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O'Malley CA, Norbury R, Smith SA, Fullerton CL, Mauger AR. Elevated muscle pain induced by a hypertonic saline injection reduces power output independent of physiological changes during fixed perceived effort cycling. J Appl Physiol (1985) 2024; 137:99-110. [PMID: 38813614 DOI: 10.1152/japplphysiol.00325.2023] [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: 05/19/2023] [Revised: 04/16/2024] [Accepted: 05/22/2024] [Indexed: 05/31/2024] Open
Abstract
Pain is a naturally occurring phenomenon that consistently inhibits exercise performance by imposing unconscious, neurophysiological alterations (e.g., corticospinal changes) as well as conscious, psychophysiological pressures (e.g., shared effort demands). Although several studies indicate that pain would elicit lower task outputs for a set intensity of perceived effort, no study has tested this. Therefore, this study investigated the impact of elevated muscle pain through a hypertonic saline injection on the power output, psychophysiological, cerebral oxygenation, and perceptual changes during fixed perceived effort exercise. Ten participants completed three visits (1 familiarization + 2 fixed perceived effort trials). Fixed perceived effort cycling corresponded to 15% above gas exchange threshold (GET) [mean rating of perceived effort (RPE) = 15 "hard"]. Before the 30-min fixed perceived effort exercise, participants received a randomized bilateral hypertonic or isotonic saline injection in the vastus lateralis. Power output, cardiorespiratory, cerebral oxygenation, and perceptual markers (e.g., affective valence) were recorded during exercise. Linear mixed-model regression assessed the condition and time effects and condition × time interactions. Significant condition effects showed that power output was significantly lower during hypertonic conditions [t107 = 208, P = 0.040, β = 4.77 W, 95% confidence interval (95% CI) [0.27 to 9.26 W]]. Meanwhile, all physiological variables (e.g., heart rate, oxygen uptake, minute ventilation) demonstrated no significant condition effects. Condition effects were observed for deoxyhemoglobin changes from baseline (t107 = -3.29, P = 0.001, β = -1.50 ΔμM, 95% CI [-2.40 to -0.61 ΔμM]) and affective valence (t127 = 6.12, P = 0.001, β = 0.93, 95% CI [0.63 to 1.23]). Results infer that pain impacts the self-regulation of fixed perceived effort exercise, as differences in power output mainly occurred when pain ratings were higher after hypertonic versus isotonic saline administration.NEW & NOTEWORTHY This study identifies that elevated muscle pain through a hypertonic saline injection causes significantly lower power output when pain is experienced but does not seem to affect exercise behavior in a residual manner. Results provide some evidence that pain operates on a psychophysiological level to alter the self-regulation of exercise behavior due to differences between conditions in cerebral deoxyhemoglobin and other perceptual parameters.
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Affiliation(s)
- Callum A O'Malley
- School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom
- School of Sport and Health Sciences, University of Exeter, Exeter, United Kingdom
| | - Ryan Norbury
- School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom
- Faculty of Sport, Technology, and Health Sciences, St Mary's University Twickenham, London, United Kingdom
| | - Samuel A Smith
- School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom
| | - Christopher L Fullerton
- School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom
- Faculty of Health Sciences and Sport, University of Stirling, Stirling, United Kingdom
| | - Alexis R Mauger
- School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom
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VanHaitsma TA, Gonzalez SP, Kajitani S, Gabriano E, Hoiosen GE, Oldach MC, Kingsley KL. Three weeks of mental training changes physiological outcomes during a time trial to exhaustion. Eur J Appl Physiol 2023; 123:1977-1989. [PMID: 37129629 PMCID: PMC10460752 DOI: 10.1007/s00421-023-05206-3] [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: 06/06/2022] [Accepted: 04/17/2023] [Indexed: 05/03/2023]
Abstract
Mental training (MT) can increase endurance performance. The purpose of this study was to examine the minimum dose of mental training needed to increase performance and elucidate the physiological mechanisms underlying this improvement. In a randomized between groups pre-test-post-test design, 33 participants visited the lab on 6 separate days. A VO2peak with ventilatory threshold (VT) was performed on day 1. The subsequent visits consisted of time trials to exhaustion (TTE) performed at 10% above VT. Between visit 3 and 6, the MT group (n = 16) watched a video for 10-15 min each day for 3 weeks, while the control group (CON; n = 17) did no mental training. Heart rate (HR), rate of perceived exertion (RPE), VAS scores for pain and fatigue, electromyography, and metabolic and neuromuscular data were collected and recorded during the time trials. The GRIT-S and CD-RISC 10 surveys were completed before study days 3 and 6. TTE increased significantly for MT beginning after 2 weeks (10.0 ± 13.1%) with no further change after 3 weeks (10.4 ± 13.2). TTE also significantly decreased during the last TTE for CON (-10.3 ± 12.7). VO2, ventilation, and frequency of breathing were significantly reduced in the latter stages of the TTE for MT. EMG was also significantly decreased for MT as compared for CON throughout the trial. Three weeks of mental training improves performance by reducing EMG, decreasing activation of the muscle and reducing metabolic factors during the latter stages of exercise.
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Affiliation(s)
| | - Stephen P Gonzalez
- Department of Kinesiology, Sport Studies, and Physical Education, Dartmouth College, Hanover, NH, USA
| | - Sten Kajitani
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
| | - Emma Gabriano
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
| | - Gavin E Hoiosen
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
| | - Michael C Oldach
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
| | - Karly L Kingsley
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
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3
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Teymoori H, Amiri E, Tahmasebi W, Hoseini R, Grospretre S, Machado DGDS. Effect of tDCS targeting the M1 or left DLPFC on physical performance, psychophysiological responses, and cognitive function in repeated all-out cycling: a randomized controlled trial. J Neuroeng Rehabil 2023; 20:97. [PMID: 37496055 PMCID: PMC10373277 DOI: 10.1186/s12984-023-01221-9] [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: 02/01/2023] [Accepted: 07/19/2023] [Indexed: 07/28/2023] Open
Abstract
BACKGROUND Despite reporting the positive effects of transcranial direct current stimulation (tDCS) on endurance performance, very few studies have investigated its efficacy in anaerobic short all-out activities. Moreover, there is still no consensus on which brain areas could provide the most favorable effects on different performance modalities. Accordingly, this study aimed to investigate the effects of anodal tDCS (a-tDCS) targeting the primary motor cortex (M1) or left dorsolateral prefrontal cortex (DLPFC) on physical performance, psychophysiological responses, and cognitive function in repeated all-out cycling. METHODS In this randomized, crossover, and double-blind study, 15 healthy physically active men underwent a-tDCS targeting M1 or the left DLPFC or sham tDCS in separate days before performing three bouts of all-out 30s cycling anaerobic test. a-tDCS was applied using 2 mA for 20 min. Peak power, mean power, fatigue index, and EMG of the quadriceps muscles were measured during each bout. Heart rate, perceived exertion, affective valence, and arousal were recorded two minutes after each bout. Color-word Stroop test and choice reaction time were measured at baseline and after the whole anaerobic test. RESULTS Neither tDCS montage significantly changed peak power, mean power, fatigue index, heart rate, affective valence, arousal, and choice reaction time (p> 0.05). a-tDCS over DLPFC significantly lowered RPE of the first bout (compared to sham; p=0.048, Δ=-12.5%) and third bout compared to the M1 (p=0.047, Δ=-12.38%) and sham (p=0.003, Δ=-10.5%), increased EMG of the Vastus Lateralis muscle during the second (p=0.016, Δ= +40.3%) and third bout (p=0.016, Δ= +42.1%) compared to sham, and improved the score of color-word Stroop test after the repeated all-out task (p=0.04, Δ= +147%). The qualitative affective response (valence and arousal) was also higher under the M1 and DLPFC compared to the sham. CONCLUSION We concluded that tDCS targeting M1 or DLPFC does not improve repeated anaerobic performance. However, the positive effect of DLPFC montage on RPE, EMG, qualitative affective responses, and cognitive function is promising and paves the path for future research using different tDCS montages to see any possible effects on anaerobic performance. TRIAL REGISTRATION This study was approved by the Ethics Committee of Razi University (IR.RAZI.REC.1400.023) and registered in the Iranian Registry of Clinical Trials (IRCT id: IRCT20210617051606N5; Registration Date: 04/02/2022).
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Affiliation(s)
- Hafez Teymoori
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran
| | - Ehsan Amiri
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran.
| | - Worya Tahmasebi
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran
| | - Rastegar Hoseini
- Exercise Metabolism and Performance Lab (EMPL), Department of Exercise Physiology, Faculty of Sport Sciences, Razi University, Kermanshah, Iran
| | - Sidney Grospretre
- EA4660-C3S Laboratory - Culture, Sports, Health and Society, University Bourgogne France- Comte, Besancon, France
| | - Daniel Gomes da Silva Machado
- Research Group in Neuroscience of the Human Movement (NeuroMove), Department of Physical Education, Federal University of Rio Grande do Norte, Natal, RN, Brazil
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4
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Lewis MT, Blain GM, Hart CR, Layec G, Rossman MJ, Park SY, Trinity JD, Gifford JR, Sidhu SK, Weavil JC, Hureau TJ, Jessop JE, Bledsoe AD, Amann M, Richardson RS. Acute high-intensity exercise and skeletal muscle mitochondrial respiratory function: role of metabolic perturbation. Am J Physiol Regul Integr Comp Physiol 2021; 321:R687-R698. [PMID: 34549627 DOI: 10.1152/ajpregu.00158.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recently it was documented that fatiguing, high-intensity exercise resulted in a significant attenuation in maximal skeletal muscle mitochondrial respiratory capacity, potentially due to the intramuscular metabolic perturbation elicited by such intense exercise. With the utilization of intrathecal fentanyl to attenuate afferent feedback from group III/IV muscle afferents, permitting increased muscle activation and greater intramuscular metabolic disturbance, this study aimed to better elucidate the role of metabolic perturbation on mitochondrial respiratory function. Eight young, healthy males performed high-intensity cycle exercise in control (CTRL) and fentanyl-treated (FENT) conditions. Liquid chromatography-mass spectrometry and high-resolution respirometry were used to assess metabolites and mitochondrial respiratory function, respectively, pre- and postexercise in muscle biopsies from the vastus lateralis. Compared with CTRL, FENT yielded a significantly greater exercise-induced metabolic perturbation (PCr: -67% vs. -82%, Pi: 353% vs. 534%, pH: -0.22 vs. -0.31, lactate: 820% vs. 1,160%). Somewhat surprisingly, despite this greater metabolic perturbation in FENT compared with CTRL, with the only exception of respiratory control ratio (RCR) (-3% and -36%) for which the impact of FENT was significantly greater, the degree of attenuated mitochondrial respiratory capacity postexercise was not different between CTRL and FENT, respectively, as assessed by maximal respiratory flux through complex I (-15% and -33%), complex II (-36% and -23%), complex I + II (-31% and -20%), and state 3CI+CII control ratio (-24% and -39%). Although a basement effect cannot be ruled out, this failure of an augmented metabolic perturbation to extensively further attenuate mitochondrial function questions the direct role of high-intensity exercise-induced metabolite accumulation in this postexercise response.
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Affiliation(s)
- Matthew T Lewis
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Gregory M Blain
- LAMHESS, University Nice Sophia Antipolis, Nice, France.,LAMHESS, University of Toulon, La Garde, France
| | - Corey R Hart
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Gwenael Layec
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah
| | - Matthew J Rossman
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Song-Young Park
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,School of Health and Kinesiology, University of Nebraska, Omaha, Nebraska
| | - Joel D Trinity
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Jayson R Gifford
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Simranjit K Sidhu
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Discipline of Physiology, School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Thomas J Hureau
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,LAMHESS, University Nice Sophia Antipolis, Nice, France.,LAMHESS, University of Toulon, La Garde, France
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Markus Amann
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,Department of Anesthesiology, University of Utah, Salt Lake City, Utah
| | - Russell S Richardson
- Division of Geriatrics, Department of Medicine, University of Utah, Salt Lake City, Utah.,Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
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5
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Brownstein CG, Millet GY, Thomas K. Neuromuscular responses to fatiguing locomotor exercise. Acta Physiol (Oxf) 2021; 231:e13533. [PMID: 32627930 DOI: 10.1111/apha.13533] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/26/2020] [Accepted: 06/29/2020] [Indexed: 12/26/2022]
Abstract
Over the last two decades, an abundance of research has explored the impact of fatiguing locomotor exercise on the neuromuscular system. Neurostimulation techniques have been implemented prior to and following locomotor exercise tasks of a wide variety of intensities, durations, and modes. These techniques have allowed for the assessment of alterations occurring within the central nervous system and the muscle, while techniques such as transcranial magnetic stimulation and spinal electrical stimulation have permitted further segmentalization of locomotor exercise-induced changes along the motor pathway. To this end, the present review provides a comprehensive synopsis of the literature pertaining to neuromuscular responses to locomotor exercise. Sections of the review were divided to discuss neuromuscular responses to maximal, severe, heavy and moderate intensity, high-intensity intermittent exercise, and differences in neuromuscular responses between exercise modalities. During maximal and severe intensity exercise, alterations in neuromuscular function reside primarily within the muscle. Although post-exercise reductions in voluntary activation following maximal and severe intensity exercise are generally modest, several studies have observed alterations occurring at the cortical and/or spinal level. During prolonged heavy and moderate intensity exercise, impairments in contractile function are attenuated with respect to severe intensity exercise, but are still widely observed. While reductions in voluntary activation are greater during heavy and moderate intensity exercise, the specific alterations occurring within the central nervous system remain unclear. Further work utilizing stimulation techniques during exercise and integrating new and emerging techniques such as high-density electromyography is warranted to provide further insight into neuromuscular responses to locomotor exercise.
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Affiliation(s)
- Callum G. Brownstein
- Inter‐University Laboratory of Human Movement Biology Université LyonUJM‐Saint‐Etienne Saint‐Etienne France
| | - Guillaume Y. Millet
- Inter‐University Laboratory of Human Movement Biology Université LyonUJM‐Saint‐Etienne Saint‐Etienne France
- Institut Universitaire de France (IUF) France
| | - Kevin Thomas
- Faculty of Health and Life Sciences Northumbria University Newcastle upon Tyne United Kingdom
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6
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Barzegarpoor H, Amoozi H, Rajabi H, Button D, Fayazmilani R. The Effects of Performing Mental Exertion during Cycling Exercise on Fatigue Indices. Int J Sports Med 2020; 41:846-857. [DOI: 10.1055/a-1179-8326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AbstractThis study investigated the effect of performing prolonged mental exertion during
submaximal cycling exercise on exercise tolerance and fatigue. Participants
performed 5 experimental sessions. Session 1: determination of cycling peak
power output. Sessions 2 and 3: cycling to exhaustion at 65% peak power
output with mental exertion or watching a movie. Sessions 4 and 5: cycling for
45 min at 65% peak power output with mental exertion or while watching a
movie. During sessions 2–5, rate of perceived exertion and heart rate
were recorded while cycling and cortisol and prolactin concentrations,
psychomotor vigilance task performance, and maximal voluntary contraction were
measured pre-and post-sessions. During sessions 2 and 3, time to exhaustion was
reduced (p<0.01) and rate of perceived exertion was increased
(p<0.01) in session 2 compared to 3. Cortisol, prolactin and
heart rate increased and psychomotor vigilance task and maximal voluntary
contraction decreased from pre-to post-sessions with no difference between
sessions. Cortisol, prolactin and rate of perceived exertion were higher
(p<0.03) in session 4 than 5. Heart rate increased and
maximal voluntary contraction decreased from pre-to post-sessions with no
difference between sessions. Prolonged mental exertion during cycling exercise
reduces exercise tolerance, which appears to be mediated psychologically rather
than physiologically.
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Affiliation(s)
- Hamidreza Barzegarpoor
- Sport Sciences and Health, Shahid Beheshti University, Tehran, Iran
(the Islamic Republic of)
- School of Human Kinetics and Recreation, Memorial University of
Newfoundland, St. John’s, Canada
| | - Hamid Amoozi
- Sport Sciences and Health, Shahid Beheshti University, Tehran, Iran
(the Islamic Republic of)
| | - Hamid Rajabi
- Sport sciences, Kharazmi University, Tehran, Iran (the Islamic Republic
of)
| | - Duane Button
- School of Human Kinetics and Recreation, Memorial University of
Newfoundland, St. John’s, Canada
| | - Rana Fayazmilani
- Sport Sciences and Health, Shahid Beheshti University, Tehran, Iran
(the Islamic Republic of)
- Department of Biological Sciences in Sport, Faculty of Sports Sciences
and Health, Shahid Beheshti University, Tehran, Iran
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7
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Ferraz RMP, van den Tillaar R, Pereira A, Marques MC. The effect of fatigue and duration knowledge of exercise on kicking performance in soccer players. JOURNAL OF SPORT AND HEALTH SCIENCE 2019; 8:567-573. [PMID: 31720069 PMCID: PMC6834994 DOI: 10.1016/j.jshs.2016.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/09/2015] [Accepted: 12/16/2015] [Indexed: 06/10/2023]
Abstract
PURPOSE The purpose of this study was to investigate the influence of fatigue upon kicking maximal ball velocity and the target-hitting accuracy of soccer players; and also to examine the effect of the knowledge of the exercise duration upon these 2 parameters. METHODS Twenty-four semi-professional soccer players participated in this study and performed maximal instep kicks before and after the implementation of an exercise protocol, either with or without knowledge of the duration of this protocol. RESULTS A mixed model of analysis of variance showed that kicking maximal ball velocity was significantly affected (F(5, 85) = 11.6, p < 0.001, η 2 = 0.39) but only after just 1 circuit of the fatigue protocol and then remained similar. Accuracy did not change during the protocol (F(5, 75) = 0.23, p = 0.76, η 2 = 0.03) and knowing the duration of exercitation did not affect accuracy and velocity development (F(1, 23) ≤ 1.04, p ≥ 0.32, η 2 ≤ 0.06). CONCLUSION These findings demonstrated the potential negative effects of fatigue on kicking ball velocity in soccer but not in the kicking accuracy and that the effect of fatigue may not be progressive over time. Knowing or not knowing the duration of exercitation did not affect the results.
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Affiliation(s)
- Ricardo Manuel Pires Ferraz
- Department of Sports Sciences, University of Beira Interior, Covilhã 6201-001, Portugal
- Research Center in Sports Sciences, Health and Human Development, CIDESD, Vila Real 5000-801, Portugal
| | | | - Ana Pereira
- Research Center in Sports Sciences, Health and Human Development, CIDESD, Vila Real 5000-801, Portugal
- Department of Technology and Science, School of Education of Polytechnic Institute of Setubal, Setúbal 2910-761, Portugal
| | - Mário C. Marques
- Department of Sports Sciences, University of Beira Interior, Covilhã 6201-001, Portugal
- Research Center in Sports Sciences, Health and Human Development, CIDESD, Vila Real 5000-801, Portugal
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8
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Gronwald T, Hoos O, Hottenrott K. Effects of Acute Normobaric Hypoxia on Non-linear Dynamics of Cardiac Autonomic Activity During Constant Workload Cycling Exercise. Front Physiol 2019; 10:999. [PMID: 31427992 PMCID: PMC6688521 DOI: 10.3389/fphys.2019.00999] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/18/2019] [Indexed: 12/12/2022] Open
Abstract
Aim Measurements of Non-linear dynamics of heart rate variability (HRV) provide new possibilities to monitor cardiac autonomic activity during exercise under different environmental conditions. Using detrended fluctuation analysis (DFA) technique to assess correlation properties of heart rate (HR) dynamics, the present study examines the influence of normobaric hypoxic conditions (HC) in comparison to normoxic conditions (NC) during a constant workload exercise. Materials and Methods Nine well trained cyclists performed a continuous workload exercise on a cycle ergometer with an intensity corresponding to the individual anaerobic threshold until voluntary exhaustion under both NC and HC (15% O2). The individual exercise duration was normalized to 10% sections (10-100%). During exercise HR and RR-intervals were continuously-recorded. Besides HRV time-domain measurements (meanRR, SDNN), fractal correlation properties using short-term scaling exponent alpha1 of DFA were calculated. Additionally, blood lactate (La), oxygen saturation of the blood (SpO2), and rating of perceived exertion (RPE) were recorded in regular time intervals. Results We observed significant changes under NC and HC for all parameters from the beginning to the end of the exercise (10% vs. 100%) except for SpO2 and SDNN during NC: increases for HR, La, and RPE in both conditions; decreases for SpO2 and SDNN during HC, meanRR and DFA-alpha1 during both conditions. Under HC HR (40-70%), La (10-90%), and RPE (50-90%) were significantly-higher, SpO2 (10-100%), meanRR (40-70%), and DFA-alpha1 (20-60%) were significantly-lower than under NC. Conclusion Under both conditions, prolonged exercise until voluntary exhaustion provokes a lower total variability combined with a reduction in the amplitude and correlation properties of RR fluctuations which may be attributed to increased organismic demands. Additionally, HC provoked higher demands and loss of correlation properties at an earlier stage during the exercise regime, implying an accelerated alteration of cardiac autonomic regulation.
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Affiliation(s)
- Thomas Gronwald
- Department of Performance, Neuroscience, Therapy and Health, MSH Medical School Hamburg, Hamburg, Germany
| | - Olaf Hoos
- Center for Sports and Physical Education, Julius Maximilians University of Würzburg, Würzburg, Germany
| | - Kuno Hottenrott
- Institute of Sports Science, Martin Luther University of Halle-Wittenberg, Halle, Germany
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9
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Thomas K, Goodall S, Howatson G. Performance Fatigability Is Not Regulated to A Peripheral Critical Threshold. Exerc Sport Sci Rev 2018; 46:240-246. [DOI: 10.1249/jes.0000000000000162] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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10
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Rating of Perceived Exertion During Concentric and Eccentric Cycling: Are We Measuring Effort or Exertion? Int J Sports Physiol Perform 2018; 13:517-523. [PMID: 29035598 DOI: 10.1123/ijspp.2017-0171] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Despite the terms' often being used interchangeably, it has been suggested that perceptions of effort and perceptions of exertion may differ. Eccentric (ECC) cycling may provide a model of exercise by which differences between these perceptions can be examined. PURPOSE To examine and compare perceptions of effort and exertion during ECC and concentric (CONC) cycling at 4 intensities. METHODS Ten healthy male participants (mean [SD]: age = 29.8 [2.3] y) performed an incremental cycling test for the determination of maximal aerobic power output, followed in a randomized and crossover design, by four 5-min bouts (30%, 60%, 80%, and maximal) of either ECC or CONC cycling. Through each bout, participants were asked to report their perceived effort, exertion, and muscle pain. Heart rate and oxygen consumption were continuously recorded throughout each bout. RESULTS Perceived exertion was greater for CONC at 30% (8.5 [1.5] vs 7.1 [1.8]; P = .01), 60% (12.4 [1.4] vs 10.3 [2.0]; P = .01), 80% (15.8 [1.7] vs 12.4 [2.5]; P < .01), and maximal (17.2 [1.3] vs 15.6 [1.8]; P = .03) in comparison with ECC. Perceptions of effort and pain were similar between CONC and ECC. Heart rate and oxygen consumption were greater during CONC than ECC. CONCLUSIONS Perceived exertion was greater during CONC compared with ECC cycling, yet effort was similar between conditions despite different physiological stress. Such findings have implications for understanding the development of such perceptions during exercise.
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Abstract
Carriker, CR. Components of fatigue: mind and body. J Strength Cond Res 31(11): 3170-3176, 2017-Maximal intensity exercise requires significant energy demand. Subsequently, prolonged high-intensity effort eventually initiates volitional cessation of the event; often preceeded by a sensation of fatigue. Those examining the basis of fatigue tend to advocate either a peripheral or central model to explain such volitional failure. Practitioners and athletes who understand the tenants of fatigue can tailor their exercise regimens to target areas of potential physical or mental limitation. This review examines the rationale surrounding 2 separate models which postulate the origination of fatigue. Although the peripheral model suggests that fatigue occurs at the muscles, others have suggested a teloanticipatory cognitive component which plays a dominant role. Those familiar with both models may better integrate practice-based evidence into evidence-based practice. The highly individual nature of human performance further highlights the compulsion to comprehend the spectrum of fatigue, such that the identification of insufficiencies should mandate the development of a training purview for peak human performance.
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Affiliation(s)
- Colin R Carriker
- Department of Exercise Science, High Point University, High Point, North Carolina
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12
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Ferraz R, van den Tillar R, Marques MC. The influence of different exercise intensities on kicking accuracy and velocity in soccer players. JOURNAL OF SPORT AND HEALTH SCIENCE 2017; 6:462-467. [PMID: 30356631 PMCID: PMC6189251 DOI: 10.1016/j.jshs.2015.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/08/2015] [Accepted: 08/30/2015] [Indexed: 06/08/2023]
Abstract
PURPOSE The aim of this study was to investigate the influence of different exercise intensities induced by a soccer specific protocol on kicking performance in soccer players. METHODS Twelve semi-professional male soccer players participated in this study and performed maximal instep kicks before and after the implementation of an exercise protocol to determine the influence of different intensities upon kicking ball velocity and the target-hitting accuracy. RESULTS Analysis of variance designs with repeated measures showed that maximal ball velocity was affected only after the most intense circuit (F(6, 66) = 2.3; p = 0.041; η 2 = 0.18), while accuracy was not affected in the protocol (F(6, 66) = 0.19; p = 0.98; η 2 = 0.02). Low and moderate intensities did not affect accuracy or kicking ball velocity. CONCLUSION These findings suggest that kicking ball velocity is influenced by high-exercise intensities. Low and moderate exercise intensities do not affect the performance of the kick, and intensity does not influence accuracy. Otherwise, it is possible that other mechanisms (not only physiological) may influence players during the exercise.
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Affiliation(s)
- Ricardo Ferraz
- Department of Sports Sciences, University of Beira Interior, Convento de St António, Covilhã 6200-001, Portugal
- Research Center in Sport Sciences, Health Sciences and Human Development, CIDESD, Vila Real 5000-801, Portugal
| | - Roland van den Tillar
- Department of Teacher Education, Nord Trøndelag University College, Levanger 7600, Norway
| | - Mario C. Marques
- Department of Sports Sciences, University of Beira Interior, Convento de St António, Covilhã 6200-001, Portugal
- Research Center in Sport Sciences, Health Sciences and Human Development, CIDESD, Vila Real 5000-801, Portugal
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13
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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: 98] [Impact Index Per Article: 14.0] [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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14
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Neuromuscular fatigue during exercise: Methodological considerations, etiology and potential role in chronic fatigue. Neurophysiol Clin 2017; 47:95-110. [PMID: 28434551 DOI: 10.1016/j.neucli.2017.03.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The term fatigue is used to describe a distressing and persistent symptom of physical and/or mental tiredness in certain clinical populations, with distinct but ultimately complex, multifactorial and heterogenous pathophysiology. Chronic fatigue impacts on quality of life, reduces the capacity to perform activities of daily living, and is typically measured using subjective self-report tools. Fatigue also refers to an acute reduction in the ability to produce maximal force or power due to exercise. The classical measurement of exercise-induced fatigue involves neuromuscular assessments before and after a fatiguing task. The limitations and alternatives to this approach are reviewed in this paper in relation to the lower limb and whole-body exercise, given the functional relevance to locomotion, rehabilitation and activities of daily living. It is suggested that under some circumstances, alterations in the central and/or peripheral mechanisms of fatigue during exercise may be related to the sensations of chronic fatigue. As such, the neurophysiological correlates of exercise-induced fatigue are briefly examined in two clinical examples where chronic fatigue is common: cancer survivors and people with multiple sclerosis. This review highlights the relationship between objective measures of fatigability with whole-body exercise and perceptions of fatigue as a priority for future research, given the importance of exercise in relieving symptoms of chronic fatigue and/or overall disease management. As chronic fatigue is likely to be specific to the individual and unlikely to be due to a simple biological or psychosocial explanation, tailored exercise programmes are a potential target for therapeutic intervention.
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15
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Skorski S, Abbiss CR. The Manipulation of Pace within Endurance Sport. Front Physiol 2017; 8:102. [PMID: 28289392 PMCID: PMC5326767 DOI: 10.3389/fphys.2017.00102] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 02/07/2017] [Indexed: 01/14/2023] Open
Abstract
In any athletic event, the ability to appropriately distribute energy is essential to prevent premature fatigue prior to the completion of the event. In sport science literature this is termed "pacing." Within the past decade, research aiming to better understand the underlying mechanisms influencing the selection of an athlete's pacing during exercise has dramatically increased. It is suggested that pacing is a combination of anticipation, knowledge of the end-point, prior experience and sensory feedback. In order to better understand the role each of these factors have in the regulation of pace, studies have often manipulated various conditions known to influence performance such as the feedback provided to participants, the starting strategy or environmental conditions. As with all research there are several factors that should be considered in the interpretation of results from these studies. Thus, this review aims at discussing the pacing literature examining the manipulation of: (i) energy expenditure and pacing strategies, (ii) kinematics or biomechanics, (iii) exercise environment, and (iv) fatigue development.
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Affiliation(s)
- Sabrina Skorski
- Institute of Sports and Preventive Medicine, Saarland University Saarbrücken, Germany
| | - Chris R Abbiss
- Centre for Exercise and Sports Science Research, School of Exercise and Health Sciences, Edith Cowan University Joondalup, WA, Australia
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16
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Flood A, Waddington G, Thompson K, Cathcart S. Increased conditioned pain modulation in athletes. J Sports Sci 2016; 35:1066-1072. [DOI: 10.1080/02640414.2016.1210196] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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17
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Blain GM, Mangum TS, Sidhu SK, Weavil JC, Hureau TJ, Jessop JE, Bledsoe AD, Richardson RS, Amann M. Group III/IV muscle afferents limit the intramuscular metabolic perturbation during whole body exercise in humans. J Physiol 2016; 594:5303-15. [PMID: 27241818 DOI: 10.1113/jp272283] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/16/2016] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS The purpose of this study was to determine the role of group III/IV muscle afferents in limiting the endurance exercise-induced metabolic perturbation assayed in muscle biopsy samples taken from locomotor muscle. Lumbar intrathecal fentanyl was used to attenuate the central projection of μ-opioid receptor-sensitive locomotor muscle afferents during a 5 km cycling time trial. The findings suggest that the central projection of group III/IV muscle afferent feedback constrains voluntary neural 'drive' to working locomotor muscle and limits the exercise-induced intramuscular metabolic perturbation. Therefore, the CNS might regulate the degree of metabolic perturbation within locomotor muscle and thereby limit peripheral fatigue. It appears that the group III/IV muscle afferents are an important neural link in this regulatory mechanism, which probably serves to protect locomotor muscle from the potentially severe functional impairment as a consequence of severe intramuscular metabolic disturbance. ABSTRACT To investigate the role of metabo- and mechanosensitive group III/IV muscle afferents in limiting the intramuscular metabolic perturbation during whole body endurance exercise, eight subjects performed 5 km cycling time trials under control conditions (CTRL) and with lumbar intrathecal fentanyl impairing lower limb muscle afferent feedback (FENT). Vastus lateralis muscle biopsies were obtained before and immediately after exercise. Motoneuronal output was estimated through vastus lateralis surface electromyography (EMG). Exercise-induced changes in intramuscular metabolites were determined using liquid and gas chromatography-mass spectrometry. Quadriceps fatigue was quantified by pre- to post-exercise changes in potentiated quadriceps twitch torque (ΔQTsingle ) evoked by electrical femoral nerve stimulation. Although motoneuronal output was 21 ± 12% higher during FENT compared to CTRL (P < 0.05), time to complete the time trial was similar (∼8.8 min). Compared to CTRL, power output during FENT was 10 ± 4% higher in the first half of the time trial, but 11 ± 5% lower in the second half (both P < 0.01). The exercise-induced increase in intramuscular inorganic phosphate, H(+) , adenosine diphosphate, lactate and phosphocreatine depletion was 55 ± 30, 62 ± 18, 129 ± 63, 47 ± 14 (P < 0.001) and 27 ± 14% (P < 0.01) greater in FENT than CTRL. ΔQTsingle was greater following FENT than CTRL (-52 ± 2 vs -31 ± 1%, P < 0.001) and this difference was positively correlated with the difference in inorganic phosphate (r(2) = 0.79; P < 0.01) and H(+) (r(2) = 0.92; P < 0.01). In conclusion, during whole body exercise, group III/IV muscle afferents provide feedback to the CNS which, in turn, constrains motoneuronal output to the active skeletal muscle. This regulatory mechanism limits the exercise-induced intramuscular metabolic perturbation, preventing an abnormal homeostatic challenge and excessive peripheral fatigue.
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Affiliation(s)
- Gregory M Blain
- LAMHESS, EA 6312, University Nice Sophia Antipolis, University of Toulon, Nice, France.
| | - Tyler S Mangum
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Simranjit K Sidhu
- Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Discipline of Physiology, School of Medicine, The University of Adelaide, Australia
| | - Joshua C Weavil
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Thomas J Hureau
- LAMHESS, EA 6312, University Nice Sophia Antipolis, University of Toulon, Nice, France.,Department of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Jacob E Jessop
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Amber D Bledsoe
- Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.,Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Centre, Salt Lake City VAMC, UT, USA
| | - Markus Amann
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.,Department of Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education, and Clinical Centre, Salt Lake City VAMC, UT, USA.,Department of Anesthesiology, University of Utah, Salt Lake City, UT, USA
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18
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Role of Ratings of Perceived Exertion during Self-Paced Exercise: What are We Actually Measuring? Sports Med 2016; 45:1235-1243. [PMID: 26054383 DOI: 10.1007/s40279-015-0344-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Ratings of perceived exertion (RPE) and effort are considered extremely important in the regulation of intensity during self-paced physical activity. While effort and exertion are slightly different constructs, these terms are often used interchangeably within the literature. The development of perceptions of both effort and exertion is a complicated process involving numerous neural processes occurring in various regions within the brain. It is widely accepted that perceptions of effort are highly dependent on efferent copies of central drive which are sent from motor to sensory regions of the brain. Additionally, it has been suggested that perceptions of effort and exertion are integrated based on the balance between corollary discharge and actual afferent feedback; however, the involvement of peripheral afferent sensory feedback in the development of such perceptions has been debated. As such, this review examines the possible difference between effort and exertion, and the implications of such differences in understanding the role of such perceptions in the regulation of pace during exercise.
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Johnson MA, Sharpe GR, Williams NC, Hannah R. Locomotor muscle fatigue is not critically regulated after prior upper body exercise. J Appl Physiol (1985) 2015; 119:840-50. [PMID: 26272315 DOI: 10.1152/japplphysiol.00072.2015] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 08/06/2015] [Indexed: 01/10/2023] Open
Abstract
This study examined the effects of prior upper body exercise on subsequent high-intensity cycling exercise tolerance and associated changes in neuromuscular function and perceptual responses. Eight men performed three fixed work-rate (85% peak power) cycling tests: 1) to the limit of tolerance (CYC); 2) to the limit of tolerance after prior high-intensity arm-cranking exercise (ARM-CYC); and 3) without prior exercise and for an equal duration as ARM-CYC (ISOTIME). Peripheral fatigue was assessed via changes in potentiated quadriceps twitch force during supramaximal electrical femoral nerve stimulation. Voluntary activation was assessed using twitch interpolation during maximal voluntary contractions. Cycling time during ARM-CYC and ISOTIME (4.33 ± 1.10 min) was 38% shorter than during CYC (7.46 ± 2.79 min) (P < 0.001). Twitch force decreased more after CYC (-38 ± 13%) than ARM-CYC (-26 ± 10%) (P = 0.004) and ISOTIME (-24 ± 10%) (P = 0.003). Voluntary activation was 94 ± 5% at rest and decreased after CYC (89 ± 9%, P = 0.012) and ARM-CYC (91 ± 8%, P = 0.047). Rating of perceived exertion for limb discomfort increased more quickly during cycling in ARM-CYC [1.83 ± 0.46 arbitrary units (AU)/min] than CYC (1.10 ± 0.38 AU/min, P = 0.003) and ISOTIME (1.05 ± 0.43 AU/min, P = 0.002), and this was correlated with the reduced cycling time in ARM-CYC (r = -0.72, P = 0.045). In conclusion, cycling exercise tolerance after prior upper body exercise is potentially mediated by central fatigue and intolerable levels of sensory perception rather than a critical peripheral fatigue limit.
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Affiliation(s)
- M A Johnson
- Sport, Health and Performance Enhancement (SHAPE) Research Group, Department of Sports Science, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom; and
| | - G R Sharpe
- Sport, Health and Performance Enhancement (SHAPE) Research Group, Department of Sports Science, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom; and
| | - N C Williams
- Sport, Health and Performance Enhancement (SHAPE) Research Group, Department of Sports Science, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom; and
| | - R Hannah
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
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20
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Amann M, Sidhu SK, Weavil JC, Mangum TS, Venturelli M. Autonomic responses to exercise: group III/IV muscle afferents and fatigue. Auton Neurosci 2014; 188:19-23. [PMID: 25458423 DOI: 10.1016/j.autneu.2014.10.018] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/17/2014] [Accepted: 10/13/2014] [Indexed: 01/07/2023]
Abstract
Group III and IV muscle afferents originating in exercising limb muscle play a significant role in the development of fatigue during exercise in humans. Feedback from these sensory neurons to the central nervous system (CNS) reflexively increases ventilation and central (cardiac output) and peripheral (limb blood flow) hemodynamic responses during exercise and thereby assures adequate muscle blood flow and O2 delivery. This response depicts a key factor in minimizing the rate of development of peripheral fatigue and in optimizing aerobic exercise capacity. On the other hand, the central projection of group III/IV muscle afferents impairs performance and limits the exercising human via its diminishing effect on the output from spinal motoneurons which decreases voluntary muscle activation (i.e. facilitates central fatigue). Accumulating evidence from recent animal studies suggests the existence of two subtypes of group III/IV muscle afferents. While one subtype only responds to physiological and innocuous levels of endogenous intramuscular metabolites (lactate, ATP, protons) associated with 'normal', predominantly aerobic exercise, the other subtype only responds to higher and concurrently noxious levels of metabolites present in muscle during ischemic contractions or following, for example, hypertonic saline infusions. This review discusses the mechanisms through which group III/IV muscle afferent feedback mediates both central and peripheral fatigue in exercising humans. We also briefly summarize the accumulating evidence from recent animal and human studies documenting the existence of two subtypes of group III/IV muscle afferents and the relevance of this discovery to the interpretation of previous work and the design of future studies.
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Affiliation(s)
- Markus Amann
- Department of Medicine, University of Utah, Salt Lake City, UT, USA; Department of Exercise & Sport Science, University of Utah, Salt Lake City, UT, USA.
| | | | - Joshua C Weavil
- Department of Exercise & Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Tyler S Mangum
- Department of Exercise & Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Massimo Venturelli
- Department of Biomedical Sciences for Health, University of Milan, Italy
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21
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Abstract
During prolonged dynamic and rhythmic exercise, muscular pain and discomfort arises as a result of an increased concentration of deleterious metabolites. Sensed by peripheral nociceptors and transmitted via afferent feedback to the brain, this provides important information regarding the physiological state of the muscle. These sensations ultimately contribute to what is termed "exercise-induced pain". Despite being well recognized by athletes and coaches, and suggested to be integral to exercise performance, this construct has largely escaped attention in experimental work. This perspective article highlights the current understanding of pacing in endurance performance, and the causes of exercise-induced pain. A new perspective is described, which proposes how exercise-induced pain may be a contributing factor in helping individuals to regulate their work rate during exercise and thus provides an important construct in pacing.
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Affiliation(s)
- Alexis R Mauger
- Endurance Research Group, School of Sport and Exercise Sciences, Faculty of Science, University of Kent, Chatham, UK
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22
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Wüthrich TU, Eberle EC, Spengler CM. Locomotor and diaphragm muscle fatigue in endurance athletes performing time-trials of different durations. Eur J Appl Physiol 2014; 114:1619-33. [DOI: 10.1007/s00421-014-2889-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/06/2014] [Indexed: 01/19/2023]
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Christian RJ, Bishop DJ, Billaut F, Girard O. The role of sense of effort on self-selected cycling power output. Front Physiol 2014; 5:115. [PMID: 24744734 PMCID: PMC3978313 DOI: 10.3389/fphys.2014.00115] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 03/08/2014] [Indexed: 01/09/2023] Open
Abstract
PURPOSE We explored the effects of the sense of effort and accompanying perceptions of peripheral discomfort on self-selected cycle power output under two different inspired O2 fractions. METHODS On separate days, eight trained males cycled for 5 min at a constant subjective effort (sense of effort of '3' on a modified Borg CR10 scale), immediately followed by five 4-s progressive submaximal (sense of effort of "4, 5, 6, 7, and 8"; 40 s between bouts) and two 4-s maximal (sense of effort of "10"; 3 min between bouts) bouts under normoxia (NM: fraction of inspired O2 [FiO2] 0.21) and hypoxia (HY: [FiO2] 0.13). Physiological (Heart Rate, arterial oxygen saturation (SpO2) and quadriceps Root Mean Square (RMS) electromyographical activity) and perceptual responses (overall peripheral discomfort, difficulty breathing and limb discomfort) were recorded. RESULTS Power output and normalized quadriceps RMS activity were not different between conditions during any exercise bout (p > 0.05) and remained unchanged across time during the constant-effort cycling. SpO2 was lower, while heart rate and ratings of perceived difficulty breathing were higher under HY, compared to NM, at all time points (p < 0.05). During the constant-effort cycling, heart rate, overall perceived discomfort, difficulty breathing and limb discomfort increased with time (all p < 0.05). All variables (except SpO2) increased along with sense of effort during the brief progressive cycling bouts (all p < 0.05). During the two maximal cycling bouts, ratings of overall peripheral discomfort displayed an interaction between time and condition with ratings higher in the second bout under HY vs. NM conditions. CONCLUSION During self-selected, constant-effort and brief progressive, sub-maximal, and maximal cycling bouts, mechanical work is regulated in parallel to the sense of effort, independently from peripheral sensations of discomfort.
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Affiliation(s)
- Ryan J. Christian
- Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria UniversityMelbourne, VIC, Australia
- Aspetar - Athlete Health and Performance Research Centre, Qatar Orthopaedic and Sports Medicine HospitalDoha, Qatar
| | - David J. Bishop
- Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria UniversityMelbourne, VIC, Australia
| | - François Billaut
- Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria UniversityMelbourne, VIC, Australia
- Départment de Kinésiology, Université LavalQuébec, QC, Canada
| | - Olivier Girard
- Aspetar - Athlete Health and Performance Research Centre, Qatar Orthopaedic and Sports Medicine HospitalDoha, Qatar
- Faculty of Biology and Medicine, Institute of Sport Sciences, University of LausanneLausanne, Switzerland
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Abstract
During exercise by healthy mammals, alveolar ventilation and alveolar-capillary diffusion increase in proportion to the increase in metabolic rate to prevent PaCO2 from increasing and PaO2 from decreasing. There is no known mechanism capable of directly sensing the rate of gas exchange in the muscles or the lungs; thus, for over a century there has been intense interest in elucidating how respiratory neurons adjust their output to variables which can not be directly monitored. Several hypotheses have been tested and supportive data were obtained, but for each hypothesis, there are contradictory data or reasons to question the validity of each hypothesis. Herein, we report a critique of the major hypotheses which has led to the following conclusions. First, a single stimulus or combination of stimuli that convincingly and entirely explains the hyperpnea has not been identified. Second, the coupling of the hyperpnea to metabolic rate is not causal but is due to of these variables each resulting from a common factor which link the circulatory and ventilatory responses to exercise. Third, stimuli postulated to act at pulmonary or cardiac receptors or carotid and intracranial chemoreceptors are not primary mediators of the hyperpnea. Fourth, stimuli originating in exercising limbs and conveyed to the brain by spinal afferents contribute to the exercise hyperpnea. Fifth, the hyperventilation during heavy exercise is not primarily due to lactacidosis stimulation of carotid chemoreceptors. Finally, since volitional exercise requires activation of the CNS, neural feed-forward (central command) mediation of the exercise hyperpnea seems intuitive and is supported by data from several studies. However, there is no compelling evidence to accept this concept as an indisputable fact.
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Affiliation(s)
- Hubert V Forster
- Medical College of Wisconsin, Department of Physiology, Milwaukee, Wisconsin, USA.
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25
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Boullosa DA, Nakamura FY. The evolutionary significance of fatigue. Front Physiol 2013; 4:309. [PMID: 24198788 PMCID: PMC3814088 DOI: 10.3389/fphys.2013.00309] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/08/2013] [Indexed: 11/16/2022] Open
Affiliation(s)
- Daniel A Boullosa
- Departamento de Educação Física, Universidade Católica de Brasília Taguatinga, Brazil
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26
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Mauger AR. Fatigue is a pain-the use of novel neurophysiological techniques to understand the fatigue-pain relationship. Front Physiol 2013; 4:104. [PMID: 23717284 PMCID: PMC3651963 DOI: 10.3389/fphys.2013.00104] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 04/24/2013] [Indexed: 11/13/2022] Open
Affiliation(s)
- Alexis R Mauger
- Endurance Research Group, School of Sport and Exercise Sciences, University of Kent Chatham, Kent, UK
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Dempsey JA. New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance. J Physiol 2012; 590:4129-44. [PMID: 22826128 DOI: 10.1113/jphysiol.2012.233908] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward 'central command' mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal 'tonic' activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O(2) transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes - probably acting in concert with feedforward central command - contribute significantly to preserving O(2) transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development.
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Affiliation(s)
- Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin - Madison, 1300 University Ave, Room 4245 MSC, Madison, WI 53706-1532, USA.
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Millet GY. Can neuromuscular fatigue explain running strategies and performance in ultra-marathons?: the flush model. Sports Med 2011; 41:489-506. [PMID: 21615190 DOI: 10.2165/11588760-000000000-00000] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
While the industrialized world adopts a largely sedentary lifestyle, ultra-marathon running races have become increasingly popular in the last few years in many countries. The ability to run long distances is also considered to have played a role in human evolution. This makes the issue of ultra-long distance physiology important. In the ability to run multiples of 10 km (up to 1000 km in one stage), fatigue resistance is critical. Fatigue is generally defined as strength loss (i.e. a decrease in maximal voluntary contraction [MVC]), which is known to be dependent on the type of exercise. Critical task variables include the intensity and duration of the activity, both of which are very specific to ultra-endurance sports. They also include the muscle groups involved and the type of muscle contraction, two variables that depend on the sport under consideration. The first part of this article focuses on the central and peripheral causes of the alterations to neuromuscular function that occur in ultra-marathon running. Neuromuscular function evaluation requires measurements of MVCs and maximal electrical/magnetic stimulations; these provide an insight into the factors in the CNS and the muscles implicated in fatigue. However, such measurements do not necessarily predict how muscle function may influence ultra-endurance running and whether this has an effect on speed regulation during a real competition (i.e. when pacing strategies are involved). In other words, the nature of the relationship between fatigue as measured using maximal contractions/stimulation and submaximal performance limitation/regulation is questionable. To investigate this issue, we are suggesting a holistic model in the second part of this article. This model can be applied to all endurance activities, but is specifically adapted to ultra-endurance running: the flush model. This model has the following four components: (i) the ball-cock (or buoy), which can be compared with the rate of perceived exertion, and can increase or decrease based on (ii) the filling rate and (iii) the water evacuated through the waste pipe, and (iv) a security reserve that allows the subject to prevent physiological damage. We are suggesting that central regulation is not only based on afferent signals arising from the muscles and peripheral organs, but is also dependent on peripheral fatigue and spinal/supraspinal inhibition (or disfacilitation) since these alterations imply a higher central drive for a given power output. This holistic model also explains how environmental conditions, sleep deprivation/mental fatigue, pain-killers or psychostimulants, cognitive or nutritional strategies may affect ultra-running performance.
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Affiliation(s)
- Guillaume Y Millet
- Université de Lyon, and Laboratoire dePhysiologie de l’Exercice (EA 4338), Médecine du Sport-Myologie, Hôpital Bellevue,F-42023, Saint-Etienne, France.
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Amann M, Blain GM, Proctor LT, Sebranek JJ, Pegelow DF, Dempsey JA. Implications of group III and IV muscle afferents for high-intensity endurance exercise performance in humans. J Physiol 2011; 589:5299-309. [PMID: 21878520 DOI: 10.1113/jphysiol.2011.213769] [Citation(s) in RCA: 191] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We investigated the influence of group III/IV muscle afferents on peripheral fatigue, central motor drive (CMD) and endurance capacity during high-intensity leg-cycling. In a double-blind, placebo-controlled design, seven males performed constant-load cycling exercise (318 ± 9 W; 80% of peak power output (W(peak))) to exhaustion under placebo conditions and with lumbar intrathecal fentanyl impairing spinal μ-opioid receptor-sensitive group III/IV muscle afferents. Peripheral fatigue was assessed via changes in pre- vs. post-exercise quadriceps force in response to supramaximal magnetic femoral nerve stimulation (ΔQ(tw,pot)). CMD was estimated via quadriceps electromyogram. To rule out a direct central effect of fentanyl, we documented unchanged resting cardioventilatory responses. Compared to placebo, significant hypoventilation during the fentanyl trial was indicated by the 9% lower V(E)/V(CO(2)), causing a 5 mmHg increase in end-tidal P(CO(2)) and a 3% lower haemoglobin saturation. Arterial pressure and heart rate averaged 8 and 10% lower, respectively, during the fentanyl trial and these differences progressively diminished towards end-exercise. Although initially similar, the percent change in CMD was 9 ± 3% higher at end-exercise with fentanyl vs. placebo (P < 0.05). Time to exhaustion was shorter (6.8 ± 0.3 min vs. 8.7 ± 0.3 min) and end-exercise ΔQ(tw,pot) was about one-third greater (-44 ± 2% vs. -34 ± 2%) following fentanyl vs. placebo. The rate of peripheral fatigue development was 67 ± 10% greater during the fentanyl trial (P < 0.01). Our findings suggest that feedback from group III/IV muscle afferents limits CMD but also minimizes locomotor muscle fatigue development by stimulating adequate ventilatory and circulatory responses to exercise. In the face of blocked group III/IV muscle afferents, CMD is less inhibited but O(2) transport compromised and locomotor muscle fatigability is exacerbated with a combined net effect of a reduced endurance performance.
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Affiliation(s)
- Markus Amann
- University of Utah, Department of Internal Medicine, Salt Lake City, UT, USA.
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Prieur F, Benoît H. Rôle de l’apport d’O2 dans la limitation de la consommation maximale d’oxygène. Sci Sports 2011. [DOI: 10.1016/j.scispo.2010.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Rooks CR, Thom NJ, McCully KK, Dishman RK. Effects of incremental exercise on cerebral oxygenation measured by near-infrared spectroscopy: A systematic review. Prog Neurobiol 2010; 92:134-50. [DOI: 10.1016/j.pneurobio.2010.06.002] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 05/22/2010] [Accepted: 06/04/2010] [Indexed: 11/25/2022]
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