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Drigny J, Calmès A, Reboursière E, Hulet C, Gauthier A. Changes in the Force-Velocity Relationship of Knee Muscles After Anterior Cruciate Ligament Reconstruction Using the Isokinetic 2-Point Model. Int J Sports Physiol Perform 2023; 18:1336-1344. [PMID: 37673416 DOI: 10.1123/ijspp.2023-0108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 09/08/2023]
Abstract
PURPOSE After anterior cruciate ligament reconstruction (ACL-R), knee muscle strength symmetry is used as part of the return-to-sport criteria. However, little is known about the changes in the force-velocity (F-V) relationship, which could affect athletic performance. This study investigated the F-V relationship of knee muscles at 4 and 8 months after ACL-R, using the 2-point method tested by isokinetic dynamometry. METHODS A total of 103 physically trained individuals (24.6 [9.3] y, 59.2% male) who underwent primary ACL-R were included. Demographic information and surgery characteristics were collected at 6 weeks postoperatively. Isokinetic knee flexors' and extensors' peak torques were measured at 60° and 240° per second in the concentric mode at 4 and 8 months postoperative. Peak torques and angular velocities were converted to force and linear velocity for calculating maximum isometric force (F0) and the slope of the regression line (F-V slope). RESULTS At 4 and 8 months postoperative, F0 was significantly lower and F-V slope was significantly less steep (less negative) on the operated leg compared with the nonoperated leg for knee extensors (P < .001) and flexors (P < .001-.002). The limb symmetry index calculated using F0 was lower than the limb symmetry indexes assessed at 60° and 240° per second, especially for knee flexors (P < .001). The use of patellar tendon grafts was associated with lower F0 and a less steep F-V slope compared with hamstring tendon grafts (P < .010). CONCLUSION The isokinetic 2-point model assessing the F-V relationship provides additional and relevant insight for evaluating knee muscle strength after ACL-R.
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Affiliation(s)
- Joffrey Drigny
- Service de Médecine Physique et de Réadaptation, Service de Médecine du Sport, CHU de Caen Normandie, Normandie Université, UNICAEN, INSERM, COMETE, GIP CYCERON, Caen, France
| | - Anaelle Calmès
- Service de Médecine du Sport, CHU de Caen Normandie, Normandie Université, UNICAEN, Caen, France
| | - Emmanuel Reboursière
- Service de Médecine du Sport, CHU de Caen Normandie, Normandie Université, UNICAEN, Caen, France
| | - Christophe Hulet
- Département d'orthopédie et de traumatologie, CHU de Caen Normandie, Normandie Université, UNICAEN, INSERM, COMETE, GIP CYCERON, Caen, France
| | - Antoine Gauthier
- Normandie Université, UNICAEN, INSERM, COMETE, GIP CYCERON, Caen, France
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Sengoku T, Nakase J, Mizuno Y, Yoshimizu R, Kanayama T, Yanatori Y, Tsuchiya H. Outcome comparison of femoral nerve block and adductor canal block during anterior cruciate ligament reconstruction: adductor canal block may cause an unexpected decrease in knee flexor strength at 6 months postoperatively. Arch Orthop Trauma Surg 2023; 143:6305-6313. [PMID: 37432497 DOI: 10.1007/s00402-023-04980-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 07/02/2023] [Indexed: 07/12/2023]
Abstract
INTRODUCTION Peripheral nerve blocks are frequently used in anterior cruciate ligament (ACL) reconstruction. While femoral nerve block (FNB) has been associated with knee extensor strength reduction in the early postoperative period, no consistent view of knee extensor strength several months after ACL reconstruction exists. This study aimed to compare the impact of intraoperative FNB and adductor canal block (ACB) during ACL reconstruction on knee extensor strength at 3 and 6 months postoperatively. MATERIALS AND METHODS This retrospective study included 108 patients divided into FNB (70 patients) and ACB (38 patients) groups based on their postoperative pain management methods. Knee joint extensor and flexor strength were measured at 3 and 6 months postoperatively, using BIODEX at angular velocities of 60°/s and 180°/s. From these results, peak torque, limb symmetry index (LSI), peak knee extensor torque (time to peak torque and angle of peak torque), hamstrings-to-quadriceps (HQ) ratio, and amount of work were computed for two-group comparison. RESULTS There were no statistically significant differences in peak torque, LSI of knee extensor strength, HQ ratio, and amount of work between the two groups. However, maximum knee extension torque at 60°/s occurred significantly later in the FNB than in the ACB group at 3 months postoperatively. Additionally, the LSI of the knee flexor at 6 months postoperatively was significantly lower in the ACB group. CONCLUSIONS In ACL reconstruction, FNB may delay the time to peak torque for knee extension at 3 months postoperatively, which is likely to improve over the treatment course. In contrast, ACB may result in unexpected loss of knee flexor strength at 6 months postoperatively and should be considered with caution. LEVEL OF EVIDENCE Level III.
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Affiliation(s)
- Takuya Sengoku
- Section of Rehabilitation, Kanazawa University Hospital, 13-1 Takaramachi, Kanazawa, 920-8641, Japan
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan
| | - Junsuke Nakase
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan.
| | - Yushin Mizuno
- Section of Rehabilitation, Kanazawa University Hospital, 13-1 Takaramachi, Kanazawa, 920-8641, Japan
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan
| | - Rikuto Yoshimizu
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan
| | - Tomoyuki Kanayama
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan
| | - Yusuke Yanatori
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan
| | - Hiroyuki Tsuchiya
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan
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Mendez-Rebolledo G, Guzmán-Venegas R, Orozco-Chavez I, Cruz-Montecinos C, Watanabe K, Martinez-Valdes E. Task-related differences in peroneus longus muscle fiber conduction velocity. J Electromyogr Kinesiol 2023; 71:102795. [PMID: 37269804 DOI: 10.1016/j.jelekin.2023.102795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/27/2023] [Accepted: 05/24/2023] [Indexed: 06/05/2023] Open
Abstract
It has been identified that the peroneus longus presents a regional activity. Specifically, a greater activation of the anterior and posterior compartments has been observed during eversion, whereas a lower activation of the posterior compartment has been reported during plantarflexion. In addition to myoelectrical amplitude, motor unit recruitment can be inferred indirectly from muscle fiber conduction velocity (MFCV). However, there are few reports of MFCV of the regions that make up a muscle, and even less, MFCV of the peroneus longus compartments. This study aimed to analyze the MFCV of peroneus longus compartments during eversion and plantarflexion. Twenty-one healthy individuals were assessed. High-density surface electromyography was recorded from the peroneus longus during eversion and plantarflexion at 10%, 30%, 50%, and 70% of maximal voluntary isometric contraction. The posterior compartment presented a lower MFCV than the anterior compartment during plantarflexion, and both compartments did not show differences in MFCV during eversion; however, the posterior compartment showed an increase in MFCV during eversion compared to plantarflexion. Differences observed in the MFCV of the peroneus longus compartments could support a regional activation strategy and, to some extent, explain different motor unit recruitment strategies of the peroneus longus during ankle movements.
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Affiliation(s)
- Guillermo Mendez-Rebolledo
- Laboratorio de Investigación Somatosensorial y Motora, Escuela de Kinesiología, Facultad de Salud, Universidad Santo Tomás, Chile.
| | - Rodrigo Guzmán-Venegas
- Laboratorio Integrativo de Biomecánica y Fisiología del Esfuerzo (LIBFE), Escuela de Kinesiología, Facultad de Medicina, Universidad de los Andes, Santiago, Chile
| | - Ignacio Orozco-Chavez
- Departamento de Ciencias del Movimiento Humano, Facultad de Ciencias de la Salud, Universidad de Talca, Talca, Chile
| | - Carlos Cruz-Montecinos
- Department of Physical Therapy, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Kohei Watanabe
- Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Toyota, Japan
| | - Eduardo Martinez-Valdes
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
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Casolo A, Maeo S, Balshaw TG, Lanza MB, Martin NRW, Nuccio S, Moro T, Paoli A, Felici F, Maffulli N, Eskofier B, Kinfe TM, Folland JP, Farina D, Vecchio AD. Non-invasive estimation of muscle fibre size from high-density electromyography. J Physiol 2023; 601:1831-1850. [PMID: 36929484 DOI: 10.1113/jp284170] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
Because of the biophysical relation between muscle fibre diameter and the propagation velocity of action potentials along the muscle fibres, motor unit conduction velocity could be a non-invasive index of muscle fibre size in humans. However, the relation between motor unit conduction velocity and fibre size has been only assessed indirectly in animal models and in human patients with invasive intramuscular EMG recordings, or it has been mathematically derived from computer simulations. By combining advanced non-invasive techniques to record motor unit activity in vivo, i.e. high-density surface EMG, with the gold standard technique for muscle tissue sampling, i.e. muscle biopsy, here we investigated the relation between the conduction velocity of populations of motor units identified from the biceps brachii muscle, and muscle fibre diameter. We demonstrate the possibility of predicting muscle fibre diameter (R2 = 0.66) and cross-sectional area (R2 = 0.65) from conduction velocity estimates with low systematic bias (∼2% and ∼4% respectively) and a relatively low margin of individual error (∼8% and ∼16%, respectively). The proposed neuromuscular interface opens new perspectives in the use of high-density EMG as a non-invasive tool to estimate muscle fibre size without the need of surgical biopsy sampling. The non-invasive nature of high-density surface EMG for the assessment of muscle fibre size may be useful in studies monitoring child development, ageing, space and exercise physiology, although the applicability and validity of the proposed methodology need to be more directly assessed in these specific populations by future studies. KEY POINTS: Because of the biophysical relation between muscle fibre size and the propagation velocity of action potentials along the sarcolemma, motor unit conduction velocity could represent a potential non-invasive candidate for estimating muscle fibre size in vivo. This relation has been previously assessed in animal models and humans with invasive techniques, or it has been mathematically derived from simulations. By combining high-density surface EMG with muscle biopsy, here we explored the relation between the conduction velocity of populations of motor units and muscle fibre size in healthy individuals. Our results confirmed that motor unit conduction velocity can be considered as a novel biomarker of fibre size, which can be adopted to predict muscle fibre diameter and cross-sectional area with low systematic bias and margin of individual error. The proposed neuromuscular interface opens new perspectives in the use of high-density EMG as a non-invasive tool to estimate muscle fibre size without the need of surgical biopsy sampling.
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Affiliation(s)
- Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Sumiaki Maeo
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
- School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, UK
| | - Thomas G Balshaw
- School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, UK
- Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, UK
| | - Marcel B Lanza
- Department of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, MD, USA
| | - Neil R W Martin
- Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, UK
| | - Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Tatiana Moro
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Antonio Paoli
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Francesco Felici
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Nicola Maffulli
- Department of Trauma and Orthopaedic Surgery, School Medicine, Surgery and Dentistry, University of Salerno, Salerno, Italy
- School of Pharmacy and Bioengineering, Keele University School of Medicine, Stoke on Trent, UK
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, Centre for Sports and Exercise Medicine, Mile End Hospital, London, UK
| | - Bjoern Eskofier
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas M Kinfe
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Jonathan P Folland
- School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, UK
- Versus Arthritis Centre for Sport, Exercise and Osteoarthritis Research, Loughborough University, Leicestershire, UK
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, UK
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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Bodkin SG, Pethick JT, Dooley EA, Russell SD, Hart JM. Torque complexity of maximal knee extensor isometric contraction in individuals following anterior cruciate ligament reconstruction. Clin Biomech (Bristol, Avon) 2023; 104:105932. [PMID: 36931165 DOI: 10.1016/j.clinbiomech.2023.105932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 02/28/2023] [Accepted: 03/03/2023] [Indexed: 03/19/2023]
Abstract
BACKGROUND Current rehabilitation goals following anterior cruciate ligament reconstruction are structured around the maximal force generating capabilities of the muscle. Force fluctuations, an index of force control, have been observed to alter post- anterior cruciate ligament reconstruction. The temporal structure, or "complexity" of force fluctuations may provide important insight into the post-operative muscular recovery. The aims of this study were 1) to compare quadriceps torque complexity in anterior cruciate ligament reconstructed patients to the contralateral limb and to healthy, controls and 2) to assess the relationships between torque complexity to patient outcomes. METHODS Data from 120 anterior cruciate ligament reconstructed participants (65 Females, 21.0 ± 8.3 years, 5.96 ± 0.48-months post-surgery) and 95 healthy controls (50 Females, 21.5 ± 2.9 years) were collected. A 30-s knee extensor maximal isometric contraction was completed to calculate approximate entropy, a measure of torque complexity. FINDINGS Approximate entropy was found to decrease throughout the 30-s trial (P < .001, Cohen's d = 1.87 [1.64,2.10]). The anterior cruciate ligament reconstructed limb demonstrated greater approximate entropy compared to the contralateral limb or to healthy controls (P < .001, Cohen's d = 0.64 [0.38,0.90]). approximate entropy at the end of the trial demonstrated weak, negatively relationships with peak torque, patient reported outcome measures, and knee extensor fatigue (r = -0.21 to -0.32, P < .05). INTERPRETATION A greater torque complexity in individuals following anterior cruciate ligament reconstruction was weakly related to lower quadriceps strength, lower subjective function, and quadriceps fatigue resistance. The complexity of force fluctuations during a sustained maximal task may draw clinical insight into the recovery of motor function following anterior cruciate ligament reconstruction.
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Affiliation(s)
- S G Bodkin
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT, USA.
| | - J T Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, Essex, UK
| | - E A Dooley
- Depatment of Biomedical Engineering, University of Virginia, Charlottesville, VA. USA
| | - S D Russell
- Depatment of Biomedical Engineering, University of Virginia, Charlottesville, VA. USA
| | - J M Hart
- Deparment of Orthopaedic Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Bartels T, Schwesig R, Brehme K, Pyschik M, Pröger S, Laube W, Kurz E. Beurteilung des neuromuskulären Funktionszustands bei Berufssportlern. ARTHROSKOPIE 2022. [DOI: 10.1007/s00142-022-00548-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ZusammenfassungIn den letzten Jahren wurden bedeutende Fortschritte in den chirurgischen Techniken, der postoperativen Rehabilitation und der Identifizierung von Risikofaktoren für eine zweite Verletzung des vorderen Kreuzbands (VKB) gemacht. Dies führte jedoch nicht zu einer Verringerung des sekundären VKB-Verletzungsrisikos. Die Wiederherstellung der anatomischen (operative Rekonstruktion) und anschließend insbesondere der trainingsbedingten funktionellen Stabilität sollte eine grundlegende Voraussetzung für die Rückkehr zu Pivot-Sportarten nach einer VKB-Verletzung sein. Das VKB hat eine bedeutende Rolle bei der Kniepropriozeption mit der Konsequenz einer eingeschränkten sensomotorischen Regulation im Verletzungsfall. Das Perturbationstraining stellt eine große Herausforderung in der spätrehabilitativen Phase nach VKB-Rekonstruktion dar. Die Diagnostik der Muskelaktivierung im Rehabilitationsverlauf nach VKB-Rekonstruktion hat deshalb eine enorme Bedeutung. Mit der entwickelten Software können Charakteristika der motorischen Einheiten knieführender Muskeln zeitnah objektiviert und somit eine mögliche Überlastung bei hochreaktivem Perturbationstraining im Rahmen der spätrehabilitativen Phase nach VKB-Rekonstruktion vermieden werden.
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Nuccio S, Del Vecchio A, Casolo A, Labanca L, Rocchi JE, Felici F, Macaluso A, Mariani PP, Falla D, Farina D, Sbriccoli P. Deficit in knee extension strength following anterior cruciate ligament reconstruction is explained by a reduced neural drive to the vasti muscles. J Physiol 2021; 599:5103-5120. [PMID: 34605556 DOI: 10.1113/jp282014] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/30/2021] [Indexed: 11/08/2022] Open
Abstract
The persistence of quadriceps weakness represents a major concern following anterior cruciate ligament reconstruction (ACLR). The underlying adaptations occurring in the activity of spinal motoneurons are still unexplored. This study examined the discharge patterns of large populations of motor units (MUs) in the vastus lateralis (VL) and vastus medialis muscles following ACLR. Nine ACLR individuals and 10 controls performed unilateral trapezoidal contractions of the knee extensor muscles at 35%, 50% and 70% of the maximal voluntary isometric force (MVIF). High-density surface electromyography (HDsEMG) was used to record the myoelectrical activity of the vasti muscles in both limbs. HDsEMG signals were decomposed with a convolutive blind source separation method and MU properties were extracted and compared between sides and groups. The ACLR group showed a lower MVIF on the reconstructed side compared to the contralateral side (28.1%; P < 0.001). This force deficit was accompanied by reduced MU discharge rates (∼21%; P < 0.05), lower absolute MU recruitment and derecruitment thresholds (∼22% and ∼22.5%, respectively; P < 0.05) and lower input-output gain of motoneurons (27.3%; P = 0.009). Deficits in MU discharge rates of the VL and in absolute recruitment and derecruitment thresholds of both vasti MUs were associated with deficits in MVIF (P < 0.05). A strong between-side correlation was found for MU discharge rates of the VL of ACLR individuals (P < 0.01). There were no significant between-group differences (P > 0.05). These results indicate that mid- to long-term strength deficits following ACLR may be attributable to a reduced neural drive to vasti muscles, with potential changes in excitatory and inhibitory synaptic inputs. KEY POINTS: Impaired expression and control of knee extension forces is common after anterior cruciate ligament reconstruction and is related to high risk of a second injury. To provide novel insights into the neural basis of this impairment, the discharge patterns of motor units in the vastus lateralis and vastus medialis were investigated during voluntary force contractions. There was lower knee extensor strength on the reconstructed side with respect to the contralateral side, which was explained by deficits in motor unit discharge rate and an altered motoneuronal input-output gain. Insufficient excitatory inputs to motoneurons and increased inhibitory afferent signals potentially contributed to these alterations. These results further our understanding of the neural underpinnings of quadriceps weakness following anterior cruciate ligament reconstruction and can help to develop effective rehabilitation protocols to regain muscle strength and reduce the risk of a second injury.
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Affiliation(s)
- Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Alessandro Del Vecchio
- Department Artificial Intelligence in Biomedical Engineering, Friedrich-Alexander University, Erlangen, Germany
| | - Andrea Casolo
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Luciana Labanca
- 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
| | - Andrea Macaluso
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy.,Villa Stuart Sport Clinic-FIFA Medical Centre of Excellence, Rome, Italy
| | - Pier Paolo Mariani
- Villa Stuart Sport Clinic-FIFA Medical Centre of Excellence, Rome, Italy
| | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, UK
| | - Paola Sbriccoli
- Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
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Ibáñez J, Angeli CA, Harkema SJ, Farina D, Rejc E. Recruitment order of motor neurons promoted by epidural stimulation in individuals with spinal cord injury. J Appl Physiol (1985) 2021; 131:1100-1110. [PMID: 34382840 PMCID: PMC8461808 DOI: 10.1152/japplphysiol.00293.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spinal cord epidural stimulation (scES) combined with activity-based training can promote motor function recovery in individuals with motor complete spinal cord injury (SCI). The characteristics of motor neuron recruitment, which influence different aspects of motor control, are still unknown when motor function is promoted by scES. Here, we enrolled five individuals with chronic motor complete SCI implanted with a scES unit to study the recruitment order of motor neurons during standing enabled by scES. We recorded high-density electromyography (HD-EMG) signals on the vastus lateralis muscle, and inferred the order of recruitment of motor neurons from the relation between amplitude and conduction velocity of the scES-evoked EMG responses along the muscle fibers. Conduction velocity of scES-evoked responses was modulated over time, while stimulation parameters and standing condition remained constant, with average values ranging between 3.0±0.1 and 4.4±0.3 m/s. We found that the human spinal circuitry receiving epidural stimulation can promote both orderly (according to motor neuron size) and inverse trends of motor neuron recruitment, and that the engagement of spinal networks promoting rhythmic activity may favor orderly recruitment trends. Conversely, the different recruitment trends did not appear to be related with time since injury or scES implant, nor to the ability to achieve independent knees extension, nor to the conduction velocity values. The proposed approach can be implemented to investigate the effects of stimulation parameters and training-induced neural plasticity on the characteristics of motor neuron recruitment order, contributing to improve mechanistic understanding and effectiveness of epidural stimulation-promoted motor recovery after SCI.
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Affiliation(s)
- Jaime Ibáñez
- Department of Bioengineering, Imperial College London, London, United Kingdom.,Department of Clinical and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Claudia A Angeli
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States.,Department of Bioengineering, University of Louisville, Louisville, Kentucky, United States.,Frazier Rehabilitation Institute, University of Louisville Health, Louisville, Kentucky, United States
| | - Susan J Harkema
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States.,Department of Bioengineering, University of Louisville, Louisville, Kentucky, United States.,Frazier Rehabilitation Institute, University of Louisville Health, Louisville, Kentucky, United States.,Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, United States
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Enrico Rejc
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States.,Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, United States
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Germer CM, Farina D, Elias LA, Nuccio S, Hug F, Del Vecchio A. Surface EMG cross talk quantified at the motor unit population level for muscles of the hand, thigh, and calf. J Appl Physiol (1985) 2021; 131:808-820. [PMID: 34236246 DOI: 10.1152/japplphysiol.01041.2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cross talk is an important source of error in interpreting surface electromyography (EMG) signals. Here, we aimed at characterizing cross talk for three groups of synergistic muscles by the identification of individual motor unit action potentials. Moreover, we explored whether spatial filtering (single and double differential) of the EMG signals influences the level of cross talk. Three experiments were conducted. Participants (total 25) performed isometric contractions at 10% of the maximal voluntary contraction (MVC) with digit muscles and knee extensors and at 30% MVC with plantar flexors. High-density surface EMG signals were recorded and decomposed into motor unit spike trains. For each muscle, we quantified the cross talk induced to neighboring muscles and the level of contamination by the nearby muscle activity. We also estimated the influence of cross talk on the EMG power spectrum and intermuscular correlation. Most motor units (80%) generated significant cross-talk signals to neighboring muscle EMG in monopolar recording mode, but this proportion decreased with spatial filtering (50% and 42% for single and double differential, respectively). Cross talk induced overestimations of intermuscular correlation and has a small effect on the EMG power spectrum, which indicates that cross talk is not reduced with high-pass temporal filtering. Conversely, spatial filtering reduced the cross-talk magnitude and the overestimations of intermuscular correlation, confirming to be an effective and simple technique to reduce cross talk. This paper presents a new method for the identification and quantification of cross talk at the motor unit level and clarifies the influence of cross talk on EMG interpretation for muscles with different anatomy.NEW & NOTEWORTHY We proposed a new method for the identification and quantification of cross talk at the motor unit level. We show that surface EMG cross talk can lead to physiological misinterpretations of EMG signals such as overestimations in the muscle activity and intermuscular correlation. Cross talk had little influence on the EMG power spectrum, which indicates that conventional temporal filtering cannot minimize cross talk. Spatial filter (single and double differential) effectively reduces but not abolish cross talk.
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Affiliation(s)
- Carina M Germer
- Neural Engineering Research Laboratory, Center for Biomedical Engineering, University of Campinas, Campinas, Brazil.,Department of Bioengineering, Federal University of Pernambuco, Recife, Brazil
| | - Dario Farina
- Department of Bioengineering, Faculty of Engineering, Imperial College London, London, United Kingdom
| | - Leonardo A Elias
- Neural Engineering Research Laboratory, Center for Biomedical Engineering, University of Campinas, Campinas, Brazil.,Department of Electronics and Biomedical Engineering, School of Electrical and Computer Engineering, University of Campinas, Campinas, Brazil
| | - Stefano Nuccio
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico," Rome, Italy
| | - François Hug
- Laboratory "Movement, Interactions, Performance," Nantes University, Nantes, France.,Institut Universitaire de France, Paris, France.,School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Alessandro Del Vecchio
- Department of Artificial Intelligence in Biomedical Engineering, Faculty of Engineering, Friedrich-Alexander University, Erlangen-Nuremberg, Germany
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