Analysis of Vibration Exercise at Varying Frequencies by Different Fatigue Estimators

Xu, Lin; Rabotti, C.; Mischi, Massimo

doi:10.1109/tnsre.2015.2493358

Cited by 19 publications

(27 citation statements)

References 55 publications

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“…Only a small number of studies have investigated the fatiguing effects of vibration stimulation through the analysis of EMG frequency variables. Mischi et al and Xu et al have recently investigated the fatiguing effects of vibration through sEMG frequency analysis [15], [27]. Our study design and the vibration stimulation device differs from these earlier reported studies [15], [27].…”

Section: Overall Fatiguing Effectsmentioning

confidence: 86%

“…This might be considered a limitation. However it is important to note that a recent ULV study found no differences in the MEF, MDF and RMS values after removing the so called motion artifacts [27]. Further, another study by the same group have reported that the so called 'motion artifacts' are in fact 'stretch reflex' responses and hence filtering them might actually remove important information about stretch reflex responses and central fatigue mechanisms [25].…”

Section: Limitations Of the Studymentioning

confidence: 99%

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Fatiguing Effects of Indirect Vibration Stimulation in Upper Limb Muscles- pre, post and during Isometric Contractions Superimposed on Upper Limb Vibration

Pujari¹,

Neilson

Cardinale³

2018

Preprint

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Background: Indirect vibration stimulation i.e. whole body vibration and upper limb vibration (ULV), are gaining popularity as exercise intervention for sports and rehabilitation applications. However, the fatiguing effects of indirect vibration stimulation are not yet fully understood. In addition, current vibration stimulation devices have a series of limitations. For this scope, we investigated the effects of ULV superimposed on fatiguing graded isometric contractions using a newly, purpose developed upper limb stimulation device. Twelve healthy volunteers were exposed to both ULV superimposed to fatiguing isometric contractions, at 80% of the maximum voluntary contractions (V) and just isometric contractions performed on a custom designed arm curl/flexion device-Control (C). The stimulation used consisted of 30Hz frequency of 0.4mm amplitude. Surface electromyographic (EMG) activity of the Biceps Brachii (BB), Triceps Brachii (TB), and Flexor Carpi Radialis (Forearm-FCR) were measured during both V and C conditions. EMG amplitude (EMGrms) and mean frequency (MEF) were computed to quantify muscle activity and fatigue levels respectively. Results: All three muscles BB, TB and FCR displayed significantly higher reduction in MEFs and corresponding significant increase in EMGrms with the V than the C, during fatiguing contractions (P < 0.05). Post vibration treatment, all muscles showed higher levels of MEFs after recovery compared to the control. Conclusions: Our results show that near maximal (80% of MVC) isometric fatiguing contractions superimposed on vibration stimulation lead to a higher rate of fatigue development compared to the isometric contraction alone in the upper limb muscles. Results also show, higher manifestation of mechanical fatigue post treatment with vibration compared to the control. Vibration superimposed on isometric contraction not only seems to alter the neuromuscular function during fatiguing efforts by inducing higher neuromuscular load but also post vibration treatment, potentially through the augmentation of stretch reflex and/or higher central motor command excitability.

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Section: Overall Fatiguing Effectsmentioning

confidence: 86%

Section: Limitations Of the Studymentioning

confidence: 99%

Fatiguing Effects of Indirect Vibration Stimulation in Upper Limb Muscles- pre, post and during Isometric Contractions Superimposed on Upper Limb Vibration

Pujari¹,

Neilson

Cardinale³

2018

Preprint

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show abstract

“…To this end, the selected 12-s bipolar EMG signal (0.5-12.5 s) was first divided into a series of 1-s, overlapped epochs [33], [34]. Each epoch was moved by one sample in order to produce a continuous CV estimation, the same as the DLL system.…”

Section: ) In Vivomentioning

confidence: 99%

“…Each epoch was moved by one sample in order to produce a continuous CV estimation, the same as the DLL system. The CV in each epoch was then calculated using the ML method [34] and then compared with the CV estimated by the DLL system at the same time instant.…”

Section: ) In Vivomentioning

confidence: 99%

Towards Real-Time Estimation of Muscle-Fiber Conduction Velocity Using Delay-Locked Loop

Rabotti

Mischi

2017

IEEE Trans. Neural Syst. Rehabil. Eng.

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Abstract-Decrease in muscle-fiber conduction velocity (MFCV) during sustained contraction has been widely accepted as myoelectric manifestation of muscle fatigue. Several methods have been proposed in the literature for MFCV estimation by analysing surface electromyography (EMG), e.g., cross-correlation (CC) function and maximum likelihood (ML). However, for all the available methods, windowing of the EMG signal and computationally demanding calculations are required, limiting the possibility to continuously monitor muscle fatigue in real time. In the present study, an adaptive scheme is proposed that permits real-time estimation of MFCV. The proposed scheme is based on a delay-locked loop (DLL). A second-order loop is adopted to track the delay variation over time. An error filter is employed to approximate a ML estimation in case of colored noise. Furthermore, the DLL system is extended for multichannel CV estimation. The performance of the proposed method is evaluated by both dedicated simulations and real EMG signals. Our results show the accuracy of the proposed method to be comparable to that of the ML method for much lower (1/40) computational complexity, especially suited for real-time MFCV measurements. Use of this method can enable new studies on myoelectric fatigue, possibly leading to new insight on the underlying physiological processes.

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“…It is clear that the neuromuscular reflex response after VE remains controversial. Studies have suggested VE to produce a large degree of mechanic and myoelectric fatigue on the upper limbs while fatigue leads to decreased excitation from Ia afferents [51,42,43]. Furthermore, studies have reported increased H-reflex amplitude after non-exhausting VE possibly due to MN hyperexcitability [50].…”

Section: Introductionmentioning

confidence: 99%

Effects of vibration-induced fatigue on the H-reflex

Sammali

Rabotti

et al. 2018

Journal of Electromyography and Kinesiology

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Vibration exercise (VE) has been suggested as an effective training for improving muscle strength and coordination. However, the underlying physiological adaptation processes are not yet fully understood, limiting the development of safe and effective exercise protocols. To better understand the neuromuscular responses elicited by VE, we aimed at investigating the acute effects of superimposed vibration on the Hoffmann reflex (H-reflex), measured after fatiguing exercise. Twenty-five volunteers performed four isometric contractions of the right Flexor Carpi Radialis (FCR) with baseline load at 80% of their maximal voluntary contraction (MVC), both with no vibration and with superimposed vibration at 15, 30, and 45 Hz. Fatigue was estimated by MVC test and estimation of electromyographic spectral compression. H-reflex suppression was estimated as the relative decrease after exercise. Our results show that fatiguing exercise determined a decrease in H-reflex amplitude compared to rest condition while vibration determined a lower H-reflex suppression as compared to no vibration. The superimposition of 30-Hz vibration determined the largest acute reduction in force generating capacity (36 N, p < 0.05) and the lowest H-reflex suppression (20%, p < 0.05). These results suggest VE to be particularly suitable in rehabilitation programs for rapid restoration of muscle form and function after immobilization periods.

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Analysis of Vibration Exercise at Varying Frequencies by Different Fatigue Estimators

Cited by 19 publications

References 55 publications

Fatiguing Effects of Indirect Vibration Stimulation in Upper Limb Muscles- pre, post and during Isometric Contractions Superimposed on Upper Limb Vibration

Fatiguing Effects of Indirect Vibration Stimulation in Upper Limb Muscles- pre, post and during Isometric Contractions Superimposed on Upper Limb Vibration

Towards Real-Time Estimation of Muscle-Fiber Conduction Velocity Using Delay-Locked Loop

Effects of vibration-induced fatigue on the H-reflex

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