scholarly journals Two forms of isometric muscle function: Interpersonal motor task supports a distinction between a holding and a pushing isometric muscle action

2020 ◽  
Author(s):  
Laura V Schaefer ◽  
Frank N Bittmann
Keyword(s):  
Muscle Function ◽  
Frequency Ratio ◽  
Neural Control ◽  
Muscle Action ◽  
Triceps Brachii ◽  
Amplitude Variation ◽  
Mean Frequency ◽  
Power Frequency ◽  
The Mean ◽  
Isometric Muscle

AbstractIn sports and movement sciences isometric muscle function is measured by pushing against a stable resistance. However, subjectively one can hold or push isometrically. Several investigations suggest a distinction of those forms. The aim of this study was to investigate, whether or not these two forms of isometric muscle action can be distinguished by objective parameters in an interpersonal setting. 20 subjects were grouped in 10 same sex pairs, in which one partner should perform the pushing isometric muscle action (PIMA) and the other partner executed the holding isometric muscle action (HIMA). The partners were coupled by an interface including a strain gauge and an acceleration sensor. The mechanical oscillations of the triceps brachii (MMGtri) muscle, its tendon (MTGtri) and the abdominal muscle (MMGobl) were recorded by piezoelectric-sensor-based measurement system (mechanomyography (MMG); mechanotendography (MTG)). Each partner performed three 15s (80% MVIC) and two fatiguing trials (90% MVIC) during PIMA and HIMA, respectively (tasks changed in the couple). Regarded parameters to compare PIMA and HIMA were (1) the mean frequency, (2) the normalized mean amplitude, (3) the amplitude variation, (4) the power in the frequency range of 8 to 15 Hz and (5) a special power-frequency ratio and the number of task failures during HIMA or PIMA (partner who quit the task).A “HIMA failure” occurred in 87.5% of trials (p<0.000). No significant differences between PIMA and HIMA were found for the mean frequency and normalized amplitude. The MMGobl showed a significantly higher values of the amplitude variation (15s: p 0.013; fatigue: p=0.007) and of the power-frequency-ratio (15s: p = 0.040; fatigue: p = 0.002) during HIMA and a higher power in the range of 8 to 15 Hz during PIMA (15s: p=0.001; fatigue: p=0.011). MMGtri and MTGtri showed no significant differences.Based on the findings it is suggested that a holding and a pushing isometric muscle action can be distinguished objectively, whereby a more complex neural control is assumed for HIMA.

scholarly journals Mechanomyography and acceleration show interlimb asymmetries in Parkinson patients without tremor compared to controls during a unilateral motor task

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Laura V. Schaefer ◽  
Nils Löffler ◽  
Julia Klein ◽  
Frank N. Bittmann
Keyword(s):  
Frequency Ratio ◽  
Biceps Brachii ◽  
Motor Task ◽  
Piezoelectric Sensor ◽  
Oscillatory Behavior ◽  
Variation Coefficient ◽  
Amplitude Variation ◽  
Mean Frequency ◽  
Power Frequency ◽  
The Mean

AbstractThe mechanical muscular oscillations are rarely the objective of investigations regarding the identification of a biomarker for Parkinson’s disease (PD). Therefore, the aim of this study was to investigate whether or not this specific motor output differs between PD patients and controls. The novelty is that patients without tremor are investigated performing a unilateral isometric motor task. The force of armflexors and the forearm acceleration (ACC) were recorded as well as the mechanomyography of the biceps brachii (MMGbi), brachioradialis (MMGbra) and pectoralis major (MMGpect) muscles using a piezoelectric-sensor-based system during a unilateral motor task at 70% of the MVIC. The frequency, a power-frequency-ratio, the amplitude variation, the slope of amplitudes and their interlimb asymmetries were analysed. The results indicate that the oscillatory behavior of muscular output in PD without tremor deviates from controls in some parameters: Significant differences appeared for the power-frequency-ratio (p = 0.001, r = 0.43) and for the amplitude variation (p = 0.003, r = 0.34) of MMGpect. The interlimb asymmetries differed significantly concerning the power-frequency-ratio of MMGbi (p = 0.013, r = 0.42) and MMGbra (p = 0.048, r = 0.39) as well as regarding the mean frequency (p = 0.004, r = 0.48) and amplitude variation of MMGpect (p = 0.033, r = 0.37). The mean (M) and variation coefficient (CV) of slope of ACC differed significantly (M: p = 0.022, r = 0.33; CV: p = 0.004, r = 0.43). All other parameters showed no significant differences between PD and controls. It remains open, if this altered mechanical muscular output is reproducible and specific for PD.

Crystal Dynamics of the Alloy Cu3Au

1974 ◽  
Vol 52 (22) ◽  
pp. 2235-2239 ◽  
Author(s):  
E. D. Hallman
Keyword(s):  
Inelastic Scattering ◽  
Frequency Ratio ◽  
Large Scale ◽  
Lattice Vibrations ◽  
Frequency Wave ◽  
Mean Frequency ◽  
Resonance Behavior ◽  
The Mean ◽  
Crystal Dynamics ◽  
Disordered Alloy

Using inelastic scattering of slow neutrons, the frequency wave vector dispersion relations for the lattice vibrations in the disordered alloy Cu3Au have been measured at 296 K. The results are similar to those for copper, with the mean frequency ratio (alloy/copper) being 0.778. A Born–von Kármán fit to the data is given. Although detailed measurements of phonon widths have not yet been made, phonons were generally well defined, with no large scale resonance behavior of frequencies or widths observed.

Features for muscle fatigue computed from electromyogram and mechanomyogram: A new one

2016 ◽  
Vol 230 (12) ◽  
pp. 1096-1105 ◽  
Author(s):  
Şükrü Okkesim ◽  
Kezban Coşkun
Keyword(s):  
Muscle Fatigue ◽  
Frequency Ratio ◽  
Biceps Brachii ◽  
Median Frequency ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Power Frequency ◽  
Ratio Change ◽  
The Mean ◽  
New Feature

Muscle fatigue produces negative effects in the performance and it may lead to a muscle failure. This problem makes the quantitative grading of muscle fatigue a necessity in ergonomic and physiological research. Moreover, the quantitative grading of muscle fatigue is needed to increase work and sport productivity and prevent several accidents that result from muscle fatigue. Even though there are many studies for this aim, there is no quantitative criterion for the evaluation of muscle fatigue. The main reason is that muscle fatigue is a complex physiological situation that is dependent on several parameters. Our aim in this study is to present a new feature to evaluate muscle fatigue and prove the reliability of the new feature by making correlation analyses between this with other features. For this aim, electromyography and mechanomyography signals were simultaneously recorded from the biceps brachii and triceps brachii muscles during the isometric and isotonic contractions of 60 healthy volunteers (30 females, 30 males). The mean power frequency and median frequency, which are used in the literature, were compared to the frequency ratio change, the new measure; correlations between the frequency ratio change and the mean power frequency and median frequency were analysed. There was a high correlation between the features, and frequency ratio change can be used to quantitatively evaluate muscle fatigue.

Activation of metabotropic glutamate receptors increase the frequency of spontaneous GABAergic currents through protein kinase A in neonatal rat hippocampal neurons

1995 ◽  
Vol 74 (3) ◽  
pp. 1118-1122 ◽  
Author(s):  
M. Sciancalepore ◽  
F. Stratta ◽  
N. D. Fisher ◽  
E. Cherubini
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Frequency Ratio ◽  
Hippocampal Neurons ◽  
Neonatal Rat ◽  
Synaptic Currents ◽  
Mean Frequency ◽  
Metabotropic Glutamate ◽  
The Mean ◽  
Kinase A

1. The tight-seal whole cell recording technique was used to study the effects of the metabotropic glutamate receptor (mGluR) agonist, trans-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) on spontaneous gamma-aminobutyric acid (GABA)-mediated synaptic currents in neonatal rat CA1 hippocampal neurons in slices obtained from postnatal (P) days P6-P12. 2. Bath application of t-ACPD (3-30 microM), in the presence of kynurenic acid, induced a concentration-dependent increase in frequency but not in amplitude of spontaneous GABAergic currents. The mean frequency ratio (t-ACPD 10 microM over control) was 2.6 +/- 1 (mean +/- SD), whereas the mean amplitude ratio was 1.1 +/- 0.3. 3. The effect of t-ACPD was partially antagonized by the mGluR antagonist (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG, 1 mM). 4. t-ACPD (10-30 microM) did not modify the frequency of miniature GABAergic synaptic currents recorded in tetrodotoxin (the mean frequency ratio of t-ACPD over control was 0.7 +/- 0.3). 5. Forskolin (30 microM), but not its analogue 1,9 dideoxyforskolin (30 microM), mimicked the effect of t-ACPD. Similar effects were obtained with 3-isobutyl-1-methylxanthine (IBMX, 200 microM). 6. The potentiating effect of t-ACPD on spontaneous GABAergic currents was prevented by Rp-cAMPS (30 microM), a specific antagonist of protein kinase A. This suggests that mGluRs localized at the soma-dendritic level of GABAergic interneurons and positively coupled to cyclic AMP may modulate GABA release during a critical period of postnatal development.

Shortening of muscle relaxation time after creatine loading

1999 ◽  
Vol 86 (3) ◽  
pp. 840-844 ◽  
Author(s):  
M. van Leemputte ◽  
K. Vandenberghe ◽  
P. Hespel
Keyword(s):  
Relaxation Time ◽  
Muscle Relaxation ◽  
Muscle Contractions ◽  
Contraction Time ◽  
Healthy Male ◽  
Healthy Male Volunteers ◽  
Torque Generation ◽  
Isometric Torque ◽  
The Mean ◽  
Isometric Muscle

The effect of creatine (Cr) supplementation on muscle isometric torque generation and relaxation was investigated in healthy male volunteers. Maximal torque (Tmax), contraction time (CT) from 0.25 to 0.75 of Tmax, and relaxation time (RT) from 0.75 to 0.25 of Tmax were measured during 12 maximal isometric 3-s elbow flexions interspersed by 10-s rest intervals. Between the pretest and the posttest, subjects ingested Cr monohydrate (4 × 5 g/day; n = 8) or placebo ( n = 8) for 5 days. Pretest Tmax, CT, and RT were similar in Cr and placebo groups. Also in the posttest, Tmax and CT were similar between groups. However, posttest RT was decreased consistently by ∼20% ( P < 0.05) in the Cr group from the first to the last of the 12 contractions. In addition, the mean decrease in RT after Cr loading was positively correlated with pretest RT ( r = 0.82). It is concluded that Cr loading facilitates the rate of muscle relaxation during brief isometric muscle contractions without affecting torque production.

35Cl NQR Spectroscopy on Salts and Molecular Compounds of Trichloroacetic Acid

1986 ◽  
Vol 41 (1-2) ◽  
pp. 215-224 ◽  
Author(s):  
Winfried Fichtner ◽  
Axel Markworth ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Frequency Shift ◽  
Temperature Dependence ◽  
Linear Relation ◽  
Trichloroacetic Acid ◽  
Mean Frequency ◽  
35Cl Nqr ◽  
The Mean ◽  
Molecular Compounds

The temperature dependence of salts M(1)H(Cl3CCOO)2 and molecular compounds of trichloroacetic acid with amines and benzaldehydes, TCA · X, was studied,The data fit rather well to the known dependence of the mean frequency shift Δ <v(35Cl)> on the pkadifference of X with respect to TCA. A linear relation is observed between the bleaching out temperature Tb of the 35Cl NQR lines and Δ <v(35Cl)> for M(1)H(Cl3CCOO)2 and for TCA · X, X = benzaldehydes.

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