scholarly journals Muscle fatigue revisited - Insights from optically pumped magnetometers

2021 ◽  
Author(s):  
Davide Sometti ◽  
Lorenzo Semeia ◽  
Hui Chen ◽  
Juergen Dax ◽  
Cornelius Kronlage ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Muscle Fatigue ◽  
Isometric Contraction ◽  
Muscle Fibers ◽  
Muscular Activity ◽  
Rectus Femoris ◽  
Optically Pumped ◽  
Rectus Femoris Muscle ◽  
The Magnetic Field ◽  
Femoris Muscle

Muscle fatigue is well characterized electromyographically, nevertheless only information about summed potential differences is detectable. In contrast, recently developed quantum sensors optically pumped magnetometers (OPMs) offer the advantage of recording both the electrical current propagation in the muscle as well as its geometry, by measuring the magnetic field generated by the muscular action potentials. Magnetomyographic investigation of muscle fatigue is still lacking and it is an open question whether fatigue is characterized similarly in magnetomyography (MMG) compared to electromyography (EMG). Herein, we investigated the muscle fatigue during a 3x1-min strong isometric contraction of the rectus femoris muscle of 12 healthy subjects using simultaneous EMG-MMG (4-channel surface EMG and 4 OPM along the rectus femoris muscle). Both EMG and MMG showed the characteristic frequency decrease in the signal magnitude during isometric contraction, which is typical for muscle fatigue. In addition, it was shown that the main part of this frequency decrease seems to occur in the circular component of the magnetic field around the muscle fibers and less longitudinally along the muscle fibers. Overall, these results show not only that magnetomyography is capable of reproducing the electromyographic standards in identifying muscular fatigue, but it also adds relevant information about the spatial characterization of the signal. Therefore, OPM-MMG offers new insights for the study of muscular activity and might serve as a new, supplementary neurophysiological method.

scholarly journals Muscle Fatigue Revisited – Insights From Optically Pumped Magnetometers

2021 ◽  
Vol 12 ◽  
Author(s):  
Davide Sometti ◽  
Lorenzo Semeia ◽  
Sangyeob Baek ◽  
Hui Chen ◽  
Giulia Righetti ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Rectus Femoris ◽  
Field Vector ◽  
Optically Pumped ◽  
Potential Alternative ◽  
Spectral Compression ◽  
Rectus Femoris Muscle ◽  
The Magnetic Field ◽  
Healthy Participants ◽  
Femoris Muscle

So far, surface electromyography (sEMG) has been the method of choice to detect and evaluate muscle fatigue. However, recent advancements in non-cryogenic quantum sensors, such as optically pumped magnetometers (OPMs), enable interesting possibilities to flexibly record biomagnetic signals. Yet, a magnetomyographic investigation of muscular fatigue is still missing. Here, we simultaneously used sEMG (4 surface electrode) and OPM-based magnetomyography (OPM-MMG, 4 sensors) to detect muscle fatigue during a 3 × 1-min isometric contractions of the left rectus femoris muscle in 7 healthy participants. Both signals exhibited the characteristic spectral compression distinctive for muscle fatigue. OPM-MMG and sEMG slope values, used to quantify the spectral compression of the signals, were positively correlated, displaying similarity between the techniques. Additionally, the analysis of the different components of the magnetic field vector enabled speculations regarding the propagation of the muscle action potentials (MAPs). Altogether these results show the feasibility of the magnetomyographic approach with OPMs and propose a potential alternative to sEMG for the study of muscle fatigue.

scholarly journals Investigation of the temporal and spatial dynamics of muscular action potentials through optically pumped magnetometers

2021 ◽  
Author(s):  
Philip J. Broser ◽  
Justus Marquetand ◽  
Thomas Middelmann ◽  
Davide Sometti ◽  
Christoph Braun
Keyword(s):  
Magnetic Field ◽  
Action Potential ◽  
Muscle Fiber ◽  
Stretch Reflex ◽  
Rectus Femoris ◽  
List Type ◽  
Contractile Apparatus ◽  
Optically Pumped ◽  
The Magnetic Field ◽  
Muscular Action

ABSTRACTAimThis study aims to simultaneously record the magnetic and electric components of the propagating muscular action potential.MethodA single-subject study of the monosynaptic stretch reflex of the musculus rectus femoris was performed; the magnetic field generated by the muscular activity was recorded in all three spatial directions by five optically pumped magnetometers. In addition, the electric field was recorded by four invasive fine-wire needle electrodes. The magnetic and electric fields were compared, and modelling and simulations were performed to compare the magnetic field vectors with the underlying muscular anatomy of the rectus femoris muscle.ResultsThe magnetomyography (MMG) signal can reliably be recorded following the stimulation of the monosynaptic stretch reflex. The MMG signal shows several phases of activity inside the muscle, the first of which is the propagating muscular action potential. As predicted by the finite wire model, the magnetic field vectors of the propagating muscular action potential are generated by the current flowing longitudinal to the muscle fiber. Based on the magnetic field vectors, it was possible to reconstruct the pinnation angle in the muscle. The later magnetic components are linked to the activated contractile apparatus.InterpretationMMG allows to analyze the muscle physiology from the propagating muscular action potential to the initiation of the contractile apparatus. At the same time this methods reveal information about muscle fiber direction and extend. With the development of high-resolution magnetic cameras, it will be possible to image the function and structure of any skeletal muscle with high precision. This method could be used in clinical medicine but also in sports and training science.What this paper adds-A robust technique for triggering a muscular action potential that can be recorded by MMG and needle EMG simultaneously-The correlation of the MMG signal with the needle EMG signal-A method for detecting the direction of the propagating muscular action potential-A method for correlating the magnetic field vectors with the pinnation angle of the examined muscle

scholarly journals Electromyographic Analysis of Traditional and Nontraditional Abdominal Exercises: Implications for Rehabilitation and Training

2006 ◽  
Vol 86 (5) ◽  
pp. 656-671 ◽  
Author(s):  
Rafael F Escamilla ◽  
Eric Babb ◽  
Ryan DeWitt ◽  
Patrick Jew ◽  
Peter Kelleher ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Latissimus Dorsi ◽  
Rectus Femoris ◽  
Rectus Abdominis ◽  
Oblique Muscle ◽  
Emg Activity ◽  
Internal Oblique ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle ◽  
Roll Out

Abstract Background and Purpose. Performing nontraditional abdominal exercises with devices such as abdominal straps, the Power Wheel, and the Ab Revolutionizer has been suggested as a way to activate abdominal and extraneous (nonabdominal) musculature as effectively as more traditional abdominal exercises, such as the crunch and bent-knee sit-up. The purpose of this study was to test the effectiveness of traditional and nontraditional abdominal exercises in activating abdominal and extraneous musculature. Subjects. Twenty-one men and women who were healthy and between 23 and 43 years of age were recruited for this study. Methods. Surface electromyography (EMG) was used to assess muscle activity from the upper and lower rectus abdominis, external and internal oblique, rectus femoris, latissimus dorsi, and lumbar paraspinal muscles while each exercise was performed. The EMG data were normalized to maximum voluntary muscle contractions. Differences in muscle activity were assessed by a 1-way, repeated-measures analysis of variance. Results. Upper and lower rectus abdominis, internal oblique, and latissimus dorsi muscle EMG activity were highest for the Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees. External oblique muscle EMG activity was highest for the Power Wheel (pike, knee-up, and roll-out) and hanging knee-up with straps. Rectus femoris muscle EMG activity was highest for the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up. Lumbar paraspinal muscle EMG activity was low and similar among exercises. Discussion and Conclusion. The Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees not only were the most effective exercises in activating abdominal musculature but also were the most effective in activating extraneous musculature. The relatively high rectus femoris muscle activity obtained with the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up may be problematic for some people with low back problems.

Ultrasonographic Morphologic Changes of the Central Aponeurosis of the Rectus Femoris Muscle in Individuals With Knee Osteoarthritis

2016 ◽  
Vol 32 (3) ◽  
pp. 241-246
Author(s):  
Yusuke Takahashi ◽  
Kyoji Okada ◽  
Akira Saito ◽  
Isao Saito ◽  
Kazuo Kinoshita ◽  
...  
Keyword(s):  
Knee Osteoarthritis ◽  
Rectus Femoris ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle ◽  
Morphologic Changes
Sign in / Sign up

Export Citation Format

Share Document