Reproducibility and validity of the quadriceps muscle integrated electromyogram threshold during incremental cycle ergometry

Taylor, A. D.; Bronks, Roger

doi:10.1007/bf00238572

Cited by 35 publications

(30 citation statements)

References 9 publications

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“…Lippold (1952) was the ®rst to identify this phenomenon during isometric contractions. Since then Taylor and Bronks (1995) have also obtained the same results during dynamic contractions. This increase in neural activity occurs during exercise of incremental intensity in response to the need to recruit progressively additional motor units.…”

Section: Introductionsupporting

confidence: 55%

“…Most of the time the detection of thresholds has been from individual data, and as a result the authors have noted problems in detecting a breakpoint (Taylor and Bronks 1994). Authors have also mentioned technical problems encountered in the collection and analysis of the EMG signal (Taylor and Bronks 1995) and intersubject variabilities (Taylor and Bronks 1994;HeÂ lal et al 1987).…”

Section: Introductionmentioning

confidence: 99%

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Electromyogram as an indicator of neuromuscular fatigue during incremental exercise

Hanon

Thépaut-Mathieu

Hausswirth

et al. 1998

European Journal of Applied Physiology

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This study analysed the changes in the electromyographic activity (EMG) of the vastus lateralis muscle (VL) during an incremental maximal oxygen uptake test on a treadmill. A breakpoint in the integrated electromyogram (iEMG)-velocity relationship has already been interpreted in two ways: either as a sign of neuromuscular fatigue or as an expression of the iEMG-velocity relationship characteristics. The aim of this study was to test a method of distinguishing fatigue eects from those due to increases in exercise power. Eight well-trained male runners took part in the study. They completed a running protocol consisting of 4-min stages of increments in power output. Between each stage (about 15 s after the start of a minute at rest), the subjects had to maintain a standard eort: a 10-s isometric leg extension contraction [50% isometric maximal voluntary contraction (IMVC)]. The EMG was recorded during the running and isometric protocols, a change in the EMG signal during the isometric exercise being considered as the sign of fatigue. The iEMG-velocity relationships were strongly ®tted by a second-order polynomial function for data taken at both the start (r 0.98) and the end (r 0.98) of the stage. Based on the stability of the 50%IMVC-iEMG relationship noted between stages, the start-iEMG has been identi®ed as expressing the iEMG-velocity relationship without fatigue. The stage after which end-iEMG increased signi®cantly more steeply than start-iEMG was considered as the iEMG threshold and was simultaneous with the ventilatory equivalent for carbon dioxide threshold. The parallel changes of minute ventilation and iEMG would suggest the existence of common regulation stimuli linked either to eort intensity and/or to metabolic conditions. The fall in intracellular [K + ] has been discussed as being one of the main factors in regulating ventilation.

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Section: Introductionsupporting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Electromyogram as an indicator of neuromuscular fatigue during incremental exercise

Hanon

Thépaut-Mathieu

Hausswirth

et al. 1998

European Journal of Applied Physiology

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“…Disagreements between previous studies could have been caused by the intrinsic variability of EMG recordings (Taylor and Bronks, 1995;Hug et al, 2004). For example, integrated EMG (iEMG) increases with increasing angular velocity during concentric contractions (Westing et al, 1991;Amiridis et al, 1996).…”

Section: Methodological Considerationsmentioning

confidence: 96%

“…However, this approach is less specific and less reproducible when the RMS obtained during an MVC is used to normalize dynamic contractions. An alternative procedure is to use RMS obtained during a reference dynamic condition as the normalizing value (Westing et al, 1991;Taylor and Bronks, 1995;Amiridis et al, 1996). Variability could be also reduced averaging some experiments performed under similar conditions, as usually done in O 2 kinetics studies ( Jones et al, 2012).…”

Section: Methodological Considerationsmentioning

confidence: 99%

Muscle Activation During Exercise in Severe Acute Hypoxia: Role of Absolute and Relative Intensity

Torres‐Peralta

Losa‐Reyna²,

González-Izal³

et al. 2014

High Altitude Medicine & Biology

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Torres-Peralta, Rafael, José Losa-Reyna, Miriam González-Izal, Ismael Perez-Suarez, Jaime Calle-Herrero, Mikel Izquierdo, and José A.L. Calbet. Muscle activation during exercise in severe acute hypoxia: Role of absolute and relative intensity. High Alt Med Biol 15:472-482, 2014.-The aim of this study was to determine the influence of severe acute hypoxia on muscle activation during whole body dynamic exercise. Eleven young men performed four incremental cycle ergometer tests to exhaustion breathing normoxic (F I o 2 = 0.21, two tests) or hypoxic gas (F I o 2 = 0.108, two tests). Surface electromyography (EMG) activities of rectus femoris (RF), vastus medialis (VL), vastus lateralis (VL), and biceps femoris (BF) were recorded. The two normoxic and the two hypoxic tests were averaged to reduce EMG variability. Peak Vo 2 was 34% lower in hypoxia than in normoxia ( p < 0.05). The EMG root mean square (RMS) increased with exercise intensity in all muscles ( p < 0.05), with greater effect in hypoxia than in normoxia in the RF and VM ( p < 0.05), and a similar trend in VL ( p = 0.10). At the same relative intensity, the RMS was greater in normoxia than in hypoxia in RF, VL, and BF ( p < 0.05), with a similar trend in VM ( p = 0.08). Median frequency increased with exercise intensity ( p < 0.05), and was higher in hypoxia than in normoxia in VL ( p < 0.05). Muscle contraction burst duration increased with exercise intensity in VM and VL ( p < 0.05), without clear effects of F I o 2 . No significant F I o 2 effects on frequency domain indices were observed when compared at the same relative intensity. In conclusion, muscle activation during whole body exercise increases almost linearly with exercise intensity, following a muscle-specific pattern, which is adjusted depending on the F I o 2 and the relative intensity of exercise. Both VL and VM are increasingly involved in power output generation with the increase of intensity and the reduction in F I o 2 .

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“…Reliability of EMG data between testing sessions has typically been assessed for isometric (11,14,16,17,23), slow dynamic (2,19), and infrequently for ballistic movements (8). The reliability of EMG data between testing sessions of isometric exercises has been shown to be highly reliable for quadriceps muscle activation, with a mean ICC of 0.99 and CVintra ranging from 5.30% to 7.2% (14,17) and moderately to high reliable for the hamstrings, with ICC values ranging from 0.69 to 0.77 (11).…”

Section: Introductionmentioning

confidence: 99%

Reliability of Surface Electromyography During Maximal Voluntary Isometric Contractions, Jump Landings, and Cutting

Fauth

Petushek

Feldmann

et al. 2010

Journal of Strength and Conditioning Research

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The reliability of electromyographic (EMG) data has been examine for isometric and slow dynamic tasks, but little is known about the repeatability of this data for ballistic movements. The purpose of this study was to examine the within-session, trial-to-trial reliability of a variety of quadriceps and hamstrings muscles during isometric and ballistic activities. Data were analayzed by way of intraclass correlation coefficients (ICC), inter-subject coefficients of variation (CVinter), and intra-subject coefficients (CVintra). Twenty-four subjects performed 3 repetitions each of 2 randomly ordered test exercises, including landing from a depth jump (J) and cutting after a 10-m sprint (C). Data were acquired and processed with root mean square EMG for the muscles assessed, and data were analyzed for each exercise using a repeated measures analysis of variance. Results revealed that all ICC values were greater than 0.80, with most values greater than 0.90, CVinter values ranged from 5.4% to 148.7%, and CVintra values ranged from 11.5% to 49.3%. This study indicates that EMG is a reliable method for assessing the reproducibility of both the quadriceps and hamstrings muscle activation during either isometric or ballistic exercises.

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Reproducibility and validity of the quadriceps muscle integrated electromyogram threshold during incremental cycle ergometry

Cited by 35 publications

References 9 publications

Electromyogram as an indicator of neuromuscular fatigue during incremental exercise

Electromyogram as an indicator of neuromuscular fatigue during incremental exercise

Muscle Activation During Exercise in Severe Acute Hypoxia: Role of Absolute and Relative Intensity

Reliability of Surface Electromyography During Maximal Voluntary Isometric Contractions, Jump Landings, and Cutting

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