Muscle sounds during voluntary and stimulated contractions of the human adductor pollicis muscle

1992 ◽  
Vol 72 (5) ◽  
pp. 1908-1913 ◽  
Author(s):  
M. J. Stokes ◽  
R. G. Cooper
Keyword(s):  
Random Order ◽  
Voluntary Contraction ◽  
Adductor Pollicis ◽  
Stimulation Frequency ◽  
Control Mechanisms ◽  
Voluntary Activity ◽  
Adductor Pollicis Muscle ◽  
Force Signal ◽  
Integrated Emg ◽  
Muscle Sounds

The relationships between force, electromyography (EMG), and muscle sounds recorded by acoustic myography (AMG) were investigated for both voluntary and stimulated isometric contractions in the adductor pollicis muscle. Voluntary activity was performed at 10, 25, 50, 75, 85, and 100% of maximal voluntary contraction (MVC) force. Stimulated contractions were produced by supramaximal electrical stimulation of the ulnar nerve at the wrist at frequencies of 10, 20, 30, 50, 70, and 100 Hz. Contractions lasted for 4 s each, and were performed in random order with a 3-min rest between each. The voluntary and stimulation studies were performed in random order between subjects. Simultaneous recordings were obtained for force, force oscillation (from the differentiated force signal), and raw and integrated AMG (IAMG) and EMG (IEMG). During voluntary contractions, IAMG increased with force up to MVC (r2 = 0.99, P less than 0.001) in a curvilinear fashion and a similar relationship was seen between force and IEMG (r2 = 0.99, P less than 0.001). Conversely, during stimulated contractions as stimulation frequency increased, IAMG decreased in a fashion mirroring the frequency-force curve. The frequency of the AMG signal matched stimulation frequency and declines in total IAMG were due to reductions in amplitude of the AMG signal. The stimulation frequency-oscillation of force relationship was identical to that seen for stimulation frequency and IAMG. Integrated EMG increased linearly with stimulation frequency (r = 0.99). The stimulation results suggest that muscle sounds reflect oscillation of muscle fibers and that AMG signal characteristics are determined by motor control mechanisms rather than intrinsic contractile processes.

Conduction velocity and EMG power spectrum changes in fatigue of sustained maximal efforts

1981 ◽  
Vol 51 (5) ◽  
pp. 1300-1305 ◽  
Author(s):  
B. Bigland-Ritchie ◽  
E. F. Donovan ◽  
C. S. Roussos
Keyword(s):  
Power Spectrum ◽  
Conduction Velocity ◽  
Surface Emg ◽  
Voluntary Contraction ◽  
Mass Action ◽  
Wave Form ◽  
Muscle Temperature ◽  
Voluntary Activity ◽  
Adductor Pollicis Muscle ◽  
Emg Power Spectrum

The relationship between the electromyographic (EMG) power spectrum and muscle conduction velocity was investigated during both fatiguing and nonfatiguing contractions of the adductor pollicis muscle. Changes in the EMG power spectrum were measured by Fourier transform analysis and by comparing the power in the high (130–238 Hz) and low (20--40 Hz) frequency bands. Changes in conduction velocity were measured during voluntary activity from changes in the muscle mass action potential evoked by periodic maximal shocks to the nerve. This was varied independently either by maintaining a 60-s fatiguing maximal voluntary contraction involving 30--50% loss of force or by changing muscle temperature in the absence of fatigue. Both procedures resulted in similar changes in the power spectrum. However, the change in conduction velocity required to generate equal changes in the EMG was about 10 times greater in the absence of fatigue than those observed during a 60-s maximum contraction initiated at any initial muscle temperature. This suggests that during fatigue of maximal voluntary contractions, factors other than changes in the wave form of individual muscle fiber action potentials must contribute to the observed shift in the total surface EMG frequency components.

scholarly journals Changes in motor cortex excitability associated with muscle fatigue in patients with Parkinson's disease

2013 ◽  
Vol 70 (3) ◽  
pp. 298-303 ◽  
Author(s):  
Sladjan Milanovic ◽  
Sasa Filipovic ◽  
Sasa Radovanovic ◽  
Suzana Blesic ◽  
Nela Ilic ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Gradual Increase ◽  
Recovery Period ◽  
Silent Period ◽  
Voluntary Contraction ◽  
Adductor Pollicis ◽  
Healthy People ◽  
Adductor Pollicis Muscle ◽  
Sustained Contraction ◽  
Motor Cortex Excitability

Background/Aim. Transcranial magnetic stimulation (TMS) is a standard technique for noninvasive assessment of changes in central nervous system excitability. The aim of this study was to examine changes in responses to TMS in patients suffering from Parkinson?s disease (PD) during sustained submaximal isometric voluntary contraction [60% of maximal voluntary contraction (MVC)] of the adductor pollicis muscle, as well as during a subsequent recovery period. Methods. Cortical excitability was tested by single TMS pulses of twice of the motor threshold intensity applied over the vertex. Testing was carried out during the sustained contraction phase every 10 s before and every 5 s after the endurance point, as well as at rest and during brief 60% MVC contractions before (control), immediately after the sustained contraction, and at 5 min intervals during the recovery period. Results. Although the PD patients could sustain the contraction at the required level for as long period of time as the healthy subjects (though contraction level subsided more rapidly after the endurance point), effects of muscle fatigue on the responses to TMS were different. In contrast to the findings observed in the healthy people where motor evoked potentials (MEP) and EMG silent period (SP) in fatigued muscle gradually diminished during contraction up to the endurance point, and increased thereafter, in the majority of patients no changes occurred in MEP size (peak and area) of the adductor pollicis muscle, either before or after the endurance point. On the other hand, changes in the SP of this muscle differed among the subjects, showing a gradual increase, a decrease or no changes in duration. The trends of changes in both MEP size and SP duration in the musculus brachioradialis varied among the tested PD patients, without any consistent pattern, which was in contrast with the findings in the healthy people where both measures showed a gradual increase from the beginning of the sustained contraction. A complete dissociation between changes in MEP and SP during fatigue was also of note, which differed sharply from the findings in the healthy people in who fatigue induced changes in these measures followed identical patterns. Conclusion. These results in the PD patients suggest the presence of impairment and/or compensatory changes in mechanisms responsible for adaptation of voluntary drive as well as for matching between cortical excitation and inhibition which become manifest in demanding motor tasks such as those imposed by muscle fatigue.

Observations on force enhancement in submaximal voluntary contractions of human adductor pollicis muscle

2005 ◽  
Vol 98 (6) ◽  
pp. 2087-2095 ◽  
Author(s):  
Ali E. Oskouei ◽  
Walter Herzog
Keyword(s):  
Steady State ◽  
Muscle Activation ◽  
Isometric Force ◽  
Fiber Type ◽  
Voluntary Contraction ◽  
Adductor Pollicis ◽  
Postactivation Potentiation ◽  
Force Enhancement ◽  
Adductor Pollicis Muscle ◽  
Voluntary Contractions

It has been observed consistently and is well accepted that the steady-state isometric force after active muscle stretch is greater than the corresponding isometric force for electrically stimulated muscles and maximal voluntary contractions. However, this so-called force enhancement has not been studied for submaximal voluntary efforts; therefore, it is not known whether this property affects everyday movements. The purpose of this study was to determine whether there was force enhancement during submaximal voluntary contractions. Human adductor pollicis muscles ( n = 17) were studied using a custom-built dynamometer, and both force and activation were measured while muscle activation and force were controlled at a level of 30% of maximal voluntary contraction. The steady-state isometric force and activation after active stretch were compared with the corresponding values obtained during isometric reference contractions. There was consistent and reliable force enhancement in 8 of the 17 subjects, whereas there was no force enhancement in the remaining subjects. Subjects with force enhancement had greater postactivation potentiation and a smaller resistance to fatigue in the adductor pollicis. We conclude from these results that force enhancement exists during submaximal voluntary contractions in a subset of the populations and suggest that it may affect everyday voluntary movements in this subset. On the basis of follow-up testing, it appears that force enhancement during voluntary contractions is linked to potentiation and fatigue resistance and therefore possibly to the fiber-type distribution in the adductor pollicis muscle.

Slower fatigue and faster recovery of the adductor pollicis muscle in women matched for strength with men

1999 ◽  
Vol 167 (3) ◽  
pp. 233-239 ◽  
Author(s):  
Fulco ◽  
Rock ◽  
Muza ◽  
Lammi ◽  
Cymerman ◽  
...  
Keyword(s):  
Adductor Pollicis ◽  
Adductor Pollicis Muscle

scholarly journals ADDUCTOR POLLICIS MUSCLE THICKNESS AND PREDICTION OF POSTOPERATIVE MORTALITY IN PATIENTS WITH STOMACH CANCER

2018 ◽  
Vol 31 (1) ◽  
Author(s):  
Aline Kirjner POZIOMYCK ◽  
Oly Campos CORLETA ◽  
Leandro Totti CAVAZZOLA ◽  
Antonio Carlos WESTON ◽  
Edson Braga LAMEU ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Stomach Cancer ◽  
Nutritional Assessment ◽  
Postoperative Mortality ◽  
Muscle Thickness ◽  
Adductor Pollicis ◽  
Dominant Hand ◽  
Adductor Pollicis Muscle ◽  
Risk Of Death ◽  
Muscle Compartment

ABSTRACT Background: Malnutrition is very prevalent in patients with gastric cancer and increases the risk of morbidity and mortality. Adductor pollicis muscle thickness (APMT) appears as an important objective, quick, inexpensive and noninvasive measure to assess the muscle compartment Aim: To compare APMT and other nutritional assessment methods and to correlate these methods with postoperative mortality Methods: Forty-four patients, 29 men and 15 women, mean age of 63±10.2 and ranging from 34-83 years, who underwent nine (20.5%) partial and 34 (77.3%) total gastrectomies due to stomach cancer (stage II to IIIa) were preoperatively assessed by Patient Generated Subjective Global Assessment (PG-SGA), anthropometry and laboratorial profile Results: APMT better predicted death (p<0.001) on both, dominant and non-dominant hand, and well correlated with albumin (p=0.039) and PG-SGA (p=0.007) Conclusion: APMT clearly allowed to determine malnutrition and to predict risk of death in patients with gastric cancer.

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