1
|
Bandini V, Carpinella I, Marzegan A, Jonsdottir J, Frigo CA, Avanzino L, Pelosin E, Ferrarin M, Lencioni T. Surface-Electromyography-Based Co-Contraction Index for Monitoring Upper Limb Improvements in Post-Stroke Rehabilitation: A Pilot Randomized Controlled Trial Secondary Analysis. SENSORS (BASEL, SWITZERLAND) 2023; 23:7320. [PMID: 37687775 PMCID: PMC10490112 DOI: 10.3390/s23177320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 07/28/2023] [Accepted: 08/04/2023] [Indexed: 09/10/2023]
Abstract
Persons post-stroke experience excessive muscle co-contraction, and consequently the arm functions are compromised during the activities of daily living. Therefore, identifying instrumental outcome measures able to detect the motor strategy adopted after a stroke is a primary clinical goal. Accordingly, this study aims at verifying whether the surface electromyography (sEMG)-based co-contraction index (CCI) could be a new clinically feasible approach for assessing and monitoring patients' motor performance. Thirty-four persons post-stroke underwent clinical assessment and upper extremity kinematic analysis, including sEMG recordings. The participants were randomized into two treatment groups (robot and usual care groups). Ten healthy subjects provided a normative reference (NR). Frost's CCI was used to quantify the muscle co-contraction of three different agonist/antagonist muscle pairs during an object-placing task. Persons post-stroke showed excessive muscle co-contraction (mean (95% CI): anterior/posterior deltoid CCI: 0.38 (0.34-0.41) p = 0.03; triceps/biceps CCI: 0.46 (0.41-0.50) p = 0.01) compared to NR (anterior/posterior deltoid CCI: 0.29 (0.21-0.36); triceps/biceps CCI: 0.34 (0.30-0.39)). After robot therapy, persons post-stroke exhibited a greater improvement (i.e., reduced CCI) in proximal motor control (anterior/posterior deltoid change score of CCI: -0.02 (-0.07-0.02) p = 0.05) compared to usual care therapy (0.04 (0.00-0.09)). Finally, the findings of the present study indicate that the sEMG-based CCI could be a valuable tool in clinical practice.
Collapse
Affiliation(s)
- Virginia Bandini
- IRCCS Fondazione Don Carlo Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy; (V.B.); (I.C.); (A.M.); (J.J.); (T.L.)
| | - Ilaria Carpinella
- IRCCS Fondazione Don Carlo Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy; (V.B.); (I.C.); (A.M.); (J.J.); (T.L.)
| | - Alberto Marzegan
- IRCCS Fondazione Don Carlo Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy; (V.B.); (I.C.); (A.M.); (J.J.); (T.L.)
| | - Johanna Jonsdottir
- IRCCS Fondazione Don Carlo Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy; (V.B.); (I.C.); (A.M.); (J.J.); (T.L.)
| | - Carlo Albino Frigo
- Department of Electronics, Information and Bioengineering (DEIB), Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy;
| | - Laura Avanzino
- Department of Experimental Medicine, Section of Human Physiology, University of Genoa, 16132 Genoa, Italy;
- IRCCS Ospedale Policlinico San Martino, IRCCS, 16132 Genoa, Italy;
| | - Elisa Pelosin
- IRCCS Ospedale Policlinico San Martino, IRCCS, 16132 Genoa, Italy;
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health, University of Genoa, 16132 Genova, Italy
| | - Maurizio Ferrarin
- IRCCS Fondazione Don Carlo Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy; (V.B.); (I.C.); (A.M.); (J.J.); (T.L.)
| | - Tiziana Lencioni
- IRCCS Fondazione Don Carlo Gnocchi Onlus, Via Capecelatro 66, 20148 Milan, Italy; (V.B.); (I.C.); (A.M.); (J.J.); (T.L.)
| |
Collapse
|
2
|
Yang H, Lv Y, Chen S, Xing B, Wu J. An Evaluation Study of a New Designed Oscillating Hydraulic Trainer of Neck. Healthcare (Basel) 2023; 11:healthcare11101518. [PMID: 37239804 DOI: 10.3390/healthcare11101518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/07/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
In view of the importance of neck strength training and the lack of adequate training equipment, this study designed a new oscillating hydraulic trainer (OHT) of neck based on oscillating hydraulic damper. We used surface electromyography (sEMG) and subjective ratings to evaluate the neck OHT and compared the results with a simple hat trainer (HATT) and traditional weight trainer (TWT) to verify the feasibility and validity of the OHT. Under similar exercise conditions, 12 subjects performed a set of neck flexion and extension exercise with these 3 trainers. The sEMG signals of targeted muscles were collected in real time, and subjects were asked to complete subjective evaluations of product usability after exercise. The results showed that the root mean square (RMS%) of sEMG indicated that the OHT could provide two-way resistance and train the flexors and extensors simultaneously. The overall degree of muscle activation with OHT was higher than that with the other two trainers in one movement cycle. In terms of resistance characteristics exhibited by the sEMG waveform, duration (D) with OHT was significantly longer than HATT and TWT when exercising at a high speed, while Peak Timing (PT) was later. The ratings of product usability and performing usability of OHT were remarkably higher than that of HATT and TWT. Based on the above results, the OHT was proved to be more suitable for strength training, such as neck muscles, which were getting more attention gradually, but lacked mature and special training equipment.
Collapse
Affiliation(s)
- Hongchun Yang
- Design and Research Institute, Zhejiang University of Technology, Hangzhou 310023, China
| | - Yawei Lv
- School of Design and Architecture, Zhejiang University of Technology, Hangzhou 310023, China
| | - Sisi Chen
- School of Design and Architecture, Zhejiang University of Technology, Hangzhou 310023, China
| | - Baixi Xing
- Design and Research Institute, Zhejiang University of Technology, Hangzhou 310023, China
| | - Jianfeng Wu
- Design and Research Institute, Zhejiang University of Technology, Hangzhou 310023, China
| |
Collapse
|
3
|
Wang L, Wu Y, Zhu M, Zhao C. Relationship between EMG features and force in orbicularis oris muscle. Technol Health Care 2023; 31:47-56. [PMID: 35754237 DOI: 10.3233/thc-213545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Lip incompetence resulting from mouth breathing is a common clinical manifestation, while there are no definite indicators of amplitude and intensity of muscle functional training in clinical practice, which leads to unsatisfactory training results. OBJECTIVE The aim was to quantify the relationship between electromyography (EMG) and force in orbicularis oris muscle, so that the indicators of muscle functional training can be evaluated using EMG signals, so as to improve the training effects. METHODS The EMG and the force signals of orbicularis oris muscle from 0% to 100% MVC within 5 s in twelve healthy subjects (six males and six females; age, 25 ± 2 years; mass, 60 ± 15 kg) were recorded simultaneously for three trials. Four EMG features consisting of RMS, WAMP, SampEn and FuzzyEn were analyzed. The regression analyses were performed using first-order and third-order polynomial model. RESULTS There were high correlations between the four EMG features and muscle force with the two models. The third-order model yielded a higher coefficient of determination (R2) than the linear model (p< 0.001) and the result of FuzzyEn (R2: 0.884 ± 0.059) was the highest in the four features. CONCLUSION The third-order model with FuzzyEn of EMG signals may be used to guide the muscle functional training.
Collapse
Affiliation(s)
- Lan Wang
- Shanghai Key Laboratory of Intelligent Manufacturing and Robotics, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
| | - Yanqi Wu
- Department of Oral and Craniofacial Surgery, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai JiaoTong University of Medicine, National Center of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Min Zhu
- Department of Oral and Craniofacial Surgery, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai JiaoTong University of Medicine, National Center of Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Cuilian Zhao
- Shanghai Key Laboratory of Intelligent Manufacturing and Robotics, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
| |
Collapse
|
4
|
Hussein M, Shebl S, Elnemr R, Elkaranshawy H. A New Muscle Activation Dynamics Model, That Simulates the Calcium Kinetics and Incorporates the Role of Store-Operated Calcium Entry Channels, to Enhance the EMG-Driven Hill-type Models. J Biomech Eng 2021; 144:1114505. [PMID: 34251438 DOI: 10.1115/1.4051718] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Indexed: 12/12/2022]
Abstract
Hill-type models are frequently used in biomechanical simulations. They are attractive for their low computational cost and close relation to commonly measured musculotendon parameters. Still, more attention is needed to improve the activation dynamics of the model specifically because of the nonlinearity observed in the EMG-Force relation. Moreover, one of the important and practical questions regarding the assessment of the model's performance is how adequately can the model simulate any fundamental type of human movement without modifying model parameters for different tasks? This paper tries to answer this question by proposing a simple physiologically based activation dynamics model. The model describes the ?kinetics of the calcium dynamics while activating and deactivating the muscle contraction process. Hence, it allowed simulating the recently discovered role of store-operated calcium entry (SOCE) channels as immediate counter-flux to calcium loss across the tubular system during excitation-contraction coupling. By comparing the ability to fit experimental data without readjusting the parameters, the proposed model has proven to have more steady performance than phenomenologically based models through different submaximal isometric contraction levels. This model indicates that more physiological insights is key for improving Hill-type model performance.
Collapse
Affiliation(s)
- Moemen Hussein
- Department of Engineering Mathematics and Physics, Faculty of Engineering, Alexandria University, Egypt
| | - Said Shebl
- Department of Engineering Mathematics and Physics, Faculty of Engineering, Alexandria University, Egypt
| | - Rehab Elnemr
- Department of Physical Medicine, Rheumatology and Rehabilitation, Faculty of Medicine, Alexandria University, Egypt
| | - Hesham Elkaranshawy
- Department of Engineering Mathematics and Physics, Faculty of Engineering, Alexandria University, Egypt
| |
Collapse
|
5
|
Yao T, Gao F, Zhang Q, Ma Y. Multi-feature gait recognition with DNN based on sEMG signals. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2021; 18:3521-3542. [PMID: 34198399 DOI: 10.3934/mbe.2021177] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This study proposed a gait recognition method based on the deep neural network of surface electromyography (sEMG) signals to improve the stability and accuracy of gait recognition using sEMG signals of the lower limbs. First, we determined the parameters of time domain features, including the mean of absolute value, root mean square, waveform length, the number of zero-crossing points of the sEMG signals after noise elimination, and the frequency domain features, including mean power frequency and median frequency. Second, the time domain feature and frequency domain feature were combined into a multi-feature combination. Then, the classifier was trained and used for gait recognition. Finally, in terms of the recognition rate, the classifier was compared with the support vector machine (SVM) and extreme learning machine (ELM). The results showed the method of deep neural network (DNN) had a better recognition rate than that of SVM and ELM. The experimental results of the participants indicated that the average recognition rate obtained with the method of DNN exceeded 95%. On the other hand, from the statistical results of standard deviation, the difference between subjects ranged from 0.46 to 0.94%, which also proved the robustness and stability of the proposed method.
Collapse
Affiliation(s)
- Ting Yao
- Institute of Intelligent Control and Robotics, School of Automation, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Farong Gao
- Institute of Intelligent Control and Robotics, School of Automation, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Qizhong Zhang
- Institute of Intelligent Control and Robotics, School of Automation, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Yuliang Ma
- Institute of Intelligent Control and Robotics, School of Automation, Hangzhou Dianzi University, Hangzhou 310018, China
| |
Collapse
|
6
|
Casolo A, Nuccio S, Bazzucchi I, Felici F, Del Vecchio A. Reproducibility of muscle fibre conduction velocity during linearly increasing force contractions. J Electromyogr Kinesiol 2020; 53:102439. [PMID: 32563844 DOI: 10.1016/j.jelekin.2020.102439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/14/2020] [Accepted: 06/06/2020] [Indexed: 12/13/2022] Open
Abstract
Muscle fibre conduction velocity (MFCV) is a basic physiological parameter biophysically related to the diameter of muscle fibres and properties of the sarcolemma. The aim of this study was to assess the intersession reproducibility of the relation between voluntary force and estimates of average muscle fibre conduction velocity (MFCV) from multichannel high-density surface electromyographic recordings (HDsEMG). Ten healthy men performed six linearly increasing isometric ankle dorsiflexions on two separate experimental sessions, 4 weeks apart. Each session involved the recordings of voluntary force during maximal isometric (MViF) and submaximal ramp contractions at 35-50-70% of MViF. Concurrently, the HDsEMG activity was detected from the tibialis anterior muscle and MFCV estimates were derived in 250-ms epochs. Absolute and relative reproducibility of MFCV initial value (intercept) and rate of change (regression slope) as a function of force were assessed by within-subject coefficient of correlation (CVw) and with intraclass correlation coefficient (ICC). MFCV was positively correlated with voluntary force (R2 = 0.75 ± 0.12) in all individuals and test conditions (P < 0.001). Average CVw for MFCV intercept and slope were of 2.6 ± 2.0% and 11.9 ± 3.2% and ICC values of 0.96 and 0.94, respectively. Overall, MFCV regression coefficients showed a high degree of intersession reproducibility in both absolute and relative terms. These results may have important practical implications in the tracking of training-induced neuromuscular changes and/or in the monitoring of the progress of neuromuscular disorders when a full sEMG signal decomposition is problematic or not possible.
Collapse
Affiliation(s)
- Andrea Casolo
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy; Department of Bioengineering, Imperial College London, SW7 2AZ London, UK
| | - Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy; Department of Bioengineering, Imperial College London, SW7 2AZ London, UK
| | - Ilenia Bazzucchi
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Alessandro Del Vecchio
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy; Department of Bioengineering, Imperial College London, SW7 2AZ London, UK.
| |
Collapse
|
7
|
Reliability of surface electromyography in estimating muscle fiber conduction velocity: A systematic review. J Electromyogr Kinesiol 2019; 48:53-68. [DOI: 10.1016/j.jelekin.2019.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 05/28/2019] [Accepted: 06/12/2019] [Indexed: 11/22/2022] Open
|
8
|
Çankaya T, Karli Ü, Buğdayci G. Comparison of exhaustive concentric and eccentric contractions: Effects on muscle damage and EMG responses during recovery period. ISOKINET EXERC SCI 2019. [DOI: 10.3233/ies-183154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Tamer Çankaya
- School of Physical Therapy and Rehabilitation, Abant İzzet Baysal University, Bolu, Turkey
| | - Ümid Karli
- School of Physical Education and Sport, Abant İzzet Baysal University, Bolu, Turkey
| | - Güler Buğdayci
- Faculty of Medicine, Department of Biochemistry, Abant İzzet Baysal University, Bolu, Turkey
| |
Collapse
|
9
|
Del Vecchio A, Bazzucchi I, Felici F. Variability of estimates of muscle fiber conduction velocity and surface EMG amplitude across subjects and processing intervals. J Electromyogr Kinesiol 2018; 40:102-109. [DOI: 10.1016/j.jelekin.2018.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/18/2018] [Accepted: 04/23/2018] [Indexed: 12/01/2022] Open
|
10
|
Tanaka H, Miyakoshi M, Makeig S. Dynamics of directional tuning and reference frames in humans: A high-density EEG study. Sci Rep 2018; 8:8205. [PMID: 29844584 PMCID: PMC5974292 DOI: 10.1038/s41598-018-26609-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 05/14/2018] [Indexed: 11/16/2022] Open
Abstract
Recent developments in EEG recording and signal processing have made it possible to record in an unconstrained, natural movement task, therefore EEG provides a promising approach to understanding the neural mechanisms of upper-limb reaching control. This study specifically addressed how EEG dynamics in the time domain encoded finger movement directions (directional tuning) and posture dependence (movement reference frames) by applying representational similarity analysis. High-density EEG covering the entire scalp was recorded while participants performed eight-directional, center-out reaching movements, thereby allowing us to explore directional selectivity of EEG sources over the brain beyond somatosensory areas. A majority of the source processes exhibited statistically significant directional tuning during peri-movement periods. In addition, directional tuning curves shifted systematically when the shoulder angle was rotated to perform the task within a more laterally positioned workspace, the degree of tuning curve rotation falling between that predicted by models assuming extrinsic and shoulder-based reference frames. We conclude that temporal dynamics of neural mechanisms for motor control can be studied noninvasively in humans using high-density EEG and that directional sensitivity of motor and non-motor processing is not limited within the sensorimotor areas but extends to the whole brain areas.
Collapse
Affiliation(s)
- Hirokazu Tanaka
- School of Information Science Japan, Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan.
| | - Makoto Miyakoshi
- Swartz Center for Computational Neuroscience, Institute of Neural Computation University of California San Diego, 9500 Gilman Drive # 0559, La Jolla, CA, 92093-0559, USA
| | - Scott Makeig
- Swartz Center for Computational Neuroscience, Institute of Neural Computation University of California San Diego, 9500 Gilman Drive # 0559, La Jolla, CA, 92093-0559, USA
| |
Collapse
|
11
|
Abraham L, Bromberg F, Forradellas R. Ensemble of shape functions and support vector machines for the estimation of discrete arm muscle activation from external biceps 3D point clouds. Comput Biol Med 2018; 95:129-139. [PMID: 29499448 DOI: 10.1016/j.compbiomed.2018.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/16/2018] [Accepted: 02/17/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Muscle activation level is currently being captured using impractical and expensive devices which make their use in telemedicine settings extremely difficult. To address this issue, a prototype is presented of a non-invasive, easy-to-install system for the estimation of a discrete level of muscle activation of the biceps muscle from 3D point clouds captured with RGB-D cameras. METHODS A methodology is proposed that uses the ensemble of shape functions point cloud descriptor for the geometric characterization of 3D point clouds, together with support vector machines to learn a classifier that, based on this geometric characterization for some points of view of the biceps, provides a model for the estimation of muscle activation for all neighboring points of view. This results in a classifier that is robust to small perturbations in the point of view of the capturing device, greatly simplifying the installation process for end-users. RESULTS In the discrimination of five levels of effort with values up to the maximum voluntary contraction (MVC) of the biceps muscle (3800 g), the best variant of the proposed methodology achieved mean absolute errors of about 9.21% MVC - an acceptable performance for telemedicine settings where the electric measurement of muscle activation is impractical. CONCLUSIONS The results prove that the correlations between the external geometry of the arm and biceps muscle activation are strong enough to consider computer vision and supervised learning an alternative with great potential for practical applications in tele-physiotherapy.
Collapse
Affiliation(s)
- Leandro Abraham
- Laboratorio DHARMa, DeSI, Universidad Tecnológica Nacional, Facultad Regional Mendoza - Rodriguez 273, PC M5502AJE Mendoza, Argentina; CEAL, Universidad Nacional de Cuyo, Facultad de Ingeniería - Centro Universitario CC 405, PC M5500AAT Mendoza, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
| | - Facundo Bromberg
- Laboratorio DHARMa, DeSI, Universidad Tecnológica Nacional, Facultad Regional Mendoza - Rodriguez 273, PC M5502AJE Mendoza, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
| | - Raymundo Forradellas
- CEAL, Universidad Nacional de Cuyo, Facultad de Ingeniería - Centro Universitario CC 405, PC M5500AAT Mendoza, Argentina.
| |
Collapse
|
12
|
Re-Evaluating Electromyogram–Force Relation in Healthy Biceps Brachii Muscles Using Complexity Measures. ENTROPY 2017. [DOI: 10.3390/e19110624] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
13
|
Del Vecchio A, Negro F, Felici F, Farina D. Associations between motor unit action potential parameters and surface EMG features. J Appl Physiol (1985) 2017; 123:835-843. [PMID: 28751374 DOI: 10.1152/japplphysiol.00482.2017] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/24/2017] [Accepted: 07/25/2017] [Indexed: 11/22/2022] Open
Abstract
The surface interference EMG signal provides some information on the neural drive to muscles. However, the association between neural drive to muscle and muscle activation has long been debated with controversial indications due to the unavailability of motor unit population data. In this study, we clarify the potential and limitations of interference EMG analysis to infer motor unit recruitment strategies with an experimental investigation of several concurrently active motor units and of the associated features of the surface EMG. For this purpose, we recorded high-density surface EMG signals during linearly increasing force contractions of the tibialis anterior muscle, up to 70% of maximal force. The recruitment threshold (RT), conduction velocity (MUCV), median frequency (MDFMU), and amplitude (RMSMU) of action potentials of 587 motor units from 13 individuals were assessed and associated with features of the interference EMG. MUCV was positively associated with RT (R2 = 0.64 ± 0.14), whereas MDFMU and RMSMU showed a weaker relation with RT (R2 = 0.11 ± 0.11 and 0.39 ± 0.24, respectively). Moreover, the changes in average conduction velocity estimated from the interference EMG predicted well the changes in MUCV (R2 = 0.71), with a strong association to ankle dorsiflexion force (R2 = 0.81 ± 0.12). Conversely, both the average EMG MDF and RMS were poorly associated with motor unit recruitment. These results clarify the limitations of EMG spectral and amplitude analysis in inferring the neural strategies of muscle control and indicate that, conversely, the average conduction velocity could provide relevant information on these strategies.NEW & NOTEWORTHY The surface EMG provides information on the neural drive to muscles. However, the associations between EMG features and neural drive have been long debated due to unavailability of motor unit population data. Here, by using novel highly accurate decomposition of the EMG, we related motor unit population behavior to a wide range of voluntary forces. The results fully clarify the potential and limitation of the surface EMG to provide estimates of the neural drive to muscles.
Collapse
Affiliation(s)
- Alessandro Del Vecchio
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy.,Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy; and
| | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, United Kingdom
| |
Collapse
|
14
|
Green LA, Christie A, Gabriel DA. Spike shape analysis for the surface and needle electromyographic interference pattern. Biomed Signal Process Control 2017. [DOI: 10.1016/j.bspc.2017.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
15
|
Torres-Peralta R, Morales-Alamo D, González-Izal M, Losa-Reyna J, Pérez-Suárez I, Izquierdo M, Calbet JAL. Task Failure during Exercise to Exhaustion in Normoxia and Hypoxia Is Due to Reduced Muscle Activation Caused by Central Mechanisms While Muscle Metaboreflex Does Not Limit Performance. Front Physiol 2016; 6:414. [PMID: 26793117 PMCID: PMC4707284 DOI: 10.3389/fphys.2015.00414] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/17/2015] [Indexed: 11/26/2022] Open
Abstract
To determine whether task failure during incremental exercise to exhaustion (IE) is principally due to reduced neural drive and increased metaboreflex activation eleven men (22 ± 2 years) performed a 10 s control isokinetic sprint (IS; 80 rpm) after a short warm-up. This was immediately followed by an IE in normoxia (Nx, PIO2:143 mmHg) and hypoxia (Hyp, PIO2:73 mmHg) in random order, separated by a 120 min resting period. At exhaustion, the circulation of both legs was occluded instantaneously (300 mmHg) during 10 or 60 s to impede recovery and increase metaboreflex activation. This was immediately followed by an IS with open circulation. Electromyographic recordings were obtained from the vastus medialis and lateralis. Muscle biopsies and blood gases were obtained in separate experiments. During the last 10 s of the IE, pulmonary ventilation, VO2, power output and muscle activation were lower in hypoxia than in normoxia, while pedaling rate was similar. Compared to the control sprint, performance (IS-Wpeak) was reduced to a greater extent after the IE-Nx (11% lower P < 0.05) than IE-Hyp. The root mean square (EMGRMS) was reduced by 38 and 27% during IS performed after IE-Nx and IE-Hyp, respectively (Nx vs. Hyp: P < 0.05). Post-ischemia IS-EMGRMS values were higher than during the last 10 s of IE. Sprint exercise mean (IS-MPF) and median (IS-MdPF) power frequencies, and burst duration, were more reduced after IE-Nx than IE-Hyp (P < 0.05). Despite increased muscle lactate accumulation, acidification, and metaboreflex activation from 10 to 60 s of ischemia, IS-Wmean (+23%) and burst duration (+10%) increased, while IS-EMGRMS decreased (−24%, P < 0.05), with IS-MPF and IS-MdPF remaining unchanged. In conclusion, close to task failure, muscle activation is lower in hypoxia than in normoxia. Task failure is predominantly caused by central mechanisms, which recover to great extent within 1 min even when the legs remain ischemic. There is dissociation between the recovery of EMGRMS and performance. The reduction of surface electromyogram MPF, MdPF and burst duration due to fatigue is associated but not caused by muscle acidification and lactate accumulation. Despite metaboreflex stimulation, muscle activation and power output recovers partly in ischemia indicating that metaboreflex activation has a minor impact on sprint performance.
Collapse
Affiliation(s)
- Rafael Torres-Peralta
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS)Las Palmas de Gran Canaria, Spain
| | - David Morales-Alamo
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS)Las Palmas de Gran Canaria, Spain
| | | | - José Losa-Reyna
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS)Las Palmas de Gran Canaria, Spain
| | - Ismael Pérez-Suárez
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS)Las Palmas de Gran Canaria, Spain
| | - Mikel Izquierdo
- Department of Health Sciences, Public University of Navarra Tudela, Spain
| | - José A L Calbet
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS)Las Palmas de Gran Canaria, Spain
| |
Collapse
|
16
|
Bazzucchi I, De Vito G, Felici F, Dewhurst S, Sgadari A, Sacchetti M. Effect of exercise training on neuromuscular function of elbow flexors and knee extensors of type 2 diabetic patients. J Electromyogr Kinesiol 2015; 25:815-23. [DOI: 10.1016/j.jelekin.2015.06.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 06/23/2015] [Accepted: 06/23/2015] [Indexed: 12/15/2022] Open
|
17
|
Torres-Peralta R, Losa-Reyna J, González-Izal M, Perez-Suarez I, Calle-Herrero J, Izquierdo M, Calbet JAL. Muscle activation during exercise in severe acute hypoxia: role of absolute and relative intensity. High Alt Med Biol 2015; 15:472-82. [PMID: 25225839 DOI: 10.1089/ham.2014.1027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The aim of this study was to determine the influence of severe acute hypoxia on muscle activation during whole body dynamic exercise. Eleven young men performed four incremental cycle ergometer tests to exhaustion breathing normoxic (FIO2=0.21, two tests) or hypoxic gas (FIO2=0.108, two tests). Surface electromyography (EMG) activities of rectus femoris (RF), vastus medialis (VL), vastus lateralis (VL), and biceps femoris (BF) were recorded. The two normoxic and the two hypoxic tests were averaged to reduce EMG variability. Peak VO2 was 34% lower in hypoxia than in normoxia (p<0.05). The EMG root mean square (RMS) increased with exercise intensity in all muscles (p<0.05), with greater effect in hypoxia than in normoxia in the RF and VM (p<0.05), and a similar trend in VL (p=0.10). At the same relative intensity, the RMS was greater in normoxia than in hypoxia in RF, VL, and BF (p<0.05), with a similar trend in VM (p=0.08). Median frequency increased with exercise intensity (p<0.05), and was higher in hypoxia than in normoxia in VL (p<0.05). Muscle contraction burst duration increased with exercise intensity in VM and VL (p<0.05), without clear effects of FIO2. No significant FIO2 effects on frequency domain indices were observed when compared at the same relative intensity. In conclusion, muscle activation during whole body exercise increases almost linearly with exercise intensity, following a muscle-specific pattern, which is adjusted depending on the FIO2 and the relative intensity of exercise. Both VL and VM are increasingly involved in power output generation with the increase of intensity and the reduction in FIO2.
Collapse
Affiliation(s)
- Rafael Torres-Peralta
- 1 Department of Physical Education, University of Las Palmas de Gran Canaria , Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, Spain
| | | | | | | | | | | | | |
Collapse
|
18
|
Green LA, McGuire J, Gabriel DA. Flexor carpi radialis surface electromyography electrode placement for evoked and voluntary measures. Muscle Nerve 2015; 52:818-25. [DOI: 10.1002/mus.24631] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 02/19/2015] [Accepted: 02/25/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Lara A. Green
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University; 500 Glenridge Avenue St. Catharines Ontario L2S 3A1 Canada
| | - Jessica McGuire
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University; 500 Glenridge Avenue St. Catharines Ontario L2S 3A1 Canada
| | - David A. Gabriel
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University; 500 Glenridge Avenue St. Catharines Ontario L2S 3A1 Canada
| |
Collapse
|
19
|
Quinzi F, Camomilla V, Felici F, Di Mario A, Sbriccoli P. Agonist and antagonist muscle activation in elite athletes: influence of age. Eur J Appl Physiol 2014; 115:47-56. [PMID: 25192778 DOI: 10.1007/s00421-014-2990-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 08/23/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE Age-related neuromuscular control adaptations have been investigated mainly in untrained populations, where higher antagonist activation in adults was observed with respect to children. In elite athletes age-related differences in neuromuscular control have scarcely been investigated. Therefore, this study aims at investigating differences in co-activation about the knee joint in two groups of karate athletes belonging to the Junior (JK) and Senior (SK) age categories, performing the roundhouse kick (RK). METHODS Six SK and six JK performed the RK impacting on a punching bag. Each participant performed three attempts during which kicking limb kinematics and sEMG from the vastus lateralis (VL) and from the biceps femoris (BF) were recorded. Co-activation index during knee flexion and extension (CIF; CIE) and agonist and antagonist activation areas of VL and BF (I AGO-VL; I AGO-BF; I ANT-VL; I ANT-BF) were computed. Hip and knee range of motion, peak angular velocity and minima and maxima of lower limb angular momentum were computed. RESULTS During knee extension, the SK demonstrated higher CIE, higher IANT-BF and higher total angular momentum with respect to the JK. Significant relationships were observed between I ANT-BF and total angular momentum maxima, and between I ANT-BF and age. CONCLUSIONS IANT-BF is partially related to the age of the group and to joint protection upon impact. Moreover, given the very brief duration of the task, a feed-forward mechanism modulating antagonist activation partly based on the stress imposed on the knee joint could be hypothesized. This mechanism potentially involves skill dependent re-modelling of the peripheral and central nervous system.
Collapse
Affiliation(s)
- Federico Quinzi
- Laboratory of Exercise Physiology, Division of Human Movement and Sport Sciences, Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Piazza Lauro de Bosis 6, 00135, Rome, Italy,
| | | | | | | | | |
Collapse
|
20
|
Electromyogram features during linear torque decrement and their changes with fatigue. Eur J Appl Physiol 2014; 114:2105-17. [DOI: 10.1007/s00421-014-2928-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 05/30/2014] [Indexed: 10/25/2022]
|
21
|
McIntosh KCD, Gabriel DA. Reliability of a simple method for determining muscle fiber conduction velocity. Muscle Nerve 2012; 45:257-65. [PMID: 22246883 DOI: 10.1002/mus.22268] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kyle C D McIntosh
- Faculty of Applied Health Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario L2S 3A1, Canada
| | | |
Collapse
|
22
|
Chen X, Zheng YP, Guo JY, Zhu Z, Chan SC, Zhang Z. Sonomyographic responses during voluntary isometric ramp contraction of the human rectus femoris muscle. Eur J Appl Physiol 2011; 112:2603-14. [PMID: 22081124 PMCID: PMC3371332 DOI: 10.1007/s00421-011-2227-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 10/27/2011] [Indexed: 11/02/2022]
Abstract
This paper aims to investigate the relationship between torque and muscle morphological change, which is derived from ultrasound image sequence and termed as sonomyography (SMG), during isometric ramp contraction of the rectus femoris (RF) muscle, and to further compare SMG with the electromyography (EMG) and mechanomyography (MMG), which represent the electrical and mechanical activities of the muscle. Nine subjects performed isometric ramp contraction of knee up to 90% of the maximal voluntary contraction (MVC) at speeds of 45, 22.5 and 15% MVC/s, and EMG, MMG and ultrasonography were simultaneously recorded from the RF muscle. Cross-sectional area, which was referred to as SMG, was automatically extracted from continuously captured ultrasound images using a newly developed image tracking algorithm. Polynomial regression analyses were applied to fit the EMG/MMG/SMG-to-torque relationships, and the regression coefficients of EMG, MMG, and SMG were compared. Moreover, the effect of contraction speed on SMG/EMG/MMG-to-torque relationships was tested by pair-wise comparisons of the mean relationship curves at different speeds for EMG, MMG and SMG. The results show that continuous SMG could provide important morphological parameters of continuous muscle contraction. Compared with EMG and MMG, SMG exhibits different changing patterns with the increase of torque during voluntary isometric ramp contraction, and it is less influenced by the contraction speed.
Collapse
Affiliation(s)
- Xin Chen
- School of Medicine, Shenzhen Key Laboratory of Biomedical Engineering, Shenzhen University, Shenzhen, China
| | | | | | | | | | | |
Collapse
|
23
|
Effects of monopolar and bipolar electrode configurations on surface EMG spike analysis. Med Eng Phys 2011; 33:1079-85. [DOI: 10.1016/j.medengphy.2011.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 04/12/2011] [Accepted: 04/23/2011] [Indexed: 11/17/2022]
|
24
|
Spatial EMG potential distribution pattern of vastus lateralis muscle during isometric knee extension in young and elderly men. J Electromyogr Kinesiol 2011; 22:74-9. [PMID: 21996320 DOI: 10.1016/j.jelekin.2011.09.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 09/20/2011] [Accepted: 09/20/2011] [Indexed: 11/20/2022] Open
Abstract
The aim of the present study was to compare spatial electromyographic (EMG) potential distribution during force production between elderly and young individuals using multi-channel surface EMG (SEMG). Thirteen elderly (72-79years) and 13 young (21-27years) healthy male volunteers performed ramp submaximal contraction during isometric knee extension from 0% to 65% of maximal voluntary contraction. During contraction, multi-channel EMG was recorded from the vastus lateralis muscle. To evaluate alteration in heterogeneity and pattern in spatial EMG potential distribution, coefficient of variation (CoV), modified entropy and correlation coefficients with initial torque level were calculated from multi-channel SEMG at 5% force increment. Increase in CoV and decrease in modified entropy of RMS with increase of exerted torque were significantly smaller in elderly group (p<0.05) and correlation coefficients with initial torque level were significantly higher in elderly group than in young group at moderate torque levels (p<0.05). These data suggest that the increase of heterogeneity and the change in the activation pattern are smaller in elderly individuals than in young individuals. We speculated that multi-channel SEMG pattern in elderly individual reflects neuromuscular activation strategy regulated predominantly by clustering of similar type of muscle fibers in aged muscle.
Collapse
|
25
|
Pereira WM, Ferreira LAB, Rossi LP, Kerpers II, Grecco St LAC, de Paula AR, Oliveira CS. Influence of heat on fatigue and electromyographic activity of the biceps brachii muscle. J Bodyw Mov Ther 2011; 15:478-84. [PMID: 21943621 DOI: 10.1016/j.jbmt.2011.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 04/26/2011] [Accepted: 04/30/2011] [Indexed: 10/18/2022]
Abstract
Electromyography enables registering muscle activity during contraction and can identify muscle fatigue. In the present study, 30 volunteers between 18 and 30 years of age were submitted to an exertion 1 min of maximal voluntary isometric contraction. The electromyographic signal of the biceps brachii muscle and the strength of the flexor muscles of the elbow were determined before and after the administration of microwave diathermy in order to analyze the influence of heat over the strength of the elbow flexor muscles and fatigue of the biceps brachii. The results demonstrate that the strength of the elbow flexor muscles diminished significantly following the application of heat (p<0.05). Heat also led to a significant reduction in the electrical activity of the muscle studied. The present study demonstrates that microwave diathermy on the biceps brachii muscle reduces the flexion strength of the elbow as well as signs of muscle fatigue in the biceps.
Collapse
Affiliation(s)
- Wagner Menna Pereira
- Universidade Estadual do Centro-Oeste, Padre Salvador 875, Guarapuava, PR, 85015-430, Brazil
| | | | | | | | | | | | | |
Collapse
|
26
|
Gabriel DA, Christie A, Inglis JG, Kamen G. Experimental and modelling investigation of surface EMG spike analysis. Med Eng Phys 2010; 33:427-37. [PMID: 21146442 DOI: 10.1016/j.medengphy.2010.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 10/27/2010] [Accepted: 11/12/2010] [Indexed: 11/15/2022]
Abstract
A pattern classification method based on five measures extracted from the surface electromyographic (sEMG) signal is used to provide a unique characterization of the interference pattern for different motor unit behaviours. This study investigated the sensitivity of the five sEMG measures during the force gradation process. Tissue and electrode filtering effects were further evaluated using a sEMG model. Subjects (N=8) performed isometric elbow flexion contractions from 0 to 100% MVC. The sEMG signals from the biceps brachii were recorded simultaneously with force. The basic building block of the sEMG model was the detection of single fibre action potentials (SFAPs) through a homogeneous, equivalent isotropic, infinite volume conduction medium. The SFAPs were summed to generate single motor unit action potentials. The physiologic properties from a well-known muscle model and motor unit recruitment and firing rate schemes were combined to generate synthetic sEMG signals. The following pattern classification measures were calculated: mean spike amplitude, mean spike frequency, mean spike slope, mean spike duration, and the mean number of peaks per spike. Root-mean-square amplitude and mean power frequency were also calculated. Taken together, the experimental data and modelling analysis showed that below 50% MVC, the pattern classification measures were more sensitive to changes in force than traditional time and frequency measures. However, there are additional limitations associated with electrode distance from the source that must be explored further. Future experimental work should ensure that the inter-electrode distance is no greater than 1cm to mitigate the effects of tissue filtering.
Collapse
Affiliation(s)
- David A Gabriel
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, ON, Canada L2S 3A1.
| | | | | | | |
Collapse
|
27
|
Orizio C, Baruzzi E, Gaffurini P, Diemont B, Gobbo M. Electromyogram and force fluctuation during different linearly varying isometric motor tasks. J Electromyogr Kinesiol 2010; 20:732-41. [PMID: 20395156 DOI: 10.1016/j.jelekin.2010.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2010] [Revised: 03/12/2010] [Accepted: 03/17/2010] [Indexed: 12/14/2022] Open
Abstract
The purpose of this work was to verify if deviation from the mirror-like behaviour of the motor units activation strategy (MUAS) and de-activation strategy (MUDS) and the degree of the error of the motor control system, during consecutive linearly increasing-decreasing isometric tension tasks, depend on the maximum reached tension and/or on the rate of tension changes. In 12 male subjects the surface EMG and force produced by the first dorsal interosseus activity were recorded during two (a and b) trapezoid isometric contractions with different plateau (a: 50% maximal voluntary contraction (MVC) and b: 100% MVC) and rate of tension changes (a: 6.7% MVC/s and b: 13.3% MVC/s) during up-going (UGR) and down-going (DGR) ramps. Ten steps (ST) 6s long at 5, 10, 20, 30, 40, 50, 60, 70, 80 and 90% MVC were also recorded. The root mean square (RMS) and mean frequency (MF) from EMG and the relative error of actual force output with respect to the target (% ERR) were computed. The EMG-RMS/% MVC and EMG-MF/% MVC relationships were not overlapped when the ST and DGR as well as the UGR and DGR data were compared. The % ERR/% MVC relationships during a and b contractions differed from ST data only below 20% MVC. It can be concluded that MUAS and MUDS are not mirroring one each other because MU recruitment or de-recruitment threshold may be influenced by the maximum effort and by the % MVC/s of UGR and DGR. The role of MUs mechanical and/or central nervous system hysteresis on force decrement control is discussed.
Collapse
Affiliation(s)
- C Orizio
- Department of Biomedical Sciences and Biotechnologies, University of Brescia, Viale Europa 11, Brescia, Italy.
| | | | | | | | | |
Collapse
|
28
|
Abstract
Accurate timing of limb displacement is crucial for effective motor control. The authors examined the effects of movement velocity, duration, direction, added mass, and auditory cueing on timing, spatial, and trajectory variability of single- and multijoint rhythmic movements. During single-joint movements, increased velocity decreased timing and spatial variability, whereas increased movement duration increased timing variability but decreased spatial variability. For multijoint movements, regardless of condition, increasing velocity decreased joint timing, spatial, and trajectory variability, but all hand variabilities were unaffected by velocity, duration, load, or direction. Timing, spatial, and trajectory variability was greater at the shoulder compared with the elbow and minimal at the hand, supporting the notion that reaching movements are planned in hand space as opposed to joint space.
Collapse
Affiliation(s)
- Tal Shafir
- School of Kinesiology, University of Michigan, Ann Arbor, MI 48109-0720, USA.
| | | |
Collapse
|
29
|
Bernasconi SM, Tordi NR, Parratte BM, Rouillon JDR. Can shoulder muscle coordination during the support scale at ring height be replicated during training exercises in gymnastics? J Strength Cond Res 2010; 23:2381-8. [PMID: 19826284 DOI: 10.1519/jsc.0b013e3181bac69f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The support scale at ring height, the swallow, is a difficult strength element, usually performed in gymnastics. Coaches try to simulate the swallow position during training to strengthen muscles, specifically in the position used for competition. However, the real effect of this position's simulation on muscle force and coordination and consequently on the muscle activity has not been determined. The purpose of the study was to compare muscle activity and coordination during a swallow performed on the rings, using a counterweight and during 2 training exercises using dumbbells or barbells, respectively. Six top-level gymnasts participated in the study. Electromyograms from the biceps brachii, triceps brachii, deltoideus (clavicular part), pectoralis major, serratus anterior, infraspinatus, trapezius (middle part), and latissimus dorsi in the right shoulder were collected during the 4 exercises and analyzed using root mean square (RMS) and mean power frequency (MPF). The RMS were normalized to the maximal voluntary contraction, and a co-activation index was also determined between biceps and triceps brachii. Our results show specific shoulder muscle coordination for each exercise. As compared with the swallow on the rings, the pectoralis major participates less in shoulder flexion during the counterweight exercise, whereas the deltoideus is more activated during the dumbbells exercise (p < 0.05). The barbell exercise reduces the participation of the serratus anterior in stabilizing the scapula (p < 0.05). Training exercises must therefore be chosen with knowledge of the specific muscle coordination induced by each. The counterweight exercise preserves the pectoralis major. The barbell exercise reduces participation of the serratus anterior. The dumbbells exercise may be useful to prepare the rotator cuff muscles carefully for use.
Collapse
Affiliation(s)
- Sylvain M Bernasconi
- IFR 133, EA 3920 Cardiovascular Physiopathology and Prevention, University of Franche Comté, Besancon, France.
| | | | | | | |
Collapse
|
30
|
Sbriccoli P, Camomilla V, Di Mario A, Quinzi F, Figura F, Felici F. Neuromuscular control adaptations in elite athletes: the case of top level karateka. Eur J Appl Physiol 2009; 108:1269-80. [PMID: 20039054 DOI: 10.1007/s00421-009-1338-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2009] [Indexed: 10/20/2022]
Abstract
This paper aimed at investigating the neuromuscular response of knee flexor and extensor muscles in elite karateka and karate amateurs (Amateurs) during isokinetic knee flexion/extensions and during the execution of a front kick (FK). Surface electromyograms (sEMG) were recorded from the right vastus lateralis (VL) and biceps femoris (BF) muscles with a four-array electrode during maximal isometric knee flexion and extension (maximal voluntary contraction), during isokinetic contractions (30 degrees , 90 degrees , 180 degrees , 270 degrees , 340 degrees , 400 degrees /s), and during the FK. The level of VL and BF agonist (ago) and antagonist (ant) activation during the isokinetic and FK protocols was quantified through normalized sEMG root mean square value (%RMS(ago/ant-ISOK/FK)). VL and BF average muscle fiber conduction velocity (CV) was computed for isokinetic and FK. Isokinetic flexion and extension torques and knee angular velocity during FK were also assessed. Analysis of variance was used to test the effect of group, angular velocity, and task on the assessed variables (P < 0.05). Elite karateka showed higher isokinetic knee flexion torque when compared with Amateurs. For all angular velocities, VL and BF %RMS(ant-isokinetic) were lower in elite karateka, while their BF-CV(isokinetic) BF-CV(front kick) and BF %RMS(ant-front kick) values were higher. For VL and BF, %RMS(ago-front kick) was lower than %RMS(ago-isokinetic) in both groups. Elite karateka demonstrated a typical neuromuscular activation strategy that seems task and skill level dependent. Knee flexion torque and CV results suggest the presence of an improved ability of elite karateka to recruit fast MUs as a part of training induced neuromuscular adaptation.
Collapse
Affiliation(s)
- Paola Sbriccoli
- Department of Human Movement and Sport Sciences, Faculty for Movement Sciences, Study University of Rome "Foro Italico", Piazza Lauro de Bosis 6, Rome 00135, Italy.
| | | | | | | | | | | |
Collapse
|
31
|
Non-invasive assessment of muscle fiber conduction velocity during an incremental maximal cycling test. J Electromyogr Kinesiol 2009; 19:e380-6. [DOI: 10.1016/j.jelekin.2009.03.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Revised: 03/19/2009] [Accepted: 03/19/2009] [Indexed: 11/18/2022] Open
|
32
|
Christie A, Greig Inglis J, Kamen G, Gabriel DA. Relationships between surface EMG variables and motor unit firing rates. Eur J Appl Physiol 2009; 107:177-85. [PMID: 19544067 DOI: 10.1007/s00421-009-1113-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2009] [Indexed: 12/13/2022]
Abstract
Although surface electromyography (sEMG) is a widely used electrophysiological technique, its physiological interpretation remains somewhat controversial. This study examined the relationship between motor unit firing rates (MUFR) and the root mean square (RMS) amplitude and mean power frequency (MPF) of the sEMG signal in the biceps brachii. Eleven subjects performed maximal isometric elbow flexion while indwelling and sEMG recordings were obtained from the biceps. The RMS amplitude and MPF of the surface signal, and the mean MUFR from the indwelling signal, were calculated over 500 ms epochs. Group means showed a strong MUFR-RMS amplitude relationship (r (2) = 0.91), but a weak MUFR-MPF relationship (r (2) = 0.20). Using all trials, the MUFR-RMS amplitude (r (2) = 0.19) and MUFR-MPF (r (2) = 0.0037) relationships were much weaker. Within individual subjects, the MUFR-RMS amplitude (mean r (2) = 0.13 +/- 0.17) and the MUFR-MPF (mean r (2) = 0.040 +/- 0.041) relationships were also weak. These results suggest that MUFR cannot be predicted from the characteristics of the sEMG signal.
Collapse
Affiliation(s)
- Anita Christie
- Department of Kinesiology, University of Massachusetts, Amherst, MA, USA
| | | | | | | |
Collapse
|
33
|
Calder KM, Gabriel DA, McLean L. Differences in EMG spike shape between individuals with and without non-specific arm pain. J Neurosci Methods 2009; 178:148-56. [DOI: 10.1016/j.jneumeth.2008.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 11/10/2008] [Accepted: 11/11/2008] [Indexed: 11/30/2022]
|
34
|
Enoka RM. Comments on Point:Counterpoint: Spectral properties of the surface EMG can characterize/do not provide information about motor unit recruitment strategies and muscle fiber type. J Appl Physiol (1985) 2008; 105:1680-1. [DOI: 10.1152/japplphysiol.zdg-8232-pcpcomm.2008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
35
|
The vastus lateralis neuromuscular activity during all-out cycling exercise. J Electromyogr Kinesiol 2008; 19:922-30. [PMID: 18539484 DOI: 10.1016/j.jelekin.2008.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Revised: 03/25/2008] [Accepted: 03/25/2008] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE The objective of this work was to study modifications in motor control through surface electromyographic (sEMG) activity during a very short all-out cycling exercise. METHODS Twelve male cyclists (age 23+/-4 years) participated in this study. After a warm-up period, each subject performed three all-out cycling exercises of 6s separated by 2 min of complete rest. This protocol was repeated three times with a minimum of 2 days between each session. The braking torque imposed on cycling motion was 19 Nm. The sEMG of the vastus lateralis was recorded during the first seven contractions of the sprint. Time-frequency analysis of sEMG was performed using continuous wavelet transform. The mean power frequency (MPF, qualitative modifications in the recruitment of motor units) and signal energy (a quantitative indicator of modifications in the motor units recruitment) were computed for the frequency range 10-500 Hz. RESULTS sEMG energy increased (P0.05) between contraction number 1 and 2, decreased (P < or =0.05) between contraction number 2 and 3 then stabilized between contraction number 3 and 7 during the all-out test. MPF increased (P < or =0.05) during the all-out test. This increase was more marked during the first two contractions. CONCLUSIONS The decrease in energy and the increase in the sEMG MPF suggest a large spatial recruitment of motor units (MUs) at the beginning of the sprint followed by a preferential recruitment of faster MUs at the end of the sprint, respectively.
Collapse
|
36
|
Lebon F, Rouffet D, Collet C, Guillot A. Modulation of EMG power spectrum frequency during motor imagery. Neurosci Lett 2008; 435:181-5. [PMID: 18343579 DOI: 10.1016/j.neulet.2008.02.033] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 02/11/2008] [Accepted: 02/15/2008] [Indexed: 10/22/2022]
Abstract
To provide evidence that motor imagery (MI) is accompanied by improvement of intramuscular conduction velocity (CV), we investigated surface electromyographic (EMG) activity of 3 muscles during the elbow flexion/extension. Thirty right-handed participants were asked to lift or to imagine lifting a weighted dumbbell under 3 types of muscular contractions, i.e. concentric, isometric and eccentric, taken as independent variables. The EMG activity of the agonist (long and short heads of biceps brachii) and the antagonist (long portion of triceps brachii) muscles was recorded and processed to determine the median frequency (MF) of EMG power spectrum as dependant variable. The MF was significantly higher during the MI sessions than during the resting condition while the participants remained strictly motionless. Moreover, the MF during imagined concentric contraction was significantly higher than during the eccentric. Thus, the MF variation was correlated to the type of contraction the muscle produced. During MI, the EMG patterns corresponding to each type of muscle contraction remained comparable to those observed during actual movement. In conclusion, specific motor programming is hypothesized to be performed as a function of muscle contraction type during MI.
Collapse
Affiliation(s)
- F Lebon
- Université de Lyon, Université Claude Bernard Lyon 1, Centre de Recherche et d'Innovation sur le Sport (C.R.I.S.) EA 647, Laboratoire de la Performance Motrice, Mentale et du Matériel (P3M), France
| | | | | | | |
Collapse
|
37
|
Gabriel DA, Kamen G. Experimental and modeling investigation of spectral compression of biceps brachii SEMG activity with increasing force levels. J Electromyogr Kinesiol 2008; 19:437-48. [PMID: 18083563 DOI: 10.1016/j.jelekin.2007.10.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 10/23/2007] [Accepted: 10/24/2007] [Indexed: 11/30/2022] Open
Abstract
This study investigated possible motor unit (MU) firing patterns underlying changes in biceps brachii (BB) surface electromyographic (SEMG) activity in 96 participants who performed isometric actions of the elbow flexors at 40%, 60%, 80%, and 100% of maximum voluntary contraction (MVC). We also conducted a modeling investigation to determine the extent to which a model would fit the experimental results. Experimentally, there was a linear increase (277%; p<0.01) in root-mean-square (RMS) amplitude with increasing force. The mean power frequency (MNF) remained stable from 40% to 80% of MVC, but there was a decrease (8.2%; p<0.01) between 80% and 100% of MVC. A modeling approach was taken wherein well-known recruitment and rate-coding schemes activated MUs whose basic building block was the muscle fibre action potential. Two conditions were investigated: (1) an increase in firing rate (rate-coding) and (2) synchronization. The levels of rate-coding and synchronization were selected to produce a linear RMS-force relationship as observed in the experimental data. Then, the impact of these two strategies on changes in MNF was assessed. The MNF remained stable from 40% to 80% of maximum excitation for both the rate-coding and synchronization conditions. There was a decrease in MNF between 80% and 100% of maximum excitation for both modeling conditions, similar to that observed for the experimental data. Thus, at these high forces at which experimental data are technically difficult to obtain, the model supports the idea that both rate-coding and synchronization are responsible for the changes observed in surface EMG amplitude and frequency characteristics.
Collapse
Affiliation(s)
- David A Gabriel
- Electromyographic Kinesiology Laboratory, Faculty of Applied Health Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, ON, Canada L2S 3A1.
| | | |
Collapse
|
38
|
Felici F, Quaresima V, Fattorini L, Sbriccoli P, Filligoi GC, Ferrari M. Biceps brachii myoelectric and oxygenation changes during static and sinusoidal isometric exercises. J Electromyogr Kinesiol 2007; 19:e1-11. [PMID: 17890107 DOI: 10.1016/j.jelekin.2007.07.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 07/17/2007] [Accepted: 07/17/2007] [Indexed: 11/22/2022] Open
Abstract
Surface myoelectric signal changes occurring during sustained isometric contractions have been extensively studied with quantitative surface electromyography (sEMG) and are described by means of some sEMG global variables in time and frequency domain (such as the median power spectral frequency). Recently, the possibility of studying local muscle O(2) saturation during exercise using non-invasive methods has been enhanced thanks to the use of near-infrared spectroscopy (NIRS). The purpose of this work was to combine NIRS and sEMG techniques to analyze the relationship between modifications of sEMG parameters and the underlying metabolic status of the exercising biceps brachii muscle. This relationship was tested under different isometric contraction modalities, namely static (ST) at 20, 40, 60 and 80%MVC and sinusoidal (SIN) at 40+/-20 and 60+/-20%MVC. Results clearly indicated the presence of an initial fast phase of muscle O(2) desaturation followed by a slow phase, regardless of the contraction modality. Moreover, the initial rate of muscle O(2) desaturation was related to the level of force output (R=0.92), but it was independent on the contraction modality (p<0.05). Similarly, changes in sEMG parameters were related to force level (Conduction Velocity-CV vs. Force: R=0.87; sEMG Median Frequency-MDF vs. Force: R=0.86). The high correlation found between CV-MDF and Tissue Oxygenation Index (TOI) slope (R=0.73 and 0.72, respectively) suggests a strong relationship between NIRS and sEMG data. This study indicates that muscle O(2) demand during isometric contractions from low to high force levels is influenced by the type of active motor units and not from the type of isometric exercise modality.
Collapse
Affiliation(s)
- Francesco Felici
- Department of Human Movement and Sport Sciences, Istituto Universitario di Scienze Motorie, Piazza Lauro De Bosis 6, 00194 Roma, Italy.
| | | | | | | | | | | |
Collapse
|
39
|
van Hedel HJA, Murer C, Dietz V, Curt A. The amplitude of lower leg motor evoked potentials is a reliable measure when controlled for torque and motor task. J Neurol 2007; 254:1089-98. [PMID: 17431701 DOI: 10.1007/s00415-006-0493-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 10/30/2006] [Accepted: 11/16/2006] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Motor evoked potential (MEP) amplitudes have the disadvantage of a high variability when repeatedly assessed. This affects the reliability of MEP amplitude measurements taken during the course of motor incomplete spinal cord injury (iSCI). The study investigated the reliability of anterior tibial (TA) MEP measures controlled for dorsal flexion torque and motor task. METHODS TA MEPs were recorded at 10, 20, 40 and 60% of maximal voluntary contraction (MVC) during a static and dynamic (isometric increase of dorsal flexion torque) motor task. To determine reliability, 20 healthy and five chronic iSCI subjects were tested twice (> or =7 days) by the same investigator. Intraclass correlation coefficients (ICCs) were calculated. MEP amplitudes and latencies were compared between 20 healthy and 29 iSCI subjects. RESULTS The reliability of MEP amplitude was in general good (ICC > or = 0.52) and was highest during the static task at 40% MVC (ICC = 0.77). The increased facilitation by the dynamic motor task showed the best reliability at 20% MVC (ICC = 0.48). The reliability was good to excellent for MEP latency (0.46 < or = ICC < or = 0.81), MVC (ICC > or = 0.90) and for the TMS threshold required to evoke a MEP response (ICC > or = 0.77). The torque generated by the MEP response ()0.02 < or = ICC < or = 0.55) and the duration of the silent period (0.07 < or = ICC < or = 0.50) were not reliable. Both MEP amplitudes and latencies differed significantly between healthy and iSCI subjects. CONCLUSIONS Controlling for torque generation and motor task establishes a reliability of TA MEP amplitudes that is sufficient for longitudinal assessments in motor incomplete SCI.
Collapse
Affiliation(s)
- Hubertus J A van Hedel
- Spinal Cord Injury Center, Balgrist University Hospital, Forchstrasse 340, 8008, Zurich, Switzerland.
| | | | | | | |
Collapse
|
40
|
Drost G, Stegeman DF, van Engelen BGM, Zwarts MJ. Clinical applications of high-density surface EMG: A systematic review. J Electromyogr Kinesiol 2006; 16:586-602. [PMID: 17085302 DOI: 10.1016/j.jelekin.2006.09.005] [Citation(s) in RCA: 189] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
High density-surface EMG (HD-sEMG) is a non-invasive technique to measure electrical muscle activity with multiple (more than two) closely spaced electrodes overlying a restricted area of the skin. Besides temporal activity HD-sEMG also allows spatial EMG activity to be recorded, thus expanding the possibilities to detect new muscle characteristics. Especially muscle fiber conduction velocity (MFCV) measurements and the evaluation of single motor unit (MU) characteristics come into view. This systematic review of the literature evaluates the clinical applications of HD-sEMG. Although beyond the scope of the present review, the search yielded a large number of "non-clinical" papers demonstrating that a considerable amount of work has been done and that significant technical progress has been made concerning the feasibility and optimization of HD-sEMG techniques. Twenty-nine clinical studies and four reviews of clinical applications of HD-sEMG were considered. The clinical studies concerned muscle fatigue, motor neuron diseases (MND), neuropathies, myopathies (mainly in patients with channelopathies), spontaneous muscle activity and MU firing rates. In principle, HD-sEMG allows pathological changes at the MU level to be detected, especially changes in neurogenic disorders and channelopathies. We additionally discuss several bioengineering aspects and future clinical applications of the technique and provide recommendations for further development and implementation of HD-sEMG as a clinical diagnostic tool.
Collapse
Affiliation(s)
- Gea Drost
- Department of Clinical Neurophysiology, Institute of Neurology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | | | | | | |
Collapse
|
41
|
Abstract
Physical exercise promotes a wide spectrum of short and long term responses of different organs and apparatuses. While skeletal muscle adaptations to the different training regimens are conveniently known and described, the neural counterpart of them are still to be described in full. In this paper, an attempt is made to fix the state of the art and particularly to point out the contribution derived from the analysis of the surface electromyographic signal. In this paper, some examples of sEMG applications in exercise physiology will be reported from studies where only strictly non-invasive techniques (or of very limited invasiveness) were applied. A consistent amount of space in this lecture will be dedicated to the advanced analysis of sEMG using non linear tools.
Collapse
Affiliation(s)
- Francesco Felici
- Department of Human Movement and Sport Sciences, Istituto Universitario di Scienze Motorie, Largo Lauro De Bosis 6, 00194 Roma, Italy.
| |
Collapse
|
42
|
Kursa K, Diao E, Lattanza L, Rempel D. In vivo forces generated by finger flexor muscles do not depend on the rate of fingertip loading during an isometric task. J Biomech 2005; 38:2288-93. [PMID: 16154416 DOI: 10.1016/j.jbiomech.2004.07.035] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Accepted: 07/16/2004] [Indexed: 11/23/2022]
Abstract
Risk factors for activity-related tendon disorders of the hand include applied force, duration, and rate of loading. Understanding the relationship between external loading conditions and internal tendon forces can elucidate their role in injury and rehabilitation. The goal of this investigation is to determine whether the rate of force applied at the fingertip affects in vivo forces in the flexor digitorum profundus (FDP) tendon and the flexor digitorum superficialis (FDS) tendon during an isometric task. Tendon forces, recorded with buckle force transducers, and fingertip forces were simultaneously measured during open carpal tunnel surgery as subjects (N=15) increased their fingertip force from 0 to 15N in 1, 3, and 10s. The rates of 1.5, 5, and 15N/s did not significantly affect FDP or FDS tendon to fingertip force ratios. For the same applied fingertip force, the FDP tendon generated more force than the FDS. The mean FDP to fingertip ratio was 2.4+/-0.7 while the FDS to tip ratio averaged 1.5+/-1.0 (p<0.01). The fine motor control needed to generate isometric force ramps at these specific loading rates probably required similar high activation levels of multiple finger muscles in order to stabilize the finger and control joint torques at the force rates studied. Therefore, for this task, no additional increase in muscle force was observed at higher rates. These findings suggest that for high precision, isometric pinch maneuvers under static finger conditions, tendon forces are independent of loading rate.
Collapse
Affiliation(s)
- Katarzyna Kursa
- Department of Bioengineering, University of California-San Francisco, 1301 South 46th Street, Building 163, Richmond, CA 94804, USA
| | | | | | | |
Collapse
|
43
|
Diehl P, Kliesch U, Dietz V, Curt A. Impaired facilitation of motor evoked potentials in incomplete spinal cord injury. J Neurol 2005; 253:51-7. [PMID: 16044213 DOI: 10.1007/s00415-005-0921-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Revised: 04/12/2005] [Accepted: 04/21/2005] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To improve the diagnosis of damaged spinal motor pathways in incomplete spinal cord injury (iSCI) by assessing the facilitation of lower limbs motor evoked potentials (MEP). METHODS Control subjects (n = 12) and iSCI patients (n = 21) performed static and dynamic isometric foot dorsiflexions. MEPs induced by transcranial magnetic stimulation and EMG background of tibialis anterior muscle (TA) were analyzed. Static and dynamic muscle activation was performed at comparable levels of maximal voluntary contraction (MVC). The influence of the motor tasks on the excitability and facilitation of MEPs was compared between controls and iSCI patients. RESULTS In the controls an increased facilitation of TA MEP at lower levels of dynamic compared with static activation (10-20% MVC) could be shown. At matched EMG background level the MEP responses were significantly increased. In the iSCI patients at a comparable level of TA activation the MEP responses were significantly reduced and 3 different patterns of MEP responses could be distinguished: i) preserved increment of TA MEP in the dynamic motor task, ii) unchanged MEP size in the dynamic and static motor task, and iii) elicitable MEPs in the dynamic motor task,which were abolished in the static motor task. CONCLUSIONS Static and dynamic motor tasks have different effects on TA MEP facilitation. The task-dependent modulation of TA MEPs is comparable to that described for upper limb muscles. Complementary to the MEP delay this approach allows for an estimation of the severity of spinal tract damage. The task-dependent modulation of TA MEPs is an additional diagnostic tool to improve the assessment and monitoring of motor function in iSCI.
Collapse
Affiliation(s)
- Philipp Diehl
- Spinal Cord Injury Center, University Hospital Balgrist, Forchstrasse 340, 8008, Zürich, Switzerland
| | | | | | | |
Collapse
|
44
|
Esposito F, Cè E, Gobbo M, Veicsteinas A, Orizio C. Surface EMG and mechanomyogram disclose isokinetic training effects on quadriceps muscle in elderly people. Eur J Appl Physiol 2005; 94:549-57. [PMID: 15942769 DOI: 10.1007/s00421-005-1371-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2005] [Indexed: 10/25/2022]
Abstract
Maximum voluntary contraction (MVC) and cross-sectional area (CSA) of fast and slow twitch fibers are reduced in the lower limb muscles of elderly subjects. Isokinetic training at medium and high velocities has been widely used to improve muscle performance and force in young as well as elderly subjects. EMG and mechanomyogram (MMG) are compound signals in which the electrical and mechanical activities of recruited motor units (MUs) are summated. The aim of the present study was to verify the hypothesis that isokinetic training in the elderly induces changes in EMG and MMG parameters, compatible with a functional retrieval of fast twitch fiber MUs. In ten sedentary males (62-78 years), the surface EMG and MMG were recorded from the vastus lateralis muscle during isometric contractions at 20, 40, 60, 80 and 100% of the MVC, before and after 12 weeks of isokinetic training (six series of ten repetitions, each at an angular velocity of 2.09 rad s(-1) and 4.19 rad s(-1), two times a week). With training: (a) MVC and CSA increased by about 35+/-5% and 8+/-1%, respectively (P<0.05); (b) the ratio MVC/CSA increased significantly in all subjects by 25+/-5%; (c) the EMG root mean square and MMG spectral mean frequency increased significantly at the highest workloads. In conclusion, our data indicate that isokinetic training in the elderly improved muscle size and performance significantly. The EMG and MMG changes suggest that these results may be due to a retrieval of the fast twitch fiber MUs, contributing to muscle action.
Collapse
Affiliation(s)
- Fabio Esposito
- Institute of Physical Exercise, Health and Sports, Division of Human Physiology, University of Milan, Via Colombo 71, 20133 Milan, Italy.
| | | | | | | | | |
Collapse
|
45
|
Bazzucchi I, Marchetti M, Rosponi A, Fattorini L, Castellano V, Sbriccoli P, Felici F. Differences in the force/endurance relationship between young and older men. Eur J Appl Physiol 2004; 93:390-7. [PMID: 15578202 DOI: 10.1007/s00421-004-1277-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2004] [Indexed: 10/26/2022]
Abstract
The aim of the present study was to ascertain if in six young (23-35 years) and in six older (70-72 years) healthy men matched for comparable absolute and specific maximal force of the dominant elbow flexors, differences in isometric endurance, myoelectrical fatigability, and shortening velocity are still recognizable. To assess the specific force, the muscle cross sectional area (CSA) was determined from magnetic resonance imaging (MRI) scans. The performance of the elbow flexors was studied by assessing the isometric endurance times (ET) at different percentages of maximal isometric contraction (MVC), the average muscle fibre conduction velocity of action potentials (CV), and the median frequency (MDF) of the surface electromyogram (sEMG) of the biceps brachii. Finally, the torque-velocity curve was assessed by means of maximal isokinetic contractions at six fixed angular velocities. All data were expressed as the mean (SD). The results showed that: (1) the ET was longer in the older subjects at the highest levels of isometric contraction, independently from the absolute force; (2) the modifications of muscle fibre CV during isometric effort progressed less rapidly in the older than the younger groups, as did those of MDF; and (3) at the same angular velocity, the older subjects exerted less absolute force than the younger subjects. These results suggest an impairment of the neuromuscular system of older men, which is less powerful and less fatigable than that of young men.
Collapse
Affiliation(s)
- Ilenia Bazzucchi
- Department of Human Movement and Sport Sciences, Istituto Universitario di Scienze Motorie, 00194 Rome, Italy
| | | | | | | | | | | | | |
Collapse
|
46
|
Bazzucchi I, Felici F, Macaluso A, De Vito G. Differences between young and older women in maximal force, force fluctuations, and surface emg during isometric knee extension and elbow flexion. Muscle Nerve 2004; 30:626-35. [PMID: 15389720 DOI: 10.1002/mus.20151] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The loss of muscle strength with aging appears to be greater in the lower than upper limbs, but strength and its neural control have never been compared in the same population of individuals in both upper and lower limbs. The aim of this study was to investigate differences between eight young (20-31 years) and eight older (68-76 years) healthy women in maximal voluntary contraction (MVC), force fluctuations, median frequency (MDF) of the surface electromyogram (sEMG), and muscle fiber conduction velocity (MFCV) during sustained isometric elbow flexion (EF) and knee extension (KE), performed at moderate to high force intensity. Older women showed larger fluctuations of force with endurance and changes in sEMG pointing to less fatigue, especially at high level of force, with no differences between upper and lower extremities. This may have significant implications in the design of rehabilitation programs directed to this population.
Collapse
Affiliation(s)
- Ilenia Bazzucchi
- Department of Applied Physiology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 76 Southbrae Drive, Glasgow G13 1PP, United Kingdom
| | | | | | | |
Collapse
|
47
|
Pozzo M, Merlo E, Farina D, Antonutto G, Merletti R, Di Prampero PE. Muscle-fiber conduction velocity estimated from surface emg signals during explosive dynamic contractions. Muscle Nerve 2004; 29:823-33. [PMID: 15170615 DOI: 10.1002/mus.20049] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Muscle-fiber conduction velocity (CV) was estimated from surface electromyographic (EMG) signals during isometric contractions and during short (150-200 ms), explosive, dynamic exercises. Surface EMG signals were recorded with four linear adhesive arrays from the vastus lateralis and medialis muscles of 12 healthy subjects. Isometric contractions were at linearly increasing force from 0% to 100% of the maximum. The dynamic contractions consisted of explosive efforts of the lower limb on a sledge ergometer. For the explosive contractions, muscle-fiber CV was estimated in seven time-windows located along the ascending time interval of the force. There was a significant correlation between CV values during the isometric ramp and explosive contractions (R = 0.75). Moreover, CV estimates increased significantly from (mean +/- SD) 4.32 +/- 0.46 m/s to 4.97 +/- 0.45 m/s during the increasing-force explosive task. It was concluded that CV can be estimated reliably during dynamic tasks involving fast limb movements and that, in these contractions, it may provide important information on motor-unit control properties.
Collapse
Affiliation(s)
- M Pozzo
- Laboratorio di Ingegneria del Sistema Neuromuscolare, Dipartimento di Elettronica, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino 10129, Italy
| | | | | | | | | | | |
Collapse
|