Muscular endurance and surface electromyogram in isometric and dynamic exercise

1981 ◽  
Vol 51 (1) ◽  
pp. 1-7 ◽  
Author(s):  
M. Hagberg
Keyword(s):  
Maximum Voluntary Contraction ◽  
Isometric Exercise ◽  
Voluntary Contraction ◽  
Dynamic Exercise ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Endurance Time ◽  
Significant Difference ◽  
Power Frequency ◽  
The Mean

In nine male volunteers, the endurance time for sustained isometric exercise (right-angle elbow flexion) and dynamic exercise (continuous concentric and eccentric elbow flexions) was measured at different contraction levels. Intermittent isometric exercises were also performed by four of the subjects in whom surface electromyographic elbow flexor recordings were obtained during the three types of exercise. A rapid decrease of the endurance time was seen at contraction levels above 15–20% of the maximum voluntary contraction for both the sustained isometric and dynamic exercise. There were no significant difference between the regression of the endurance time vs. the contraction level for the sustained isometric exercise and that of the dynamic exercise. However, the endurance time was enhanced in the intermittent isometric exercise compared with the sustained isometric exercise. The development of muscle fatigue was well correlated to change of the myoelectric rootmean-square amplitude and the mean power frequency. Differences in exercise did not significantly affect the relation between the time constant of the mean power frequency decrease and the endurance time.

scholarly journals Comparison of Endurance Time Prediction of Biceps Brachii Using Logarithmic Parameters of a Surface Electromyogram during Low-Moderate Level Isotonic Contractions

2021 ◽  
Vol 11 (6) ◽  
pp. 2861
Author(s):  
Chang-ok Cho ◽  
Jin-Hyoung Jeong ◽  
Yun-jeong Kim ◽  
Jee Hun Jang ◽  
Sang-Sik Lee ◽  
...  
Keyword(s):  
Biceps Brachii ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Endurance Capacity ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Spectral Parameters ◽  
Endurance Time ◽  
Surface Electromyogram ◽  
Isotonic Contractions

At relatively low effort level tasks, surface electromyogram (sEMG) spectral parameters have demonstrated an inconsistent ability to monitor localized muscle fatigue and predict endurance capacity. The main purpose of this study was to assess the potential of the endurance time (Tend) prediction using logarithmic parameters compared to raw data. Ten healthy subjects performed five sets of voluntary isotonic contractions until their exhaustion at 20% of their maximum voluntary contraction (MVC) level. We extracted five sEMG spectral parameters namely the power in the low frequency band (LFB), the mean power frequency (MPF), the high-to-low ratio between two frequency bands (H/L-FB), the Dimitrov spectral index (DSI), and the high-to-low ratio between two spectral moments (H/L-SM), and then converted them to logarithms. Changes in these ten parameters were monitored using area ratio and linear regressive slope as statistical predictors and estimating from onset at every 10% of Tend. Significant correlations (r > 0.5) were found between log(Tend) and the linear regressive slopes in the logarithmic H/L-SM at every 10% of Tend. In conclusion, logarithmic parameters can be used to describe changes in the fatigue content of sEMG and can be employed as a better predictor of Tend in comparison to the raw parameters.

Dependence of the mean power frequency of the electromyogram on muscle force and fibre type

1991 ◽  
Vol 142 (4) ◽  
pp. 457-465 ◽  
Author(s):  
B. GERDLE ◽  
K. HENRIKSSON-LARSÉN ◽  
R. LORENTZON ◽  
M.-L. WRETLING
Keyword(s):  
Fibre Type ◽  
Muscle Force ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Power Frequency ◽  
The Mean

The effect of leg extension training on the mean power frequency of the mechanomyographic signal

2000 ◽  
Vol 23 (6) ◽  
pp. 973-975 ◽  
Author(s):  
Tammy K. Evetovich ◽  
Terry J. Housh ◽  
Joseph P. Weir ◽  
Dona J. Housh ◽  
Glen O. Johnson ◽  
...  
Keyword(s):  
Mean Power ◽  
Mean Power Frequency ◽  
Leg Extension ◽  
Power Frequency ◽  
The Mean

Aircraft Passenger Comfort Based on Muscle Activation and Perceived Discomfort During Long Flights

2020 ◽  
Vol 91 (5) ◽  
pp. 416-421
Author(s):  
Huining Pei ◽  
Suihuai Yu ◽  
Man Ding ◽  
Zhonghang Bai
Keyword(s):  
Muscle Activation ◽  
Upper Body ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Passenger Comfort ◽  
Body Regions ◽  
Lower Back ◽  
Significant Difference ◽  
Power Frequency ◽  
Subjective Discomfort

OBJECTIVE: The purpose of this study was to investigate the comfort of aircraft passengers during long flights and to determine the effects of the seatback angle and the seat pitch on passengers’ upper body muscles (neck, shoulder, and lower back) and subjective comfort.METHODS: All subjects sat on an aircraft seat for 2 h with different levels of seatback angle and seat pitch. Subjective discomfort scores and root mean square (RMS) and mean power frequency (MPF) values were used to evaluate muscle fatigue, and all data were calculated for every 15-min interval.RESULTS: Significant increases of MPF for all three muscles were found at 30 min, along with significant increases in the perceived levels of discomfort (PLD) over 2 h. Besides, a 120° seatback angle and a 34˝ seat pitch resulted in lower PLD values for the lower back and hip areas than smaller ones (significant difference).DISCUSSION: It took around 30 min before pronounced discomfort in the upper body regions occurred during flight. The larger parameters of seatback angle and seat pitch may significantly contribute to the easing of subjective discomfort. Moreover, a decrease in MPF coupled with a concomitant increase in RMS does not appear to be a reliable indicator of discomfort rate. The need for further development of discomfort indicators which are more directly related to muscular activation is recognized.Pei H, Yu S, Ding M, Bai Z. Aircraft passenger comfort based on muscle activation and perceived discomfort during long flights. Aerosp Med Hum Perform. 2020; 91(5):416–421.

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.

scholarly journals Muscle Fatigue in the Temporal and Masseter Muscles in Patients with Temporomandibular Dysfunction

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Krzysztof Woźniak ◽  
Mariusz Lipski ◽  
Damian Lichota ◽  
Liliana Szyszka-Sommerfeld
Keyword(s):  
Muscle Fatigue ◽  
Isometric Contraction ◽  
Temporomandibular Disorders ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Temporomandibular Dysfunction ◽  
Maximum Effort ◽  
Power Frequency ◽  
The Mean ◽  
Masseter Muscles

The aim of this study is to evaluate muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction (TMD). Two hundred volunteers aged 19.3 to 27.8 years (mean 21.50, SD 0.97) participated in this study. Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany). Muscle fatigue was evaluated on the basis of a maximum effort test. The test was performed during a 10-second maximum isometric contraction (MVC) of the jaws. An analysis of changes in the mean power frequency of the two pairs of temporal and masseter muscles (MPF%) revealed significant differences in the groups of patients with varying degrees of temporomandibular disorders according to Di (P<0.0000). The study showed an increase in the muscle fatigue of the temporal and masseter muscles correlated with the intensity of temporomandibular dysfunction symptoms in patients. The use of surface electromyography in assessing muscle fatigue is an excellent diagnostic tool for identifying patients with temporomandibular dysfunction.

Postural sway following inversion sprain of the ankle

1991 ◽  
Vol 81 (5) ◽  
pp. 243-247 ◽  
Author(s):  
MW Cornwall ◽  
P Murrell
Keyword(s):  
Ankle Sprain ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Control Group ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Linear Distance ◽  
History Of ◽  
Power Frequency ◽  
The Mean

The single-limb sway of 20 individuals with a history of unilateral inversion ankle sprain was compared to that of a control group of 30 individuals without a history of ankle sprain. Using a force platform to obtain center-of-pressure data, the linear distance traveled (mm) and the mean power frequency, (Hz) of postural sway were calculated for each subject. The results of this study showed that postural sway amplitude was significantly greater in the injured group than in the control group. Contrary to previous investigations, this study indicates that individuals with a history of inversion ankle sprain are less stable in single-limb stance compared to a noninjured control group. This decreased stability is evident as much as 2 years following the injury.

Sign in / Sign up

Export Citation Format

Share Document