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Zhang J, McClean ZJ, Khaledi N, Morgan SJ, Millet GY, Aboodarda SJ. Reliability of transcranial magnetic stimulation-evoked responses on knee extensor muscles during cycling. Exp Brain Res 2024; 242:1681-1695. [PMID: 38806709 DOI: 10.1007/s00221-024-06859-y] [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: 02/21/2024] [Accepted: 05/19/2024] [Indexed: 05/30/2024]
Abstract
Transcranial magnetic stimulation (TMS) measures the excitability and inhibition of corticomotor networks. Despite its task-specificity, few studies have used TMS during dynamic movements and the reliability of TMS paired pulses has not been assessed during cycling. This study aimed to evaluate the reliability of motor evoked potentials (MEP) and short- and long-interval intracortical inhibition (SICI and LICI) on vastus lateralis and rectus femoris muscle activity during a fatiguing single-leg cycling task. Nine healthy adults (2 female) performed two identical sessions of counterweighted single-leg cycling at 60% peak power output until failure. Five single pulses and ten paired pulses were delivered to the motor cortex, and two maximal femoral nerve stimulations (Mmax) were administered during two baseline cycling bouts (unfatigued) and every 5 min throughout cycling (fatigued). When comparing both baseline bouts within the same session, MEP·Mmax-1 and LICI (both ICC: >0.9) were rated excellent while SICI was rated good (ICC: 0.7-0.9). At baseline, between sessions, in the vastus lateralis, Mmax (ICC: >0.9) and MEP·Mmax-1 (ICC: 0.7) demonstrated good reliability; LICI was moderate (ICC: 0.5), and SICI was poor (ICC: 0.3). Across the fatiguing task, Mmax demonstrated excellent reliability (ICC > 0.8), MEP·Mmax-1 ranged good to excellent (ICC: 0.7-0.9), LICI was moderate to excellent (ICC: 0.5-0.9), and SICI remained poorly reliable (ICC: 0.3-0.6). These results corroborate the cruciality of retaining mode-specific testing measurements and suggest that during cycling, Mmax, MEP·Mmax-1, and LICI measures are reliable whereas SICI, although less reliable across days, can be reliable within the same session.
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Affiliation(s)
- Jenny Zhang
- Faculty of Kinesiology, University of Calgary, KNB 420, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Zachary J McClean
- Faculty of Kinesiology, University of Calgary, KNB 420, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Neda Khaledi
- Faculty of Kinesiology, University of Calgary, KNB 420, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
- Faculty of Physical Education and Sport Sciences, Kharazmi University, Tehran, Iran
| | - Sophie-Jayne Morgan
- Faculty of Kinesiology, University of Calgary, KNB 420, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Guillaume Y Millet
- Inter-university Laboratory of Human Movement Biology, Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Lyon 1, Saint-Etienne, F-42023, France
| | - Saied Jalal Aboodarda
- Faculty of Kinesiology, University of Calgary, KNB 420, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
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2
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Amann M, Sidhu SK, McNeil CJ, Gandevia SC. Critical considerations of the contribution of the corticomotoneuronal pathway to central fatigue. J Physiol 2022; 600:5203-5214. [PMID: 36326193 PMCID: PMC9772161 DOI: 10.1113/jp282564] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
Neural drive originating in higher brain areas reaches exercising limb muscles through the corticospinal-motoneuronal pathway, which links the motor cortex and spinal motoneurones. The properties of this pathway have frequently been observed to change during fatiguing exercise in ways that could influence the development of central fatigue (i.e. the progressive reduction in voluntary muscle activation). However, based on differences in motor cortical and motoneuronal excitability between exercise modalities (e.g. single-joint vs. locomotor exercise), there is no characteristic response that allows for a categorical conclusion about the effect of these changes on functional impairments and performance limitations. Despite the lack of uniformity in findings during fatigue, there is strong evidence for marked 'inhibition' of motoneurones as a direct result of voluntary drive. Endogenous forms of neuromodulation, such as via serotonin released from neurones, can directly affect motoneuronal output and central fatigue. Exogenous forms of neuromodulation, such as brain stimulation, may achieve a similar effect, although the evidence is weak. Non-invasive transcranial direct current stimulation can cause transient or long-lasting changes in cortical excitability; however, variable results across studies cast doubt on its claimed capacity to enhance performance. Furthermore, with these studies, it is difficult to establish a cause-and-effect relationship between brain responsiveness and exercise performance. This review briefly summarizes changes in the corticomotoneuronal pathway during various types of exercise, and considers the relevance of these changes for the development of central fatigue, as well as the potential of non-invasive brain stimulation to enhance motor cortical excitability, motoneuronal output and, ultimately, exercise performance.
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Affiliation(s)
- Markus Amann
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Simranjit K. Sidhu
- School of Biomedicine, The University of Adelaide, South Australia, Australia
| | - Chris J McNeil
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Simon C Gandevia
- Neuroscience Research Australia and University of New South Wales, Sydney, Australia
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3
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Tan R, Black M, Home J, Blackwell J, Clark I, Wylie L, Vanhatalo A, Jones AM. Physiological and performance effects of dietary nitrate and N-acetylcysteine supplementation during prolonged heavy-intensity cycling. J Sports Sci 2022; 40:2585-2594. [PMID: 36759944 DOI: 10.1080/02640414.2023.2176052] [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: 10/31/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/11/2023]
Abstract
The purpose of this study was to investigate effects of concurrent and independent administration of dietary nitrate (NO3-), administered as NO3--rich beetroot juice (BR; ~12.4 mmol of NO3-), and N-acetylcysteine (NAC; 70 mg·kg-1) on physiological responses during prolonged exercise and subsequent high-intensity exercise tolerance. Sixteen recreationally active males supplemented with NO3--depleted beetroot juice (PL) or BR for 6 days and ingested an acute dose of NAC or maltodextrin (MAL) 1 h prior to performing 1 h of heavy-intensity cycling exercise immediately followed by a severe-intensity time-to-exhaustion (TTE) test in four conditions: 1) PL+MAL, 2) PL+NAC, 3) BR+MAL and 4) BR+NAC. Pre-exercise plasma [NO3-] and nitrite ([NO2-]) were elevated following BR+NAC and BR+MAL (both P < 0.01) compared with PL+NAC and PL+MAL; plasma [cysteine] was increased in PL+NAC and BR+NAC (both P < 0.01) compared to PL+MAL. Muscle excitability declined over time during the prolonged cycling bout in all conditions but was better preserved in PL+NAC compared to BR+NAC (P < 0.01) and PL+MAL (P < 0.05). There was no effect of supplementation on subsequent TTE . These findings indicate that co-ingestion of BR and NAC does not appreciably alter physiological responses during prolonged heavy-intensity cycling or enhance subsequent exercise tolerance.
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Affiliation(s)
- Rachel Tan
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, UK
| | - Matthew Black
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, UK
| | - Joseph Home
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, UK
| | - Jamie Blackwell
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, UK
| | - Ida Clark
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, UK
| | - Lee Wylie
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, UK
| | - Anni Vanhatalo
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, UK
| | - Andrew M Jones
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, UK
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4
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Clos P, Mater A, Legrand H, Poirier G, Ballay Y, Martin A, Lepers R. Corticospinal Excitability Is Lower During Eccentric Than Concentric Cycling in Men. Front Physiol 2022; 13:854824. [PMID: 35370788 PMCID: PMC8966379 DOI: 10.3389/fphys.2022.854824] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 02/14/2022] [Indexed: 11/16/2022] Open
Abstract
How corticospinal excitability changes during eccentric locomotor exercise is unknown. In the present study, 13 volunteers performed 30-min strenuous concentric and eccentric cycling bouts at the same power output (60% concentric peak power output). Transcranial magnetic and electrical femoral nerve stimulations were applied at exercise onset (3rd min) and end (25th min). Motor-evoked potentials (MEPs) amplitude was measured for the rectus femoris (RF) and vastus lateralis (VL) muscles with surface electromyography (EMG) and expressed as a percentage of maximal M-wave amplitude (MMAX). EMG amplitude 100 ms prior to MEPs and the silent period duration were calculated. There was no change in any neural parameter during the exercises (all P > 0.24). VL and RF MMAX were unaffected by exercise modality (all P > 0.38). VL MEP amplitude was greater (26 ± 11.4 vs. 15.2 ± 7.7% MMAX; P = 0.008) during concentric than eccentric cycling whereas RF MEP amplitude was not different (24.4 ± 10.8 vs. 17.2 ± 9.8% MMAX; P = 0.051). While VL EMG was higher during concentric than eccentric cycling (P = 0.03), RF EMG showed no significant difference (P = 0.07). Similar silent period durations were found (RF: 120 ± 30 ms; VL: 114 ± 27 ms; all P > 0.61), but the silent period/MEP ratio was higher during eccentric than concentric cycling for both muscles (all P < 0.02). In conclusion, corticospinal excitability to the knee extensors is lower and relative silent period longer during eccentric than concentric cycling, yet both remained unaltered with time.
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Power KE, Lockyer EJ, Botter A, Vieira T, Button DC. Endurance-exercise training adaptations in spinal motoneurones: potential functional relevance to locomotor output and assessment in humans. Eur J Appl Physiol 2022; 122:1367-1381. [PMID: 35226169 DOI: 10.1007/s00421-022-04918-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 02/11/2022] [Indexed: 12/14/2022]
Abstract
It is clear from non-human animal work that spinal motoneurones undergo endurance training (chronic) and locomotor (acute) related changes in their electrical properties and thus their ability to fire action potentials in response to synaptic input. The functional implications of these changes, however, are speculative. In humans, data suggests that similar chronic and acute changes in motoneurone excitability may occur, though the work is limited due to technical constraints. To examine the potential influence of chronic changes in human motoneurone excitability on the acute changes that occur during locomotor output, we must develop more sophisticated recording techniques or adapt our current methods. In this review, we briefly discuss chronic and acute changes in motoneurone excitability arising from non-human and human work. We then discuss the potential interaction effects of chronic and acute changes in motoneurone excitability and the potential impact on locomotor output. Finally, we discuss the use of high-density surface electromyogram recordings to examine human motor unit firing patterns and thus, indirectly, motoneurone excitability. The assessment of single motor units from high-density recording is mainly limited to tonic motor outputs and minimally dynamic motor output such as postural sway. Adapting this technology for use during locomotor outputs would allow us to gain a better understanding of the potential functional implications of endurance training-induced changes in human motoneurone excitability on motor output.
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Affiliation(s)
- Kevin E Power
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada. .,Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - Evan J Lockyer
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Alberto Botter
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunication, Politecnico di Torino, Turin, Italy.,PoliToBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Taian Vieira
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunication, Politecnico di Torino, Turin, Italy.,PoliToBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Duane C Button
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
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6
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Di Domenico H, Beaume JB, Peyrard A, Samozino P, Bowen M, Hintzy F, Millet GP, Hayes M, Lapole T, Rupp T. Neuromuscular fatigability during repeated sprints assessed with an innovative cycle ergometer. Eur J Appl Physiol 2022; 122:1189-1204. [PMID: 35212845 DOI: 10.1007/s00421-021-04871-6] [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: 07/23/2021] [Accepted: 12/07/2021] [Indexed: 11/03/2022]
Abstract
PURPOSE Repeated sprint ability is an integral component of team sports. This study aimed to evaluate fatigability development and its aetiology during and immediately after a cycle repeated sprint exercise performed until a given fatigability threshold. METHODS On an innovative cycle ergometer, 16 healthy males completed an RSE (10-s sprint/28-s recovery) until task failure (TF): a 30% decrease in sprint mean power (Pmean). Isometric maximum voluntary contraction of the quadriceps (IMVC), central alterations [voluntary activation (VA)], and peripheral alterations [twitch (Pt)] were evaluated before (pre), immediately after each sprint (post), at TF and 3 min after. Sprints were expressed as a percentage of the total number of sprints to TF (TSTF). Individual data were extrapolated at 20, 40, 60, and 80% TSTF. RESULTS Participants completed 9.7 ± 4.2 sprints before reaching a 30% decrease in Pmean. Post-sprint IMVCs were decreased from pre to 60% TSTF and then plateaued (pre: 345 ± 56 N, 60% 247 ± 55 N, TF: 233 ± 57 N, p < 0.001). Pt decreased from 20% and plateaued after 40% TSTF (p < 0.001, pre-TF = - 45 ± 13%). VA was not significantly affected by repeated sprints until 60% TSTF (pre-TF = - 6.5 ± 8.2%, p = 0.036). Unlike peripheral parameters, VA recovered within 3 min (p = 0.042). CONCLUSION During an RSE, Pmean and IMVC decreases were first concomitant to peripheral alterations up to 40% TSTF and central alterations was only observed in the second part of the test, while peripheral alterations plateaued. The distinct recovery kinetics in central versus peripheral components of fatigability further confirm the necessity to reduce traditional delays in neuromuscular fatigue assessment post-exercise.
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Affiliation(s)
- H Di Domenico
- Inter-University Laboratory of Human Movement Sciences, Univ Savoie Mont-Blanc, EA 7424, Chambéry, France
| | - J B Beaume
- Inter-University Laboratory of Human Movement Sciences, Univ Savoie Mont-Blanc, EA 7424, Chambéry, France
| | - A Peyrard
- Inter-University Laboratory of Human Movement Sciences, Univ Savoie Mont-Blanc, EA 7424, Chambéry, France
| | - P Samozino
- Inter-University Laboratory of Human Movement Sciences, Univ Savoie Mont-Blanc, EA 7424, Chambéry, France
| | - M Bowen
- Inter-University Laboratory of Human Movement Sciences, Univ Savoie Mont-Blanc, EA 7424, Chambéry, France
| | - F Hintzy
- Inter-University Laboratory of Human Movement Sciences, Univ Savoie Mont-Blanc, EA 7424, Chambéry, France
| | - G P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - M Hayes
- Environmental Extremes Laboratory, School of Sport and Health Sciences, University of Brighton, Eastbourne, UK
| | - T Lapole
- Inter-University Laboratory of Human Movement Sciences, Univ Lyon, UJM-Saint-Etienne, EA 7424, 42023, Saint-Étienne, France
| | - Thomas Rupp
- Inter-University Laboratory of Human Movement Sciences, Univ Savoie Mont-Blanc, EA 7424, Chambéry, France.
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7
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Sidhu SK. Remote muscle priming anodal transcranial direct current stimulation attenuates short interval intracortical inhibition and increases time to task failure of a constant workload cycling exercise. Exp Brain Res 2021; 239:1975-1985. [PMID: 33891144 DOI: 10.1007/s00221-021-06103-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
Anodal transcranial direct current stimulation (atDCS), a non-invasive neuromodulatory technique has been shown to increase the excitability of targeted brain area and influence endurance exercise performance. However, the effect of atDCS applied on an unexercised muscle motor cortex (M1) representation on GABAA-mediated intracortical inhibition and endurance exercise performance remains unknown. In two separate sessions, twelve subjects performed fatigue cycling exercise (80% peak power output) sustained to task failure in a double-blinded design, following either ten minutes of bicephalic anodal tDCS (atDCS) or sham applied on a non-exercised hand muscle M1 representation. Short interval intracortical inhibition (SICI) was measured at baseline, post neuromodulation and post-exercise using paired-pulse transcranial magnetic stimulation (TMS) in a resting hand muscle. There was a greater decrease in SICI (P < 0.05) post fatigue cycling with atDCS priming compared to sham. Time to task failure (TTF) was significantly increased following atDCS compared to sham (P < 0.05). These findings suggest that atDCS applied over the non-exercised muscle M1 representation can augment cycling exercise performance; and although this outcome may be mediated via a multitude of mechanisms, a decrease in the global excitability of GABAA inhibitory interneurons may be a possible contributing factor.
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Affiliation(s)
- Simranjit K Sidhu
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, S433, Helen Mayo South, Frome Rd, Adelaide, SA, 5005, Australia.
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8
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Proessl F, Beckner ME, Sinnott AM, Eagle SR, LaGoy AD, Conkright WR, Canino MC, Sterczala AJ, Midhe Ramkumar PP, Sciavolino BM, Connaboy C, Ferrarelli F, Germain A, Nindl BC, Flanagan SD. Reliability of corticospinal excitability estimates for the vastus lateralis: Practical considerations for lower limb TMS task selection. Brain Res 2021; 1761:147395. [PMID: 33662340 DOI: 10.1016/j.brainres.2021.147395] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/14/2021] [Accepted: 02/16/2021] [Indexed: 11/29/2022]
Abstract
Transcranial magnetic stimulation (TMS) is increasingly used to examine lower extremity corticospinal excitability (CSE) in clinical and sports research. Because CSE is task-specific, there is growing emphasis on the use of ecological tasks. Nevertheless, the comparative reliability of CSE measurements during established (e.g. knee extensions; KE) and more recent ecological (e.g. squats; SQT) lower extremity tasks has received less attention. The aim of this study was to compare the test-retest reliability of CSE, force, and muscle activity (EMG) during isometric SQT and KE. 19 right-footed men (age: 25 ± 5 yrs) with similar fitness and body composition performed SQT (N = 7) or KE (N = 12) on two consecutive days. Force and EMG were recorded during maximum voluntary isometric contractions (MVC). Corticospinal excitability was determined in the dominant leg during light (15% MVC) contractions based on motor evoked potential (MEP) stimulus-response-curves (SRC). Test-retest reliability, absolute agreement, and consistency were determined for force, EMG, and SRC MEP maximum (MEPMAX) and rising phase midpoint (V50). As a secondary analysis, all outcomes were compared between groups with mixed-methods ANCOVAs (Task × Time, covariate: body-fat-percentage). Compared with SQT, KE displayed better test-retest reliability and agreement for MEPMAX whereas V50, force, and EMG were similarly reliable. Force (p = 0.01) and MEPMAX (p = 0.02) were also greater during KE despite a similar V50 (p = 0.11). Differences in test-retest reliability, absolute agreement, and between-group comparisons highlight the need to carefully select lower limb TMS assessment tasks and encourage future efforts to balance ecological validity with statistical sensitivity.
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Affiliation(s)
- F Proessl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - M E Beckner
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - A M Sinnott
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - S R Eagle
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - A D LaGoy
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA; Department of Psychiatry, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - W R Conkright
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - M C Canino
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - A J Sterczala
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - P P Midhe Ramkumar
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - B M Sciavolino
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - C Connaboy
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - F Ferrarelli
- Department of Psychiatry, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - A Germain
- Department of Psychiatry, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - B C Nindl
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA
| | - S D Flanagan
- Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition University of Pittsburgh, Pittsburgh, PA, USA.
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9
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Coates KD, Aboodarda SJ, Krüger RL, Martin T, Metz LM, Jarvis SE, Millet GY. Multiple sclerosis-related fatigue: the role of impaired corticospinal responses and heightened exercise fatigability. J Neurophysiol 2020; 124:1131-1143. [PMID: 32877296 DOI: 10.1152/jn.00165.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
It is unclear whether motor fatigability and perceived fatigue share a common pathophysiology in people with multiple sclerosis (PwMS). This cross-sectional investigation explored the relationship between the mechanisms of motor fatigability from cycling and fatigue severity in PwMS. Thirteen highly fatigued (HF) and thirteen nonfatigued (LF) PwMS and thirteen healthy controls (CON) completed a step test until volitional exhaustion on an innovative cycle ergometer. Neuromuscular evaluations involving femoral nerve electrical stimulation and transcranial magnetic stimulation were performed every 3 min throughout cycling. One-way ANOVA at baseline and exhaustion uncovered evidence of consistently smaller motor evoked potential (MEP) amplitudes (P = 0.011) and prolonged MEP latencies (P = 0.041) in HF as well as a greater decline in maximal voluntary contraction force (HF: 63 ± 13%; LF: 75 ± 13%; CON: 73 ± 11% of pre; P = 0.037) and potentiated twitch force (HF: 35 ± 13%; LF: 50 ± 16%; CON: 47 ± 17% of pre; P = 0.049) in HF at volitional exhaustion. Hierarchical regression determined that fatigue severity on the Fatigue Severity Scale was predicted by prolonged MEP latencies (change in r2 = 0.389), elevated peripheral muscle fatigability (change in r2 = 0.183), and depressive symptoms (change in r2 = 0.213). These findings indicate that MS-related fatigue is distinguished by disrupted corticospinal responsiveness, which could suggest progressive pathology, but fatigability from whole body exercise and depressive symptoms also influence perceptions of fatigue in PwMS.NEW & NOTEWORTHY The etiology of fatigability from whole body exercise was examined for the first time to accurately elucidate the relationship between fatigue and fatigability in multiple sclerosis (MS). Compromised corticospinal responsiveness predicted fatigue severity, providing a novel, objective indicator of fatigue in MS. Although the impaired corticomotor transmission did not aggravate muscle activation in this group of people with multiple sclerosis (PwMS) of lower disability, heightened muscle fatigability was seen to contribute to perceptions of fatigue in PwMS.
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Affiliation(s)
- Kyla D Coates
- Neuromuscular Fatigue Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Saied Jalal Aboodarda
- Neuromuscular Fatigue Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Renata L Krüger
- Neuromuscular Fatigue Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Tristan Martin
- Neuromuscular Fatigue Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Unité Mixte de Recherche-S 1075 Comete Moblites: Vieillissement Pathologies Santé, Institut National de la Santé et de la Recherche Médicale, Normandy University, Caen, France
| | - Luanne M Metz
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Scott E Jarvis
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Guillaume Y Millet
- Neuromuscular Fatigue Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Inter-University Laboratory of Human Movement Biology, Jean Monnet University-Saint-Etienne, University of Lyon, Saint-Etienne, France.,Institut Universitaire de France, Paris, France
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10
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Evidence of the Homeostatic Regulation With the Combination of Transcranial Direct Current Stimulation and Physical Activity. Am J Phys Med Rehabil 2019; 97:727-733. [PMID: 29683810 DOI: 10.1097/phm.0000000000000956] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) can optimize beneficial effects induced by motor practice in patients with neurological disorders. However, possibly because of homeostatic regulation, the conditioning effects of tDCS are often imprecise and variable, limiting its therapeutic application. OBJECTIVE The aim of the study was to explore the magnitude and direction of the after effects induced by physical activity (PA) on tDCS-preconditioned cortical excitability (CE). DESIGN First, a crossover experiment was performed with 12 subjects to determine whether a single session of low-, moderate-, and high-intensity PA on a treadmill modulates the motor CE measured by transcranial magnetic stimulation. In a second crossover experiment, we investigated long-lasting changes (until 90 mins) of the effects induced by PA (with intensities defined by the first experiment) on motor CE after the subject had been preconditioned by tDCS (using different polarities). RESULTS AND CONCLUSIONS In experiment 1, we found that high- and moderate-intensity PA modulate the CE. Experiment 2 demonstrated that preconditioning the CE using tDCS homeostatically changes the direction and magnitude of after effects induced by subsequent PA plasticity caused by motor activity. In conclusion, the results suggest that the direction of after effects induced by the combination of physical exercise with tDCS on the CE is regulated within a physiologically defined range.
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Krüger RL, Aboodarda SJ, Jaimes LM, Samozino P, Millet GY. Cycling performed on an innovative ergometer at different intensities-durations in men: neuromuscular fatigue and recovery kinetics. Appl Physiol Nutr Metab 2019; 44:1320-1328. [PMID: 31082324 DOI: 10.1139/apnm-2018-0858] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The majority of studies have routinely measured neuromuscular (NM) fatigue with a delay (∼1-3 min) after cycling exercises. This is problematic since NM fatigue can massively recover within the first 1-2 min after exercise. This study investigated the etiology of knee extensors (KE) NM fatigue and recovery kinetics in response to cycling exercises by assessing NM function as early as 10 s following cycling and up to 8 min of recovery. Ten young males performed different cycling exercises on different days: a Wingate (WING), a 10-min task at severe-intensity (SEV), and a 90-min task at moderate-intensity (MOD). Electrically evoked and isometric maximal voluntary contractions (IMVC) of KE were assessed before, after, and during recovery. SEV induced the highest decrease in IMVC. Peak twitch (Pt) was more reduced in WING and SEV than in MOD (p < 0.001), whereas voluntary activation decreased more after MOD than WING (p = 0.043). Regarding Pt and the ratio between low- and high-frequency doublet (i.e., low-frequency fatigue), recovery was faster for WING, whereas IMVC and high-frequency doublet recovered slower during MOD (p < 0.05). Our results confirm that peripheral fatigue is greater after WING and SEV, while central fatigue is greater following MOD. Peripheral fatigue can substantially recover within minutes after a supramaximal exercise while NM function recovered slower after prolonged, moderate-intensity exercise. This study provides an accurate estimation of NM fatigue and recovery kinetics because of dynamic exercise with large muscle mass by significantly shortening the delay for postexercise measurements.
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Affiliation(s)
- Renata L Krüger
- The Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Saied Jalal Aboodarda
- The Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Libia Marcela Jaimes
- The Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Pierre Samozino
- The University of Savoie Mont Blanc, Inter-university Laboratory of Human Movement Sciences, EA 7424, F-73000 Chambéry, France
| | - Guillaume Y Millet
- The Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
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12
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Morgan PT, Vanhatalo A, Bowtell JL, Jones AM, Bailey SJ. Acetaminophen ingestion improves muscle activation and performance during a 3-min all-out cycling test. Appl Physiol Nutr Metab 2019; 44:434-442. [DOI: 10.1139/apnm-2018-0506] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Acute acetaminophen (ACT) ingestion has been shown to enhance cycling time-trial performance. The purpose of this study was to assess whether ACT ingestion enhances muscle activation and critical power (CP) during maximal cycling exercise. Sixteen active male participants completed two 3-min all-out tests against a fixed resistance on an electronically braked cycle ergometer 60 min after ingestion of 1 g of ACT or placebo (maltodextrin, PL). CP was estimated as the mean power output over the final 30 s of the test and W′ (the curvature constant of the power–duration relationship) was estimated as the work done above CP. The femoral nerve was stimulated every 30 s to measure membrane excitability (M-wave) and surface electromyography (EMGRMS) was recorded continuously to infer muscle activation. Compared with PL, ACT ingestion increased CP (ACT: 297 ± 32 W vs. PL: 288 ± 31 W, P < 0.001) and total work done (ACT: 66.4 ± 6.5 kJ vs. PL: 65.4 ± 6.4 kJ, P = 0.03) without impacting W′ (ACT: 13.1 ± 2.9 kJ vs. PL: 13.6 ± 2.4 kJ, P = 0.19) or the M-wave amplitude (P = 0.66) during the 3-min all-out cycling test. Normalised EMGRMS amplitude declined throughout the 3-min protocol in both PL and ACT conditions; however, the decline in EMGRMS amplitude was attenuated in the ACT condition, such that the EMGRMS amplitude was greater in ACT compared with PL over the last 60 s of the test (P = 0.04). These findings indicate that acute ACT ingestion might increase performance and CP during maximal cycling exercise by enhancing muscle activation.
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Affiliation(s)
- Paul T. Morgan
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
| | - Anni Vanhatalo
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
| | - Joanna L. Bowtell
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
| | - Andrew M. Jones
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
| | - Stephen J. Bailey
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, Exeter EX1 2LU, UK
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13
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Corticospinal excitability during fatiguing whole body exercise. PROGRESS IN BRAIN RESEARCH 2018; 240:219-246. [PMID: 30390833 DOI: 10.1016/bs.pbr.2018.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The corticospinal pathway is considered the primary conduit for voluntary motor control in humans. The efficacy of the corticospinal pathway to relay neural signals from higher brain areas to the locomotor muscle, i.e., corticospinal excitability, is subject to alterations during exercise. While the integrity of this motor pathway has historically been examined during single-joint contractions, a small number of investigations have recently focused on whole body exercise, such as cycling or rowing. Although differences in methodologies employed between these studies complicate the interpretation of the existing literature, it appears that the net excitability of the corticospinal pathway remains unaltered during fatiguing whole body exercise. Importantly, this lack of an apparent effect does not designate the absence of change, but a counterbalance of excitatory and inhibitory influences on the two components of the corticospinal pathway, namely the motor cortex and the spinal motoneurons. Specific emphasis is put on group III/IV afferent feedback from locomotor muscle which has been suggested to play a significant role in mediating these changes. Overall, this review aims at summarizing our limited understanding of how fatiguing whole body exercise influences the corticospinal pathway.
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14
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Sidhu SK, Weavil JC, Thurston TS, Rosenberger D, Jessop JE, Wang E, Richardson RS, McNeil CJ, Amann M. Fatigue-related group III/IV muscle afferent feedback facilitates intracortical inhibition during locomotor exercise. J Physiol 2018; 596:4789-4801. [PMID: 30095164 DOI: 10.1113/jp276460] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 07/25/2018] [Indexed: 01/22/2023] Open
Abstract
KEY POINTS This study investigated the influence of group III/IV muscle afferents on corticospinal excitability during cycling exercise and focused on GABAB neuron-mediated inhibition as a potential underlying mechanism. The study provides novel evidence to demonstrate that group III/IV muscle afferent feedback facilitates inhibitory intracortical neurons during whole body exercise. Firing of these interneurons probably contributes to the development of central fatigue during physical activity. ABSTRACT We investigated the influence of group III/IV muscle afferents in determining corticospinal excitability during cycling exercise and focused on GABAB neuron-mediated inhibition as a potential underlying mechanism. Both under control conditions (CTRL) and with lumbar intrathecal fentanyl (FENT) impairing feedback from group III/IV leg muscle afferents, subjects (n = 11) cycled at a comparable vastus-lateralis EMG signal (∼0.26 mV) before (PRE; 100 W) and immediately after (POST; 90 ± 2 W) fatiguing constant-load cycling exercise (80% Wpeak; 221 ± 10 W; ∼8 min). During, PRE and POST cycling, single and paired-pulse (100 ms interstimulus interval) transcranial magnetic stimulations (TMS) were applied to elicit unconditioned and conditioned motor-evoked potentials (MEPs), respectively. To distinguish between cortical and spinal contributions to the MEPs, cervicomedullary stimulations (CMS) were used to elicit unconditioned (CMS only) and conditioned (TMS+CMS, 100 ms interval) cervicomedullary motor-evoked potentials (CMEPs). While unconditioned MEPs were unchanged from PRE to POST in CTRL, unconditioned CMEPs increased significantly, resulting in a decrease in unconditioned MEP/CMEP (P < 0.05). This paralleled a reduction in conditioned MEP (P < 0.05) and no change in conditioned CMEP. During FENT, unconditioned and conditioned MEPs and CMEPs were similar and comparable during PRE and POST (P > 0.2). These findings reveal that feedback from group III/IV muscle afferents innervating locomotor muscle decreases the excitability of the motor cortex during fatiguing cycling exercise. This impairment is, at least in part, determined by the facilitating effect of these sensory neurons on inhibitory GABAB intracortical interneurons.
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Affiliation(s)
- Simranjit K Sidhu
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Adelaide Medical School, Discipline of Physiology, The University of Adelaide, Australia
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA
| | - Taylor S Thurston
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | | | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Eivind Wang
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Chris J McNeil
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Markus Amann
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Center, VAMC, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.,Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
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15
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O'Leary TJ, Collett J, Morris MG. High-intensity exhaustive exercise reduces long-interval intracortical inhibition. Exp Brain Res 2018; 236:3149-3158. [PMID: 30159591 DOI: 10.1007/s00221-018-5364-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 08/17/2018] [Indexed: 12/19/2022]
Abstract
The development of fatigue during single-joint isolated muscle contractions is accompanied by an increase in long-interval intracortical inhibition (LICI). However, the effect of whole-body locomotor endurance exercise on LICI is unknown. Eighteen healthy men completed three exercise trials on a cycle ergometer. The first trial was completed to determine the lactate threshold (LT) and maximal oxygen uptake ([Formula: see text]). The remaining two trials (familiarisation and experimental) involved cycling to volitional exhaustion at an intensity equivalent to halfway between the LT and [Formula: see text] (50%Δ). Responses to stimulation of the femoral nerve [motor nerve stimulation (MNS)] and motor cortex [transcranial magnetic stimulation (TMS)] were determined pre- and post-exercise to determine the level of peripheral fatigue [potentiated quadriceps twitch (Qtw,pot)] and central fatigue [voluntary activation measured by MNS and TMS (VAMNS and VATMS, respectively)]. Corticospinal excitability (motor evoked potentials) and intracortical inhibition [LICI and corticospinal silent period (SP)] were also measured from electromyography recordings on the vastus lateralis. There were exercise-induced reductions in maximal voluntary contraction torque (- 21 ± 10%), Qtw,pot (- 37 ± 18%), VAMNS (- 7 ± 7%) and VATMS (- 8 ± 10) (all P < 0.01). There were increases in the LICI ratio and reductions in SP duration from pre- to post-exercise (mean absolute change of 16 ± 14% and - 31 ± 28 s, respectively) (both P < 0.01). The pre- and post-exercise MEP amplitudes were not different (P = 0.86). The neural inhibitory circuits that mediate the LICI and SP became less excitable with fatigue following high-intensity exhaustive cycling, which could be important in the aetiology of central fatigue during whole-body locomotor endurance exercise.
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Affiliation(s)
- Thomas J O'Leary
- Department of Sport and Health Sciences, Oxford Brookes University, Oxford, UK.,Army Personnel Research Capability, HQ Army, Andover, UK
| | - Johnny Collett
- Department of Sport and Health Sciences, Oxford Brookes University, Oxford, UK
| | - Martyn G Morris
- Department of Sport and Health Sciences, Oxford Brookes University, Oxford, UK. .,School of Life Sciences, Coventry University, Whitefriars Street, Coventry, CV1 2DS, UK.
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16
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Brownstein CG, Ansdell P, Škarabot J, Frazer A, Kidgell D, Howatson G, Goodall S, Thomas K. Motor cortical and corticospinal function differ during an isometric squat compared with isometric knee extension. Exp Physiol 2018; 103:1251-1263. [DOI: 10.1113/ep086982] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/19/2018] [Indexed: 02/01/2023]
Affiliation(s)
- Callum G. Brownstein
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - Paul Ansdell
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - Jakob Škarabot
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - Ash Frazer
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, School of Primary and Allied Health Care; Monash University; Melbourne Victoria Australia
| | - Dawson Kidgell
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, School of Primary and Allied Health Care; Monash University; Melbourne Victoria Australia
| | - Glyn Howatson
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
- Water Research Group, School of Environmental Sciences and Development; Northwest University; Potchefstroom South Africa
| | - Stuart Goodall
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - Kevin Thomas
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
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17
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Weavil JC, Hureau TJ, Thurston TS, Sidhu SK, Garten RS, Nelson AD, McNeil CJ, Richardson RS, Amann M. Impact of age on the development of fatigue during large and small muscle mass exercise. Am J Physiol Regul Integr Comp Physiol 2018; 315:R741-R750. [PMID: 29995457 DOI: 10.1152/ajpregu.00156.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To examine the impact of aging on neuromuscular fatigue following cycling (CYC; large active muscle mass) and single-leg knee-extension (KE; small active muscle mass) exercise, 8 young (25 ± 4 years) and older (72 ± 6 years) participants performed CYC and KE to task failure at a given relative intensity (80% of peak power output). The young also matched CYC and KE workload and duration of the old (iso-work comparison). Peripheral and central fatigue were quantified via pre-/postexercise decreases in quadriceps twitch torque (∆Qtw, electrical femoral nerve stimulation) and voluntary activation (∆VA). Although young performed 77% and 33% more work during CYC and KE, respectively, time to task failure in both modalities was similar to the old (~9.5 min; P > 0.2). The resulting ΔQtw was also similar between groups (CYC ~40%, KE ~55%; P > 0.3); however, ∆VA was, in both modalities, approximately double in the young (CYC ~6%, KE ~9%; P < 0.05). While causing substantial peripheral and central fatigue in both exercise modalities in the old, ∆Qtw in the iso-work comparison was not significant (CYC; P = 0.2), or ~50% lower (KE; P < 0.05) in the young, with no central fatigue in either modality ( P > 0.4). Based on iso-work comparisons, healthy aging impairs fatigue resistance during aerobic exercise. Furthermore, comparisons of fatigue following exercise at a given relative intensity mask the age-related difference observed following exercise performed at the same workload. Finally, although active muscle mass has little influence on the age-related difference in the rate of fatigue at a given relative intensity, it substantially impacts the comparison during exercise at a given absolute intensity.
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Affiliation(s)
- Joshua C Weavil
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center , Salt Lake City, Utah
| | - Thomas J Hureau
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Taylor S Thurston
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Simranjit K Sidhu
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Ryan S Garten
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center , Salt Lake City, Utah
| | - Ashley D Nelson
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Chris J McNeil
- School of Health and Exercise Sciences, University of British Columbia , Kelowna , Canada
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center , Salt Lake City, Utah
| | - Markus Amann
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center , Salt Lake City, Utah.,Department of Anesthesiology, University of Utah , Salt Lake City, Utah
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18
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DOYLE-BAKER DOUGLAS, TEMESI JOHN, MEDYSKY MARYE, HOLASH ROBERTJ, MILLET GUILLAUMEY. An Innovative Ergometer to Measure Neuromuscular Fatigue Immediately after Cycling. Med Sci Sports Exerc 2018; 50:375-387. [DOI: 10.1249/mss.0000000000001427] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Finn HT, Rouffet DM, Kennedy DS, Green S, Taylor JL. Motoneuron excitability of the quadriceps decreases during a fatiguing submaximal isometric contraction. J Appl Physiol (1985) 2018; 124:970-979. [PMID: 29357479 DOI: 10.1152/japplphysiol.00739.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
During fatiguing voluntary contractions, the excitability of motoneurons innervating arm muscles decreases. However, the behavior of motoneurons innervating quadriceps muscles is unclear. Findings may be inconsistent because descending cortical input influences motoneuron excitability and confounds measures during exercise. To overcome this limitation, we examined effects of fatigue on quadriceps motoneuron excitability tested during brief pauses in descending cortical drive after transcranial magnetic stimulation (TMS). Participants ( n = 14) performed brief (~5-s) isometric knee extension contractions before and after a 10-min sustained contraction at ~25% maximal electromyogram (EMG) of vastus medialis (VM) on one ( n = 5) or two ( n = 9) days. Electrical stimulation over thoracic spine elicited thoracic motor evoked potentials (TMEP) in quadriceps muscles during ongoing voluntary drive and 100 ms into the silent period following TMS (TMS-TMEP). Femoral nerve stimulation elicited maximal M-waves (Mmax). On the 2 days, either large (~50% Mmax) or small (~15% Mmax) TMS-TMEPs were elicited. During the 10-min contraction, VM EMG was maintained ( P = 0.39), whereas force decreased by 52% (SD 13%) ( P < 0.001). TMEP area remained unchanged ( P = 0.9), whereas large TMS-TMEPs decreased by 49% (SD 28%) ( P = 0.001) and small TMS-TMEPs by 71% (SD 22%) ( P < 0.001). This decline was greater for small TMS-TMEPs ( P = 0.019; n = 9). Therefore, without the influence of descending drive, quadriceps TMS-TMEPs decreased during fatigue. The greater reduction for smaller responses, which tested motoneurons that were most active during the contraction, suggests a mechanism related to repetitive activity contributes to reduced quadriceps motoneuron excitability during fatigue. By contrast, the unchanged TMEP suggests that ongoing drive compensates for altered motoneuron excitability. NEW & NOTEWORTHY We provide evidence that the excitability of quadriceps motoneurons decreases with fatigue. Our results suggest that altered intrinsic properties brought about by repetitive activation of the motoneurons underlie their decreased excitability. Furthermore, we note that testing during voluntary contraction may not reflect the underlying depression of motoneuron excitability because of compensatory changes in ongoing voluntary drive. Thus, this study provides evidence that processes intrinsic to the motoneuron contribute to muscle fatigue of the knee extensors.
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Affiliation(s)
- Harrison T Finn
- Neuroscience Research Australia, Randwick, New South Wales , Australia.,University of New South Wales , Kensington, New South Wales , Australia
| | - David M Rouffet
- Victoria University , Melbourne, Victoria , Australia.,Australian Institute for Musculoskeletal Science, Victoria University , Melbourne , Australia.,Institute of Sport, Exercise, and Active Living, Victoria University , Melbourne , Australia
| | - David S Kennedy
- University of Sydney, Cumberland, New South Wales , Australia.,University of Technology , Ultimo, New South Wales , Australia
| | - Simon Green
- Western Sydney University, Campbelltown, New South Wales , Australia
| | - Janet L Taylor
- Neuroscience Research Australia, Randwick, New South Wales , Australia.,University of New South Wales , Kensington, New South Wales , Australia.,Edith Cowan University , Perth, Western Australia , Australia
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20
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Jubeau M, Rupp T, Temesi J, Perrey S, Wuyam B, Millet GY, Verges S. Neuromuscular Fatigue during Prolonged Exercise in Hypoxia. Med Sci Sports Exerc 2017; 49:430-439. [PMID: 27753741 DOI: 10.1249/mss.0000000000001118] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE Prolonged cycling exercise performance in normoxia is limited because of both peripheral and central neuromuscular impairments. It has been reported that cerebral perturbations are greater during short-duration exercise in hypoxia compared with normoxia. The purpose of this study was to test the hypothesis that central deficits are accentuated in hypoxia compared with normoxia during prolonged (three bouts of 80 min separated by 25 min) whole-body exercise at the same relative intensity. METHODS Ten subjects performed two sessions consisting of three 80-min cycling bouts at 45% of their relative maximal aerobic power in normoxia and hypoxia (FiO2 = 0.12). Before exercise and after each bout, maximal voluntary force, voluntary activation assessed with nerve stimulation and transcranial magnetic stimulation, corticospinal excitability (motor evoked potential), intracortical inhibition (cortical silent period), and electrical (M-wave) and contractile (twitch and doublet peak forces) properties of the knee extensors were measured. Prefrontal and motor cortical oxygenation was also recorded during each cycling bout in both conditions. RESULTS A significant but similar force reduction (≈-22%) was observed at the end of exercise in normoxia and hypoxia. The modifications of voluntary activation assessed with transcranial magnetic stimulation and nerve stimulation, motor evoked potential, cortical silent period, and M-wave were also similar in both conditions. However, cerebral oxygenation was reduced in hypoxia compared with normoxia. CONCLUSION These findings show that when performed at the same relative low intensity, prolonged exercise does not induce greater supraspinal fatigue in hypoxia compared with normoxia. Despite lower absolute exercise intensities in hypoxia, reduced brain O2 availability might contribute to similar amounts of central fatigue compared with normoxia.
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Affiliation(s)
- Marc Jubeau
- 1Laboratory HP2, Grenoble Alpes University, Grenoble, FRANCE; 2INSERM U1042, Grenoble, FRANCE; 3Laboratory "Movement, Interactions, Performance" (EA 4334), Faculty of Sport Sciences, University of Nantes, Nantes, FRANCE; 4Inter-university Laboratory of Human Movement Biology, University Savoie Mont Blanc, Chambéry, FRANCE; 5Inter-university Laboratory of Human Movement Biology, University of Lyon, UJM-Saint-Etienne, Saint-Etienne, FRANCE; 6Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, CANADA; and 7EuroMov, University of Montpellier, FRANCE
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21
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Brownstein CG, Dent JP, Parker P, Hicks KM, Howatson G, Goodall S, Thomas K. Etiology and Recovery of Neuromuscular Fatigue following Competitive Soccer Match-Play. Front Physiol 2017; 8:831. [PMID: 29118716 PMCID: PMC5661001 DOI: 10.3389/fphys.2017.00831] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 10/06/2017] [Indexed: 02/02/2023] Open
Abstract
Aim: Previous research into the etiology of neuromuscular fatigue following competitive soccer match-play has primarily focused on peripheral perturbations, with limited research assessing central nervous system function in the days post-match. The aim of the present study was to examine the contribution and time-course of recovery of central and peripheral factors toward neuromuscular fatigue following competitive soccer match-play. Methods: Sixteen male semi-professional soccer players completed a 90-min soccer match. Pre-, post- and at 24, 48, and 72 h participants completed a battery of neuromuscular, physical, and perceptual tests. Maximal voluntary contraction force (MVC) and twitch responses to electrical (femoral nerve) and transcranial magnetic stimulation (TMS) of the motor cortex during isometric knee-extension and at rest were measured to assess central nervous system (voluntary activation, VA) and muscle contractile (potentiated twitch force, Qtw, pot) function. Electromyography responses of the rectus femoris to single- and paired-pulse TMS were used to assess corticospinal excitability and short-interval intracortical inhibition (SICI), respectively. Fatigue and perceptions of muscle soreness were assessed via visual analog scales, and physical function was assessed through measures of jump (countermovement jump height and reactive strength index) and sprint performance. Results: Competitive match-play elicited significant post-match declines in MVC force (−14%, P < 0.001) that persisted for 48 h (−4%, P = 0.01), before recovering by 72 h post-exercise. VA (motor point stimulation) was reduced immediately post-match (−8%, P < 0.001), and remained depressed at 24 h (−5%, P = 0.01) before recovering by 48 h post-exercise. Qtw,pot was reduced post-match (−14%, P < 0.001), remained depressed at 24 h (−6%, P = 0.01), before recovering by 48 h post-exercise. No changes were evident in corticospinal excitability or SICI. Jump performance took 48 h to recover, while perceptions of fatigue persisted at 72 h. Conclusion: Competitive soccer match-play elicits substantial impairments in central nervous system and muscle function, requiring up to 48 h to resolve. The results of the study could have important implications for fixture scheduling, the optimal management of the training process, squad rotation during congested competitive schedules, and the implementation of appropriate recovery interventions.
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Affiliation(s)
- Callum G Brownstein
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Jack P Dent
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Paul Parker
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Kirsty M Hicks
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom.,Water Research Group, School of Environmental Sciences and Development, Northwest University, Potchefstroom, South Africa
| | - Stuart Goodall
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Kevin Thomas
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom
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Thomas K, Elmeua M, Howatson G, Goodall S. Intensity-Dependent Contribution of Neuromuscular Fatigue after Constant-Load Cycling. Med Sci Sports Exerc 2017; 48:1751-60. [PMID: 27187101 DOI: 10.1249/mss.0000000000000950] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
PURPOSE We tested the hypothesis that central and peripheral fatigue after constant-load cycling exercise would vary with exercise intensity and duration. METHODS Twelve well-trained male cyclists (V˙O2max, 4.49 ± 0.35 L·min) completed three constant-load cycling trials to the limit of tolerance in a randomized crossover design. Exercise intensities were set according to the respiratory responses to a preliminary ramp test to elicit cardiorespiratory and metabolic responses consistent with exercise in the severe and heavy exercise domains: 1) at power at V˙O2max (S+, 379 ± 31 W), 2) at 60% of the difference between gas exchange threshold and V˙O2max (S-, 305 ± 23 W), and 3) at the respiratory compensation point (RCP, 254 ± 26 W). Pre- and postexercise twitch responses from the quadriceps to the electrical stimulation of the femoral nerve and magnetic stimulation of the motor cortex were recorded to assess neuromuscular and corticospinal function, respectively. RESULTS Exercise time was 3.14 ± 0.59, 11.11 ± 1.86, and 42.14 ± 9.09 min for S+, S-, and RCP, respectively. All trials resulted in similar reductions in maximum voluntary force (P = 0.61). However, the degree of peripheral fatigue varied in an intensity-dependent manner, with greater reductions in potentiated twitch force after S+ (-33% ± 9%) compared with both S- (-16% ± 9%, P < 0.001) and RCP trials (-11% ± 9%, P < 0.001) and greater after S- compared with RCP (P < 0.05). For central fatigue, this trend was reversed, with smaller reductions in voluntary activation after S+ compared with RCP (-2.7% ± 2.2% vs -9.0% ± 4.7%, P < 0.01). CONCLUSION These data suggest the magnitude of peripheral and central fatigue after locomotor cycling exercise is exacerbated with exercise intensity and duration, respectively.
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Affiliation(s)
- Kevin Thomas
- 1Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UNITED KINGDOM; and 2Water Research Group, School of Environmental Sciences and Development, Northwest University, Potchefstroom, SOUTH AFRICA
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Mira J, Lapole T, Souron R, Messonnier L, Millet GY, Rupp T. Cortical voluntary activation testing methodology impacts central fatigue. Eur J Appl Physiol 2017; 117:1845-1857. [DOI: 10.1007/s00421-017-3678-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/30/2017] [Indexed: 10/19/2022]
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24
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Suruagy I, Baltar A, Gomes LP, Berenguer M, Dornelas A, Monte-Silva K. Intensity-dependent effects of cycling exercise on corticospinal excitability in healthy humans: a pilot study. MOTRIZ: REVISTA DE EDUCACAO FISICA 2017. [DOI: 10.1590/s1980-6574201700020002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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25
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THOMAS KEVIN, DENT JACK, HOWATSON GLYN, GOODALL STUART. Etiology and Recovery of Neuromuscular Fatigue after Simulated Soccer Match Play. Med Sci Sports Exerc 2017; 49:955-964. [DOI: 10.1249/mss.0000000000001196] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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26
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Neva JL, Brown KE, Mang CS, Francisco BA, Boyd LA. An acute bout of exercise modulates both intracortical and interhemispheric excitability. Eur J Neurosci 2017; 45:1343-1355. [PMID: 28370664 DOI: 10.1111/ejn.13569] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 11/28/2022]
Abstract
Primary motor cortex (M1) excitability is modulated following a single session of cycling exercise. Specifically, short-interval intracortical inhibition and intracortical facilitation are altered following a session of cycling, suggesting that exercise affects the excitability of varied cortical circuits. Yet we do not know whether a session of exercise also impacts the excitability of interhemispheric circuits between, and other intracortical circuits within, M1. Here we present two experiments designed to address this gap in knowledge. In experiment 1, single and paired pulse transcranial magnetic stimulation (TMS) were used to measure intracortical circuits including, short-interval intracortical facilitation (SICF) tested at 1.1, 1.5, 2.7, 3.1 and 4.5 ms interstimulus intervals (ISIs), contralateral silent period (CSP) and interhemispheric interactions by measuring transcallosal inhibition (TCI) recorded from the abductor pollicus brevis muscles. All circuits were assessed bilaterally pre and two time points post (immediately, 30 min) moderate intensity lower limb cycling. SICF was enhanced in the left hemisphere after exercise at the 1.5 ms ISI. Also, CSP was shortened and TCI decreased bilaterally after exercise. In Experiment 2, corticospinal and spinal excitability were tested before and after exercise to investigate the locus of the effects found in Experiment 1. Exercise did not impact motor-evoked potential recruitment curves, Hoffman reflex or V-wave amplitudes. These results suggest that a session of exercise decreases intracortical and interhemispheric inhibition and increases facilitation in multiple circuits within M1, without concurrently altering spinal excitability. These findings have implications for developing exercise strategies designed to potentiate M1 plasticity and skill learning in healthy and clinical populations.
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Affiliation(s)
- J L Neva
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - K E Brown
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - C S Mang
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - B A Francisco
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - L A Boyd
- Department of Physical Therapy, Faculty of Medicine, University of British Columbia, 212-2177 Westbrook Mall, Vancouver, BC, V6T 1Z3, Canada
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27
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Black MI, Jones AM, Blackwell JR, Bailey SJ, Wylie LJ, McDonagh STJ, Thompson C, Kelly J, Sumners P, Mileva KN, Bowtell JL, Vanhatalo A. Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains. J Appl Physiol (1985) 2016; 122:446-459. [PMID: 28008101 PMCID: PMC5429469 DOI: 10.1152/japplphysiol.00942.2016] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/12/2016] [Accepted: 12/16/2016] [Indexed: 01/15/2023] Open
Abstract
The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities. Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4–5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; <CP but >GET) CWR test until Tlim, and a moderate-intensity (MOD; <GET) CWR test until Tlim. Muscle biopsies revealed that a similar (P > 0.05) muscle metabolic milieu (i.e., low pH and [PCr] and high [lactate]) was attained at Tlim (approximately 2–14 min) for all SEV exercise bouts. The muscle metabolic perturbation was greater at Tlim following SEV compared with HVY, and also following SEV and HVY compared with MOD (all P < 0.05). The normalized M-wave amplitude for the vastus lateralis (VL) muscle decreased to a similar extent following SEV (−38 ± 15%), HVY (−68 ± 24%), and MOD (−53 ± 29%), (P > 0.05). Neural drive to the VL increased during SEV (4 ± 4%; P < 0.05) but did not change during HVY or MOD (P > 0.05). During SEV and HVY, but not MOD, the rates of change in M-wave amplitude and neural drive were correlated with changes in muscle metabolic ([PCr], [lactate]) and blood ionic/acid-base status ([lactate], [K+]) (P < 0.05). The results of this study indicate that the metabolic and neuromuscular determinants of fatigue development differ according to the intensity domain in which the exercise is performed. NEW & NOTEWORTHY The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole-body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities.
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Affiliation(s)
- Matthew I Black
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom.,School of Sport, Exercise and Health Sciences, Loughborough University, United Kingdom; and
| | - Andrew M Jones
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Jamie R Blackwell
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Stephen J Bailey
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom.,School of Sport, Exercise and Health Sciences, Loughborough University, United Kingdom; and
| | - Lee J Wylie
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Sinead T J McDonagh
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Christopher Thompson
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - James Kelly
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Paul Sumners
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom
| | - Katya N Mileva
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom
| | - Joanna L Bowtell
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Anni Vanhatalo
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom;
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Taylor JL, Amann M, Duchateau J, Meeusen R, Rice CL. Neural Contributions to Muscle Fatigue: From the Brain to the Muscle and Back Again. Med Sci Sports Exerc 2016; 48:2294-2306. [PMID: 27003703 PMCID: PMC5033663 DOI: 10.1249/mss.0000000000000923] [Citation(s) in RCA: 294] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
: During exercise, there is a progressive reduction in the ability to produce muscle force. Processes within the nervous system as well as within the muscles contribute to this fatigue. In addition to impaired function of the motor system, sensations associated with fatigue and impairment of homeostasis can contribute to the impairment of performance during exercise. This review discusses some of the neural changes that accompany exercise and the development of fatigue. The role of brain monoaminergic neurotransmitter systems in whole-body endurance performance is discussed, particularly with regard to exercise in hot environments. Next, fatigue-related alterations in the neuromuscular pathway are discussed in terms of changes in motor unit firing, motoneuron excitability, and motor cortical excitability. These changes have mostly been investigated during single-limb isometric contractions. Finally, the small-diameter muscle afferents that increase firing with exercise and fatigue are discussed. These afferents have roles in cardiovascular and respiratory responses to exercise, and in the impairment of exercise performance through interaction with the motor pathway, as well as in providing sensations of muscle discomfort. Thus, changes at all levels of the nervous system, including the brain, spinal cord, motor output, sensory input, and autonomic function, occur during exercise and fatigue. The mix of influences and the importance of their contribution vary with the type of exercise being performed.
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Affiliation(s)
- Janet L Taylor
- 1Neuroscience Research Australia, Sydney, AUSTRALIA; 2School of Medical Sciences, the University of New South Wales, Sydney, AUSTRALIA; 3Department of Medicine, University of Utah, Salt Lake City, UT; 4Laboratory of Applied Biology and Neurophysiology, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, BELGIUM; 5Human Physiology Research Group Vrije Universiteit Brussel, Brussels, BELGIUM; 6School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Queensland, AUSTRALIA; and 7School of Kinesiology, and Department of Anatomy and Cell Biology, The University of Western Ontario, London, CANADA
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29
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Kennedy DS, McNeil CJ, Gandevia SC, Taylor JL. Effects of fatigue on corticospinal excitability of the human knee extensors. Exp Physiol 2016; 101:1552-1564. [PMID: 27652591 DOI: 10.1113/ep085753] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 09/19/2016] [Indexed: 01/05/2023]
Abstract
NEW FINDINGS What is the central question of this study? Do group III and IV muscle afferents act at the spinal or cortical level to affect the ability of the central nervous system to drive quadriceps muscles during fatiguing exercise? What is the main finding and its importance? The excitability of the motoneurone pool of vastus lateralis was unchanged by feedback from group III and IV muscle afferents. In contrast, feedback from these afferents may contribute to inhibition at the cortex. However, the excitability of the corticospinal pathway was not directly affected by feedback from these afferents. These findings are important for understanding neural processes during fatiguing exercise. In upper limb muscles, changes in afferent feedback, motoneurone excitability, and motor cortical output can contribute to failure of the central nervous system to recruit muscles fully during fatigue. It is not known whether similar changes occur with fatigue of muscles in the lower limb. We assessed the corticospinal pathway to vastus lateralis during fatiguing sustained maximal voluntary contractions (MVCs) of the knee extensors and during firing of fatigue-sensitive group III/IV muscle afferents maintained by postexercise ischaemia after fatiguing MVCs of the knee extensors and, separately, the flexors. In two experiments, subjects (n = 9) performed brief knee extensor MVCs before and after 2-min sustained MVCs of the knee extensors (experiment 1) or knee flexors (experiment 2). During MVCs, motor evoked potentials (MEPs) were elicited by transcranial magnetic stimulation over the motor cortex and thoracic motor evoked potentials (TMEPs) by electrical stimulation over the thoracic spine. During the 2-min extensor contraction, the size of vastus lateralis MEPs normalized to the maximal M-wave increased (P < 0.05), but normalized TMEPs were unchanged (P = 0.16). After the 2-min MVC, maintained firing of group III/IV muscle afferents had no effect on vastus lateralis MEPs or TMEPs (P = 0.18 and P = 0.50, respectively). Likewise, after the 2-min knee flexor MVC, maintained firing of these afferents showed no effect on vastus lateralis MEPs or TMEPs (P = 0.69 and P = 0.34, respectively). Motoneurones of vastus lateralis do not become less excitable during fatiguing isometric MVCs. Moreover, fatigue-sensitive group III/IV muscle afferents fail to affect the overall excitability of vastus lateralis motoneurones during MVCs.
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Affiliation(s)
- David S Kennedy
- Neuroscience Research Australia, Randwick, NSW, Australia.,University of New South Wales, Kensington, NSW, Australia
| | - Chris J McNeil
- Neuroscience Research Australia, Randwick, NSW, Australia.,Centre for Heart, Lung and Vascular Health, School of Health & Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Simon C Gandevia
- Neuroscience Research Australia, Randwick, NSW, Australia.,University of New South Wales, Kensington, NSW, Australia
| | - Janet L Taylor
- Neuroscience Research Australia, Randwick, NSW, Australia.,University of New South Wales, Kensington, NSW, Australia
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30
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Group III/IV locomotor muscle afferents alter motor cortical and corticospinal excitability and promote central fatigue during cycling exercise. Clin Neurophysiol 2016; 128:44-55. [PMID: 27866119 DOI: 10.1016/j.clinph.2016.10.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 08/17/2016] [Accepted: 10/09/2016] [Indexed: 12/15/2022]
Abstract
OBJECTIVE To investigate the influence of group III/IV muscle afferents on the development of central fatigue and corticospinal excitability during exercise. METHODS Fourteen males performed cycling-exercise both under control-conditions (CTRL) and with lumbar intrathecal fentanyl (FENT) impairing feedback from leg muscle afferents. Transcranial magnetic- and cervicomedullary stimulation was used to monitor cortical versus spinal excitability. RESULTS While fentanyl-blockade during non-fatiguing cycling had no effect on motor-evoked potentials (MEPs), cervicomedullary-evoked motor potentials (CMEPs) were 13±3% higher (P<0.05), resulting in a decrease in MEP/CMEP (P<0.05). Although the pre- to post-exercise reduction in resting twitch was greater in FENT vs. CTRL (-53±3% vs. -39±3%; P<0.01), the reduction in voluntary muscle activation was smaller (-2±2% vs. -10±2%; P<0.05). Compared to the start of fatiguing exercise, MEPs and CMEPs were unchanged at exhaustion in CTRL. In contrast, MEPs and MEP/CMEP increased 13±3% and 25±6% in FENT (P<0.05). CONCLUSION During non-fatiguing exercise, group III/IV muscle afferents disfacilitate, or inhibit, spinal motoneurons and facilitate motor cortical cells. In contrast, during exhaustive exercise, group III/IV muscle afferents disfacilitate/inhibit the motor cortex and promote central fatigue. SIGNIFICANCE Group III/IV muscle afferents influence corticospinal excitability and central fatigue during whole-body exercise in humans.
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31
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Khong TK, Selvanayagam VS, Sidhu SK, Yusof A. Role of carbohydrate in central fatigue: a systematic review. Scand J Med Sci Sports 2016; 27:376-384. [PMID: 27714855 DOI: 10.1111/sms.12754] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2016] [Indexed: 12/29/2022]
Abstract
Carbohydrate (CHO) depletion is linked to neuromuscular fatigue during exercise. While its role at peripheral level is relatively well understood, less is known about its impact centrally. The aim of this systematic review was to critically analyze the effects of CHO on central fatigue (CF) assessed by various neurophysiological techniques. Four databases were searched using PRISMA guidelines through February 2016. The inclusion criteria were: CHO as intervention against a placebo control, fatigue induced by prolonged exercise and assessed using neurophysiological measures [voluntary activation (VA), superimposed twitch (SIT), M-wave, electromyography], alongside maximal voluntary contraction (MVC). Seven papers were reviewed, where exercise duration lasted between 115 and 180 min. CHO improved exercise performance in three studies, whereby two of them attributed it to CF via attenuation of VA and SIT reductions, while the other indicated peripheral involvement via attenuation of M-wave reduction. Although a few studies suggest that CHO attenuates CF, data on its direct effects on neurophysiological outcome measures are limited and mixed. Generally, measures employed in these studies were inadequate to conclude central contribution to fatigue. Factors including the techniques used and the lack of controls render additional confounding factors to make definitive deductions. Future studies should employ consistent techniques and appropriate neurophysiological controls to distinguish CHO effect at central level. The use of pharmacological intervention should be incorporated to elucidate involvement of central mechanisms.
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Affiliation(s)
- T K Khong
- Sports Centre, University of Malaya, Kuala Lumpur, Malaysia
| | | | - S K Sidhu
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - A Yusof
- Sports Centre, University of Malaya, Kuala Lumpur, Malaysia
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32
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Mooney RA, Coxon JP, Cirillo J, Glenny H, Gant N, Byblow WD. Acute aerobic exercise modulates primary motor cortex inhibition. Exp Brain Res 2016; 234:3669-3676. [PMID: 27590480 DOI: 10.1007/s00221-016-4767-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 08/27/2016] [Indexed: 11/30/2022]
Abstract
Aerobic exercise can enhance neuroplasticity although presently the neural mechanisms underpinning these benefits remain unclear. One possible mechanism is through effects on primary motor cortex (M1) function via down-regulation of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). The aim of the present study was to examine how corticomotor excitability (CME) and M1 intracortical inhibition are modulated in response to a single bout of moderate intensity aerobic exercise. Ten healthy right-handed adults were participants. Single- and paired-pulse transcranial magnetic stimulation was applied over left M1 to obtain motor-evoked potentials in the right flexor pollicis brevis. We examined CME, cortical silent period (SP) duration, short- and long-interval intracortical inhibition (SICI, LICI), and late cortical disinhibition (LCD), before and after acute aerobic exercise (exercise session) or an equivalent duration without exercise (control session). Aerobic exercise was performed on a cycle ergometer for 30 min at a workload equivalent to 60 % of maximal cardiorespiratory fitness (VO2 peak; heart rate reserve = 75 ± 3 %, perceived exertion = 13.5 ± 0.7). LICI was reduced at 10 (52 ± 17 %, P = 0.03) and 20 min (27 ± 8 %, P = 0.03) post-exercise compared to baseline (13 ± 4 %). No significant changes in CME, SP duration, SICI or LCD were observed. The present study shows that GABAB-mediated intracortical inhibition may be down-regulated after acute aerobic exercise. The potential effects this may have on M1 plasticity remain to be determined.
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Affiliation(s)
- Ronan A Mooney
- Movement Neuroscience Laboratory, The University of Auckland, Auckland, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - James P Coxon
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, VIC, Australia.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - John Cirillo
- Movement Neuroscience Laboratory, The University of Auckland, Auckland, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Helen Glenny
- Movement Neuroscience Laboratory, The University of Auckland, Auckland, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Nicholas Gant
- Exercise Neurometabolism Laboratory, Department of Exercise Sciences, The University of Auckland, Auckland, New Zealand.,Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Winston D Byblow
- Movement Neuroscience Laboratory, The University of Auckland, Auckland, New Zealand. .,Centre for Brain Research, The University of Auckland, Auckland, New Zealand.
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Weavil JC, Sidhu SK, Mangum TS, Richardson RS, Amann M. Fatigue diminishes motoneuronal excitability during cycling exercise. J Neurophysiol 2016; 116:1743-1751. [PMID: 27440242 DOI: 10.1152/jn.00300.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/15/2016] [Indexed: 11/22/2022] Open
Abstract
Exercise-induced fatigue influences the excitability of the motor pathway during single-joint isometric contractions. This study sought to investigate the influence of fatigue on corticospinal excitability during cycling exercise. Eight men performed fatiguing constant-load (80% Wpeak; 241 ± 13 W) cycling to exhaustion during which the percent increase in quadriceps electromyography (ΔEMG; vastus lateralis and rectus femoris) was quantified. During a separate trial, subjects performed two brief (∼45 s) nonfatiguing cycling bouts (244 ± 15 and 331 ± 23W) individually chosen to match the ΔEMG across bouts to that observed during fatiguing cycling. Corticospinal excitability during exercise was quantified by transcranial magnetic, electric transmastoid, and femoral nerve stimulation to elicit motor-evoked potentials (MEP), cervicomedullary evoked potentials (CMEP), and M waves in the quadriceps. Peripheral and central fatigue were expressed as pre- to postexercise reductions in quadriceps twitch force (ΔQtw) and voluntary quadriceps activation (ΔVA). Whereas nonfatiguing cycling caused no measureable fatigue, fatiguing cycling resulted in significant peripheral (ΔQtw: 42 ± 6%) and central (ΔVA: 4 ± 1%) fatigue. During nonfatiguing cycling, the area of MEPs and CMEPs, normalized to M waves, similarly increased in the quadriceps (∼40%; P < 0.05). In contrast, there was no change in normalized MEPs or CMEPs during fatiguing cycling. As a consequence, the ratio of MEP to CMEP was unchanged during both trials (P > 0.5). Therefore, although increases in muscle activation promote corticospinal excitability via motoneuronal facilitation during nonfatiguing cycling, this effect is abolished during fatigue. We conclude that the unaltered excitability of the corticospinal pathway from start of intense cycling exercise to exhaustion is, in part, determined by inhibitory influences on spinal motoneurons obscuring the facilitating effects of muscle activation.
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Affiliation(s)
- Joshua C Weavil
- Department of Exercise & Sport Science, University of Utah, Salt Lake City, Utah
| | - Simranjit K Sidhu
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah; Discipline of Physiology, University of Adelaide, Australia; and
| | - Tyler S Mangum
- Department of Exercise & Sport Science, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Department of Exercise & Sport Science, University of Utah, Salt Lake City, Utah; Department of Internal Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Markus Amann
- Department of Exercise & Sport Science, University of Utah, Salt Lake City, Utah; Department of Internal Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah
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Lauber B, Keller M, Leukel C, Gollhofer A, Taube W. Force and Position Control in Humans - The Role of Augmented Feedback. J Vis Exp 2016. [PMID: 27404742 DOI: 10.3791/53291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
During motor behaviour, humans interact with the environment by for example manipulating objects and this is only possible because sensory feedback is constantly integrated into the central nervous system and these sensory inputs need to be weighted in order meet the task specific goals. Additional feedback presented as augmented feedback was shown to have an impact on motor control and motor learning. A number of studies investigated whether force or position feedback has an influence on motor control and neural activation. However, as in the previous studies the presentation of the force and position feedback was always identical, a recent study assessed whether not only the content but also the interpretation of the feedback has an influence on the time to fatigue of a sustained submaximal contraction and the (inhibitory) activity of the primary motor cortex using subthreshold transcranial magnetic stimulation. This paper describes one possible way to investigate the influence of the interpretation of feedback on motor behaviour by investigating the time to fatigue of submaximal sustained contractions together with the neuromuscular adaptations that can be investigated using surface EMG. Furthermore, the current protocol also describes how motor cortical (inhibitory) activity can be investigated using subthreshold TMS, a method known to act solely on the cortical level. The results show that when participants interpret the feedback as position feedback, they display a significantly shorter time to fatigue of a submaximal sustained contraction. Furthermore, subjects also displayed an increased inhibitory activity of the primary cortex when they believed to receive position feedback compared when they believed to receive force feedback. Accordingly, the results show that interpretation of feedback results in differences on a behavioural level (time to fatigue) that is also reflected in interpretation-specific differences in the amount of inhibitory M1 activity.
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Affiliation(s)
- Benedikt Lauber
- Department of Sport Science, University of Freiburg; Department of Medicine, Movement and Sport Science, University of Fribourg;
| | - Martin Keller
- Department of Medicine, Movement and Sport Science, University of Fribourg
| | - Christian Leukel
- Department of Sport Science, University of Freiburg; Bernsteincenter Freiburg
| | | | - Wolfgang Taube
- Department of Medicine, Movement and Sport Science, University of Fribourg
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FROYD CHRISTIAN, BELTRAMI FERNANDOGABE, MILLET GUILLAUMEY, NOAKES TIMOTHYD. Central Regulation and Neuromuscular Fatigue during Exercise of Different Durations. Med Sci Sports Exerc 2016; 48:1024-32. [DOI: 10.1249/mss.0000000000000867] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Spring JN, Place N, Borrani F, Kayser B, Barral J. Movement-Related Cortical Potential Amplitude Reduction after Cycling Exercise Relates to the Extent of Neuromuscular Fatigue. Front Hum Neurosci 2016; 10:257. [PMID: 27313522 PMCID: PMC4887485 DOI: 10.3389/fnhum.2016.00257] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/17/2016] [Indexed: 01/16/2023] Open
Abstract
Exercise-induced fatigue affects the motor control and the ability to generate a given force or power. Surface electroencephalography allows researchers to investigate movement-related cortical potentials (MRCP), which reflect preparatory brain activity 1.5 s before movement onset. Although the MRCP amplitude appears to increase after repetitive single-joint contractions, the effects of large-muscle group dynamic exercise on such pre-motor potential remain to be described. Sixteen volunteers exercised 30 min at 60% of the maximal aerobic power on a cycle ergometer, followed by a 10-km all-out time trial. Before and after each of these tasks, knee extensor neuromuscular function was investigated using maximal voluntary contractions (MVC) combined with electrical stimulations of the femoral nerve. MRCP was recorded during 60 knee extensions after each neuromuscular sequence. The exercise resulted in a significant decrease in the knee extensor MVC force after the 30-min exercise (−10 ± 8%) and the time trial (−21 ± 9%). The voluntary activation level (VAL; −6 ± 8 and −12 ± 10%), peak twitch (Pt; −21 ± 16 and −32 ± 17%), and paired stimuli (P100 Hz; −7 ± 11 and −12 ± 13%) were also significantly reduced after the 30-min exercise and the time trial. The first exercise was followed by a decrease in the MRCP, mainly above the mean activity measured at electrodes FC1-FC2, whereas the reduction observed after the time trial was related to the FC1-FC2 and C2 electrodes. After both exercises, the reduction in the late MRCP component above FC1-FC2 was significantly correlated with the reduction in P100 Hz (r = 0.61), and the reduction in the same component above C2 was significantly correlated with the reduction in VAL (r = 0.64). In conclusion, large-muscle group exercise induced a reduction in pre-motor potential, which was related to muscle alterations and resulted in the inability to produce a maximal voluntary contraction.
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Affiliation(s)
- Jérôme Nicolas Spring
- Institute of Sport Sciences, Faculty of Social and Political Sciences, University of Lausanne Lausanne, Switzerland
| | - Nicolas Place
- Institute of Sport Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne Lausanne, Switzerland
| | - Fabio Borrani
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sport Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne Lausanne, Switzerland
| | - Jérôme Barral
- Institute of Sport Sciences, Faculty of Social and Political Sciences, University of Lausanne Lausanne, Switzerland
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Yunoki T, Matsuura R, Yamanaka R, Afroundeh R, Lian CS, Shirakawa K, Ohtsuka Y, Yano T. Relationship between motor corticospinal excitability and ventilatory response during intense exercise. Eur J Appl Physiol 2016; 116:1117-26. [PMID: 27055665 DOI: 10.1007/s00421-016-3374-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 03/28/2016] [Indexed: 11/26/2022]
Abstract
PURPOSE Effort sense has been suggested to be involved in the hyperventilatory response during intense exercise (IE). However, the mechanism by which effort sense induces an increase in ventilation during IE has not been fully elucidated. The aim of this study was to determine the relationship between effort-mediated ventilatory response and corticospinal excitability of lower limb muscle during IE. METHODS Eight subjects performed 3 min of cycling exercise at 75-85 % of maximum workload twice (IE1st and IE2nd). IE2nd was performed after 60 min of resting recovery following 45 min of submaximal cycling exercise at the workload corresponding to ventilatory threshold. Vastus lateralis muscle response to transcranial magnetic stimulation of the motor cortex (motor evoked potentials, MEPs), effort sense of legs (ESL, Borg 0-10 scale), and ventilatory response were measured during the two IEs. RESULTS The slope of ventilation (l/min) against CO2 output (l/min) during IE2nd (28.0 ± 5.6) was significantly greater than that (25.1 ± 5.5) during IE1st. Mean ESL during IE was significantly higher in IE2nd (5.25 ± 0.89) than in IE1st (4.67 ± 0.62). Mean MEP (normalized to maximal M-wave) during IE was significantly lower in IE2nd (66 ± 22 %) than in IE1st (77 ± 24 %). The difference in mean ESL between the two IEs was significantly (p < 0.05, r = -0.82) correlated with the difference in mean MEP between the two IEs. CONCLUSIONS The findings suggest that effort-mediated hyperventilatory response to IE may be associated with a decrease in corticospinal excitability of exercising muscle.
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Affiliation(s)
- Takahiro Yunoki
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan.
| | - Ryouta Matsuura
- Department of Health and Physical Education, Joetsu University of Education, Joetsu, Japan
| | - Ryo Yamanaka
- Japan Institute of Sports Sciences, Tokyo, Japan
| | - Roghayyeh Afroundeh
- Department of Physical Education and Sports Science, Faculty of Education and Psychology, University of Mohaghegh Ardabilli, Ardabil, Iran
| | - Chang-Shun Lian
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan
| | - Kazuki Shirakawa
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan
| | - Yoshinori Ohtsuka
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan
| | - Tokuo Yano
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan
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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.
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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
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Weavil JC, Sidhu SK, Mangum TS, Richardson RS, Amann M. Intensity-dependent alterations in the excitability of cortical and spinal projections to the knee extensors during isometric and locomotor exercise. Am J Physiol Regul Integr Comp Physiol 2015; 308:R998-1007. [PMID: 25876651 DOI: 10.1152/ajpregu.00021.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/08/2015] [Indexed: 11/22/2022]
Abstract
We investigated the role of exercise intensity and associated central motor drive in determining corticomotoneuronal excitability. Ten participants performed a series of nonfatiguing (3 s) isometric single-leg knee extensions (ISO; 10-100% of maximal voluntary contractions, MVC) and cycling bouts (30-160% peak aerobic capacity, W peak). At various exercise intensities, electrical potentials were evoked in the vastus lateralis (VL) and rectus femoris (RF) via transcranial magnetic stimulation (motor-evoked potentials, MEP), and electrical stimulation of both the cervicomedullary junction (cervicomedullary evoked potentials, CMEP) and the femoral nerve (maximal M-waves, M max). Whereas M max remained unchanged in both muscles (P > 0.40), voluntary electromyographic activity (EMG) increased in an exercise intensity-dependent manner for ISO and cycling exercise in VL and RF (both P < 0.001). During ISO exercise, MEPs and CMEPs progressively increased in VL and RF until a plateau was reached at ∼ 75% MVC; further increases in contraction intensity did not cause additional changes (P > 0.35). During cycling exercise, VL-MEPs and CMEPs progressively increased by ∼ 65% until a plateau was reached at W peak. In contrast, RF MEPs and CMEPs progressively increased by ∼ 110% throughout the tested cycling intensities without the occurrence of a plateau. Furthermore, alterations in EMG below the plateau influenced corticomotoneuronal excitability similarly between exercise modalities. In both exercise modalities, the MEP-to-CMEP ratio did not change with exercise intensity (P > 0.22). In conclusion, increases in exercise intensity and EMG facilitates the corticomotoneuronal pathway similarly in isometric knee extension and locomotor exercise until a plateau occurs at a submaximal exercise intensity. This facilitation appears to be primarily mediated by increases in excitability of the motoneuron pool.
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Affiliation(s)
- J C Weavil
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - S K Sidhu
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - T S Mangum
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - R S Richardson
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Department of Internal Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Salt Lake City, Utah
| | - M Amann
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Department of Internal Medicine, University of Utah, Salt Lake City, Utah; Geriatric Research, Education, and Clinical Center, Salt Lake City Veterans Affairs Medical Center, Salt Lake City, Utah
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Coelho AC, Cannon DT, Cao R, Porszasz J, Casaburi R, Knorst MM, Rossiter HB. Instantaneous quantification of skeletal muscle activation, power production, and fatigue during cycle ergometry. J Appl Physiol (1985) 2014; 118:646-54. [PMID: 25539940 DOI: 10.1152/japplphysiol.00948.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A rapid switch from hyperbolic to isokinetic cycling allows the velocity-specific decline in maximal power to be measured, i.e., fatigue. We reasoned that, should the baseline relationship between isokinetic power (Piso) and electromyography (EMG) be reproducible, then contributions to fatigue may be isolated from 1) the decline in muscle activation (muscle activation fatigue); and 2) the decline in Piso at a given activation (muscle fatigue). We hypothesized that the EMG-Piso relationship is linear, velocity dependent, and reliable for instantaneous fatigue assessment at intolerance during and following whole body exercise. Healthy participants (n = 13) completed short (5 s) variable-effort isokinetic bouts at 50, 70, and 100 rpm to characterize baseline EMG-Piso. Repeated ramp incremental exercise tests were terminated with maximal isokinetic cycling (5 s) at 70 rpm. Individual baseline EMG-Piso relationships were linear (r(2) = 0.95 ± 0.04) and velocity dependent (analysis of covariance). Piso at intolerance (two legs, 335 ± 88 W) was ∼45% less than baseline [630 ± 156 W, confidence interval of the difference (CIDifference) 211, 380 W, P < 0.05]. Following intolerance, Piso recovered rapidly (F = 44.1; P < 0.05; η(2) = 0.79): power was reduced (P < 0.05) vs. baseline only at 0-min (CIDifference 80, 201 W) and 1-min recovery (CIDifference 13, 80 W). Activation fatigue and muscle fatigue (one leg) were 97 ± 55 and 60 ± 50 W, respectively. Mean bias ± limits of agreement for reproducibility were as follows: baseline Piso 1 ± 30 W; Piso at 0-min recovery 3 ± 35 W; and EMG at Piso 3 ± 14%. EMG power is linear, velocity dependent, and reproducible. Deviation from this relationship at the limit of tolerance can quantify the "activation" and "muscle" related components of fatigue during cycling.
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Affiliation(s)
- A C Coelho
- Rehabilitation Clinical Trials Center, Division of Respiratory & Critical Care Physiology & Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California; Programa de Pós-Graduação em Ciências Pneumológicas, Universidade Federal do Rio Grande do Sul, Brazil; and
| | - D T Cannon
- Rehabilitation Clinical Trials Center, Division of Respiratory & Critical Care Physiology & Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California
| | - R Cao
- Rehabilitation Clinical Trials Center, Division of Respiratory & Critical Care Physiology & Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California
| | - J Porszasz
- Rehabilitation Clinical Trials Center, Division of Respiratory & Critical Care Physiology & Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California
| | - R Casaburi
- Rehabilitation Clinical Trials Center, Division of Respiratory & Critical Care Physiology & Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California
| | - M M Knorst
- Programa de Pós-Graduação em Ciências Pneumológicas, Universidade Federal do Rio Grande do Sul, Brazil; and
| | - H B Rossiter
- Rehabilitation Clinical Trials Center, Division of Respiratory & Critical Care Physiology & Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, California; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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Kennedy DS, Fitzpatrick SC, Gandevia SC, Taylor JL. Fatigue-related firing of muscle nociceptors reduces voluntary activation of ipsilateral but not contralateral lower limb muscles. J Appl Physiol (1985) 2014; 118:408-18. [PMID: 25525208 DOI: 10.1152/japplphysiol.00375.2014] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During fatiguing upper limb exercise, maintained firing of group III/IV muscle afferents can limit voluntary drive to muscles within the same limb. It is not known if this effect occurs in the lower limb. We investigated the effects of group III/IV muscle afferent firing from fatigued ipsilateral and contralateral extensor muscles and ipsilateral flexor muscles of the knee on voluntary activation of the knee extensors. In three experiments, we examined voluntary activation of the knee extensors by measuring changes in superimposed twitches evoked by femoral nerve stimulation. Subjects attended on 2 days for each experiment. On one day a sphygmomanometer cuff occluded blood flow of the fatigued muscles to maintain firing of group III/IV muscle afferents. After a 2-min extensor contraction (experiment 1; n = 9), mean voluntary activation was lower with than without maintained ischemia (47 ± 19% vs. 87 ± 8%, respectively; P < 0.001). After a 2-min knee flexor maximal voluntary contraction (MVC) (experiment 2; n = 8), mean voluntary activation was also lower with than without ischemia (59 ± 21% vs. 79 ± 9%; P < 0.01). After the contralateral (left) MVC (experiment 3; n = 8), mean voluntary activation of the right leg was similar with or without ischemia (92 ± 6% vs. 93 ± 4%; P = 0.65). After fatiguing exercise, activity in group III/IV muscle afferents reduces voluntary activation of the fatigued muscle and nonfatigued antagonist muscles in the same leg. However, group III/IV muscle afferents from the fatigued left leg had no effect on the unfatigued right leg. This suggests that any "crossover" of central fatigue in the lower limbs is not mediated by group III/IV muscle afferents.
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Affiliation(s)
- David S Kennedy
- Neuroscience Research Australia, Randwick, NSW, Australia; and University of New South Wales, Kensington, NSW, Australia
| | - Siobhan C Fitzpatrick
- Neuroscience Research Australia, Randwick, NSW, Australia; and University of New South Wales, Kensington, NSW, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Randwick, NSW, Australia; and University of New South Wales, Kensington, NSW, Australia
| | - Janet L Taylor
- Neuroscience Research Australia, Randwick, NSW, Australia; and University of New South Wales, Kensington, NSW, Australia
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Gruet M, Temesi J, Brisswalter J, Millet G, Vergès S. Stimulation magnétique transcrânienne : application à la physiologie de l’exercice. Sci Sports 2014. [DOI: 10.1016/j.scispo.2014.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gruet M, Temesi J, Rupp T, Levy P, Verges S, Millet GY. Dynamics of corticospinal changes during and after high-intensity quadriceps exercise. Exp Physiol 2014; 99:1053-64. [PMID: 24907029 DOI: 10.1113/expphysiol.2014.078840] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study tested the hypothesis that during fatiguing quadriceps exercise, supraspinal fatigue develops late, is associated with both increased corticospinal excitability and inhibition and recovers quickly. Eight subjects performed 20 s contractions [15 s at 50% maximal voluntary contraction (MVC) followed by 5 s MVC] separated by a 10 s rest period until task failure. Transcranial magnetic stimulation (TMS) and electrical femoral nerve stimulation (PNS) were delivered ∼ 2 s apart during 50% MVC, during MVC and after MVC in relaxed muscle. Voluntary activation was assessed by TMS (VATMS) immediately before and after exercise and then three times over a 6 min recovery period. During exercise, MVC and twitch force evoked by PNS in relaxed muscle decreased progressively to 48 ± 8 and 36 ± 16% of control values, respectively (both P < 0.01). Significant changes in voluntary activation assessed by PNS and twitch evoked by TMS during MVC were observed during the last quarter of exercise only (from 96.4 ± 1.7 to 86 ± 13%, P = 0.03 and from 0.76 ± 0.8 to 4.9 ± 4.7% MVC, P = 0.02, from baseline to task failure, respectively). The TMS-induced silent period increased linearly during both MVC (by ∼ 79 ms) and 50% MVC (by ∼ 63 ms; both P < 0.01). Motor-evoked potential amplitude did not change during the protocol at any force levels. Both silent period and VATMS recovered within 2 min postexercise, whereas MVC and twitch force evoked by PNS in relaxed muscle recovered to only 84 ± 9 and 73 ± 17% of control values 6 min after exercise, respectively. In conclusion, high-intensity single-joint quadriceps exercise induces supraspinal fatigue near task failure, with increased intracortical inhibition and, in contrast to previous upper-limb results, unchanged corticospinal excitability. These changes recover rapidly after task failure, emphasizing the need to measure corticospinal adaptations immediately at task failure to avoid underestimation of exercise-induced corticospinal changes.
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Affiliation(s)
- Mathieu Gruet
- Université Grenoble-Alpes, Laboratoire HP2, F-38000, Grenoble, France INSERM, U1042, F-38000, Grenoble, France Laboratoire Motricité Humaine, Education, Sport, Santé, Université de Toulon, France
| | - John Temesi
- Université de Lyon, F-42023, Saint-Etienne, France Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Thomas Rupp
- Université Grenoble-Alpes, Laboratoire HP2, F-38000, Grenoble, France INSERM, U1042, F-38000, Grenoble, France
| | - Patrick Levy
- Université Grenoble-Alpes, Laboratoire HP2, F-38000, Grenoble, France INSERM, U1042, F-38000, Grenoble, France
| | - Samuel Verges
- Université Grenoble-Alpes, Laboratoire HP2, F-38000, Grenoble, France INSERM, U1042, F-38000, Grenoble, France
| | - Guillaume Y Millet
- INSERM, U1042, F-38000, Grenoble, France Université de Lyon, F-42023, Saint-Etienne, France Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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TEMESI JOHN, RUPP THOMAS, MARTIN VINCENT, ARNAL PIERRICKJ, FÉASSON LÉONARD, VERGES SAMUEL, MILLET GUILLAUMEY. Central Fatigue Assessed by Transcranial Magnetic Stimulation in Ultratrail Running. Med Sci Sports Exerc 2014; 46:1166-75. [DOI: 10.1249/mss.0000000000000207] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Williams PS, Hoffman RL, Clark BC. Cortical and spinal mechanisms of task failure of sustained submaximal fatiguing contractions. PLoS One 2014; 9:e93284. [PMID: 24667484 PMCID: PMC3965562 DOI: 10.1371/journal.pone.0093284] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 03/04/2014] [Indexed: 01/19/2023] Open
Abstract
In this and the subsequent companion paper, results are presented that collectively seek to delineate the contribution that supraspinal circuits have in determining the time to task failure (TTF) of sustained submaximal contractions. The purpose of this study was to compare adjustments in supraspinal and spinal excitability taken concurrently throughout the performance of two different fatigue tasks with identical mechanical demands but different TTF (i.e., force-matching and position-matching tasks). On separate visits, ten healthy volunteers performed the force-matching or position-matching task at 15% of maximum strength with the elbow flexors to task failure. Single-pulse transcranial magnetic stimulation (TMS), paired-pulse TMS, paired cortico-cervicomedullary stimulation, and brachial plexus electrical stimulation were delivered in a 6-stimuli sequence at baseline and every 2-3 minutes throughout fatigue-task performance. Contrary to expectations, the force-matching task TTF was 42% shorter (17.5 ± 7.9 min) than the position-matching task (26.9 ± 15.11 min; p<0.01); however, both tasks caused the same amount of muscle fatigue (p = 0.59). There were no task-specific differences for the total amount or rate of change in the neurophysiologic outcome variables over time (p>0.05). Therefore, failure occurred after a similar mean decline in motorneuron excitability developed (p<0.02, ES = 0.35-0.52) coupled with a similar mean increase in measures of corticospinal excitability (p<0.03, ES = 0.30-0.41). Additionally, the amount of intracortical inhibition decreased (p<0.03, ES = 0.32) and the amount of intracortical facilitation (p>0.10) and an index of upstream excitation of the motor cortex remained constant (p>0.40). Together, these results suggest that as fatigue develops prior to task failure, the increase in corticospinal excitability observed in relationship to the decrease in spinal excitability results from a combination of decreasing intracortical inhibition with constant levels of intracortical facilitation and upstream excitability that together eventually fail to provide the input to the motor cortex necessary for descending drive to overcome the spinal cord resistance, thereby contributing to task failure.
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Affiliation(s)
- Petra S. Williams
- Ohio Musculoskeletal & Neurological Institute (OMNI), Ohio University, Athens, Ohio, United States of America
- Department of Physical Therapy and Athletic Training, Northern Arizona University, Flagstaff, Arizona, United States of America
| | - Richard L. Hoffman
- Ohio Musculoskeletal & Neurological Institute (OMNI), Ohio University, Athens, Ohio, United States of America
| | - Brian C. Clark
- Ohio Musculoskeletal & Neurological Institute (OMNI), Ohio University, Athens, Ohio, United States of America
- Department of Biomedical Sciences, Ohio University, Athens, Ohio, United States of America
- Department of Geriatric Medicine and Gerontology, Ohio University, Athens, Ohio, United States of America
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Smith AE, Goldsworthy MR, Garside T, Wood FM, Ridding MC. The influence of a single bout of aerobic exercise on short-interval intracortical excitability. Exp Brain Res 2014; 232:1875-82. [PMID: 24570388 DOI: 10.1007/s00221-014-3879-z] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 02/13/2014] [Indexed: 12/18/2022]
Abstract
Regular physical activity can have positive effects on brain function and plasticity. Indeed, there is some limited evidence that even a single bout of exercise may promote plasticity within the cortex. However, the mechanisms by which exercise acutely promotes plasticity are not clear. To further explore the effects of acute exercise on cortical function, we examined whether a single bout of exercise was associated with changes in cortical excitability and inhibition. Using standard techniques, cortical stimulus-response curves [90% resting motor threshold (RMT)-150% RMT] were investigated in nine subjects (four females, 31.1 ± 11.7 years) and short-interval intracortical inhibition (SICI) [interstimulus interval 2 ms and 3 ms, conditioning intensities of 80% active motor threshold (AMT) and 90% AMT] in 13 subjects (six females, 28.4 ± 5.1 years) before and at 0 and 15 min following 30 min of ergometer cycling at low-moderate or moderate-high intensity. There were no changes in cortical excitability following exercise but less SICI at both 0 and 15 min post-exercise (F [2, 24] = 7.7, P = 0.003). These findings show that a short period of exercise can transiently reduce SICI. Such a change in inhibition after exercise may contribute to the development of a cortical environment that would be more optimal for plasticity and may partially explain previous findings of enhanced neuroplasticity following low-intensity exercise.
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Affiliation(s)
- Ashleigh E Smith
- School of Paediatrics and Reproductive Health, Robinson Institute, The University of Adelaide, Adelaide, Australia,
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Jubeau M, Rupp T, Perrey S, Temesi J, Wuyam B, Levy P, Verges S, Millet GY. Changes in voluntary activation assessed by transcranial magnetic stimulation during prolonged cycling exercise. PLoS One 2014; 9:e89157. [PMID: 24586559 PMCID: PMC3931682 DOI: 10.1371/journal.pone.0089157] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 01/15/2014] [Indexed: 01/13/2023] Open
Abstract
Maximal central motor drive is known to decrease during prolonged exercise although it remains to be determined whether a supraspinal deficit exists, and if so, when it appears. The purpose of this study was to evaluate corticospinal excitability and muscle voluntary activation before, during and after a 4-h cycling exercise. Ten healthy subjects performed three 80-min bouts on an ergocycle at 45% of their maximal aerobic power. Before exercise and immediately after each bout, neuromuscular function was evaluated in the quadriceps femoris muscles under isometric conditions. Transcranial magnetic stimulation was used to assess voluntary activation at the cortical level (VATMS), corticospinal excitability via motor-evoked potential (MEP) and intracortical inhibition by cortical silent period (CSP). Electrical stimulation of the femoral nerve was used to measure voluntary activation at the peripheral level (VAFNES) and muscle contractile properties. Maximal voluntary force was significantly reduced after the first bout (13±9%, P<0.01) and was further decreased (25±11%, P<0.001) at the end of exercise. CSP remained unchanged throughout the protocol. Rectus femoris and vastus lateralis but not vastus medialis MEP normalized to maximal M-wave amplitude significantly increased during cycling. Finally, significant decreases in both VATMS and VAFNES (∼8%, P<0.05 and ∼14%, P<0.001 post-exercise, respectively) were observed. In conclusion, reductions in VAFNES after a prolonged cycling exercise are partly explained by a deficit at the cortical level accompanied by increased corticospinal excitability and unchanged intracortical inhibition. When comparing the present results with the literature, this study highlights that changes at the cortical and/or motoneuronal levels depend not only on the type of exercise (single-joint vs. whole-body) but also on exercise intensity and/or duration.
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Affiliation(s)
- Marc Jubeau
- INSERM U1042, Grenoble, France
- Université de Lyon, Saint-Etienne, France
- MIP, Nantes, France
| | - Thomas Rupp
- INSERM U1042, Grenoble, France
- Laboratoire HP2, Grenoble Alpes University, Grenoble, France
| | - Stephane Perrey
- Movement To Health (M2H), Montpellier-I University, Euromov, France
| | | | - Bernard Wuyam
- INSERM U1042, Grenoble, France
- Laboratoire HP2, Grenoble Alpes University, Grenoble, France
| | - Patrick Levy
- INSERM U1042, Grenoble, France
- Laboratoire HP2, Grenoble Alpes University, Grenoble, France
| | - Samuel Verges
- INSERM U1042, Grenoble, France
- Laboratoire HP2, Grenoble Alpes University, Grenoble, France
| | - Guillaume Y. Millet
- INSERM U1042, Grenoble, France
- Université de Lyon, Saint-Etienne, France
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada
- * E-mail:
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Sidhu SK, Lauber B, Cresswell AG, Carroll TJ. Sustained cycling exercise increases intracortical inhibition. Med Sci Sports Exerc 2013. [PMID: 23190593 DOI: 10.1249/mss.0b013e31827b119c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE In the current study, we measured EMG suppression induced by subthreshold transcranial magnetic stimulation (TMS) to investigate the effects of sustained cycling exercise on intracortical inhibition. METHODS Sixteen subjects cycled at 75% of their maximum workload (Wmax) for 30 min, during which subthreshold TMS was applied at a defined crank angle where vastus lateralis (VL) EMG amplitude was increasing and approximately 50% of its recorded maximum. Subthreshold TMS was also applied during nonfatiguing control cycling bouts at 75% and 37.5% of Wmaxbefore sustained cycling. RESULTS Although EMG in VL during control cycling at 37.5% Wmax was approximately half that during cycling at 75% Wmax (P ≤ 0.05), the amount of EMG suppression was not different between workloads (P > 0.05). EMG amplitude in VL recorded in the last 5 min of sustained cycling was not different from the first 5 min (P > 0.05), whereas the amount of EMG suppression at the end of the sustained cycling was significantly greater than that at the start (P ≤ 0.05). CONCLUSIONS The increase in TMS-evoked EMG suppression during sustained cycling implies an increase in the excitability of the intracortical inhibitory interneurons during the exercise. The observed increase in intracortical inhibition is similar to that observed during sustained single joint contractions, suggesting that changes in the responsiveness of intracortical inhibitory interneurons are similar during locomotor exercise and static single joint contractions.
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Affiliation(s)
- Simranjit K Sidhu
- School of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia.
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Abstract
OBJECTIVES Although fatigue is experienced by everyone, its definition and classification remains under debate. METHODS A review of the previously published data on fatigue. RESULTS Fatigue is influenced by age, gender, physical condition, type of food, latency to last meal, mental status, psychological conditions, personality type, life experience, and the health status of an individual. Fatigue may not only be a symptom but also a measurable and quantifiable dimension, also known as fatigability. Additionally, it may be classified as a condition occurring at rest or under exercise or stress, as physiologic reaction or pathologic condition, as spontaneous phenomenon or triggerable state, as resistant or irresistant to preconditioning, training, or attitude, as prominent or collateral experience, and as accessible or inaccessible to any type of treatment or intervention. Fatigue may be the sole symptom of a disease or one among others. It may be also classified as acute or chronic. Quantification of fatigability is achievable by fatigue scores, force measurement, electromyography, or other means. Fatigue and fatigability need to be delineated from conditions such as sleepiness, apathy, exhaustion, exercise intolerance, lack of vigor, weakness, inertia, or tiredness. Among neurological disorders, the prevalence of fatigue is particularly increased in multiple sclerosis, amyotrophic lateral sclerosis, Parkinson disease, traumatic brain injury, stroke, and bleeding and also in neuromuscular disorders. Fatigue may be influenced by training, mental preconditioning, or drugs. CONCLUSIONS Fatigue needs to be recognized as an important condition that is not only a symptom but may also be quantified and can be modified by various measures depending on the underlying cause.
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Affiliation(s)
| | - Sinda Zarrouk Mahjoub
- Laboratory of Biochemistry, UR "Human Nutrition and Metabolic Disorders" Faculty of Medicine Monastir, Monastir, Tunisie
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Gruet M, Temesi J, Rupp T, Millet GY, Verges S. Effect of different approaches to target force on transcranial magnetic stimulation responses. Muscle Nerve 2013; 48:430-2. [DOI: 10.1002/mus.23786] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Mathieu Gruet
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
| | - John Temesi
- Laboratoire LPE; Université de Lyon; Saint-Etienne France
| | - Thomas Rupp
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
| | | | - Samuel Verges
- Laboratoire HP2, U1042 INSERM; Université Joseph Fourier; Grenoble France
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