Maximal contraction methods influence the magnitude and reliability of global electromyographic signal characteristics

Tomko, Patrick M.; Colquhoun, Ryan J.; Banks, Nile F.; Magrini, Mitchel A.; Muddle, Tyler W.D.

doi:10.1016/j.jelekin.2019.07.002

Cited by 4 publications

(16 citation statements)

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“…ICCs > 0.75 represent good reliability, 0.50 to 0.75 moderate reliability, and <0.50 poor reliability [ 39 ]. Our findings were in line with the ones reported in recent studies: Desmyttere and colleagues claimed as “good to excellent” the reliability of a hip strength assessment system whose ICC values resulted in the range of 0.77–0.95 [ 40 ]. Sung et al found ICC values of 0.96–0.98 for a portable dynamometer anchoring system to be used in a supine position to assess knee extensor strength [ 32 ].…”

Section: Discussionsupporting

confidence: 93%

Reliability of a Custom Device Used to Measure Isometric Knee Flexor and Extensor Strength in Standing Position

Minuti

Cigni

Costagli³

et al. 2023

Life

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Background: Assessing lower limb strength in the field is problematic, as the “gold standard assessment” with isokinetic strength is cumbersome, and the device is costly and not transportable and keeps the angle of the hip at around 90°. Methods: We evaluated isometric muscle strength in a standing position with the help of an exoskeleton that holds the subject and makes the test easily repeatable. Results: The optimal device angles for hip and knee were, respectively, 20° and 80° for flexor tests and 30° and 40° for extensor tests. Test–retest reliability was very high for the right knee extensor (ICC 0.96-0.98), left knee extensor (ICC 0.96–0.97), right knee flexor (ICC 0.91–0.96), and left knee flexor (ICC 0.96–0.97). Furthermore, the typical error in percent (T.E.%) ranged from 2.50 to 5.50%, and the change in the mean in percent ranged from 0.84 to 7.72%, making it possible to determine even a slight variation in force. Conclusions: this new method could represent a valid alternative for assessing strength, due to the high reliability and the favorable joint position, particularly in football.

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Section: Discussionsupporting

confidence: 93%

Reliability of a Custom Device Used to Measure Isometric Knee Flexor and Extensor Strength in Standing Position

Minuti

Cigni

Costagli³

et al. 2023

Life

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“…The firing rates of active MUs provide a gauge of neural drive to the muscle (Farina et al, 2014). Previous studies examined agonist and antagonist activity via EMG amplitude and frequency (Tomko et al, 2018(Tomko et al, , 2019, which are indicators of muscle activation, but not necessarily of neural drive (Farina et al, 2014;Martinez-Valdes et al, 2018). A common method used to assess changes in neural drive is to calculate MFR as a function of MUAP AMP (Hu et al, 2013;Miller et al, 2018Miller et al, , 2019Sterczala et al, 2018b).…”

Section: Discussionmentioning

confidence: 99%

“…Agonist muscle activity dictates the rate of force development and the output of the limb during voluntary efforts (Maffiuletti et al, 2016;Miller et al, 2019;Tomko et al, 2018Tomko et al, , 2019. It is reported that the torque output of a limb is regulated by the firing rates of the motoneurons innervating agonist and antagonist muscles (Carolan & Cafarelli, 1992;De Luca & Mambrito, 1987;Hendrix et al, 2010;Klein et al, 2001;Mullany et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…MUs, regardless of MVC type. The analysis of MU firing rates during the steady torque regions of MVC EXP and MVC RAMP was done to align better with previous research analysing EMG signal characteristicsF I G U R E 9The plotted mean firing (MFR) versus motor unit action potential amplitude (MUAP AMP ) relationships with 95% confidence bands from the biceps brachii (BB) during the explosive (MVC EXP ) and ramp (MVC RAMP ) maximum voluntary contractions for all subjects included in the BB firing rate ANOVA model(Tomko et al, 2018(Tomko et al, , 2019. Our results indicate that the rate of torque development should be controlled for during investigations where MU control strategies are being evaluated.…”

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confidence: 99%

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An examination of motor unit firing rates during steady torque of maximal efforts with either an explosive or slower rate of torque development

Reece

Arnold

Herda

2021

Experimental Physiology

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The primary purpose of the present study was to examine motor unit (MU) firing rates in agonist and antagonist muscles during periods of steady, maximal efforts using explosive and slower rates of torque development. A secondary purpose was to analyse the MU firing rate versus action potential amplitude relationships of the agonist and antagonist muscles during maximal efforts. Thirteen subjects (mean ± SD; age, 21.2 ± 3.6 years; mass 81.1 ± 21.3 kg; and stature, 177.1±9.9 cm) performed two maximal isometric trapezoid muscle actions of the elbow flexors that included either an explosive or a slower, linearly increasing rate (ramp) of torque development. Surface EMG signals of the biceps brachii (BB) and triceps brachii (TB) muscles were collected and decomposed into their constituent MU action potential trains. The MU firing rate versus action potential amplitude relationships of the BB (agonist) and TB (antagonist) muscles were analysed. Moderate to strong relationships (|r| ≥ 0.65) were present for the explosive and ramp contractions in the agonist and antagonist muscles.Firing rates of smaller and larger MUs were higher during the explosive [mean ± SD; agonist = 18.1 ± 6.9 pulses per second (pps), antagonist = 22.0±3.9 pps] than the ramp (agonist = 14.0 ± 5.1 pps, antagonist = 18.3 ± 4.4 pps) contractions for the agonist (P = 0.013) and antagonist muscles (P = 0.007). The antagonist muscle exhibits a similar MU firing rate versus action potential amplitude relationship to the agonist muscle at maximal efforts. Future research should investigate the effects of shortterm resistance training on antagonist firing rates and the involvement of peripheral feedback on firing rates during maximal efforts performed at various rates of torque development.

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“…It is expected that there are subtle, but meaningful differences in the actual pennation angle between subjects due to natural variability in the anatomical structure of the vastus lateralis. Despite this known limitation, EMG MPF still routinely provides indirect evidence of fatigue-induced decreases in muscle fiber conduction velocity [24,35]. Taken together, the present study extended the previous isometric [37] and cycle ergometry [36] findings to maximal, bilateral, concentric, isokinetic, leg extensions and also found a lack of consistent day-to-day fatigue-induced responses for EMG MPF, which may be due to electrode placement and/or inter-individual differences in actual vastus lateralis pennation angle.…”

Section: Discussionmentioning

confidence: 99%

Day to Day Consistency and Inter-subject Variability of Neuromuscular Responses and Performance Fatigability as the Result of Maximal, Bilateral, Dynamic Leg Extensions

Keller

Housh

Anders

et al. 2020

J. of SCI. IN SPORT AND EXERCISE

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Purpose The purpose of the present study was to examine the day-to-day consistency and inter-subject variability of composite and individual, neuromuscular and torque patterns of responses as a result of a fatiguing bout of maximal, bilateral, isokinetic leg extension muscle actions. Methods Ten men (Mean ± SD = 21.6 ± 2.5 years) completed two testing visits consisting of pretest and posttest maximal voluntary isometric contractions (MVIC) as well as 25 maximal, bilateral, isokinetic (180°/s), leg extension muscle actions. Electromyographic (EMG) and mechanomyographic (MMG) signals were collected from the vastus lateralis and normalized to the MVIC. Performance fatigability was defined as the percent decline in torque between the average of repetitions 1, 2, and 3 and repetitions 23, 24, and 25. Polynomial regression was used to examine the individual and composite relationships between EMG amplitude (AMP), EMG mean power frequency (MPF), MMG AMP, MMG MPF, and torque versus repetitions. Results There was no significant difference (d = 0.80; P = 0.17) in the performance fatigability between Day 1 (19.3% ± 7.1%) and Day 2 (26.9% ± 11.3%). Polynomial regression indicated substantial inter-subject variability, but high day-to-day consistency. ConclusionThe composite EMG AMP, MMG AMP, and MMG MPF patterns of responses demonstrated consistency across days. The composite EMG MPF patterns of responses, however, were not consistent between Day 1 and Day 2. In addition, based on the high inter-subject variability, future studies should present both composite patterns of neuromuscular responses and the patterns of responses on a subject-by-subject basis to make inferences regarding fatigue-induced changes in motor unit activation strategies.

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Maximal contraction methods influence the magnitude and reliability of global electromyographic signal characteristics

Cited by 4 publications

References 40 publications

Reliability of a Custom Device Used to Measure Isometric Knee Flexor and Extensor Strength in Standing Position

Reliability of a Custom Device Used to Measure Isometric Knee Flexor and Extensor Strength in Standing Position

An examination of motor unit firing rates during steady torque of maximal efforts with either an explosive or slower rate of torque development

Day to Day Consistency and Inter-subject Variability of Neuromuscular Responses and Performance Fatigability as the Result of Maximal, Bilateral, Dynamic Leg Extensions

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