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Lanfranchi C, Rodriguez-Falces J, Place N. The first and second phases of the muscle compound action potential in the thumb are differently affected by electrical stimulation trains. J Appl Physiol (1985) 2024; 136:1122-1128. [PMID: 38511213 DOI: 10.1152/japplphysiol.00861.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 03/22/2024] Open
Abstract
Sarcolemmal membrane excitability is often evaluated by considering the peak-to-peak amplitude of the compound muscle action potential (M wave). However, the first and second M-wave phases represent distinct properties of the muscle action potential, which are differentially affected by sarcolemma properties and other factors such as muscle architecture. Contrasting with previous studies in which voluntary contractions have been used to induce muscle fatigue, we used repeated electrically induced tetanic contractions of the adductor pollicis muscle and assessed the kinetics of M-wave properties during the course of the contractions. Eighteen participants (24 ± 6 yr; means ± SD) underwent 30 electrically evoked tetanic contractions delivered at 30 Hz, each lasting 3 s with 1 s intervals. We recorded the amplitudes of the first and second M-wave phases for each stimulation. During the initial stimulation train, the first and second M-wave phases exhibited distinct kinetics. The first phase amplitude showed a rapid decrease to reach ∼59% of its initial value (P < 0.001), whereas the second phase amplitude displayed an initial transient increase of ∼19% (P = 0.007). Within subsequent trains, both the first and second phase amplitudes consistently decreased as fatigue developed with a reduction during the last train reaching ∼47% of its initial value (P < 0.001). Analyzing the first M wave of each stimulation train unveiled different kinetics for the first and second phases during the initial trains, but these distinctions disappeared as fatigue progressed. These findings underscore the interplay of factors affecting the M wave and emphasize the significance of separately scrutinizing its first and second phases when assessing membrane excitability adjustments during muscle contractions.NEW & NOTEWORTHY Our understanding of how the first and second phases of the compound muscle action potential (M wave) behave during fatigue remains incomplete. Using electrically evoked repeated tetanic contractions of the adductor pollicis, we showed that the first and second phases of the M wave followed distinct kinetics only during the early stages of fatigue development. This suggests that the factors affecting the M-wave first and second phases may change as fatigue develops.
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Affiliation(s)
- Clément Lanfranchi
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
| | - Nicolas Place
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Gkesou A, Papavasileiou A, Karagiaridis S, Kannas T, Amiridis IG, Hatzitaki V, Patikas DA. Fatigability of the thenar muscles using electrical nerve stimulation with fixed stimuli count, while varying the frequency and duty cycle. J Electromyogr Kinesiol 2023; 73:102838. [PMID: 37976607 DOI: 10.1016/j.jelekin.2023.102838] [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: 06/30/2023] [Revised: 09/30/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023] Open
Abstract
Our aim was to compare three electrical stimulation protocols (P20, P30 and P40), with the same number of stimuli, but different stimulation frequencies (20, 30 and 40 Hz, respectively) and duty cycles [1.2:1.2 s (continuous), 0.8:1.2 s (intermittent) and 0.6:1.2 s (intermittent), respectively). Twitch force and the peak-to-peak M-wave amplitude of the thenar muscles were measured before, during and after each protocol at 1-40 Hz in random order. Twelve healthy adults (23-41 years old) were examined for each protocol in random order and in separate sessions. P20 elicited the highest mean force, and P40 the lowest decrease in percent force at the end of the protocol. Force evoked at 1 and 10 Hz decreased less after P40, compared with P20 and P30. The M-wave amplitude was significantly reduced throughout all protocols, with the largest decrease observed during P30. Although an increase in frequency typically induced earlier and greater decrement in force, this was compensated or even reversed by increasing the interval between each stimulation train, while keeping the number of pulses per stimulation cycle constant. The lesser decrease in M-wave amplitude during P40 compared with P20 indicates that longer between-train intervals may help maintaining the integrity of neuromuscular propagation.
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Affiliation(s)
- A Gkesou
- School of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Greece
| | - A Papavasileiou
- School of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Greece
| | - S Karagiaridis
- School of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Greece
| | - T Kannas
- School of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Greece
| | - I G Amiridis
- School of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Greece
| | - V Hatzitaki
- School of Physical Education and Sports Science, Aristotle University of Thessaloniki, Greece
| | - D A Patikas
- School of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Greece.
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Rodriguez-Falces J, Malanda A, Navallas J, Place N. M-wave changes caused by brief voluntary and stimulated isometric contractions. Eur J Appl Physiol 2023; 123:2087-2098. [PMID: 37202629 PMCID: PMC10460755 DOI: 10.1007/s00421-023-05228-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 04/05/2023] [Indexed: 05/20/2023]
Abstract
INTRODUCTION Under isometric conditions, the increase in muscle force is accompanied by a reduction in the fibers' length. The effects of muscle shortening on the compound muscle action potential (M wave) have so far been investigated only by computer simulation. This study was undertaken to assess experimentally the M-wave changes caused by brief voluntary and stimulated isometric contractions. METHODS Two different methods of inducing muscle shortening under isometric condition were adopted: (1) applying a brief (1 s) tetanic contraction and (2) performing brief voluntary contractions of different intensities. In both methods, supramaximal stimulation was applied to the brachial plexus and femoral nerves to evoke M waves. In the first method, electrical stimulation (20 Hz) was delivered with the muscle at rest, whereas in the second, stimulation was applied while participants performed 5-s stepwise isometric contractions at 10, 20, 30, 40, 50, 60, 70, and 100% MVC. The amplitude and duration of the first and second M-wave phases were computed. RESULTS The main findings were: (1) on application of tetanic stimulation, the amplitude of the M-wave first phase decreased (~ 10%, P < 0.05), that of the second phase increased (~ 50%, P < 0.05), and the M-wave duration decreased (~ 20%, P < 0.05) across the first five M waves of the tetanic train and then plateaued for the subsequent responses; (2) when superimposing a single electrical stimulus on muscle contractions of increasing forces, the amplitude of the M-wave first phase decreased (~ 20%, P < 0.05), that of the second phase increased (~ 30%, P < 0.05), and M-wave duration decreased (~ 30%, P < 0.05) as force was raised from 0 to 60-70% MVC force. CONCLUSIONS The present results will help to identify the adjustments in the M-wave profile caused by muscle shortening and also contribute to differentiate these adjustments from those caused by muscle fatigue and/or changes in Na+-K+ pump activity.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Campus de Arrosadía s/n. 31006, Pamplona, Spain.
| | - Armando Malanda
- Department of Electrical and Electronical Engineering, Public University of Navarra, Campus de Arrosadía s/n. 31006, Pamplona, Spain
| | - Javier Navallas
- Department of Electrical and Electronical Engineering, Public University of Navarra, Campus de Arrosadía s/n. 31006, Pamplona, Spain
| | - Nicolas Place
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Effects of muscle shortening on single-fiber, motor unit, and compound muscle action potentials. Med Biol Eng Comput 2021; 60:349-364. [PMID: 34936063 PMCID: PMC8766404 DOI: 10.1007/s11517-021-02482-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 12/04/2021] [Indexed: 11/03/2022]
Abstract
Even under isometric conditions, muscle contractions are associated with some degree of fiber shortening. The effects of muscle shortening on extracellular electromyographic potentials have not been characterized in detail. Moreover, the anatomical, biophysical, and detection factors influencing the muscle-shortening effects have been neither identified nor understood completely. Herein, we investigated the effects of muscle shortening on the amplitude and duration characteristics of single-fiber, motor unit, and compound muscle action potentials. We found that, at the single-fiber level, two main factors influenced the muscle-shortening effects: (1) the electrode position and distance relative to the myotendinous zone and (2) the electrode distance to the maxima of the dipole field arising from the stationary dipole created at the fiber-tendon junction. Besides, at the motor unit and muscle level, two additional factors were involved: (3) the overlapping between the propagating component of some fibers with the non-propagating component of other fibers and (4) the spatial spreading of the fiber-tendon junctions. The muscle-shortening effects depend critically on the electrode longitudinal distance to the myotendinous zone. When the electrode was placed far from the myotendinous zone, muscle shortening resulted in an enlargement and narrowing of the final (negative) phase of the potential, and this enlargement became less pronounced as the electrode approached the fiber endings. For electrode locations close to the myotendinous zone, muscle shortening caused a depression of both the main (positive) and final (negative) phases of the potential. Beyond the myotendinous zone, muscle shortening led to a decrease of the final (positive) phase. The present results provide reference information that will help to identify changes in MUPs and M waves due to muscle shortening, and thus to differentiate these changes from those caused by muscle fatigue.
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Rodriguez-Falces J, Place N. Sarcolemmal Excitability, M-Wave Changes, and Conduction Velocity During a Sustained Low-Force Contraction. Front Physiol 2021; 12:732624. [PMID: 34721063 PMCID: PMC8554155 DOI: 10.3389/fphys.2021.732624] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/14/2021] [Indexed: 11/20/2022] Open
Abstract
This study was undertaken to investigate whether sarcolemmal excitability is impaired during a sustained low-force contraction [10% maximal voluntary contraction (MVC)] by assessing muscle conduction velocity and also by analyzing separately the first and second phases of the muscle compound action potential (M wave). Twenty-one participants sustained an isometric knee extension of 10% MVC for 3min. M waves were evoked by supramaximal single shocks to the femoral nerve given at 10-s intervals. The amplitude, duration, and area of the first and second M-wave phases were computed. Muscle fiber conduction velocity, voluntary surface electromyographic (EMG), perceived effort, MVC force, peak twitch force, and temperature were also recorded. The main findings were: (1) During the sustained contraction, conduction velocity remained unchanged. (2) The amplitude of the M-wave first phase decreased for the first ~30s (−7%, p<0.05) and stabilized thereafter, whereas the second phase amplitude increased for the initial ~30s (+7%, p<0.05), before stabilizing. (3) Both duration and area decreased steeply during the first ~30s, and then more gradually for the rest of the contraction. (4) During the sustained contraction, perceived effort increased fivefold, whereas knee extension EMG increased by ~10%. (5) Maximal voluntary force and peak twitch force decreased (respectively, −9% and −10%, p<0.05) after the low-force contraction. Collectively, the present results indicate that sarcolemmal excitability is well preserved during a sustained 10% MVC task. A depression of the M-wave first phase during a low-force contraction can occur even in the absence of changes in membrane excitability. The development of fatigue during a low-force contraction can occur without alteration of membrane excitability.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarre, Pamplona, Spain
| | - Nicolas Place
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Deficits in corticospinal control of stretch reflex thresholds in stroke: Implications for motor impairment. Clin Neurophysiol 2020; 131:2067-2078. [DOI: 10.1016/j.clinph.2020.05.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 03/24/2020] [Accepted: 05/18/2020] [Indexed: 11/22/2022]
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Recovery of the first and second phases of the M wave after prolonged maximal voluntary contractions. J Electromyogr Kinesiol 2020; 50:102385. [DOI: 10.1016/j.jelekin.2019.102385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/18/2019] [Accepted: 12/23/2019] [Indexed: 11/24/2022] Open
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Arjunan SP, Siddiqi A, Swaminathan R, Kumar DK. Implementation and experimental validation of surface electromyogram and force model of Tibialis Anterior muscle for examining muscular factors. Proc Inst Mech Eng H 2020; 234:200-209. [DOI: 10.1177/0954411919890150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study reports a surface electromyogram and force of contraction model. The objective was to investigate the effect of changes in the size, type and number of motor units in the Tibialis Anterior muscle to surface electromyogram and force of dorsiflexion. A computational model to simulate surface electromyogram and associated force of contraction by the Tibialis Anterior muscle was developed. This model was simulated for isometric dorsiflexion, and comparative experiments were conducted for validation. Repeated simulations were performed to investigate the different parameters and evaluate inter-experimental variability. An equivalence statistical test and the Bland–Altman method were used to observe the significance between the simulated and experimental data. Simulated and experimentally recorded data had high similarity for the three measures: maximal power of power spectral density ( p < 0.0001), root mean square of surface electromyogram ( p < 0.0001) and force recorded at the footplate ( p < 0.03). Inter-subject variability in the experimental results was in-line with the variability in the repeated simulation results. This experimentally validated computational model for the surface electromyogram and force of the Tibialis Anterior muscle is significant as it allows the examination of three important muscular factors associated with ageing and disease: size, fibre type and number of motor units.
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Affiliation(s)
| | - Ariba Siddiqi
- Biosignals Lab, School of Engineering, RMIT University, Melbourne, VIC, Australia
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Rodriguez-Falces J, Vieira T, Place N, Botter A. Potentiation of the first and second phases of the M wave after maximal voluntary contractions in the biceps brachii muscle. Med Biol Eng Comput 2019; 57:2231-2244. [PMID: 31410691 DOI: 10.1007/s11517-019-02025-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 07/30/2019] [Indexed: 10/26/2022]
Abstract
The study was undertaken to examine separately the potentiation of the first and second phases of the M wave in biceps brachii after conditioning maximal voluntary contractions (MVCs) of different durations. M waves were evoked in the biceps brachii muscle before and after isometric MVCs of 1, 3, 6, 10, 30, and 60 s. The amplitude, duration, and area of the first and second phases of monopolar M waves were measured during the 10-min period following each contraction. Our results indicated that the amplitude and area of the M-wave first phase increased after MVCs of long (≥ 30 s) duration (P < 0.05), while it decreased after MVCs of short (≤ 10 s) duration (P < 0.05). The enlargement after the long MVCs persisted for 5 min, whereas the depression after the short contractions lasted only for 15 s. The amplitude of the second phase increased immediately (1 s) after all MVCs tested (P < 0.05), regardless of their duration, and then returned rapidly (10 s) to control levels. Unexpectedly, the amplitude of the second phase decreased below control values between 15 s and 1 min after the MVCs lasting ≥ 6 s (P < 0.05). Our results reinforce the idea that the presence of fatigue is a necessary condition to induce an enlargement of the M-wave first phase and that this enlargement would be greater (and occur sooner) in muscles with a predominance of type II fibers (quadriceps and biceps brachii) compared to type-I predominant muscles (tibialis anterior). The unique findings observed for the M-wave second phase indicate that changes in this phase are highly muscle dependent. Graphical abstract Left panel-Representative examples of M waves recorded in one participant before (control) and at various times after conditioning maximal voluntary contractions (MVCs) of short (a1) and long (a2) duration. Left panel-Time course of recovery of the amplitude of the first (b1) and second (b2) phases of the M wave after conditioning MVCs of different durations.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain. .,Department of Electrical and Electronical Engineering, Universidad Pública de Navarra D.I.E.E, Campus de Arrosadía s/n, 31006, Pamplona, Spain.
| | - Taian Vieira
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunication, Politecnico di Torino, Torino, Italy
| | - Nicolas Place
- Institute of Sport Sciences, Faculty of Biology Medicine, University of Lausanne, Lausanne, Switzerland
| | - Alberto Botter
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunication, Politecnico di Torino, Torino, Italy
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Rodriguez-Falces J, Place N. Sarcolemmal membrane excitability during repeated intermittent maximal voluntary contractions. Exp Physiol 2018; 104:136-148. [PMID: 30357996 DOI: 10.1113/ep087218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/23/2018] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Is impaired membrane excitability reflected by an increase or by a decrease in M-wave amplitude? What is the main finding and its importance? The magnitude of the M-wave first and second phases changed in completely different ways during intermittent maximal voluntary contractions, leading to the counterintuitive conclusion that it is an increase (and not a decrease) of the M-wave first phase that reflects impaired membrane excitability. ABSTRACT The study was undertaken to investigate separately the changes in the first and second phases of the muscle compound action potential (M-wave) during 4 min of intermittent maximal voluntary contractions (MVCs) of the quadriceps. M-waves were evoked by supramaximal single electrical stimulation to the femoral nerve delivered in the resting periods between 48 successive MVCs of 3 s. The amplitude, duration and area of the M-wave first and second phases were measured separately, together with muscle conduction velocity and MVC force. During the intermittent MVCs, the amplitude of the M-wave first phase increased uninterruptedly for the first 3 min (12-16%, P < 0.05) and stabilized thereafter, whereas the second phase initially increased for 55-75 s (11-22%, P < 0.05), but decreased subsequently. The enlargement of the first phase occurred in parallel with an increase in its duration, and concomitantly with a decline in conduction velocity (maximal cross-correlations, 0.89-0.97; time lag, 0 s). Also, a significant temporal association was found between the amplitude of the first phase and MVC force (time lag, 0 s; maximal cross-correlations, 0.85-0.97). Conversely, there was no temporal association between the second phase amplitude and conduction velocity or MVC force (time lag, 73-117 s; maximal cross-correlations, 0.65-0.77). It is concluded that the enlargement of the M-wave first phase is the electrical manifestation of impaired muscle membrane excitability. The results highlight the importance of independently analysing the first and second phases, as only the first phase can be used reliably to detect changes in membrane excitability, while the second might be affected by muscle architecture.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
| | - Nicolas Place
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Rodriguez-Falces J, Place N. End-of-Fiber Signals Strongly Influence the First and Second Phases of the M Wave in the Vastus Lateralis: Implications for the Study of Muscle Excitability. Front Physiol 2018; 9:162. [PMID: 29568271 PMCID: PMC5852100 DOI: 10.3389/fphys.2018.00162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 02/19/2018] [Indexed: 11/13/2022] Open
Abstract
It has been recurrently observed that, for compound muscle action potentials (M wave) recorded over the innervation zone of the vastus lateralis, the descending portion of the first phase generally shows an “inflection” or “shoulder.” We sought to clarify the electrical origin of this shoulder-like feature and examine its implications. M waves evoked by maximal single shocks to the femoral nerve were recorded in monopolar and bipolar configurations from 126 individuals using classical (10-mm recording diameter, 20-mm inter-electrode distance) electrodes and from eight individuals using small electrodes arranged in a linear array. The changes of the M-wave waveform at different positions along the muscle fibers' direction were examined. The shoulder was identified more frequently in monopolar (97%) than in bipolar (46%) M waves. The shoulder of M waves recorded at different distances from the innervation zone had the same latency. Furthermore, the shoulder of the M wave recorded over the innervation zone coincided in latency with the positive peak of that recorded beyond the muscle. The positive phase of the M wave detected 20 mm away from the innervation zone was essentially composed of non-propagating components. The shoulder-like feature in monopolar and bipolar M waves results from the termination of action potentials at the superficial aponeurosis of the vastus lateralis. We conclude that, only the amplitude of the first phase, and not the second, of M waves recorded monopolarly and/or bipolarly in close proximity to the innervation zone can be used reliably to monitor possible changes in muscle membrane excitability.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
| | - Nicolas Place
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Rodriguez-Falces J, Place N. Determinants, analysis and interpretation of the muscle compound action potential (M wave) in humans: implications for the study of muscle fatigue. Eur J Appl Physiol 2017; 118:501-521. [DOI: 10.1007/s00421-017-3788-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/06/2017] [Indexed: 10/18/2022]
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Different recoveries of the first and second phases of the M-wave after intermittent maximal voluntary contractions. Eur J Appl Physiol 2017; 117:607-618. [DOI: 10.1007/s00421-017-3553-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/20/2017] [Indexed: 11/25/2022]
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Rodriguez-Falces J, Place N. Muscle excitability during sustained maximal voluntary contractions by a separate analysis of the M-wave phases. Scand J Med Sci Sports 2016; 27:1761-1775. [DOI: 10.1111/sms.12819] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2016] [Indexed: 11/29/2022]
Affiliation(s)
- J. Rodriguez-Falces
- Department of Electrical and Electronical Engineering; Public University of Navarra; Pamplona Spain
| | - N. Place
- Institute of Sport Sciences and Department of Physiology; University of Lausanne; Lausanne Switzerland
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Rodriguez‐Falces J, Place N. New insights into the potentiation of the first and second phases of the M‐wave after voluntary contractions in the quadriceps muscle. Muscle Nerve 2016; 55:35-45. [DOI: 10.1002/mus.25186] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/09/2016] [Accepted: 05/11/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Javier Rodriguez‐Falces
- Department of Electrical and Electronical EngineeringUniversidad Pública de Navarra D.I.E.E.Campus de Arrosadía s/n31006Pamplona Spain
| | - Nicolas Place
- Institute of Sport Sciences and Department of PhysiologyUniversity of LausanneLausanne Switzerland
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Rodriguez-Falces J, Place N. Differences in the recruitment curves obtained with monopolar and bipolar electrode configurations in the quadriceps femoris. Muscle Nerve 2016; 54:118-31. [PMID: 26662294 DOI: 10.1002/mus.25006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 11/24/2015] [Accepted: 12/03/2015] [Indexed: 12/14/2022]
Abstract
INTRODUCTION We sought to verify whether the stimulation intensity at which M-wave amplitude reaches a plateau actually corresponds to full motor unit activation in monopolar and bipolar configurations. METHODS M-waves and twitches were evoked using femoral nerve stimulation of gradually increasing intensity in 21 subjects. Recruitment curves corresponding to the amplitude of the first phase (AmpliFIRST ) and peak-to-peak amplitude (AmpliPP ) of the M-wave were obtained in the vastus lateralis, vastus medialis, and rectus femoris in monopolar and bipolar configurations. RESULTS In all muscles, bipolar M-waves and twitches reached plateau at a significantly lower stimulus intensity compared with monopolar M-waves (P < 0.05). The different behavior of monopolar and bipolar M-waves with stimulus intensity was found for both AmpliFIRST and AmpliPP . CONCLUSIONS In a bipolar configuration, the stimulus intensity at which M-waves plateau should be increased by at least 10%-20% to achieve complete motor unit recruitment. Muscle Nerve 54: 118-131, 2016.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Campus de Arrosadía, s/n., 31006, Pamplona, Spain
| | - Nicolas Place
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Rodriguez-Falces J, Duchateau J, Muraoka Y, Baudry S. M-wave potentiation after voluntary contractions of different durations and intensities in the tibialis anterior. J Appl Physiol (1985) 2015; 118:953-64. [DOI: 10.1152/japplphysiol.01144.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/11/2015] [Indexed: 11/22/2022] Open
Abstract
The study was undertaken to provide insight into the mechanisms underlying the potentiation of the muscle compound action potential (M wave) after conditioning contractions. M waves were evoked in the tibialis anterior before and after isometric maximal voluntary contractions (MVC) of 1, 3, 6, 10, 30, and 60 s, and after 3-s contractions at 10, 30, 50, 70, 90, and 100% MVC. The amplitude, duration, and area of the first and second phases of the M wave, together with the median frequency (Fmedian) and muscle fiber conduction velocity (MFCV) were recorded. Furthermore, twitch force, muscle fascicle length, and pennation angle were measured at rest, before, and 1 s after the conditioning contractions. The results indicate that only the amplitude of the second phase of the M wave was significantly increased after conditioning contractions. The extent of this potentiation was similar for MVC durations ranging from 1 to 10 s and augmented progressively with contraction intensity from 30 to 70% MVC. After these conditioning contractions, the duration and area of the two M-wave phases decreased ( P < 0.05), whereas MFCV and Fmedian increased ( P < 0.05). For all of these parameters, the greatest changes occurred 1 s after the conditioning contraction. Changes in MFCV after the contractions were correlated with those in M-wave second-phase amplitude ( r2 = 0.42; P < 0.05) and Fmedian ( r2 = 0.53; P < 0.05). In contrast, fascicle length and pennation angle did not change after the conditioning contractions. It is concluded that the potentiation of the second phase of the M wave is mainly due to an increased MFCV.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
| | - Jacques Duchateau
- Laboratory of Applied Biology, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium; and
| | | | - Stéphane Baudry
- Laboratory of Applied Biology, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium; and
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Rodriguez-Falces J, Place N. Power spectral changes of the superimposed M wave during isometric voluntary contractions of increasing strength. Muscle Nerve 2015; 51:580-91. [PMID: 25111456 DOI: 10.1002/mus.24418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 07/25/2014] [Accepted: 08/04/2014] [Indexed: 11/08/2022]
Abstract
INTRODUCTION We examined the power spectral changes of the compound muscle action potential (M wave) evoked during isometric contractions of increasing strength. METHODS Surface electromyography (sEMG) of the vastus lateralis and medialis was recorded from 20 volunteers who performed 4-s step-wise isometric contractions of different intensities. A maximal M wave was elicited by a single stimulus to the femoral nerve and superimposed on the voluntary contractions. The spectral characteristics (Fmean and Fmedian) of sEMG and M-wave signals were calculated. RESULTS M-wave spectral indicators increased systematically with contraction intensity up to 60% MVC and then leveled off at higher forces. Over the 10-60% MVC range, the increase in spectral indicators was 3 times higher for M waves (36%) than for sEMG (12%). CONCLUSIONS The consistent increase in M-wave spectral characteristics with force is due to the fact that the number of motor units recruited by the superimposed supramaximal stimulus is approximately stable.
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Affiliation(s)
- Javier Rodriguez-Falces
- Universidad Pública de Navarra D.I.E.E., Department of Electrical and Electronical Engineering, Campus de Arrosadía s/n., 31006, Pamplona, Spain
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Rodriguez-Falces J, Izquierdo M, González-Izal M, Place N. Comparison of the power spectral changes of the voluntary surface electromyogram and M wave during intermittent maximal voluntary contractions. Eur J Appl Physiol 2014; 114:1943-54. [PMID: 24917355 DOI: 10.1007/s00421-014-2924-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/23/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION To compare the power spectral changes of the voluntary surface electromyogram (sEMG) and of the compound action potential (M wave) in the vastus medialis and vastus lateralis muscles during fatiguing contractions. METHODS Interference sEMG and force were recorded during 48 intermittent 3-s isometric maximal voluntary contractions (MVC) from 13 young, healthy subjects. M waves and twitches were evoked using supramaximal femoral nerve stimulation between the successive MVCs. Mean frequency (F mean), and median frequency were calculated from the sEMG and M waves. Muscle fiber conduction velocity (MFCV) was computed by cross-correlation. RESULTS The power spectral shift to lower frequencies was significantly greater for the voluntary sEMG than for the M waves (P < 0.05). Over the fatiguing protocol, the overall average decrease in MFCV (~25%) was comparable to that of sEMG F mean (~22%), but significantly greater than that of M-wave F mean (~9%) (P < 0.001). The mean decline in MFCV was highly correlated with the mean decreases in both sEMG and M-wave F mean. CONCLUSIONS The present findings indicated that, as fatigue progressed, central mechanisms could enhance the relative weight of the low-frequency components of the voluntary sEMG power spectrum, and/or the end-of-fiber (non-propagating) components could reduce the sensitivity of the M-wave spectrum to changes in conduction velocity.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Campus de Arrosadía s/n, 31006, Pamplona, Spain,
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Rodriguez-Falces J, Navallas J, Malanda A, Rodriguez-Martin O. Comparison of the duration and power spectral changes of monopolar and bipolar M waves caused by alterations in muscle fibre conduction velocity. J Electromyogr Kinesiol 2014; 24:452-64. [PMID: 24774228 DOI: 10.1016/j.jelekin.2014.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/21/2014] [Accepted: 04/01/2014] [Indexed: 02/07/2023] Open
Abstract
The muscle compound action potential (M wave) recorded under monopolar configuration reflects both the propagation of the action potentials along the muscle fibres and their extinction at the tendon. M waves recorded under a bipolar configuration contain less cross talk and noise than monopolar M waves, but they do not contain the entire informative content of the propagating potential. The objective of this study was to compare the effect of changes in muscle fibre conduction velocity (MFCV) on monopolar and bipolar M waves and how this effect depends on the distance between the recording electrodes and tendon. The study was based on a simulation approach and on an experimental investigation of the characteristics of surface M waves evoked in the vastus lateralis during 4-s step-wise isometric contractions in knee extension at 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% MVC. The peak-to-peak duration (Durpp) and median frequency (Fmedian) of the M waves were calculated. For monopolar M waves, changes in Durpp and Fmedian produced by MFCV depended on the distance from the electrode to the tendon, whereas, for bipolar M waves, changes in Durpp and Fmedian were largely independent of the electrode-to-tendon distance. When the distance between the detection point and tendon lay between approximately 15 and 40mm, changes in Durpp of bipolar M waves were more pronounced than those of distal monopolar M waves but less marked than those of proximal monopolar M waves, and the opposite occurred for Fmedian. Since, for bipolar M waves, changes in duration and power spectral features produced by alterations in MFCV are not influenced by the electrode-to-tendon distance, the bipolar electrode configuration is a preferable choice over monopolar arrangements to estimate changes in conduction velocity.
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Affiliation(s)
- Javier Rodriguez-Falces
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain.
| | - Javier Navallas
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
| | - Armando Malanda
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
| | - Olivia Rodriguez-Martin
- Department of Electrical and Electronical Engineering, Public University of Navarra, Pamplona, Spain
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