1
|
Borzelli D, Vieira TMM, Botter A, Gazzoni M, Lacquaniti F, d'Avella A. Synaptic inputs to motor neurons underlying muscle coactivation for functionally different tasks have different spectral characteristics. J Neurophysiol 2024; 131:1126-1142. [PMID: 38629162 DOI: 10.1152/jn.00199.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 04/11/2024] [Accepted: 04/11/2024] [Indexed: 06/01/2024] Open
Abstract
The central nervous system (CNS) may produce the same endpoint trajectory or torque profile with different muscle activation patterns. What differentiates these patterns is the presence of cocontraction, which does not contribute to effective torque generation but allows to modulate joints' mechanical stiffness. Although it has been suggested that the generation of force and the modulation of stiffness rely on separate pathways, a characterization of the differences between the synaptic inputs to motor neurons (MNs) underlying these tasks is still missing. In this study, participants coactivated the same pair of upper-limb muscles, i.e., the biceps brachii and the triceps brachii, to perform two functionally different tasks: limb stiffness modulation or endpoint force generation. Spike trains of MNs were identified through decomposition of high-density electromyograms (EMGs) collected from the two muscles. Cross-correlogram showed a higher synchronization between MNs recruited to modulate stiffness, whereas cross-muscle coherence analysis revealed peaks in the β-band, which is commonly ascribed to a cortical origin. These peaks did not appear during the coactivation for force generation, thus suggesting separate cortical inputs for stiffness modulation. Moreover, a within-muscle coherence analysis identified two subsets of MNs that were selectively recruited to generate force or regulate stiffness. This study is the first to highlight different characteristics, and probable different neural origins, of the synaptic inputs driving a pair of muscles under different functional conditions. We suggest that stiffness modulation is driven by cortical inputs that project to a separate set of MNs, supporting the existence of a separate pathway underlying the control of stiffness.NEW & NOTEWORTHY The characterization of the pathways underlying force generation or stiffness modulation are still unknown. In this study, we demonstrated that the common input to motor neurons of antagonist muscles shows a high-frequency component when muscles are coactivated to modulate stiffness but not to generate force. Our results provide novel insights on the neural strategies for the recruitment of multiple muscles by identifying specific spectral characteristics of the synaptic inputs underlying functionally different tasks.
Collapse
Affiliation(s)
- Daniele Borzelli
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, Messina, Italy
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Taian M M Vieira
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
- PoliToBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Alberto Botter
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
- PoliToBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Marco Gazzoni
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
- PoliToBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Francesco Lacquaniti
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Systems Medicine and Center of Space BioMedicine, University of Rome Tor Vergata, Rome, Italy
| | - Andrea d'Avella
- Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, Messina, Italy
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
| |
Collapse
|
2
|
Beretta-Piccoli M, Cescon C, Barbero M, D’Antona G. Identification of muscle innervation zones using linear electrode arrays: a fundamental step to measure fibers conduction velocity. ARAB JOURNAL OF BASIC AND APPLIED SCIENCES 2021. [DOI: 10.1080/25765299.2021.1894731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Matteo Beretta-Piccoli
- Rehabilitation Research Laboratory, Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, SUPSI, Manno, Switzerland
- Criams-Sport Medicine Centre Voghera, University of Pavia, Pavia, Italy
| | - Corrado Cescon
- Rehabilitation Research Laboratory, Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, SUPSI, Manno, Switzerland
| | - Marco Barbero
- Rehabilitation Research Laboratory, Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, SUPSI, Manno, Switzerland
| | - Giuseppe D’Antona
- Criams-Sport Medicine Centre Voghera, University of Pavia, Pavia, Italy
- Department of Public Health, Experimental and Forensic medicine, University of Pavia, Pavia, Italy
| |
Collapse
|
3
|
Huang C, Klein CS, Meng Z, Zhang Y, Li S, Zhou P. Innervation zone distribution of the biceps brachii muscle examined using voluntary and electrically-evoked high-density surface EMG. J Neuroeng Rehabil 2019; 16:73. [PMID: 31186009 PMCID: PMC6560814 DOI: 10.1186/s12984-019-0544-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 05/28/2019] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND High density surface electromyography (EMG) can be used to estimate muscle innervation zones (IZ). The objective of this study was to compare the differences in the distribution of the biceps brachii (BB) IZ derived from voluntary contractions (VC) and electrical stimulation (ES) of the musculocutaneous nerve. METHODS Surface EMG signals were recorded from the medial and lateral BB with two 64-channel high density electrode matrices in eight healthy men. The surface EMG was recorded at different percentages of the maximal voluntary contraction (MVC) force (20-100% MVC) and at different percentages of the current needed to elicit a maximal M-wave (20-100% Imax). The IZs of the medial and lateral BB were identified from the EMG signals and expressed as a row number within a given medial-lateral column. RESULTS ES current intensity had no significant effect on the group mean IZ location (p > 0.05). However, The IZ during VC was located more proximally with increasing force (p < 0.05), likely due to muscle shortening. The position of the IZ varied slightly (by up to ~ 8 mm) in a medial-lateral direction under both contraction types, but this spatial effect was not significant. The IZ during ES and weak VC (20, 40% MVC) was similar (p > 0.05), but was more proximal in the latter than the former during 60-100% MVC (p < 0.05). CONCLUSION ES can be used to detect spatial differences in IZ location free of the confounding effects of muscle shortening and recruitment order of different sized motor units. The method may prove beneficial for locating the IZ in patients who lack voluntary control of their musculature.
Collapse
Affiliation(s)
- Chengjun Huang
- Guangdong Work Injury Rehabilitation Center, Guangzhou, Guangdong, China
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, USA
- TIRR Memorial Hermann Research Center, 1333B Moursund St, TIRR Research Building, Suite 326, Houston, TX, 77030, USA
| | - Cliff S Klein
- Guangdong Work Injury Rehabilitation Center, Guangzhou, Guangdong, China
| | - Zhaojian Meng
- Guangdong Work Injury Rehabilitation Center, Guangzhou, Guangdong, China
| | - Yingchun Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Sheng Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, USA
- TIRR Memorial Hermann Research Center, 1333B Moursund St, TIRR Research Building, Suite 326, Houston, TX, 77030, USA
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, USA.
- TIRR Memorial Hermann Research Center, 1333B Moursund St, TIRR Research Building, Suite 326, Houston, TX, 77030, USA.
| |
Collapse
|
4
|
Motor unit innervation zone localization based on robust linear regression analysis. Comput Biol Med 2019; 106:65-70. [PMID: 30684784 DOI: 10.1016/j.compbiomed.2019.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 01/13/2019] [Accepted: 01/13/2019] [Indexed: 11/23/2022]
Abstract
With the aim of developing a flexible and reliable procedure for superficial muscle innervation zone (IZ) localization, we proposed a method to estimate IZ location using surface electromyogram (EMG) based on robust linear regression. Regression lines were used to model the bidirectional propagation pattern of a single motor unit action potential (MUAP) and visualize the trajectory of the MUAP propagation. IZ localization was performed by identifying the origin of the bidirectional MUAP propagation. Robust linear regression and MUAP peak detection, combined with propagation phase reversal identification, may provide an efficient way to estimate IZ location. Our method offers high resolution in locating IZs based on simulation studies and experimental tests. Furthermore, our method is flexible and may also be applied using a relatively small number of EMG channels. A comparative study of the proposed method with the cross-correlation method for IZ localization was conducted. The results obtained with simulated MUAPs and measured spontaneous MUAPs in the biceps brachii muscle in six subjects (four males and two females, 57 ± 10 years old) with amyotrophic lateral sclerosis (ALS). Our method achieved estimation performance comparable to that obtained by using the cross-correlation method but with higher resolution. This study provides an accurate and practical method to estimate IZ location.
Collapse
|
5
|
Zhang C, Peng Y, Liu Y, Li S, Zhou P, Rymer WZ, Zhang Y. Imaging three-dimensional innervation zone distribution in muscles from M-wave recordings. J Neural Eng 2017; 14:036011. [PMID: 28358718 DOI: 10.1088/1741-2552/aa65dd] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To localize neuromuscular junctions in skeletal muscles in vivo which is of great importance in understanding, diagnosing and managing of neuromuscular disorders. APPROACH A three-dimensional global innervation zone imaging technique was developed to characterize the global distribution of innervation zones, as an indication of the location and features of neuromuscular junctions, using electrically evoked high-density surface electromyogram recordings. MAIN RESULTS The performance of the technique was evaluated in the biceps brachii of six intact human subjects. The geometric centers of the distributions of the reconstructed innervation zones were determined with a mean distance of 9.4 ± 1.4 cm from the reference plane, situated at the medial epicondyle of the humerus. A mean depth was calculated as 1.5 ± 0.3 cm from the geometric centers to the closed points over the skin. The results are consistent with those reported in previous histology studies. It was also found that the volumes and distributions of the reconstructed innervation zones changed as the stimulation intensities increased until the supramaximal muscle response was achieved. SIGNIFICANCE Results have demonstrated the high performance of the proposed imaging technique in noninvasively imaging global distributions of the innervation zones in the three-dimensional muscle space in vivo, and the feasibility of its clinical applications, such as guiding botulinum toxin injections in spasticity management, or in early diagnosis of neurodegenerative progression of amyotrophic lateral sclerosis.
Collapse
Affiliation(s)
- Chuan Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, United States of America
| | | | | | | | | | | | | |
Collapse
|
6
|
Re-evaluation of EMG-torque relation in chronic stroke using linear electrode array EMG recordings. Sci Rep 2016; 6:28957. [PMID: 27349938 PMCID: PMC4923947 DOI: 10.1038/srep28957] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 06/13/2016] [Indexed: 11/08/2022] Open
Abstract
The objective was to re-evaluate the controversial reports of EMG-torque relation between impaired and non-impaired sides using linear electrode array EMG recordings. Ten subjects with chronic stroke performed a series of submaximal isometric elbow flexion tasks. A 20-channel linear array was used to record surface EMG of the biceps brachii muscles from both impaired and non-impaired sides. M-wave recordings for bilateral biceps brachii muscles were also made. Distribution of the slope of the EMG-torque relations for the individual channels showed a quasi-symmetrical "M" shaped pattern. The lowest value corresponded to the innervation zone (IZ) location. The highest value from the slope curve for each side was selected for comparison to minimize the effect of electrode placement and IZ asymmetry. The slope was greater on the impaired side in 4 of 10 subjects. There were a weak correlation between slope ratio and strength ratio and a moderate to high correlation between slope ratio and M-wave ratio between two sides. These findings suggest that the EMG-torque relations are likely mediated and influenced by multiple factors. Our findings emphasize the importance of electrode placement and suggest the primary role of peripheral adaptive changes in the EMG-torque relations in chronic stroke.
Collapse
|
7
|
Guzmán-Venegas R, Bralic M, Cordero J, Cavada G, Araneda O. Concordance of the location of the innervation zone of the tibialis anterior muscle using voluntary and imposed contractions by electrostimulation. J Electromyogr Kinesiol 2016; 27:18-23. [DOI: 10.1016/j.jelekin.2016.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 12/11/2015] [Accepted: 01/04/2016] [Indexed: 11/28/2022] Open
|
8
|
Martinez-Valdes E, Guzman-Venegas RA, Silvestre RA, Macdonald JH, Falla D, Araneda OF, Haichelis D. Electromyographic adjustments during continuous and intermittent incremental fatiguing cycling. Scand J Med Sci Sports 2015; 26:1273-1282. [DOI: 10.1111/sms.12578] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2015] [Indexed: 11/28/2022]
Affiliation(s)
- E. Martinez-Valdes
- University Outpatient Clinic; Sports Medicine and Sports Orthopaedics; University of Potsdam; Potsdam Germany
| | - R. A. Guzman-Venegas
- Facultad de Medicina; Escuela de Kinesiología; Universidad de Los Andes; Santiago Chile
| | - R. A. Silvestre
- Faculty of Medicine; School of Kinesiology; Mayor University; Santiago Chile
| | - J. H. Macdonald
- School of Sport, Health and Exercise Sciences; Bangor University; Bangor UK
| | - D. Falla
- Department of Neurorehabilitation Engineering; Bernstein Focus Neurotechnology Göttingen; Bernstein Center for Computational Neuroscience; University Medical Center; Göttingen Germany
| | - O. F. Araneda
- Facultad de Medicina; Escuela de Kinesiología; Universidad de Los Andes; Santiago Chile
| | - D. Haichelis
- Instituto de Ciencias del Ejercicio; Universidad Santo Tomás; Santiago Chile
| |
Collapse
|
9
|
Ye X, Beck TW, Wages NP. Prolonged passive static stretching-induced innervation zone shift in biceps brachii. Appl Physiol Nutr Metab 2015; 40:482-8. [DOI: 10.1139/apnm-2014-0546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to examine the influence of a bout of repeated and prolonged passive static stretching on the innervation zone (IZ) location of the human biceps brachii muscle. Eleven men performed 12 sets of 100-s passive stretches on their biceps brachii. Before (Pre) and immediately after (Post) the stretching intervention, isometric strength was tested during the maximal voluntary contractions (MVCs) of the forearm flexors. The subjects also performed several separate isometric forearm flexion muscle actions at 30%, 50%, and 70% of their predetermined MVCs for examining the locations of the IZ at different contraction intensities. The IZ was identified through multi-channel surface electromyographic (EMG) recordings from a linear electrode array. The stretching intervention induced an average of 10% isometric strength loss for the forearm flexors (mean ± SD: Pre-MVC vs. Post-MVC = 332.12 ± 59.40 N vs. 299.53 ± 70.51 N; p < 0.001). In addition, the average IZ shift was nearly 4.5 mm in average in the proximal direction. However, this shift was not specific to the contraction intensity. We believe that the IZ shift was caused by the elongation of the entire muscle-tendon unit in the proximal direction. Therefore, caution should be taken when using surface EMG technique to examine possible changes in the EMG variables after a stretching protocol, as these variables can be contaminated by the shift of the IZ.
Collapse
Affiliation(s)
- Xin Ye
- Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA
- Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA
| | - Travis W. Beck
- Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA
- Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA
| | - Nathan P. Wages
- Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA
- Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA
| |
Collapse
|
10
|
Herda TJ, Zuniga JM, Ryan ED, Camic CL, Bergstrom HC, Smith DB, Weir JP, Cramer JT, Housh TJ. The influence of electromyographic recording methods and the innervation zone on the mean power frequency-torque relationships. J Electromyogr Kinesiol 2015; 25:423-30. [PMID: 25851079 DOI: 10.1016/j.jelekin.2015.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 01/30/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022] Open
Abstract
This study examined the effects of electromyographic (EMG) recording methods and innervation zone (IZ) on the mean power frequency (MPF)-torque relationships. Nine subjects performed isometric ramp muscle actions of the leg extensors from 5% to 100% of maximal voluntary contraction with an eight channel linear electrode array over the IZ of the vastus lateralis. The slopes were calculated from the log-transformed monopolar and bipolar EMG MPF-torque relationships for each channel and subject and 95% confidence intervals (CI) were constructed around the slopes for each relationship and the composite of the slopes. Twenty-two to 55% of the subjects exhibited 95% CIs that did not include a slope of zero for the monopolar EMG MPF-torque relationships while 25-75% of the subjects exhibited 95% CIs that did not include a slope of zero for the bipolar EMG MPF-torque relationships. The composite of the slopes from the EMG MPF-torque relationships were not significantly different from zero for any method or channel, however, the method and IZ location slightly influenced the number of significant slopes on a subject-by-subject basis. The log-transform model indicated that EMG MPF-torque patterns were nonlinear regardless of recording method or distance from the IZ.
Collapse
Affiliation(s)
- Trent J Herda
- Department of Health, Sport, and Exercise Sciences, Neuromechanics Laboratory, University of Kansas, Lawrence, KS, USA.
| | - Jorge M Zuniga
- Exercise Science Department, Creighton University, Omaha, NE, USA
| | - Eric D Ryan
- Department of Exercise and Sport Science, Neuromuscular Research Laboratory, University of North Carolina - Chapel Hill, Chapel Hill, NC, USA
| | - Clayton L Camic
- Exercise and Sport Science Department, University of Wisconsin-La Crosse, La Crosse, WI, USA
| | - Haley C Bergstrom
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA
| | - Doug B Smith
- Department of Health and Human Performance, Oklahoma State University, Stillwater, OK, USA
| | - Joseph P Weir
- Department of Health, Sport, and Exercise Sciences, Neuromechanics Laboratory, University of Kansas, Lawrence, KS, USA
| | - Joel T Cramer
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Terry J Housh
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| |
Collapse
|
11
|
Mordhorst M, Heidlauf T, Röhrle O. Predicting electromyographic signals under realistic conditions using a multiscale chemo-electro-mechanical finite element model. Interface Focus 2015; 5:20140076. [PMID: 25844148 DOI: 10.1098/rsfs.2014.0076] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This paper presents a novel multiscale finite element-based framework for modelling electromyographic (EMG) signals. The framework combines (i) a biophysical description of the excitation-contraction coupling at the half-sarcomere level, (ii) a model of the action potential (AP) propagation along muscle fibres, (iii) a continuum-mechanical formulation of force generation and deformation of the muscle, and (iv) a model for predicting the intramuscular and surface EMG. Owing to the biophysical description of the half-sarcomere, the model inherently accounts for physiological properties of skeletal muscle. To demonstrate this, the influence of membrane fatigue on the EMG signal during sustained contractions is investigated. During a stimulation period of 500 ms at 100 Hz, the predicted EMG amplitude decreases by 40% and the AP propagation velocity decreases by 15%. Further, the model can take into account contraction-induced deformations of the muscle. This is demonstrated by simulating fixed-length contractions of an idealized geometry and a model of the human tibialis anterior muscle (TA). The model of the TA furthermore demonstrates that the proposed finite element model is capable of simulating realistic geometries, complex fibre architectures, and can include different types of heterogeneities. In addition, the TA model accounts for a distributed innervation zone, different fibre types and appeals to motor unit discharge times that are based on a biophysical description of the α motor neurons.
Collapse
Affiliation(s)
- Mylena Mordhorst
- Institute of Applied Mechanics (CE) , University of Stuttgart , Pfaffenwaldring 7, 70569 Stuttgart , Germany ; Stuttgart Research Centre for Simulation Technology , Pfaffenwaldring 5a, 70569 Stuttgart , Germany
| | - Thomas Heidlauf
- Institute of Applied Mechanics (CE) , University of Stuttgart , Pfaffenwaldring 7, 70569 Stuttgart , Germany ; Stuttgart Research Centre for Simulation Technology , Pfaffenwaldring 5a, 70569 Stuttgart , Germany
| | - Oliver Röhrle
- Institute of Applied Mechanics (CE) , University of Stuttgart , Pfaffenwaldring 7, 70569 Stuttgart , Germany ; Stuttgart Research Centre for Simulation Technology , Pfaffenwaldring 5a, 70569 Stuttgart , Germany
| |
Collapse
|
12
|
Real time estimation of generation, extinction and flow of muscle fibre action potentials in high density surface EMG. Comput Biol Med 2015; 57:8-19. [DOI: 10.1016/j.compbiomed.2014.11.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 10/17/2014] [Accepted: 11/17/2014] [Indexed: 10/24/2022]
|
13
|
Real time identification of active regions in muscles from high density surface electromyogram. Comput Biol Med 2015; 56:37-50. [DOI: 10.1016/j.compbiomed.2014.10.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/07/2014] [Accepted: 10/17/2014] [Indexed: 11/23/2022]
|
14
|
Investigation of innervation zone shift with continuous dynamic muscle contraction. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:174342. [PMID: 23762179 PMCID: PMC3677009 DOI: 10.1155/2013/174342] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 04/15/2013] [Accepted: 05/03/2013] [Indexed: 11/18/2022]
Abstract
Innervation zone (IZ) has been identified as the origin of action potential propagation in isometric contraction. However, IZ shifts with changes in muscle length during muscle activity. The IZ shift has been estimated using raw EMG signals. This study aimed to investigate the movement of IZ location during continuous dynamic muscle contraction, using a computer program. Subjects flexed their elbow joint as repetitive dynamic muscle contractions. EMG signals were recorded from the biceps brachii muscle using an eight-channel surface electrode array. Approximately 100 peaks from EMG signals were detected for each channel and summed to estimate the IZ location. For each subject, the estimated IZ locations were subtracted from the IZ location during isometric contractions with the elbow flexed at 90°. The results showed that the IZ moved significantly with elbow joint movement from 45° to 135°. However, IZ movement was biased with only a 3.9 mm IZ shift on average when the elbow angle was acute but a 16 mm IZ shift on average when it was obtuse. The movement of IZ location during continuous dynamic muscle contraction can be investigated using this signal processing procedure without subjective judgment.
Collapse
|
15
|
Herda TJ, Zuniga JM, Ryan ED, Camic CL, Bergstrom HC, Smith DB, Weir JP, Cramer JT, Housh TJ. Quantifying the effects of electrode distance from the innervation zone on the electromyographic amplitude versus torque relationships. Physiol Meas 2013; 34:315-24. [PMID: 23399865 DOI: 10.1088/0967-3334/34/3/315] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The present study applied a log-transformation model to compare the electromyographic (EMG) amplitude versus torque relationships from monopolar EMG signals up to 35 mm proximal and distal from the innervation zone (IZ). Seven men (age = 23 ± 2 year; mass = 82 ± 10 kg) and two women (age = 21 ± 1 year; mass = 62 ± 8 kg) performed isometric ramp contractions of the right leg extensors with an eight-channel linear electrode array positioned over the vastus lateralis with the IZ located between channels 4 and 5. Linear regression models were fit to the log-transformed monopolar EMG(RMS)-torque relationships with the b terms (slope) and the a terms (Y-intercept) calculated for each channel and subject. The b terms for channels 4, 5, and 6 were higher (P ≤ 0.05) than the more distal channels 7 and 8 (P < 0.05). In contrast, there were no differences (P > 0.05) among the a terms of the eight channels. Thus, the shapes of the monopolar EMG(RMS)-torque relationships were altered as a function of distance between the IZ and recording area, which may be helpful for clinicians and researchers who infer changes in motor control strategies based on the shapes of the EMG(RMS)-torque relationships.
Collapse
Affiliation(s)
- Trent J Herda
- Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, KS, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Beck TW, DeFreitas JM, Stock MS. Accuracy of three different techniques for automatically estimating innervation zone location. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2012; 105:13-21. [PMID: 20692064 DOI: 10.1016/j.cmpb.2010.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2009] [Revised: 06/04/2010] [Accepted: 07/13/2010] [Indexed: 05/29/2023]
Abstract
The purpose of this study was to compare the accuracy of the estimated innervation zone (IZ) locations obtained from cross-correlation, the minimum amplitude, and maximum center frequency criteria. Eight healthy men (mean±SD age=23.0±4.3 yrs) performed isometric muscle actions of the leg extensors, and 15 separate bipolar surface electromyographic (EMG) signals were detected from the vastus lateralis. A custom software program was used to estimate the location of the IZ based on: (1) the EMG channel that demonstrated the lowest amplitude, (2) the EMG channel that showed the highest mean frequency, and (3) the EMG channel that demonstrated the lowest peak cross-correlation between the signals from adjacent channels. The IZ location estimates from the lowest amplitude and highest mean frequency criteria were accurate in only 43.75% and 7.5% of the cases, respectively. The accuracy of the cross-correlation-based method was 90%. The cross-correlation-based method was much more accurate for estimating IZ location than were the lowest amplitude and highest mean frequency criteria. Cross-correlation could potentially be used for estimating the location of the IZ without the need for visual inspection of EMG signals.
Collapse
Affiliation(s)
- Travis W Beck
- Department of Health and Exercise Science, University of Oklahoma, 110 Huston Huffman Center, Norman, OK, USA.
| | | | | |
Collapse
|
17
|
Mechanomyographic responses are not influenced by the innervation zone for the vastus medialis. Muscle Nerve 2011; 44:424-31. [DOI: 10.1002/mus.22116] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2011] [Indexed: 11/07/2022]
|
18
|
Barbero M, Gatti R, Lo Conte L, Macmillan F, Coutts F, Merletti R. Reliability of surface EMG matrix in locating the innervation zone of upper trapezius muscle. J Electromyogr Kinesiol 2011; 21:827-33. [PMID: 21752668 DOI: 10.1016/j.jelekin.2011.05.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 04/15/2011] [Accepted: 05/27/2011] [Indexed: 10/18/2022] Open
Abstract
The identification of the motor unit (MU) innervation zone (IZ) using surface electromyographic (sEMG) signals detected on the skin with a linear array or a matrix of electrodes has been recently proposed in the literature. However, an analysis of the reliability of this procedure and, therefore, of the suitability of the sEMG signals for this purpose has not been reported. The purpose of this work is to describe the intra and inter-rater reliability and the suitability of surface EMG in locating the innervation zone of the upper trapezius muscle. Two operators were trained on electrode matrix positioning and sEMG signal analysis. Ten healthy subjects, instructed to perform a series of isometric contractions of the upper trapezius muscle participated in the study. The two operators collected sEMG signals and then independently estimated the IZ location through visual analysis. Results showed an almost perfect agreement for intra-rater and inter-rater reliability. The constancy of IZ location could be affected by the factors reflecting the population of active MUs and their IZs, including: the contraction intensity, the acquisition period analyzed, the contraction repetition. In almost all cases the IZ location shift due to these factors did not exceed 4mm. Results generalization to other muscles should be made with caution.
Collapse
Affiliation(s)
- Marco Barbero
- School of Health Sciences, Queen Margaret University, Edinburgh, UK.
| | | | | | | | | | | |
Collapse
|