The influence of electrode placement over the innervation zone on electromyographic amplitude and mean power frequency versus isokinetic torque relationships

Spectral electromyographic (EMG) changes in human quadriceps muscles were studied to reinvestigate discrepant results concerning mean power frequency (MPF) changes during dynamic exercise. An incremental test consisting of a quasi-linear increase in mechanical power on a bicycle ergometer (for 20–100% of maximal aerobic power) was performed by forty subjects. During this test, surface EMGs from the quadriceps muscles showed that EMG total power (PEMG) increased with a curvilinear pattern for every subject, whereas MPF kinetics varied from one subject to another. PEMG changes had the same shape, which would lead to disappointing results in terms of discrimination between subjects. The ability of normalized MPF kinetics to define significant clusters of subjects was tested using a principal component analysis. This analysis led to the projection of all experiments onto a plane and revealed a relevant grouping of MPF profiles. Differences in MPF kinetics between clusters are interpreted in terms of various possibilities of balance between physiological events leading to an increase or a decrease in MPF.

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Mean power frequency during speech in myalgia patients

Journal of Oral Rehabilitation ◽

10.1111/j.1365-2842.2010.02101.x ◽

2010 ◽

Vol 37 (9) ◽

pp. 692-697 ◽

Cited By ~ 2

Author(s):

E. SUZUKI ◽

S. ISHIGAKI ◽

H. YATANI ◽

E. MORISHIGE ◽

M. UCHIDA

Keyword(s):

Mean Power ◽

Mean Power Frequency ◽

Power Frequency

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Interlimb Neuromuscular Responses During Fatiguing, Bilateral, Leg Extension Exercise at a Moderate Versus High Load

Motor Control ◽

10.1123/mc.2020-0050 ◽

2021 ◽

Vol 25 (1) ◽

pp. 59-74

Author(s):

Taylor K. Dinyer ◽

Pasquale J. Succi ◽

M. Travis Byrd ◽

Caleb C. Voskuil ◽

Evangeline P. Soucie ◽

...

Keyword(s):

Vastus Lateralis ◽

High Load ◽

Mean Power ◽

Mean Power Frequency ◽

Leg Extension ◽

Neuromuscular Responses ◽

Power Frequency ◽

The Central Nervous System ◽

Common Drive ◽

Repetitions To Failure

This study determined the load- and limb-dependent neuromuscular responses to fatiguing, bilateral, leg extension exercise performed at a moderate (50% one-repetition maximum [1RM]) and high load (80% 1RM). Twelve subjects completed 1RM testing for the bilateral leg extension, followed by repetitions to failure at 50% and 80% 1RM, on separate days. During all visits, the electromyographic (EMG) and mechanomyographic (MMG), amplitude (AMP) and mean power frequency (MPF) signals were recorded from the vastus lateralis of both limbs. There were no limb-dependent responses for any of the neuromuscular signals and no load-dependent responses for EMG AMP, MMG AMP, or MMG MPF (p = .301–.757), but there were main effects for time that indicated increases in EMG and MMG AMP and decreases in MMG MPF. There was a load-dependent decrease in EMG MPF over time (p = .032) that suggested variability in the mechanism responsible for metabolite accumulation at moderate versus high loads. These findings suggested that common drive from the central nervous system was used to modulate force during bilateral leg extension performed at moderate and high loads.

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