An EMG frequency-based test for estimating the neuromuscular fatigue threshold during cycle ergometry

Abstract

The purposes of this investigation were twofold: (1) to determine if the model used for estimating the physical working capacity at the fatigue threshold (PWC(FT)) from electromyographic (EMG) amplitude data could be applied to the frequency domain of the signal to derive a new fatigue threshold for cycle ergometry called the mean power frequency fatigue threshold (MPF(FT)), and (2) to compare the power outputs associated with the PWC(FT), MPF(FT), ventilatory threshold (VT), and respiratory compensation point (RCP). Sixteen men [mean (SD) age = 23.4 (3.2) years] performed incremental cycle ergometer rides to exhaustion with bipolar surface EMG signals recorded from the vastus lateralis. There were significant (p < 0.05) mean differences for PWC(FT) [mean (SD) = 168 (36) W] versus MPF(FT) [208 (37) W] and VT [152 (33) W] versus RCP [205 (84) W], but no mean differences for PWC(FT) versus VT or MPF(FT) versus RCP. The mean difference between PWC(FT) and MPF(FT) may be due to the effects of specific metabolites that independently influence the time and frequency domains of the EMG signal. These findings indicated that the PWC(FT) model could be applied to the frequency domain of the EMG signal to estimate MPF(FT). Furthermore, the current findings suggested that the PWC(FT) may demarcate the moderate from heavy exercise domains, while the MPF(FT) demarcates heavy from severe exercise intensities.

Resposta da cinética de consumo de oxigênio e da eficiência mecânica delta de homens e mulheres em diferentes intensidades de esforço

“…Although neither significant difference (p = 0.060) nor interaction (p = 0.062) has been observed between genders, a phenomenon of different magnitude of EMΔ ( (22)(23)(24)(25)(26)(27) . Bell and Ferguson (28) showed in young women, high correlations of the type I myosin heavy chain in 60 and 75 revolutions per minute in cycle ergometer (r = 0.80 and r = 0.84, respectively), when confronted with the mechanical efficiency.…”

“…Bonne et al (25) showed progressive increase of amplitude of the electromyographic activity, demonstrated by the integrated EMG (iEMG) in maximum exertion tests performed in cycle ergometer. The RMS has been applied to study the increase of the total myoelectrical activity in maximum exertion tests in cycle ergometer and can be applied as an indicator of recruiting of motor units of high excitement threshold (25)(26)(27) . In the present study, the hypothesis of high glycolytic metabolism as well as high RER (table 1) observed in the high work loads was corroborated.…”

The Utility of Electromyography and Mechanomyography for Assessing Neuromuscular Function: A Noninvasive Approach

“…Several recent studies have successfully attempted to use the EMG frequency domain as an index of neuromuscular fatigue during isometric muscle action of the biceps brachii [32][33][34] or the vastus lateralis during cycle ergometry. 24,35 Future studies, however, are needed to validate these new methods and determine their application in rehabilitation settings.…”

“…The intersection between the regression line and the y-intercept is identified as the fatigue threshold for that individual, and is theoretically the maximal workload that the individual could continue indefinitely. Recently, Camic and colleagues 24 proposed a method of determining EMG fatigue threshold from a single incremental cycle ergometry test. Briefly, the investigators recorded EMG amplitude from the vastus lateralis at each workload.…”

The influence of the muscle fiber pennation angle and innervation zone on the identification of neuromuscular fatigue during cycle ergometry

“…Previous studies (deVries et al, 1987(deVries et al, , 1990 have shown that the PWC FT is moderately correlated with the onset of blood lactate, can be determined using only submaximal workbouts, and is sensitive to training adaptations in older populations. The PWC FT test has also been utilized to assess physical fitness (deVries et al, 1987), differentiate fatiguing from non-fatiguing work (deVries et al, 1987), demarcate the moderate and heavy exercise intensity domains (Camic et al, 2010a), examine the physiological mechanisms associated with neuromuscular fatigue (Housh et al, 1991), and evaluate the efficacy of creatine, beta-alanine, and arginine as ergogenic aids (Camic et al, 2010b;Stout et al, 2000Stout et al, , 2008. Furthermore, it has been demonstrated (deVries et al, 1990;Housh et al, 1996) that the PWC FT test is not affected by differences in protocol (i.e.…”