units is between 5% and 15% of the total number of active motor units. It is discussed that current detection and decomposition methods of multi-channel surface EMG signals allow decoding this relative sample of the active motor unit pool. However, even when this condition is not met, our results show that the estimates provided by the new method are anyway always superior to those obtained by the spike triggered average approach, especially for high motor unit synchronization levels and when a relatively small number of triggers is available. In conclusion, we present a new method that overcome the main limitations of the spike-triggered average for the study of contractile properties of individual motor units. The method provides a new reliable tool for the investigation of the determinants of muscle force.

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Section: Discussionmentioning

confidence: 99%

Robust estimation of average twitch contraction forces of populations of motor units in humans

Negro

Orizio

2017

Journal of Electromyography and Kinesiology

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“…For example, joint rotation [5] could shorten the fascicles and, therefore, would not operate on their optimum or dedicated length. Furthermore, the maximal activation assessment at maximal voluntary contractions, as measured using the twitch interpolation technique [1,11], could also be affected by the elasticity of the subject-dynamometer system, resulting in a systematically smaller twitch force [12]. Additionally, the nonrigidity of the dynamometer-subject system can have further implications on the estimation of the tendon’s mechanical (stress, strain or young modulus, stiffness) characteristics.…”

Section: Introductionmentioning

confidence: 99%

Anterior subject positioning affects the maximal exerted isometric plantar flexion moment

Stafilidis

Sickinger

2019

PLoS ONE

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We examined the effect of increased anterior subject positioning toward the dynamometer’s footplate during maximal voluntary isometric contractions (MVCs) on the joint moment, rotation and rate of torque development (RTD). Fourteen subjects, with their hip flexed (110°) and knee fully extended (180°), underwent ramp maximal and rapid voluntary isometric plantar flexion contractions at 4 different positions (0, 3, 6 and 8 cm; randomized). At position “0 cm”, the foot was in full contact with the footplate; at the additional positions, the chair was moved forward. Body kinematics (VICON) and kinetics (HUMAC Norm, PEDAR) were captured synchronously during MVCs and RTDs. The results showed that the maximal exerted joint moment was significantly (p<0.01) increased by >32% from the 0-cm to 8-cm position (126 and 172 Nm, respectively); however, at the “6 cm” and “8 cm” positions, no significant difference was found. The joint rotation was significantly (p<0.01) reduced by >50% (from 15.5 to 7.1°; 0–8 cm). The maxRTD was only significantly higher at “6 cm” compared with the “0 cm” position. The time to reach maxRTD showed shorter tendencies for the “8 cm” position than for all other positions. The results indicate an underestimation of the plantar flexor maximal force potential with the current measuring technique. This could be critical in pre-post study designs where a 2-cm alteration in the chair position can induce an error of ~9% in the joint moment. The joint rotation could be reduced but not completely eliminated. For position standardization purposes, a pressure >220 kPa under the subject’s foot is needed to achieve the maximal joint moment. We discussed the possible origins (fascicle length, neural drive) of the increased joint moment.

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“…The twitch interpolation technique was used to determine VA, which has been reported and validated in previous research 23 . The pulses were delivered to the femoral nerve as for Mmax, described above.…”

Section: Methodsmentioning

confidence: 99%

“…The twitch interpolation technique was used to determine VA, which has been reported and validated in previous research. 23 The pulses were delivered to the femoral nerve as for Mmax, described above. Three maximal voluntary isometric contractions (MVICs) were performed at 60° knee flexion, with the first pulse delivered when the force output reached a stable plateau (superimposed twitch) and a second pulse delivered after relaxation (resting twitch).…”

Section: Peripheral Nerve Stimulationmentioning

confidence: 99%

The effects of verbal cueing for high intended movement velocity on power, neuromuscular activation, and performance

Rheese

Drinkwater

Leung

et al. 2021

Scandinavian Med Sci Sports

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It is widely believed that lifting heavy loads slowly, but with a conscious intention to move at high velocity, can produce resistance training (RT) adaptations indicative of rapid movements. This study investigated the effects of verbally cued high “intended” movement velocity (HIMV) during RT on neuromuscular and performance outcomes. 20 untrained volunteers (aged 24.2 ± 3.9 years) participated in 3 weeks of knee extension training. Participants were randomly allocated to receive verbal cues focusing on high intended movement velocity, HIMV, or steady and controlled movement, TRAD (traditional training). All other training variables, including actual movement velocity (30° s−1), remained constant. Increase in mean power output at 30° s−1 was greater for TRAD than HIMV (76% and 33%, respectively, P = 0.027). There were main effects for time (but no between‐group differences) for maximal isometric force (+14%, P = 0.003), peak torque at 180° s−1 (+22%, P = 0.006), peak torque at 30° s−1 (+29%, P < 0.001), 3‐repetition maximum (+20%, P < 0.001), and resting corticospinal excitability (+43%, P = 0.017). There were no differences between groups or across time for voluntary activation (P = 0.793), spinal excitability (P = 0.686), or intracortical inhibition (all P > 0.05). HIMV verbal cueing did not produce additional neurophysiological or performance benefits when compared to traditional cueing. Overall, our results demonstrated that verbal cueing did not alter the principle of velocity‐specific adaptation. Cueing that increases the duration of maximal effort may be optimal for maximizing average power output at low speeds.

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Comparison of techniques to determine human skeletal muscle voluntary activation

Cited by 14 publications

References 25 publications

Robust estimation of average twitch contraction forces of populations of motor units in humans

Robust estimation of average twitch contraction forces of populations of motor units in humans

Anterior subject positioning affects the maximal exerted isometric plantar flexion moment

The effects of verbal cueing for high intended movement velocity on power, neuromuscular activation, and performance

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