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Kavalcı Kol B, Boşnak Güçlü M, Baytok E, Yılmaz Demirci N. Comparison of the muscle oxygenation during submaximal and maximal exercise tests in patients post-coronavirus disease 2019 syndrome with pulmonary involvement. Physiother Theory Pract 2024:1-14. [PMID: 38469863 DOI: 10.1080/09593985.2024.2327534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 03/03/2024] [Indexed: 03/13/2024]
Abstract
INTRODUCTION Pulmonary involvement is prevalent in patients with coronavirus disease 2019 (COVID-19). Arterial hypoxemia may reduce oxygen transferred to the skeletal muscles, possibly leading to impaired exercise capacity. Oxygen uptake may vary depending on the increased oxygen demand of the muscles during submaximal and maximal exercise. OBJECTIVE This study aimed to compare muscle oxygenation during submaximal and maximal exercise tests in patients with post-COVID-19 syndrome with pulmonary involvement. METHODS Thirty-nine patients were included. Pulmonary function (spirometry), peripheral muscle strength (dynamometer), quadriceps femoris (QF) muscle oxygenation (Moxy® device), and submaximal exercise capacity (six-minute walk test (6-MWT)) were tested on the first day, maximal exercise capacity (cardiopulmonary exercise test (CPET)) was tested on the second day. Physical activity level was evaluated using an activity monitor worn for five consecutive days. Cardiopulmonary responses and muscle oxygenation were compared during 6-MWT and CPET. RESULTS Patients' minimum and recovery muscle oxygen saturation were significantly decreased; maximum total hemoglobin increased, heart rate, blood pressure, breathing frequency, dyspnea, fatigue, and leg fatigue at the end-of-test and recovery increased in CPET compared to 6-MWT (p < .050). Peak oxygen consumption (VO2peak) was 18.15 ± 4.75 ml/min/kg, VO2peak; percent predicted < 80% was measured in 51.28% patients. Six-MWT distance and QF muscle strength were less than 80% predicted in 58.9% and 76.9% patients, respectively. CONCLUSIONS In patients with post-COVID-19 syndrome with pulmonary involvement, muscle deoxygenation of QF is greater during maximal exercise than during submaximal exercise. Specifically, patients with lung impairment should be evaluated for deoxygenation and should be taken into consideration during pulmonary rehabilitation.
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Affiliation(s)
- Başak Kavalcı Kol
- Pilot Health Coordinatorship, Kırşehir Ahi Evran University, Kırşehir, Türkiye
| | - Meral Boşnak Güçlü
- Faculty of Health Sciences, Department of Physical Therapy and Rehabilitation, Gazi University, Çankaya, Ankara, Türkiye
| | - Ece Baytok
- Faculty of Health Sciences, Department of Physical Therapy and Rehabilitation, Gazi University, Çankaya, Ankara, Türkiye
| | - Nilgün Yılmaz Demirci
- Faculty of Medicine, Department of Pulmonology, Gazi University, Yenimahalle, Ankara, Türkiye
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Dominelli PB, Senefeld JW, Wiggins CC, Baker SE, Clayburn AJ, Joyner MJ. Quadriceps fatigue during hypoxic and ischemic knee-extension exercise is similar in males and females. J Appl Physiol (1985) 2024; 136:177-188. [PMID: 38059290 DOI: 10.1152/japplphysiol.00656.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/29/2023] [Accepted: 12/04/2023] [Indexed: 12/08/2023] Open
Abstract
Hypoxia is known to increase muscle fatigue via both central and peripheral mechanisms. Females are typically less fatigable than males during isometric fatiguing contractions due to greater peripheral blood flow. However, sex differences in fatigue are blunted during dynamic fatiguing tasks. Thus, this study determined the interactions of sex and hypoxia on knee extensor muscle contractile function during a dynamic, ischemic fatiguing contraction. Electrical stimulation was used to determine contractile properties of the knee extensor muscles in eight males and eight females before and after an ischemic, dynamic fatiguing task while inspiring room air or a hypoxic gas mixture (10% O2:90% N2). Fatigue (assessed as time-to-task failure) was ∼10% greater during the hypoxic condition (94.3 ± 33.4 s) compared with normoxic condition (107.0 ± 42.8 s, P = 0.041) and ∼40% greater for females than males (77.1 ± 18.8 vs. 124.2 ± 38.7, P < 0.001). Immediately after the dynamic fatiguing task, there were reductions in maximal voluntary contraction force (P = 0.034) and electrically evoked twitch force (P < 0.001), and these reductions did not differ based on sex or inspirate. Cerebral tissue oxygenation showed a significant interaction of time and inspirate (P = 0.003) whereby it increased during normoxia and remained unchanged in hypoxia. No sex-related differences in the changes of cerebral tissue oxygenation were observed (P = 0.528). These data suggest that acute hypoxia increases central fatigue during ischemic single-leg exercise resulting in earlier exercise termination, but the effect does not differ based on sex.NEW & NOTEWORTHY Hypoxia exacerbates fatigue via central mechanisms after ischemic single-leg exercise. The greater fatigue observed during ischemic dynamic fatiguing exercise with hypoxia inspirate did not differ between the sexes. Hypoxia-induced central limitations are present in acute ischemic exercise and do not appear different in males and females.
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Affiliation(s)
- Paolo B Dominelli
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Jonathon W Senefeld
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
| | - Chad C Wiggins
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Kinesiology, Michigan State University, East Lansing, Michigan, United States
| | - Sarah E Baker
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Andrew J Clayburn
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Michael J Joyner
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
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Farra SD, Jacobs I. Arterial desaturation rate does not influence self-selected knee extension force but alters ventilatory response to progressive hypoxia: A pilot study. Physiol Rep 2024; 12:e15892. [PMID: 38172088 PMCID: PMC10764295 DOI: 10.14814/phy2.15892] [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: 11/15/2023] [Revised: 12/04/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
The absolute magnitude and rate of arterial desaturation each independently impair whole-body aerobic exercise. This study examined potential mechanisms underlying the rate-dependent relationship. Utilizing an exercise protocol involving unilateral, intermittent, isometric knee extensions (UIIKE), we provided sufficient reperfusion time between contractions to reduce the accumulation of intramuscular metabolic by-products that typically stimulate muscle afferents. The objective was to create a milieu conducive to accentuating any influence of arterial desaturation rate on muscular fatigue. Eight participants completed four UIIKE sessions, performing one 3 s contraction every 30s at a perceived intensity of 50% MVC for 25 min. Participants voluntarily adjusted their force generation to maintain perceptual effort at 50% MVC without feedback. Reductions in inspired oxygen fraction (FI O2 ) decreased arterial saturation from >98% to 70% with varying rates in three trials: FAST (5.3 ± 1.3 min), MED (11.8 ± 2.7 min), and SLOW (19.9 ± 3.7 min). FI O2 remained at 0.21 during the control trial. Force generation and muscle activation remained at baseline levels throughout UIIKE trials, unaffected by the magnitude or rate of desaturation. Minute ventilation increased with hypoxia (p < 0.05), and faster desaturation rates magnified this response. These findings demonstrate that arterial desaturation magnitude and rate independently affect ventilation, but do not influence fatigue development during UIIKE.
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Affiliation(s)
- Saro D. Farra
- Faculty of Kinesiology & Physical EducationUniversity of TorontoTorontoOntarioCanada
| | - Ira Jacobs
- Faculty of Kinesiology & Physical EducationUniversity of TorontoTorontoOntarioCanada
- Tanenbaum Institute for Science in Sport, University of TorontoTorontoOntarioCanada
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Drouin PJ, Forbes SPA, Liu T, Lew LA, McGarity-Shipley E, Tschakovsky ME. Muscle contraction force conforms to muscle oxygenation during constant activation voluntary forearm exercise. Exp Physiol 2022; 107:1360-1374. [PMID: 35971738 DOI: 10.1113/ep090576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 08/11/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? In electrically stimulated skeletal muscle, force production is downregulated when oxygen delivery is compromised and rapidly restored upon oxygen delivery restoration. Whether "oxygen conforming" of force production occurs during voluntary muscle activation in humans and whether it is exercise intensity dependent remains unknown. What is the main finding and its importance? Here we show in humans that force at a given voluntary muscle activation does conform to a decrease in oxygen delivery and rapidly and completely recovers with restoration of oxygen delivery. This oxygen conforming response of contraction force appears to happen only at higher intensities. ABSTRACT In electrically stimulated skeletal muscle, force production is downregulated when oxygen delivery is compromised and rapidly restored upon oxygen delivery restoration in the absence of cellular disturbance. Whether this "oxygen conforming" response of force occurs and is exercise intensity dependent during stable voluntary muscle activation in humans is unknown. In 12-participants (6-female), handgrip force, forearm muscle activation (electromyography; EMG), muscle oxygenation, and forearm blood flow (FBF) were measured during rhythmic handgrip exercise at forearm EMG achieving 50, 75 or 90% critical impulse (CI). 4-min of brachial artery compression to reduce FBF by ∼60% (Hypoperfusion) or sham compression (adjacent to artery; Control) was performed during exercise. Sham compression had no effect. Hypoperfusion rapidly reduced muscle oxygenation at all exercise intensities, resulting in contraction force per muscle activation (force/EMG) progressively declining over 4 min by ∼16% in 75 and 90% CI. No force/EMG decline occurred in 50% CI. Rapid restoration of muscle oxygenation post-compression was closely followed by force/EMG such that it was not different from Control within 30-sec for 90% CI and after 90-sec for 75% CI. Our findings reveal an oxygen conforming response does occur in voluntary exercising muscle in humans. Within the exercise modality and magnitude of fluctuation of oxygenation in this study, the oxygen conforming response appears to be exercise intensity dependent. Mechanisms responsible for this oxygen conforming response have implications for exercise tolerance and warrant investigation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Patrick J Drouin
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Stacey P A Forbes
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Taylor Liu
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Lindsay A Lew
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Ellen McGarity-Shipley
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Michael E Tschakovsky
- Human Vascular Control Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, K7L 3N6, Canada
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McKeown DJ, McNeil CJ, Simmonds MJ, Kavanagh JJ. Post-fatigue ability to activate muscle is compromised across a wide range of torques during acute hypoxic exposure. Eur J Neurosci 2022; 56:4653-4668. [PMID: 35841186 PMCID: PMC9546238 DOI: 10.1111/ejn.15773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 06/11/2022] [Accepted: 07/13/2022] [Indexed: 11/30/2022]
Abstract
The purpose of this study was to assess how severe acute hypoxia alters the neural mechanisms of muscle activation across a wide range of torque output in a fatigued muscle. Torque and electromyography responses to transcranial and motor nerve stimulation were collected from 10 participants (27 years ± 5 years, 1 female) following repeated performance of a sustained maximal voluntary contraction that reduced torque to 60% of the pre‐fatigue peak torque. Contractions were performed after 2 h of hypoxic exposure and during a sham intervention. For hypoxia, peripheral blood oxygen saturation was titrated to 80% over a 15‐min period and remained at 80% for 2 h. Maximal voluntary torque, electromyography root mean square, voluntary activation and corticospinal excitability (motor evoked potential area) and inhibition (silent period duration) were then assessed at 100%, 90%, 80%, 70%, 50% and 25% of the target force corresponding to the fatigued maximal voluntary contraction. No hypoxia‐related effects were identified for voluntary activation elicited during motor nerve stimulation. However, during measurements elicited at the level of the motor cortex, voluntary activation was reduced at each torque output considered (P = .002, ηp2 = .829). Hypoxia did not impact the correlative linear relationship between cortical voluntary activation and contraction intensity or the correlative curvilinear relationship between motor nerve voluntary activation and contraction intensity. No other hypoxia‐related effects were identified for other neuromuscular variables. Acute severe hypoxia significantly impairs the ability of the motor cortex to voluntarily activate fatigued muscle across a wide range of torque output.
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Affiliation(s)
- Daniel J McKeown
- Neural Control of Movement Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Chris J McNeil
- Integrated Neuromuscular Physiology Laboratory, Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Michael J Simmonds
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Justin J Kavanagh
- Neural Control of Movement Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
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Hiraoui M, Gmada N, Al-Hadabi B, Mezlini A, Al Busafi M, Doutrellot PL, Bouhlel E, Ahmaidi S. Effects of multimodal training program on muscle deoxygenation in women with breast cancer: A randomized controlled trial. Physiol Int 2022; 109:246-260. [DOI: 10.1556/2060.2022.00148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 02/19/2022] [Accepted: 03/04/2022] [Indexed: 11/19/2022]
Abstract
Abstract
Purpose
Chemotherapy and/or radiation are the most often delivered treatments to cancer patients. Usually during the adjuvant treatment, patients complain about fatigue. In addition, physical exercise during adjuvant treatment of cancer seems to have beneficial effects. The aim of this investigation was to assess the effects of multimodal aerobic and strength exercises programs on muscle deoxygenation of patients with breast cancer undergoing adjuvant chemotherapy treatment.
Methods
Thirty-two women with breast cancer (20 patients as the training group and 12 patients as the control group) undergoing adjuvant chemotherapy participated in the study. The training group took part in 6 weeks of supervised intermittent aerobic cycling, home-based walking, isometric and electrical muscle stimulation (EMS) exercise training programs. The Outcome measures were muscle deoxygenation (ΔHHb), Maximal Voluntary isometric Contraction (MViC) and Endurance Time (ET) before and after the training period.
Results
Compared to the control group, a significant increase in ΔHHb (P < 0.01) accompanied with an increase in ET (P < 0.01) and MViC (P < 0.01) of the quadriceps was obtained in the training group. However, no significant differences of MViC, ET and ΔHHb were observed in the control group.
Conclusion
Multimodal aerobic and strength exercise programs enhance muscle oxygen utilization, which may partly explain the improvement in muscular strength and endurance, and the reduction of muscle fatigue in patients with breast cancer during an adjuvant chemotherapy period.
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Affiliation(s)
- Mouadh Hiraoui
- EA-3300: APERE, Exercise Physiology and Rehabilitation Laboratory, Sport Sciences Department, Picardie Jules Verne University, Amiens Cedex, France
- Medical Oncology Department, Salah Azaiez Oncologic Hospital, Tunis, Tunisia
- Bizerte Sciences Faculty, Carthage University, Bizerte, Tunisia
| | - Nabil Gmada
- Physical Education and Sport Sciences Department, College of Education, Sultan Qaboos University, Muscat, Sultanate of Oman
- Research Unit, “Sportive Performance and Physical Rehabilitation,” High Institute of Sports and Physical Education, Kef, University of Jendouba, Jendouba, Tunisia
| | - Badria Al-Hadabi
- Physical Education and Sport Sciences Department, College of Education, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - Amel Mezlini
- Medical Oncology Department, Salah Azaiez Oncologic Hospital, Tunis, Tunisia
| | - Majid Al Busafi
- Physical Education and Sport Sciences Department, College of Education, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - Pierre Louis Doutrellot
- EA-3300: APERE, Exercise Physiology and Rehabilitation Laboratory, Sport Sciences Department, Picardie Jules Verne University, Amiens Cedex, France
| | - Ezdine Bouhlel
- Laboratory of Physiology, Faculty of Medicine of Sousse, University of Sousse, Sousse, Tunisia
| | - Said Ahmaidi
- EA-3300: APERE, Exercise Physiology and Rehabilitation Laboratory, Sport Sciences Department, Picardie Jules Verne University, Amiens Cedex, France
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Ruggiero L, Harrison SWD, Rice CL, McNeil CJ. Neuromuscular fatigability at high altitude: Lowlanders with acute and chronic exposure, and native highlanders. Acta Physiol (Oxf) 2022; 234:e13788. [PMID: 35007386 PMCID: PMC9286620 DOI: 10.1111/apha.13788] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 01/18/2023]
Abstract
Ascent to high altitude is accompanied by a reduction in partial pressure of inspired oxygen, which leads to interconnected adjustments within the neuromuscular system. This review describes the unique challenge that such an environment poses to neuromuscular fatigability (peripheral, central and supraspinal) for individuals who normally reside near to sea level (SL) (<1000 m; ie, lowlanders) and for native highlanders, who represent the manifestation of high altitude-related heritable adaptations across millennia. Firstly, the effect of acute exposure to high altitude-related hypoxia on neuromuscular fatigability will be examined. Under these conditions, both supraspinal and peripheral fatigability are increased compared with SL. The specific mechanisms contributing to impaired performance are dependent on the exercise paradigm and amount of muscle mass involved. Next, the effect of chronic exposure to high altitude (ie, acclimatization of ~7-28 days) will be considered. With acclimatization, supraspinal fatigability is restored to SL values, regardless of the amount of muscle mass involved, whereas peripheral fatigability remains greater than SL except when exercise involves a small amount of muscle mass (eg, knee extensors). Indeed, when whole-body exercise is involved, peripheral fatigability is not different to acute high-altitude exposure, due to competing positive (haematological and muscle metabolic) and negative (respiratory-mediated) effects of acclimatization on neuromuscular performance. In the final section, we consider evolutionary adaptations of native highlanders (primarily Himalayans of Tibet and Nepal) that may account for their superior performance at altitude and lesser degree of neuromuscular fatigability compared with acclimatized lowlanders, for both single-joint and whole-body exercise.
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Affiliation(s)
- Luca Ruggiero
- Laboratory of Physiomechanics of Locomotion Department of Pathophysiology and Transplantation University of Milan Milan Italy
| | - Scott W. D. Harrison
- School of Kinesiology Faculty of Health Sciences The University of Western Ontario London Ontario Canada
| | - Charles L. Rice
- School of Kinesiology Faculty of Health Sciences The University of Western Ontario London Ontario Canada
- Department of Anatomy and Cell Biology Schulich School of Medicine and Dentistry The University of Western Ontario London Ontario Canada
| | - Chris J. McNeil
- Centre for Heart, Lung & Vascular Health School of Health and Exercise Sciences University of British Columbia Kelowna British Columbia Canada
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Kolind MI, Gam S, Phillip JG, Pareja-Blanco F, Olsen HB, Gao Y, Søgaard K, Nielsen JL. Effects of low load exercise with and without blood-flow restriction on microvascular oxygenation, muscle excitability and perceived pain. Eur J Sport Sci 2022; 23:542-551. [PMID: 35125067 DOI: 10.1080/17461391.2022.2039781] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This paper aimed to examine the acute effect of low-load (LL) exercise with blood-flow restriction (LL-BFR) on microvascular oxygenation and muscle excitability of the vastus medialis (VM) and vastus lateralis (VL) muscles during a single bout of unilateral knee extension exercise performed to task failure. Seventeen healthy recreationally resistance-trained males were enrolled in a within-group randomized cross-over study design. Participants performed one set of unilateral knee extensions at 20% of one-repetition maximum (1RM) to task failure, using a LL-BFR or LL free-flow (LL-FF) protocol in a randomized order on separate days. Changes in microvascular oxygenation and muscle excitability in VL and VM were assessed using near-infrared spectroscopy (NIRS) and surface electromyography (sEMG), respectively. Pain measures were collected using the visual analog scale (VAS) before and following set completion. Within- and between- protocol comparisons were performed at multiple time points of set completion for each muscle. During LL-BFR, participants performed 43% fewer repetitions and reported feeling more pain compared to LL-FF (p<0.05). Normalized to time to task failure, LL-BFR and LL-FF generally demonstrated similar progression in microvascular oxygenation and muscle excitability during exercise to task failure. The present results demonstrate that LL-BFR accelerates time to task failure, compared with LL-FF, resulting in a lower dose of mechanical work to elicit similar levels of oxygenation, blood-pooling, and muscle excitability. LL-BFR may be preferable to LL-FF in clinical settings where high workloads are contraindicated, although increased pain experienced during BFR may limit its application.HighlightsCompared to free flow (FF), neuromuscular fatigue mechanisms are accelerated during blood flow restricted (BFR) training. This can be observed as changes in microvascular oxygenation and muscle excitability occurring at a ∼43% faster mean rate during BFR compared to FF.BFR exercise seems to elicit the same level of neuromuscular fatigue as FF training within a shorter timeframe. This reduces total joint load and may be especially helpful in cases where high training volumes may be contraindicated (e.g. recovering from a sports injury or orthopedic surgery).
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Affiliation(s)
- Mikkel I. Kolind
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campus vej 55, 5230 Odense, Denmark
| | - Søren Gam
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campus vej 55, 5230 Odense, Denmark
| | - Jeppe G. Phillip
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campus vej 55, 5230 Odense, Denmark
| | - Fernando Pareja-Blanco
- Physical Performance & Sports Research Center, Universidad Pablo de Olavide, Ctra. de Utrera, 1, 41013 Sevilla, Spain
| | - Henrik B. Olsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campus vej 55, 5230 Odense, Denmark
| | - Ying Gao
- Department of Sports Science, College of Education, Zhejiang University, 310028 Hangzhou, China
- Faculty of Sport and Health Sciences, University of Jyväskylä, Seminaarinkatu 15, 40014 Jyväskylä, Finland
| | - Karen Søgaard
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campus vej 55, 5230 Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, Campus vej 55, 5230 Odense, Denmark
| | - Jakob L. Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campus vej 55, 5230 Odense, Denmark
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Volianitis S, Rasmussen P, Petersen NC, Secher NH. The Effect of Hyperoxia on Central and Peripheral Factors of Arm Flexor Muscles Fatigue Following Maximal Ergometer Rowing in Men. Front Physiol 2022; 13:829097. [PMID: 35185623 PMCID: PMC8850913 DOI: 10.3389/fphys.2022.829097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 01/11/2022] [Indexed: 11/16/2022] Open
Abstract
Purpose This study evaluates the effect of hyperoxia on cerebral oxygenation and neuromuscular fatigue mechanisms of the elbow flexor muscles following ergometer rowing. Methods In 11 competitive male rowers (age, 30 ± 4 years), we measured near-infrared spectroscopy determined frontal lobe oxygenation (ScO2) and transcranial Doppler ultrasound determined middle cerebral artery mean flow velocity (MCA Vmean) combined with maximal voluntary force (MVC), peak resting twitch force (Ptw) and cortical voluntary activation (VATMS) of the elbow flexor muscles using electrical motor point and magnetic motor cortex stimulation, respectively, before, during, and immediately after 2,000 m all-out effort on rowing ergometer with normoxia and hyperoxia (30% O2). Results Arterial hemoglobin O2 saturation was reduced to 92.5 ± 0.2% during exercise with normoxia but maintained at 98.9 ± 0.2% with hyperoxia. The MCA Vmean increased by 38% (p < 0.05) with hyperoxia, while only marginally increased with normoxia. Similarly, ScO2 was not affected with hyperoxia but decreased by 7.0 ± 4.8% from rest (p = 0.04) with normoxia. The MVC and Ptw were reduced (7 ± 3% and 31 ± 9%, respectively, p = 0.014), while VATMS was not affected by the rowing effort in normoxia. With hyperoxia, the deficit in MVC and Ptw was attenuated, while VATMS was unchanged. Conclusion These data indicate that even though hyperoxia restores frontal lobe oxygenation the resultant attenuation of arm muscle fatigue following maximal rowing is peripherally rather than centrally mediated.
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Affiliation(s)
- Stefanos Volianitis
- Department of Physical Education, College of Education, Qatar University, Doha, Qatar
| | - Peter Rasmussen
- Department of Anesthesiology, Rigshospitalet, Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Nicolas C Petersen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Niels H Secher
- Department of Anesthesiology, Rigshospitalet, Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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McKeown DJ, McNeil CJ, Brotherton EJ, Simmonds MJ, Kavanagh JJ. Severe acute hypoxia impairs recovery of voluntary muscle activation after sustained submaximal elbow flexion. J Physiol 2021; 599:5379-5395. [PMID: 34761807 DOI: 10.1113/jp281897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 11/04/2021] [Indexed: 11/08/2022] Open
Abstract
The purpose of this study was to determine how severe acute hypoxia alters neural mechanisms during, and following, a sustained fatiguing contraction. Fifteen participants (25 ± 3.2 years, six female) were exposed to a sham condition and a hypoxia condition where they performed a 10 min elbow flexor contraction at 20% of maximal torque. For hypoxia, peripheral blood oxygen saturation ( S p O 2 ) was titrated to 80% over a 15 min period and maintained for 2 h. Maximal voluntary contraction torque, EMG root mean square, voluntary activation, rating of perceived muscle fatigue, and corticospinal excitability (motor-evoked potential) and inhibition (silent period duration) were then assessed before, during and for 6 min after the fatiguing contraction. No hypoxia-related effects were identified for neuromuscular variables during the fatigue task. However, for recovery, voluntary activation assessed by motor point stimulation of biceps brachii was lower for hypoxia than sham at 4 min (sham: 89% ± 7%; hypoxia: 80% ± 12%; P = 0.023) and 6 min (sham: 90% ± 7%; hypoxia: 78% ± 11%; P = 0.040). Similarly, voluntary activation (P = 0.01) and motor-evoked potential area (P = 0.002) in response to transcranial magnetic stimulation of the motor cortex were 10% and 11% lower during recovery for hypoxia compared to sham, respectively. Although an S p O 2 of 80% did not affect neural activity during the fatiguing task, motor cortical output and corticospinal excitability were reduced during recovery in the hypoxic environment. This was probably due to hypoxia-related mechanisms involving supraspinal motor circuits. KEY POINTS: Acute hypoxia has been shown to impair voluntary activation of muscle and alter the excitability of the corticospinal motor pathway during exercise. However, little is known about how hypoxia alters the recovery of the motor system after performing fatiguing exercise. Here we assessed hypoxia-related responses of motor pathways both during active contractions and during recovery from active contractions, with transcranial magnetic stimulation and motor point stimulation of the biceps brachii. Fatiguing exercise caused reductions in voluntary activation, which was exacerbated during recovery from a 10 min sustained elbow flexion in a hypoxic environment. These results suggest that reductions in blood oxygen concentration impair the ability of motor pathways in the CNS to recover from fatiguing exercise, which is probably due to hypoxia-induced mechanisms that reduce output from the motor cortex.
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Affiliation(s)
- Daniel J McKeown
- Neural Control of Movement Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Chris J McNeil
- Integrated Neuromuscular Physiology Laboratory, Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Emily J Brotherton
- Neural Control of Movement Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Michael J Simmonds
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Justin J Kavanagh
- Neural Control of Movement Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
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11
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Paris HL, Sinai EC, Shei RJ, Keller AM, Mickleborough TD. The influence of carbohydrate ingestion on peripheral and central fatigue during exercise in hypoxia: A narrative review. Eur J Sport Sci 2021; 21:1423-1435. [PMID: 33106121 PMCID: PMC8140067 DOI: 10.1080/17461391.2020.1842512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Hypoxia impairs aerobic performance by accelerating fatiguing processes. These processes may originate from sites either distal (peripheral) or proximal (central) to the neuromuscular junction, though these are not mutually exclusive. Peripheral mechanisms include decrements in muscle glycogen or fluctuations in intramuscular metabolites, whereas central responses commonly refer to reductions in central motor drive elicited by alterations in blood glucose and neurotransmitter concentrations as well as arterial hypoxemia. Hypoxia may accelerate both peripheral and central pathways of fatigue, with the level of hypoxia strongly dictating the degree and primary locus of impairment. As more people journey to hypoxic settings for work and recreation, developing strategies to improve work capacity in these environments becomes increasingly relevant. Given that sea level performance improves with nutritional interventions such as carbohydrate (CHO) ingestion, a similar strategy may prove effective in delaying fatigue in hypoxia, particularly considering how the metabolic pathways enhanced with CHO supplementation overlap the fatiguing pathways upregulated in hypoxia. Many questions regarding the relationship between CHO, hypoxia, and fatigue remain unanswered, including specifics on when to ingest, what to ingest, and how varying altitudes influence supplementation effectiveness. Therefore, the purpose of this narrative review is to examine the peripheral and central mechanisms contributing to fatigue during aerobic exercise at varying degrees of hypoxia and to assess the role of CHO ingestion in attenuating fatigue onset.
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Affiliation(s)
- Hunter L Paris
- Department of Sports Medicine, Pepperdine University, Malibu, CA, USA
| | - Erin C Sinai
- Department of Sports Medicine, Pepperdine University, Malibu, CA, USA
| | - Ren-Jay Shei
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, and Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Timothy D Mickleborough
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA
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12
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Auger K, Shedlock G, Coutinho K, Myers NE, Lorenzo S. Effects of osteopathic manipulative treatment and bio-electromagnetic energy regulation therapy on lower back pain. J Osteopath Med 2021; 121:561-569. [PMID: 33694338 DOI: 10.1515/jom-2020-0132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 11/23/2020] [Indexed: 11/15/2022]
Abstract
CONTEXT Lower back pain (LBP) is prevalent and is a leading contributor to disease burden worldwide. Osteopathic manipulative treatment (OMT) can alleviate alterations in the body that leads to musculoskeletal disorders such as LBP. Bio-electromagnetic Energy Regulation (BEMER; BEMER International AG), which has also been shown to relieve musculoskeletal pain, is a therapeutic modality that deploys a biorhythmically defined stimulus through a pulsed electromagnetic field (PEMF). Therefore, it is possible that combined OMT and BEMER therapy could reduce low back pain in adults more than the effect of either treatment modality alone. OBJECTIVES To investigate the individual and combined effects of OMT and BEMER therapy on LBP in adults. METHODS Employees and students at a medical college were recruited to this study by email. Participants were included if they self-reported chronic LBP of 3 months' duration or longer; participants were excluded if they were experiencing acute LBP of 2 weeks' duration or less, were currently being treated for LBP, were pregnant, or had a known medical history of several conditions. Ultimately, 40 participants were randomly assigned to four treatment groups: an OMT only, BEMER only, OMT+BEMER, or control (light touch and sham). Treatments were given regularly over a 3 week period. Data on LBP and quality of life were gathered through the Visual Analog Scale (VAS), Short Form 12 item (SF-12) health survey, and Oswestry Low Back Pain Questionnaire/Oswestry Disability Index prior to treatment and immediately after the 3 week intervention protocol. One-way analysis of variance (ANOVA) was performed retrospectively and absolute changes for each participant were calculated. Normal distribution and equal variances were confirmed by Shapiro-Wilk test (p>0.05) and Brown-Forsythe, respectively. Significance was set at p<0.05. RESULTS Despite a lack of statistical significance between groups, subjective reports of pain reported on the VAS showed a substantial mean percentage decrease (50.8%) from baseline in the OMT+BEMER group, compared with a 10.2% decrease in the OMT-only and 9.8% in BEMER-only groups when comparing the difference in VAS ratings from preintervention to postintervention. Participants also reported in quality of life assessed on the Oswestry Low Back Pain Questionnaire/Oswestry Disability Index, with the OMT+BEMER group showing a decrease of 30.3% in score, the most among all groups. The OMT+BEMER group also reported the greatest improvement in score in the physical component of the SF-12, with an increase of 21.8%. CONCLUSIONS The initial data from this study shows a potential additive effect of combination therapy (OMT and BEMER) for management of LBP, though the results did not achieve statistical significance.
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Affiliation(s)
- Kyle Auger
- Lake Erie College of Osteopathic Medicine, Bradenton, FL, USA
| | | | - Kasey Coutinho
- Lake Erie College of Osteopathic Medicine, Bradenton, FL, USA
| | - Nicole E Myers
- Lake Erie College of Osteopathic Medicine, Bradenton, FL, USA
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13
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Poole DC, Behnke BJ, Musch TI. The role of vascular function on exercise capacity in health and disease. J Physiol 2021; 599:889-910. [PMID: 31977068 PMCID: PMC7874303 DOI: 10.1113/jp278931] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/10/2019] [Indexed: 12/16/2022] Open
Abstract
Three sentinel parameters of aerobic performance are the maximal oxygen uptake ( V ̇ O 2 max ), critical power (CP) and speed of the V ̇ O 2 kinetics following exercise onset. Of these, the latter is, perhaps, the cardinal test of integrated function along the O2 transport pathway from lungs to skeletal muscle mitochondria. Fast V ̇ O 2 kinetics demands that the cardiovascular system distributes exercise-induced blood flow elevations among and within those vascular beds subserving the contracting muscle(s). Ideally, this process must occur at least as rapidly as mitochondrial metabolism elevates V ̇ O 2 . Chronic disease and ageing create an O2 delivery (i.e. blood flow × arterial [O2 ], Q ̇ O 2 ) dependency that slows V ̇ O 2 kinetics, decreasing CP and V ̇ O 2 max , increasing the O2 deficit and sowing the seeds of exercise intolerance. Exercise training, in contrast, does the opposite. Within the context of these three parameters (see Graphical Abstract), this brief review examines the training-induced plasticity of key elements in the O2 transport pathway. It asks how structural and functional vascular adaptations accelerate and redistribute muscle Q ̇ O 2 and thus defend microvascular O2 partial pressures and capillary blood-myocyte O2 diffusion across a ∼100-fold range of muscle V ̇ O 2 values. Recent discoveries, especially in the muscle microcirculation and Q ̇ O 2 -to- V ̇ O 2 heterogeneity, are integrated with the O2 transport pathway to appreciate how local and systemic vascular control helps defend V ̇ O 2 kinetics and determine CP and V ̇ O 2 max in health and how vascular dysfunction in disease predicates exercise intolerance. Finally, the latest evidence that nitrate supplementation improves vascular and therefore aerobic function in health and disease is presented.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA
| | - Brad J Behnke
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA
| | - Timothy I Musch
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University, Manhattan, KS, 66506, USA
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14
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Clebone A, Reis K, Tung A, OConnor M, Ruskin KJ. Chest Compression Duration May Be Improved When Rescuers Breathe Supplemental Oxygen. Aerosp Med Hum Perform 2020; 91:918-922. [PMID: 33243334 DOI: 10.3357/amhp.5698.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND: At sea level, performing chest compressions is a demanding physical exercise. On a commercial flight at cruise altitude, the barometric pressure in the cabin is approximately equal to an altitude of 2438 m. This results in a Po₂ equivalent to breathing an FIo₂ of 15% at sea level, a condition under which both the duration and quality of cardiopulmonary resuscitation (CPR) may deteriorate. We hypothesized that rescuers will be able to perform fewer rounds of high-quality CPR at an FIo₂ of 15%.METHODS: In this crossover simulation trial, 16 healthy volunteers participated in 2 separate sessions and performed up to 14 2-min rounds of chest compressions at an FIo₂ of either 0.15 or 0.21 in randomized order. Subjects were stopped if their Spo₂ was below 80%, if chest compression rate or depth was not achieved for 2/3 of compressions, or if they felt fatigued or dyspneic.RESULTS: Fewer rounds of chest compressions were successfully completed in the hypoxic than in the normoxic condition, (median [IQR] 4.5 [3,8.5]) vs. 5 [4,14]). The decline in arterial Spo₂ while performing chest compressions was greater in the hypoxic condition than in the normoxic condition [mean (SD), 6.19% (4.1) vs. 2% (1.66)].DISCUSSION: Our findings suggest that the ability of rescuers to perform chest compressions in a commercial airline cabin at cruising altitude may be limited due to hypoxia. One possible solution is supplemental oxygen for rescuers who perform chest compressions for in-flight cardiac arrest.Clebone A, Reis K, Tung A, OConnor M, Ruskin KJ. Chest compression duration may be improved when rescuers breathe supplemental oxygen. Aerosp Med Hum Perform. 2020; 91(12):918922.
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15
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Archiza B, Reinhard PA, Welch JF, Sheel AW. Sex differences in diaphragmatic fatigue: Effects of hypoxia during inspiratory loading. J Physiol 2020; 599:1319-1333. [PMID: 33180958 DOI: 10.1113/jp280704] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/26/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Under normoxic conditions, both healthy female and male diaphragms fatigue at a similar degree when matched for absolute diaphragmatic work during inspiratory loading. We investigated whether similarities in diaphragm fatigability persist under acute hypoxic conditions. We found that, in acute hypoxia, fatigue of the diaphragm is greater in women compared to men, whereas the magnitude of fatigue in normoxia did not differ between sexes. When matched for maximal diaphragm strength, women and men had a similar pressor response to work-matched inspiratory loading, independent of oxygen availability. ABSTRACT In normoxia, women and men display a comparable magnitude of diaphragmatic fatigue (DF) after work-matched inspiratory loading. Whether these sex similarities are maintained under acute hypoxic conditions is unknown. We investigated the influence of acute hypoxia during work-matched inspiratory pressure-threshold loading (PTL) on DF in healthy women (n = 8) and men (n = 8). Two 5 min isocapnic PTL tasks targeting a transdiaphragmatic pressure (Pdi ) of 92 cmH2 O in normoxia and hypoxia (8% O2 ) were performed on separate days (≥48 h). DF was quantified by twitch Pdi (Pdi,tw ) via cervical magnetic stimulation post-PTL. Women and men had similar maximal Pdi (Pdi,max ; women: 171 ± 16, men: 178 ± 20 cmH2 O) and relative target workload (women: 54 ± 5%, men: 53 ± 6% Pdi,max ). The absolute cumulative diaphragmatic work did not differ between sexes in normoxia (women: 12,653 ± 1796 cmH2 O s-1 , men: 13,717 ± 1231 cmH2 O s-1 ; P = 0.202) or hypoxia (women: 11,624 ± 1860 cmH2 O s-1 , men: 12 722 ± 1502 cmH2 O s-1 ; P = 0.189). In normoxia, the magnitude of reduction in Pdi,tw post-PTL was similar between sexes (women: -21.1 ± 8.4%, men: -22.5 ± 4.9 %; P = 0.193); however, a higher degree of DF was observed in women compared to men following PTL in acute hypoxia (women: -27.6 ± 7.7%, men: -23.4 ± 9.6%, P = 0.019). We conclude that the female diaphragm is more susceptible to fatigue after inspiratory loading under acute hypoxic conditions. This finding may be related to sex differences in diaphragm muscle metabolism, such as fibre type composition, contractile properties, substrate utilisation and blood perfusion.
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Affiliation(s)
- Bruno Archiza
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Paige A Reinhard
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Joseph F Welch
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
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16
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Nell HJ, Castelli LM, Bertani D, Jipson AA, Meagher SF, Melo LT, Zabjek K, Reid WD. The effects of hypoxia on muscle deoxygenation and recruitment in the flexor digitorum superficialis during submaximal intermittent handgrip exercise. BMC Sports Sci Med Rehabil 2020; 12:16. [PMID: 32467763 PMCID: PMC7226965 DOI: 10.1186/s13102-020-00163-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 02/20/2020] [Indexed: 12/02/2022]
Abstract
Background Decreased oxygenation of muscle may be accentuated during exercise at high altitude. Monitoring the oxygen saturation of muscle (SmO2) during hand grip exercise using near infrared spectroscopy during acute exposure to hypoxia could provide a model for a test of muscle performance without the competing cardiovascular stresses that occur during a cycle ergometer or treadmill test. The purpose of this study was to examine and compare acute exposure to normobaric hypoxia versus normoxia on deoxygenation and recruitment of the flexor digitorum superficialis (FDS) during submaximal intermittent handgrip exercise (HGE) in healthy adults. Methods Twenty subjects (11 M/9 F) performed HGE at 50% of maximum voluntary contraction, with a duty cycle of 2 s:1 s until task failure on two occasions one week apart, randomly assigned to normobaric hypoxia (FiO2 = 12%) or normoxia (FiO2 = 21%). Near-infrared spectroscopy monitored SmO2, oxygenated (O2Hb), deoxygenated (HHb), and total hemoglobin (tHb) over the FDS. Surface electromyography derived root mean square and mean power frequency of the FDS. Results Hypoxic compared to normoxic HGE induced a lower FDS SmO2 (63.8 ± 2.2 vs. 69.0 ± 1.5, p = 0.001) and both protocols decreased FDS SmO2 from baseline to task failure. FDS mean power frequency was lower during hypoxic compared to normoxic HGE (64.0 ± 1.4 vs. 68.2 ± 2.0 Hz, p = 0.04) and both decreased mean power frequency from the first contractions to task failure (p = 0.000). Under both hypoxia and normoxia, HHb, tHb and root mean square increased from baseline to task failure whereas O2Hb decreased and then increased during HGE. Arterial oxygen saturation via pulse oximetry (SpO2) was lower during hypoxia compared to normoxia conditions (p = 0.000) and heart rate and diastolic blood pressure only demonstrated small increases. Task durations and the tension-time index of HGE did not differ between normoxic and hypoxic trials. Conclusion Hypoxic compared to normoxic HGE decreased SmO2 and induced lower mean power frequency in the FDS, during repetitive hand grip exercise however did not result in differences in task durations or tension-time indices. The fiber type composition of FDS, and high duty cycle and intensity may have contributed greater dependence on anaerobiosis.
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Affiliation(s)
- Hayley J Nell
- 1Department of Physical Therapy, University of Toronto, 160-500 University Avenue, Toronto, ON M5G 1V7 Canada
| | - Laura M Castelli
- 1Department of Physical Therapy, University of Toronto, 160-500 University Avenue, Toronto, ON M5G 1V7 Canada
| | - Dino Bertani
- 1Department of Physical Therapy, University of Toronto, 160-500 University Avenue, Toronto, ON M5G 1V7 Canada
| | - Aaron A Jipson
- 1Department of Physical Therapy, University of Toronto, 160-500 University Avenue, Toronto, ON M5G 1V7 Canada
| | - Sean F Meagher
- 1Department of Physical Therapy, University of Toronto, 160-500 University Avenue, Toronto, ON M5G 1V7 Canada
| | - Luana T Melo
- 1Department of Physical Therapy, University of Toronto, 160-500 University Avenue, Toronto, ON M5G 1V7 Canada
| | - Karl Zabjek
- 1Department of Physical Therapy, University of Toronto, 160-500 University Avenue, Toronto, ON M5G 1V7 Canada.,2KITE, Toronto Rehab-University Health Network, 550 University Ave, Toronto, ON M5G 2A2 Canada
| | - W Darlene Reid
- 1Department of Physical Therapy, University of Toronto, 160-500 University Avenue, Toronto, ON M5G 1V7 Canada.,2KITE, Toronto Rehab-University Health Network, 550 University Ave, Toronto, ON M5G 2A2 Canada.,3Interdepartmental Division of Critical Care Medicine, University of Toronto, Li Ka Shing Knowledge Institute, 209 Victoria Street, 4th Floor, Room 411, Toronto, ON M5B 1T8 Canada
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17
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Yoshiko A, Katayama K, Ishida K, Ando R, Koike T, Oshida Y, Akima H. Muscle deoxygenation and neuromuscular activation in synergistic muscles during intermittent exercise under hypoxic conditions. Sci Rep 2020; 10:295. [PMID: 31941906 PMCID: PMC6962371 DOI: 10.1038/s41598-019-57099-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 12/20/2019] [Indexed: 11/09/2022] Open
Abstract
The purpose of this study was to elucidate the effects of hypoxia on deoxygenation and neuromuscular activation in synergistic quadriceps femoris (QF) muscles (i.e., the rectus femoris, vastus medialis, vastus intermedius, and vastus lateralis) during submaximal intermittent knee extension. Ten healthy men performed isometric intermittent knee extension exercises with the right leg at 50% of maximal voluntary contraction for 3 min while inhaling a normoxic [inspired oxygen (O2) fraction = 0.21] or hypoxic (inspired O2 fraction = 0.10–0.12) gas mixture. Muscle deoxygenation was measured by tissue O2 saturation (StO2), and neuromuscular activation by root mean square (RMS) of the surface electromyographic signals, from individual muscles of the QF using near-infrared spectroscopy and surface electromyography. StO2 was decreased more in hypoxia than normoxia during the exercises, and there was a greater increase in RMS during intermittent knee extension in hypoxia than normoxia in individual muscles of the QF. There were no differences in the ratios of StO2 and RMS in hypoxia compared with normoxia between individual muscles of the QF. These findings suggest that submaximal, isometric, and intermittent exercises in hypoxic conditions enhanced muscle oxygen consumption and muscle activity similarly for synergistic muscles.
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Affiliation(s)
- Akito Yoshiko
- School of International Liberal Studies, Chukyo University, Toyota, Japan. .,Graduate School of Medicine, Nagoya University, Nagoya, Japan.
| | - Keisho Katayama
- Graduate School of Medicine, Nagoya University, Nagoya, Japan.,Research Center of Health, Physical Fitness & Sports, Nagoya University, Nagoya, Japan
| | - Koji Ishida
- Graduate School of Medicine, Nagoya University, Nagoya, Japan.,Research Center of Health, Physical Fitness & Sports, Nagoya University, Nagoya, Japan
| | - Ryosuke Ando
- Department of Sports Research, Japan Institute of Sports Sciences, Tokyo, Japan
| | - Teruhiko Koike
- Graduate School of Medicine, Nagoya University, Nagoya, Japan.,Research Center of Health, Physical Fitness & Sports, Nagoya University, Nagoya, Japan
| | | | - Hiroshi Akima
- Research Center of Health, Physical Fitness & Sports, Nagoya University, Nagoya, Japan.,Graduate School of Education and Human Development, Nagoya University, Nagoya, Japan
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18
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Ruggiero L, Hoiland RL, Hansen AB, Ainslie PN, McNeil CJ. High-Altitude Acclimatization Improves Recovery from Muscle Fatigue. Med Sci Sports Exerc 2019; 52:161-169. [PMID: 31343519 DOI: 10.1249/mss.0000000000002100] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We investigated the effect of high-altitude acclimatization on peripheral fatigue compared with sea level and acute hypoxia. METHODS At sea level (350 m), acute hypoxia (environmental chamber), and chronic hypoxia (5050 m, 5-9 d) (partial pressure of inspired oxygen = 140, 74 and 76 mm Hg, respectively), 12 participants (11 in chronic hypoxia) had the quadriceps of their dominant leg fatigued by three bouts of 75 intermittent electrically evoked contractions (12 pulses at 15 Hz, 1.6 s between train onsets, and 15 s between bouts). The initial peak force was ~30% of maximal voluntary force. Recovery was assessed by single trains at 1, 2, and 3 min postprotocol. Tissue oxygenation of rectus femoris was recorded by near-infrared spectroscopy. RESULTS At the end of the fatigue protocol, the impairments of peak force and peak rates of force development and relaxation were greater (all P < 0.05) in acute hypoxia (~51%, 53%, and 64%, respectively) than sea level (~43%, 43%, and 52%) and chronic hypoxia (~38%, 35%, and 48%). Peak force and rate of force development recovered faster (P < 0.05) in chronic hypoxia (pooled data for 1-3 min: ~84% and 74% baseline, respectively) compared with sea level (~73% and 63% baseline) and acute hypoxia (~70% and 55% baseline). Tissue oxygenation did not differ among conditions for fatigue or recovery (P > 0.05). CONCLUSIONS Muscle adaptations occurring with chronic hypoxia, independent of other adaptations, positively influence muscle contractility during and after repeated contractions at high altitude.
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Affiliation(s)
- Luca Ruggiero
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, CANADA
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19
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Brechbuhl C, Brocherie F, Millet GP, Schmitt L. Effects of Repeated-Sprint Training in Hypoxia on Tennis-Specific Performance in Well-Trained Players. Sports Med Int Open 2018; 2:E123-E132. [PMID: 30539129 PMCID: PMC6259464 DOI: 10.1055/a-0719-4797] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 08/02/2018] [Accepted: 08/12/2018] [Indexed: 11/28/2022] Open
Abstract
This study examined the physiological, physical and technical responses to repeated-sprint training in normobaric hypoxia [RSH, inspired fraction of oxygen (FiO
2
) 14.5%] vs. normoxia (RSN, FiO
2
20.9%). Within 12 days, eighteen well-trained tennis players (RSH, n=9 vs. RSN, n=9) completed five specific repeated-sprint sessions that consisted of four sets of 5 maximal shuttle-run sprints. Testing sessions included repeated-sprint ability and Test to Exhaustion Specific to Tennis (TEST). TEST’s maximal duration to exhaustion and time to attain the ‘onset of blood lactate accumulation’ at 4 mMol.L
−1
(OBLA) improvements were significantly higher in RSH compared to RSN. Change in time to attain OBLA was concomitant with observations similar in time to the second ventilatory threshold. Significant interaction (P=0.003) was found for ball accuracy with greater increase in RSH (+13.8%, P=0.013) vs. RSN (–4.6%, P=0.15). A correlation (r=0.59, P<0.001) was observed between change in ball accuracy and TEST’s time to exhaustion. Greater improvement in some tennis-specific physical and technical parameters was observed after only 5 sessions of RSH vs. RSN in well-trained tennis players.
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Affiliation(s)
- Cyril Brechbuhl
- French Tennis Federation, National Tennis Center, 4 Place de la Porte Molitor, Paris, France.,ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), Research Unit, French Institute of Sport (INSEP), Paris, France
| | - Gregoire P Millet
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Laurent Schmitt
- ISSUL, Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.,National Ski-Nordic Center, Premanon, Les Rousses, France
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20
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Looft JM, Herkert N, Frey-Law L. Modification of a three-compartment muscle fatigue model to predict peak torque decline during intermittent tasks. J Biomech 2018; 77:16-25. [PMID: 29960732 PMCID: PMC6092960 DOI: 10.1016/j.jbiomech.2018.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 05/18/2018] [Accepted: 06/09/2018] [Indexed: 01/16/2023]
Abstract
This study aimed to test whether adding a rest recovery parameter, r, to the analytical three-compartment controller (3CC) fatigue model (Xia and Frey Law, 2008) will improve fatigue estimates during intermittent contractions. The 3CC muscle fatigue model uses differential equations to predict the flow of muscle between three muscle states: Resting (MR), Active (MA), and Fatigued (MF). This model uses a feedback controller to match the active state to target loads and two joint-specific parameters: F, fatigue rate controlling flow from active to fatigued compartments) and R, the recovery rate controlling flow from the fatigued to the resting compartments. This model does well to predict intensity-endurance time curves for sustained isometric tasks. However, previous studies find when rest intervals are present that the model over predicts fatigue. Intermittent rest periods would allow for the occurrence of subsequent reactive vasodilation and post-contraction hyperemia. We hypothesize a modified 3CC-r fatigue model will improve predictions of force decay during intermittent contractions with the addition of a rest recovery parameter, r, to augment recovery during rest intervals, representing muscle re-perfusion. A meta-analysis compiling intermittent fatigue data from 63 publications reporting decline in peak torque (% torque decline) were used for comparison. The original model over-predicted fatigue development from 19 to 29% torque decline; the addition of a rest multiplier significantly improved fatigue estimates to 6-10% torque decline. We conclude the addition of a rest multiplier to the three-compartment controller fatigue model provides a physiologically consistent modification for tasks involving rest intervals, resulting in improved estimates of muscle fatigue.
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Affiliation(s)
- John M Looft
- Department of Physical Therapy, University of Minnesota, Minneapolis, MN 55455, USA; Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242, USA
| | - Nicole Herkert
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242, USA
| | - Laura Frey-Law
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242, USA.
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21
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Abstract
Hyperoxia results from the inhalation of mixtures of gas containing higher partial pressures of oxygen (O2) than normal air at sea level. Exercise in hyperoxia affects the cardiorespiratory, neural and hormonal systems, as well as energy metabolism in humans. In contrast to short-term exposure to hypoxia (i.e. a reduced partial pressure of oxygen), acute hyperoxia may enhance endurance and sprint interval performance by accelerating recovery processes. This narrative literature review, covering 89 studies published between 1975 and 2016, identifies the acute ergogenic effects and health concerns associated with hyperoxia during exercise; however, long-term adaptation to hyperoxia and exercise remain inconclusive. The complexity of the biological responses to hyperoxia, as well as the variations in (1) experimental designs (e.g. exercise intensity and modality, level of oxygen, number of participants), (2) muscles involved (arms and legs) and (3) training status of the participants may account for the discrepancies.
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Poitras VJ, Hudson RW, Tschakovsky ME. Exercise intolerance in Type 2 diabetes: is there a cardiovascular contribution? J Appl Physiol (1985) 2018; 124:1117-1139. [PMID: 29420147 DOI: 10.1152/japplphysiol.00070.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Physical activity is critically important for Type 2 diabetes management, yet adherence levels are poor. This might be partly due to disproportionate exercise intolerance. Submaximal exercise tolerance is highly sensitive to muscle oxygenation; impairments in exercising muscle oxygen delivery may contribute to exercise intolerance in Type 2 diabetes since there is considerable evidence for the existence of both cardiac and peripheral vascular dysfunction. While uncompromised cardiac output during submaximal exercise is consistently observed in Type 2 diabetes, it remains to be determined whether an elevated cardiac sympathetic afferent reflex could sympathetically restrain exercising muscle blood flow. Furthermore, while deficits in endothelial function are common in Type 2 diabetes and are often cited as impairing exercising muscle oxygen delivery, no direct evidence in exercise exists, and there are several other vasoregulatory mechanisms whose dysfunction could contribute. Finally, while there are findings of impaired oxygen delivery, conflicting evidence also exists. A definitive conclusion that Type 2 diabetes compromises exercising muscle oxygen delivery remains premature. We review these potentially dysfunctional mechanisms in terms of how they could impair oxygen delivery in exercise, evaluate the current literature on whether an oxygen delivery deficit is actually manifest, and correspondingly identify key directions for future research.
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Affiliation(s)
- Veronica J Poitras
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada.,Department of Physiology, Queen's University , Kingston, Ontario , Canada.,Children's Hospital of Eastern Ontario, Research Institute , Ottawa, Ontario , Canada
| | - Robert W Hudson
- Department of Medicine, Division of Endocrinology, Queen's University , Kingston, Ontario , Canada
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
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Ruggiero L, Yacyshyn AF, Nettleton J, McNeil CJ. UBC-Nepal expedition: acclimatization to high-altitude increases spinal motoneurone excitability during fatigue in humans. J Physiol 2017; 596:3327-3339. [PMID: 29130497 DOI: 10.1113/jp274872] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/09/2017] [Indexed: 01/28/2023] Open
Abstract
KEY POINTS Acute exposure and acclimatization to hypoxia are associated with an impairment and partial recovery, respectively, of the capability of the central nervous system to drive muscles during prolonged efforts. Motoneurones play a vital role in muscle contraction and in fatigue, although the effect of hypoxia on motoneurone excitability during exercise has not been assessed in humans. We studied the impact of fatigue on motoneurone excitability in normoxia, acute and chronic exposure (5050 m) to hypoxia. Performance was worse in acute hypoxia but recovered to the normoxic standard in chronic hypoxia, in parallel with an increased excitability of the motoneurones compared to acute exposure to hypoxia. These findings reveal that prolonged hypoxia causes a heightened motoneurone responsiveness during fatiguing exercise; such an adaptation might favour the restoration of performance where low pressures of oxygen are chronically present. ABSTRACT The fatigue-induced failure of the motor cortex to drive muscles maximally increases in acute hypoxia (AH) compared to normoxia (N) but improves with acclimatization (chronic hypoxia; CH). Despite their importance to muscle output, it is unknown how locomotor motoneurones in humans are affected by hypoxia and acclimatization. Eleven participants performed 16 min of submaximal [25% maximal torque (maximal voluntary contraction, MVC)] intermittent isometric elbow flexions in N, AH (environmental chamber) and CH (7-14 days at 5050 m) (PI O2 = 140, 74 and 76 mmHg, respectively). For each minute of the fatigue protocol, motoneurone responsiveness was measured with cervicomedullary stimulation delivered 100 ms after transcranial magnetic stimulation (TMS) used to transiently silence voluntary drive. Every 2 min, cortical voluntary activation (cVA) was measured with TMS. After the task, MVC torque declined more in AH (∼20%) than N and CH (∼11% and 14%, respectively, P < 0.05), with no differences between N and CH. cVA was lower in AH than N and CH at baseline (∼92%, 95% and 95%, respectively) and at the end of the protocol (∼82%, 90% and 90%, P < 0.05). During the fatiguing task, motoneurone excitability in N and AH declined to ∼65% and 40% of the baseline value (P < 0.05). In CH, motoneurone excitability did not decline and, late in the protocol, was ∼40% higher compared to AH (P < 0.05). These novel data reveal that acclimatization to hypoxia leads to a heightened motoneurone responsiveness during fatiguing exercise. Positive spinal and supraspinal adaptations during extended periods at altitude might therefore play a vital role for the restoration of performance after acclimatization to hypoxia.
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Affiliation(s)
- Luca Ruggiero
- Integrated Neuromuscular Physiology Laboratory, Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Alexandra F Yacyshyn
- Integrated Neuromuscular Physiology Laboratory, Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Jane Nettleton
- Integrated Neuromuscular Physiology Laboratory, Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Chris J McNeil
- Integrated Neuromuscular Physiology Laboratory, Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
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Kaneko Y, Kime R, Furuya E, Sakamoto A, Katsumura T. Effects of Acupuncture Stimulation on Muscle Tissue Oxygenation at Different Points. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 923:327-333. [PMID: 27526160 DOI: 10.1007/978-3-319-38810-6_43] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Muscle tissue oxygenation is a critical issue in muscle complications such as pain, exhaustion, stiffness, or fatigue during and after exercise. The aim of this study was to investigate whether the changes of muscle tissue oxygenation could be observed at both erector spinae muscle at S1 level and gastrocnemius during and after acupuncture stimulation to ipsilateral erector spinae at S1 level. The subjects were ten healthy males. Muscle oxygenation was monitored by near infrared spectroscopy (NIRS), and the probes were placed on the right side of the erector spinae muscle at S1 level (Guanyuanshu, BL26) and the belly of the gastrocnemius on the right (Chengjin, BL56). The subjects lay on the bed in prone position for 10 min, followed by acupuncture insertion into the right side of BL26. The needle was left for 10 min and subjects were kept still for 10 min after removal. At BL26, oxygenated-hemoglobin (oxy-Hb) was significantly increased compared to the baseline at 10 min after insertion (p < 0.05), then continued increasing. Total hemoglobin (t-Hb) was increased at 2 min after removal (p < 0.05). Tissue-oxygen saturation (StO2) was increased at 7 min after insertion (p < 0.05). At BL56, oxy-Hb and t-Hb were increased at 6 and 2 min after removal, respectively (p < 0.05). StO2 showed no significant change. The acupuncture stimulation affected muscle tissue oxygenation differently at both stimulated and non-stimulated points in the same innervation.
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Affiliation(s)
- Yasuhisa Kaneko
- Department of Sports Medicine for Health Promotion, Tokyo Medical University, Tokyo, Japan. .,Department of Oriental Medicine, Kuretake College of Medical Arts and Sciences, Tokyo, Japan.
| | - Ryotaro Kime
- Department of Sports Medicine for Health Promotion, Tokyo Medical University, Tokyo, Japan
| | - Eiji Furuya
- Department of Oriental Medicine, Kuretake College of Medical Arts and Sciences, Tokyo, Japan
| | - Ayumi Sakamoto
- Department of Oriental Medicine, Kuretake College of Medical Arts and Sciences, Tokyo, Japan
| | - Toshihito Katsumura
- Department of Sports Medicine for Health Promotion, Tokyo Medical University, Tokyo, Japan
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Scott BR, Slattery KM, Sculley DV, Smith SM, Peiffer JJ, Dascombe BJ. Acute physiological and perceptual responses to high-load resistance exercise in hypoxia. Clin Physiol Funct Imaging 2017; 38:595-602. [DOI: 10.1111/cpf.12451] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Accepted: 06/13/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Brendan R. Scott
- School of Psychology and Exercise Science; Murdoch University; Perth WA Australia
| | - Katie M. Slattery
- New South Wales Institute of Sport; Sydney Olympic Park NSW Australia
| | - Dean V. Sculley
- Biomedical Sciences and Pharmacy; Faculty of Health and Medicine; University of Newcastle; Ourimbah NSW Australia
| | - Scott M. Smith
- Applied Sports Science and Exercise Testing Laboratory; Faculty of Science and Information Technology; University of Newcastle; Ourimbah NSW Australia
| | - Jeremiah J. Peiffer
- School of Psychology and Exercise Science; Murdoch University; Perth WA Australia
| | - Ben J. Dascombe
- Department of Rehabilitation, Nutrition and Sport; La Trobe University; Bundoora VIC Australia
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Scott BR, Slattery KM, Sculley DV, Lockhart C, Dascombe BJ. Acute Physiological Responses to Moderate-Load Resistance Exercise in Hypoxia. J Strength Cond Res 2017; 31:1973-1981. [DOI: 10.1519/jsc.0000000000001649] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Klenze H, Köhler TC, Farquharson F, Walterspacher S, Duerschmied D, Roecker K, Kabitz HJ, Walker DJ. Resting limb muscle perfusion during inspiratory muscle loading in hypoxia and normoxia. Respir Physiol Neurobiol 2017. [PMID: 28625661 DOI: 10.1016/j.resp.2017.06.003] [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] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Fatiguing of respiratory muscles reduces peripheral muscle perfusion. Further, acute hypoxia enhances respiratory muscle fatigue. This study investigated the effects of inspiratory muscle loading (IML) on resting locomotor muscle perfusion in hypoxia compared to normoxia. METHODS Ten subjects completed two study days of fatiguing IML (blinded, randomized) in normobaric hypoxia (targeted oxygen saturation 80%) and normoxia, respectively. Contrast-enhanced ultrasound (CEUS) of the gastrocnemius muscle and popliteal doppler ultrasonography were used to monitor muscle perfusion. Based on CEUS and monitored cardiac output, perfusion surrogate parameters (CLPaer and CLPap) were established. RESULTS Muscle perfusion declines early during IML in normoxia (CLPaer: -54±25%, p<0.01; CLPap: -58±32%, p<0.01) and hypoxia (CLPaer: -43±23%, p<0.01; CLPap: -41±20%, p<0.01). Hypoxia compared to normoxia increased cardiac output before (+23±19%, p<0.01 ANOVA) and during (+22±20%, p<0.01 ANOVA) IML, while local muscle perfusion during IML remained unchanged (CLPaer: p=0.41 ANOVA; CLPap: p=0.29 ANOVA). CONCLUSION Acute hypoxia compared to normoxia does not affect locomotor muscle perfusion during fatiguing IML.
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Affiliation(s)
- Hannes Klenze
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany.
| | | | - Franziska Farquharson
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany
| | - Stephan Walterspacher
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany; Department of Medicine/Pneumology, Faculty of Health, Witten/Herdecke University, Witten, Germany
| | - Daniel Duerschmied
- Cardiology and Angiology I, University Heart Center Freiburg - Bad Krozingen and Interdisciplinary Medical Intensive Care, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany
| | - Kai Roecker
- Department of Applied Public Health (AGW), Furtwangen University, Germany
| | - Hans-Joachim Kabitz
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany
| | - David Johannes Walker
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany; Department of Medicine/Pneumology, Faculty of Health, Witten/Herdecke University, Witten, Germany
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28
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Carroll TJ, Taylor JL, Gandevia SC. Recovery of central and peripheral neuromuscular fatigue after exercise. J Appl Physiol (1985) 2017; 122:1068-1076. [DOI: 10.1152/japplphysiol.00775.2016] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 12/29/2022] Open
Abstract
Sustained physical exercise leads to a reduced capacity to produce voluntary force that typically outlasts the exercise bout. This “fatigue” can be due both to impaired muscle function, termed “peripheral fatigue,” and a reduction in the capacity of the central nervous system to activate muscles, termed “central fatigue.” In this review we consider the factors that determine the recovery of voluntary force generating capacity after various types of exercise. After brief, high-intensity exercise there is typically a rapid restitution of force that is due to recovery of central fatigue (typically within 2 min) and aspects of peripheral fatigue associated with excitation-contraction coupling and reperfusion of muscles (typically within 3–5 min). Complete recovery of muscle function may be incomplete for some hours, however, due to prolonged impairment in intracellular Ca2+ release or sensitivity. After low-intensity exercise of long duration, voluntary force typically shows rapid, partial, recovery within the first few minutes, due largely to recovery of the central, neural component. However, the ability to voluntarily activate muscles may not recover completely within 30 min after exercise. Recovery of peripheral fatigue contributes comparatively little to the fast initial force restitution and is typically incomplete for at least 20–30 min. Work remains to identify what factors underlie the prolonged central fatigue that usually accompanies long-duration single joint and locomotor exercise and to document how the time course of neuromuscular recovery is affected by exercise intensity and duration in locomotor exercise. Such information could be useful to enhance rehabilitation and sports performance.
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Affiliation(s)
- T. J. Carroll
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, University of Queensland; and
| | - J. L. Taylor
- Neuroscience Research Australia and University of New South Wales
| | - S. C. Gandevia
- Neuroscience Research Australia and University of New South Wales
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29
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Hettinga FJ, Konings MJ, Cooper CE. Differences in Muscle Oxygenation, Perceived Fatigue and Recovery between Long-Track and Short-Track Speed Skating. Front Physiol 2016; 7:619. [PMID: 28018244 PMCID: PMC5156719 DOI: 10.3389/fphys.2016.00619] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/28/2016] [Indexed: 11/26/2022] Open
Abstract
Due to the technical nature of speed skating, that is affecting physiological mechanisms such as oxygenation and blood flow, this sport provides a unique setting allowing us to uncover novel mechanistic insights of the physiological response to exercise in elite middle-distance and endurance sports. The present study aimed to examine the influence of skating mode (short-track vs. long-track) on muscle oxygenation, perceived fatigue, and recovery in elite speed skating. Muscle oxygenation of 12 talented short-track speed skaters was continuously monitored during a long-track (LT) and a short-track (ST) skating time-trial of maximal effort using near-infrared spectroscopy (NIRS) on the m. vastus lateralis for both legs. Video captures were made of each testing session for further interpretation of the muscle oxygenation. To determine recovery, perceived exertion was measured 2 and 4 h after each testing sessions. Repeated measures ANOVA's were used for statistical analysis (p < 0.05). After a rapid desaturation in both legs directly after the start, an asymmetry in muscle oxygenation between both legs was found during LT (tissue saturation-index (TSI%)-slope: left = 0.053 ± 0.032; right = 0.023 ± 0.020, p < 0.05) and ST speed skating (TSI%-slope: left = 0.050 ± 0.052, right = 0.001 ± 0.053, p < 0.05). Resaturation of the right leg was relatively lower in ST compared to LT. For the left leg, no difference was found between skating modes in muscle oxygenation. Respectively, two (ST = 5.8 ± 2.0; LT = 4.2 ± 1.5) and 4 h (ST = 4.6 ± 1.9; LT = 3.1 ± 1.6) after the time-trials, a higher rate of perceived exertion was found for ST. Based on our results, ST seems more physiologically demanding, and longer periods of recovery are needed after training compared to LT. Technical aspects unique to the exercise mode seem to impact on oxygenation, affecting processes related to the regulation of exercise intensity such as fatigue and recovery.
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Affiliation(s)
- Florentina J Hettinga
- Centre for Sports and Exercise Science, School of Biological Sciences, University of Essex Colchester, Essex, UK
| | - Marco J Konings
- Centre for Sports and Exercise Science, School of Biological Sciences, University of Essex Colchester, Essex, UK
| | - Chris E Cooper
- Centre for Sports and Exercise Science, School of Biological Sciences, University of Essex Colchester, Essex, UK
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30
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Freitas FFMD, Azevedo DPD, Medeiros WM, Neder JA, Chiavegato LD, Amorim CF. Microvascular oxygen extraction during maximal isometric contraction in patients with chronic obstructive pulmonary disease. FISIOTERAPIA EM MOVIMENTO 2016. [DOI: 10.1590/1980-5918.029.004.ao16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstract Introduction: COPD presents decrease in oxidative metabolism with possible losses of cardiovascular adjustments, suggesting slow kinetics microvascular oxygen during intense exercise. Objective: To test the hypothesis that chronic obstructive pulmonary disease (COPD) patients have lower muscle performance in physical exercise not dependent on central factors, but also greater muscle oxygen extraction, regardless of muscle mass. Methods: Cross-sectional study with 11 COPD patients and nine healthy subjects, male, paired for age. Spirometry and body composition by DEXA were evaluated. Muscular performance was assessed by maximal voluntary isometric contraction (MVIC) in isokinetic dynamometer and muscle oxygen extraction by the NIRS technique. Student t-test and Pearson correlation were applied. A significance level of p<0.05 was adopted. Results: Patients had moderate to severe COPD (FEV1 = 44.5 ± 9.6% predicted; SpO2 = 94.6 ± 1.6%). Lean leg mass was 8.3 ± 0.9 vs. 8.9 ± 1.0 kg (p =0.033), when comparing COPD and control patients, respectively. The decreased muscle oxygen saturation corrected by muscle mass was 53.2% higher (p=0.044) in the COPD group in MVIC-1 and 149.6% higher (p=0.006) in the MVIC-2. Microvascular extraction rate of oxygen corrected by muscle mass and total work was found to be 114.5% higher (p=0.043) in the COPD group in MVIC-1 and 210.5% higher (p=0.015) in the MVIC-2. Conclusion: COPD patients have low muscle performance and high oxygen extraction per muscle mass unit and per unit of work. The high oxygen extraction suggests that quantitative and qualitative mechanisms can be determinants of muscle performance in patients with COPD.
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31
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Sundberg CW, Hunter SK, Bundle MW. Rates of performance loss and neuromuscular activity in men and women during cycling: evidence for a common metabolic basis of muscle fatigue. J Appl Physiol (1985) 2016; 122:130-141. [PMID: 27856712 DOI: 10.1152/japplphysiol.00468.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 11/13/2016] [Accepted: 11/14/2016] [Indexed: 11/22/2022] Open
Abstract
The durations that muscular force and power outputs can be sustained until failure fall predictably on an exponential decline between an individual's 3-s burst maximum to the maximum performance they can sustain aerobically. The exponential time constants describing these rates of performance loss are similar across individuals, suggesting that a common metabolically based mechanism governs muscle fatigue; however, these conclusions come from studies mainly on men. To test whether the same physiological understanding can be applied to women, we compared the performance-duration relationships and neuromuscular activity between seven men [23.3 ± 1.9 (SD) yr] and seven women (21.7 ± 1.8 yr) from multiple exhaustive bouts of cycle ergometry. Each subject performed trials to obtain the peak 3-s power output (Pmax), the mechanical power at the aerobic maximum (Paer), and 11-14 constant-load bouts eliciting failure between 3 and 300 s. Collectively, men and women performed 180 exhaustive bouts spanning an ~6-fold range of power outputs (118-1116 W) and an ~35-fold range of trial durations (8-283 s). Men generated 66% greater Pmax (956 ± 109 W vs. 632 ± 74 W) and 68% greater Paer (310 ± 47 W vs. 212 ± 15 W) than women. However, the metabolically based time constants describing the time course of performance loss were similar between men (0.020 ± 0.003/s) and women (0.021 ± 0.003/s). Additionally, the fatigue-induced increases in neuromuscular activity did not differ between the sexes when compared relative to the pedal forces at Paer These data suggest that muscle fatigue during short-duration dynamic exercise has a common metabolically based mechanism determined by the extent that ATP is resynthesized by anaerobic metabolism. NEW & NOTEWORTHY Although men and women differed considerably in their absolute cycling performances, there was no sex difference in the metabolically based exponential time constant that described the performance-duration relationship. Similarly, the fatigue-induced increases in neuromuscular activity were not different between the sexes when compared from a metabolic perspective. These data suggest that men and women have similar rate-limiting mechanisms for short-duration dynamic exercise that are determined by the extent the exercise is supported by anaerobic metabolism.
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Affiliation(s)
- Christopher W Sundberg
- Biomechanics Laboratory, Departments of Health and Human Performance and Organismal Biology and Ecology, University of Montana, Missoula, Montana; and .,Neuromuscular Physiology Laboratory, Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin
| | - Sandra K Hunter
- Neuromuscular Physiology Laboratory, Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin
| | - Matthew W Bundle
- Biomechanics Laboratory, Departments of Health and Human Performance and Organismal Biology and Ecology, University of Montana, Missoula, Montana; and
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Walker DJ, Farquharson F, Klenze H, Walterspacher S, Storz L, Duerschmied D, Roecker K, Kabitz HJ. Diaphragmatic fatigue during inspiratory muscle loading in normoxia and hypoxia. Respir Physiol Neurobiol 2016; 227:1-8. [PMID: 26845453 DOI: 10.1016/j.resp.2016.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 01/15/2016] [Accepted: 01/26/2016] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Diaphragmatic fatigue (DF) occurs during strenuous loading of respiratory muscles (e.g., heavy-intensity whole-body exercise, normocapnic hyperpnea, inspiratory resistive breathing). DF develops early on during normoxia, without further decline toward task failure; however, its progression during inspiratory muscle loading in during hypoxia remains unclear. Therefore, the present study used volume-corrected transdiaphragmatic pressures during supramaximal magnetic phrenic nerve stimulation (Pdi,twc) to investigate the effect of hypoxia on the progression of diaphragmatic fatigue during inspiratory muscle loading. METHODS Seventeen subjects completed two standardized rounds of inspiratory muscle loading (blinded, randomized) under the following conditions: (i) normoxia, and (ii) normobaric hypoxia (SpO2 80%), with Pdi,twc assessment every 45 s. RESULTS In fatiguers (i.e., Pdi,twc reduction >10%, n=10), biometric approximation during normoxia is best represented by Pdi,twc=4.06+0.83 exp(-0.19 × x), in contrast to Pdi,twc=4.38-(0.05 × x) during hypoxia. CONCLUSION Progression of diaphragmatic fatigue during inspiratory muscle loading assessed by Pdi,tw differs between normoxia and normobaric hypoxia: in the former, Pdi,tw follows an exponential decay, whereas during hypoxia, Pdi,tw follows a linear decline.
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Affiliation(s)
- David Johannes Walker
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany; Department of Pneumology, University Hospital Freiburg, Germany.
| | - Franziska Farquharson
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany; Department of Pneumology, University Hospital Freiburg, Germany
| | - Hannes Klenze
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany; Department of Pneumology, University Hospital Freiburg, Germany
| | - Stephan Walterspacher
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany
| | - Lucia Storz
- Department of Pneumology, University Hospital Freiburg, Germany
| | - Daniel Duerschmied
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Germany
| | - Kai Roecker
- Department of Applied Public Health (AGW), Furtwangen University, Germany
| | - Hans-Joachim Kabitz
- Department of Pneumology and Intensive Care Medicine, Academic Teaching Hospital Klinikum Konstanz, Germany
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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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Kume D, Akahoshi S, Yamagata T, Wakimoto T, Nagao N. Does voluntary hypoventilation during exercise impact EMG activity? SPRINGERPLUS 2016; 5:149. [PMID: 27026846 PMCID: PMC4766162 DOI: 10.1186/s40064-016-1845-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 02/15/2016] [Indexed: 11/17/2022]
Abstract
It has been reported that exercise under hypoxic conditions induces reduced muscle oxygenation, which could be related to enhanced activity on electromyography (EMG). Although it has been demonstrated that exercise under conditions of voluntary hypoventilation (VH) evokes muscle deoxygenation, it is unclear whether VH during exercise impacts EMG. Seven men performed bicycle exercise for 5 min at 65 % of peak oxygen uptake with normal breathing (NB) and VH. Muscle oxygenation; concentration changes in oxyhemoglobin (Oxy-Hb), deoxyhemoglobin (Deoxy-Hb) and total hemoglobin (Total-Hb); and surface EMG in the vastus lateralis muscle were simultaneously measured. In the VH condition, Oxy-Hb was significantly lower and Deoxy-Hb was significantly higher compared to those in the NB condition (P < 0.05 for both), whereas there was no significant difference in Total-Hb between the two conditions. We observed significantly higher values (P < 0.05) on integrated EMG during exercise under VH conditions compared to those under NB conditions. This study suggests that VH during exercise augments EMG activity.
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Affiliation(s)
- Daisuke Kume
- Department of Integrated Arts and Science, National Institute of Technology, Okinawa College, 905, Henoko, Nago, Okinawa 905-2192 Japan
| | - Shogo Akahoshi
- Department of Health and Sports Science, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193 Japan
| | - Takashi Yamagata
- Department of Clothing, Japan Women's University, 2-8-1, Mejirodai, Bunkyoku, Tokyo 112-8681 Japan
| | - Toshihiro Wakimoto
- Department of Health and Sports Science, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193 Japan
| | - Noriki Nagao
- Department of Nursing, Hyogo University, 2301, Hiraokachoshinzaike, Kakogawa, Hyogo 675-0195 Japan
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Katayama K, Ishida K, Saito M, Koike T, Ogoh S. Hypoxia attenuates cardiopulmonary reflex control of sympathetic nerve activity during mild dynamic leg exercise. Exp Physiol 2016; 101:377-86. [PMID: 27094223 DOI: 10.1113/ep085632] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/04/2016] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? The cardiopulmonary baroreflex inhibits adjustment of sympathetic vasomotor outflow during mild-intensity dynamic exercise. However, it is unclear how suppression of sympathetic vasomotor outflow by the cardiopulmonary baroreflex is modulated by a powerful sympatho-excitatory drive from the exercise pressor reflex, central command and/or the arterial chemoreflex. What is the main finding and its importance? Hypoxia-induced heightened sympathetic nerve activity during dynamic exercise attenuated cardiopulmonary baroreflex control of sympathetic vasomotor outflow. This could facilitate the redistribution of blood flow to the active muscles by sympathetically mediated vasoconstriction of inactive muscles. Muscle sympathetic nerve activity (MSNA) does not increase during mild-intensity dynamic leg exercise in normoxic conditions, despite activation of central command and the exercise pressor reflex. Suppression of MSNA could be caused by muscle pump-induced loading of cardiopulmonary baroreceptors. In contrast, MSNA increases during mild dynamic leg exercise in hypoxic conditions. We hypothesized that hypoxic exercise, which induces a powerful sympatho-excitatory drive from the exercise pressor reflex, central command and/or arterial chemoreflex, attenuates cardiopulmonary reflex control of sympathetic vasomotor outflow. To test this hypothesis, MSNA was recorded during leg cycling in hypoxic conditions and with increased central blood volume by increasing the pedalling frequency to change the cardiopulmonary baroreflex. Subjects performed two leg cycle exercises at different pedal cadences of 60 and 80 r.p.m. (60EX and 80EX trials, respectively) in two (haemodynamic and MSNA) measurement conditions while breathing a hypoxic gas mixture (inspired oxygen fraction = 0.12). Thoracic impedance, stroke volume and cardiac output were measured non-invasively using impedance cardiography. During the MSNA test, MSNA was recorded via microneurography at the right median nerve at the elbow. Changes in thoracic impedance, stroke volume and cardiac output during the 80EX trial were greater than those during the 60EX trial. The MSNA burst frequency during hypoxic exercise in the 80EX trial (39 ± 4 bursts min(-1)) did not differ from that during the 60EX trial (39 ± 3 bursts min(-1)). These results suggest that the cardiopulmonary baroreflex of sympathetic vasomotor outflow during dynamic exercise is modulated by heightened hypoxia-induced sympathetic nerve activity.
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Affiliation(s)
- Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan.,Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan.,Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Mitsuru Saito
- Faculty of Psychological and Physical Science, Aichigakuin University, Nisshin, Japan
| | - Teruhiko Koike
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan.,Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
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Lloyd A, Raccuglia M, Hodder S, Havenith G. Interaction between environmental temperature and hypoxia on central and peripheral fatigue during high-intensity dynamic knee extension. J Appl Physiol (1985) 2016; 120:567-79. [PMID: 26769955 DOI: 10.1152/japplphysiol.00876.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/06/2016] [Indexed: 11/22/2022] Open
Abstract
This study investigated causative factors behind the expression of different interaction types during exposure to multistressor environments. Neuromuscular fatigue rates and time to exhaustion (TTE) were investigated in active men (n = 9) exposed to three climates [5 °C, 50% relative humidity (rh); 23 °C, 50% rh; and 42 °C, 70% rh] at two inspired oxygen fractions (0.209 and 0.125 FiO2; equivalent attitude = 4,100 m). After a 40-min rest in the three climatic conditions, participants performed constant-workload (high intensity) knee extension exercise until exhaustion, with brief assessments of neuromuscular function every 110 s. Independent exposure to cold, heat, and hypoxia significantly (P < 0.01) reduced TTE from thermoneutral normoxia (reductions of 190, 405, and 505 s from 915 s, respectively). The TTE decrease was consistent with a faster rate of peripheral fatigue development (P < 0.01) compared with thermoneutral normoxia (increase of 1.6, 3.1, and 4.9%/min from 4.1%/min, respectively). Combined exposure to hypoxic-cold resulted in an even greater TTE reduction (-589 s), likely due to an increase in the rate of peripheral fatigue development (increased by 7.6%/min), but this was without significant interaction between stressors (P > 0.198). In contrast, combined exposure to hypoxic heat reduced TTE by 609 s, showing a significant antagonistic interaction (P = 0.003) similarly supported by an increased rate of peripheral fatigue development (which increased by 8.3%/min). A small decline (<0.4%/min) in voluntary muscle activation was observed only in thermoneutral normoxia. In conclusion, interaction type is influenced by the impact magnitude of the effect of the individual stressors' effect on exercise capacity, whereby the greater the effect of stressors, the greater the probability that one stressor will be abolished by the other. This indicates that humans respond to severe and simultaneous physiological strains on the basis of a worst-strain-takes-precedence principle.
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Affiliation(s)
- Alex Lloyd
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
| | - Margherita Raccuglia
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
| | - Simon Hodder
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
| | - George Havenith
- Environmental Ergonomics Research Centre, Loughborough University, Loughborough, United Kingdom
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Panagiotou M, Polychronopoulos V, Strange C. Respiratory and lower limb muscle function in interstitial lung disease. Chron Respir Dis 2016; 13:162-72. [PMID: 26768011 DOI: 10.1177/1479972315626014] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Growing evidence suggests that respiratory and limb muscle function may be impaired in patients with interstitial lung disease (ILD). Importantly, muscle dysfunction could promote dyspnoea, fatigue and functional limitation all of which are cardinal features of ILD. This article examines the risk factors for skeletal muscle dysfunction in ILD, reviews the current evidence on overall respiratory and limb muscle function and focuses on the occurrence and implications of skeletal muscle dysfunction in ILD. Research limitations and pathways to address the current knowledge gaps are highlighted.
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Affiliation(s)
- Marios Panagiotou
- Scottish Pulmonary Vascular Unit, Golden Jubilee National Hospital, Glasgow, UK
| | | | - Charlie Strange
- Division of Pulmonary and Critical Care Medicine, Medical University of South Carolina, Charleston, SC, USA
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38
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Morales-Artacho AJ, Padial P, Rodríguez-Matoso D, Rodríguez-Ruiz D, García-Ramos A, García-Manso JM, Calderón C, Feriche B. Assessment of Muscle Contractile Properties at Acute Moderate Altitude Through Tensiomyography. High Alt Med Biol 2015; 16:343-9. [PMID: 26562625 DOI: 10.1089/ham.2015.0078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Under hypoxia, alterations in muscle contractile properties and faster fatigue development have been reported. This study investigated the efficacy of tensiomyography (TMG) in assessing muscle contractile function at acute moderate altitude. Biceps femoris (BF) and vastus lateralis (VL) muscles of 18 athletes (age 20.1 ± 6.1 years; body mass 65.4 ± 13.9 kg; height 174.6 ± 9.5 cm) were assessed at sea level and moderate altitude using electrically evoked contractions on two consecutive days. Maximum radial displacement (Dm), time of contraction (Tc), reaction time (Td), sustained contraction time (Ts), and relaxation time (Tr) were recorded at 40, 60, 80, and 100 mA. At altitude, VL showed lower Dm values at 40 mA (p = 0.008; ES = -0.237). Biceps femoris showed Dm decrements in all electrical stimulations (p < 0.001, ES > 0.61). In VL, Tc was longer at altitude at 40 (p = 0.031, ES = 0.56), and 100 mA (p = 0.03, ES = 0.51). Regarding Td, VL showed significant increases in all electrical intensities under hypoxia (p ≤ 0.03, ES ≥ 0.33). TMG appears effective at detecting slight changes in the muscle contractile properties at moderate altitude. Further research involving TMG along with other muscle function assessment methods is needed to provide additional insight into peripheral neuromuscular alterations at moderate altitude.
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Affiliation(s)
- Antonio J Morales-Artacho
- 1 Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada , Granada, Spain
| | - Paulino Padial
- 1 Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada , Granada, Spain
| | | | | | - Amador García-Ramos
- 1 Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada , Granada, Spain
| | | | - Carmen Calderón
- 3 Sport Performance Centre of Sierra Nevada , Granada, Spain
| | - Belén Feriche
- 1 Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada , Granada, Spain
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39
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Poitras VJ, Bentley RF, Hopkins-Rosseel DH, LaHaye SA, Tschakovsky ME. Lack of independent effect of type 2 diabetes beyond characteristic comorbidities and medications on small muscle mass exercising muscle blood flow and exercise tolerance. Physiol Rep 2015; 3:3/8/e12487. [PMID: 26265750 PMCID: PMC4562573 DOI: 10.14814/phy2.12487] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Persons with type 2 diabetes (T2D) are believed to have reduced exercise tolerance; this may be partly due to impaired exercising muscle blood flow (MBF). Whether there is an impact of T2D on exercising MBF within the typical constellation of comorbidities (hypertension, dyslipidemia, obesity) and their associated medications has not been investigated. We tested the hypothesis that small muscle mass exercise tolerance is reduced in persons with T2D versus Controls (matched for age, body mass index, fitness, comorbidities, non-T2D medications) and that this is related to blunted MBF. Eight persons with T2D and eight controls completed a forearm critical force (fCFimpulse) test as a measure of exercise tolerance (10-min intermittent maximal effort forearm contractions; the average contraction impulse in the last 30 sec quantified fCFimpulse). Forearm blood flow (FBF; ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured; forearm vascular conductance (FVK) was calculated. Data are means ± SD, T2D versus Control. fCFimpulse was not different between groups (136.9 ± 47.3 N·sec vs. 163.1 ± 49.7 N·sec, P = 0.371) nor was the ΔFBF from rest to during exercise at fCFimpulse (502.9 ± 144.6 vs. 709.1 ± 289.2 mL/min, P = 0.092), or its determinants ΔFVK and ΔMAP (both P > 0.05), although there was considerable interindividual variability. ΔFBF was strongly related to fCFimpulse (r = 0.727, P = 0.002), providing support for the relationship between oxygen delivery and exercise tolerance. We conclude that small muscle mass exercising MBF and exercise tolerance are not impaired in representative persons with T2D versus appropriately matched controls. This suggests that peripheral vascular control impairment does not contribute to reduced exercise tolerance in this population.
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Affiliation(s)
- Veronica J Poitras
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Robert F Bentley
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Diana H Hopkins-Rosseel
- Cardiac Rehabilitation Centre, Hotel Dieu Hospital, Kingston, Ontario, Canada School of Rehabilitation Therapy, Queen's University, Kingston, Ontario, Canada
| | - Stephen A LaHaye
- Cardiac Rehabilitation Centre, Hotel Dieu Hospital, Kingston, Ontario, Canada
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
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40
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Katayama K, Suzuki Y, Hoshikawa M, Ohya T, Oriishi M, Itoh Y, Ishida K. Hypoxia exaggerates inspiratory accessory muscle deoxygenation during hyperpnoea. Respir Physiol Neurobiol 2015; 211:1-8. [DOI: 10.1016/j.resp.2015.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/23/2015] [Accepted: 02/26/2015] [Indexed: 10/23/2022]
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41
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The interactive effect of cooling and hypoxia on forearm fatigue development. Eur J Appl Physiol 2015; 115:2007-18. [DOI: 10.1007/s00421-015-3181-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/30/2015] [Indexed: 11/25/2022]
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42
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Layec G, Bringard A, Le Fur Y, Micallef JP, Vilmen C, Perrey S, Cozzone PJ, Bendahan D. Opposite effects of hyperoxia on mitochondrial and contractile efficiency in human quadriceps muscles. Am J Physiol Regul Integr Comp Physiol 2015; 308:R724-33. [PMID: 25695290 DOI: 10.1152/ajpregu.00461.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/10/2015] [Indexed: 01/06/2023]
Abstract
Exercise efficiency is an important determinant of exercise capacity. However, little is known about the physiological factors that can modulate muscle efficiency during exercise. We examined whether improved O2 availability would 1) impair mitochondrial efficiency and shift the energy production toward aerobic ATP synthesis and 2) reduce the ATP cost of dynamic contraction owing to an improved neuromuscular efficiency, such that 3) whole body O2 cost would remain unchanged. We used (31)P-magnetic resonance spectroscopy, surface electromyography, and pulmonary O2 consumption (V̇o2p) measurements in eight active subjects during 6 min of dynamic knee-extension exercise under different fractions of inspired O2 (FiO2 , 0.21 in normoxia and 1.0 in hyperoxia). V̇o2p (755 ± 111 ml/min in normoxia and 799 ± 188 ml/min in hyperoxia, P > 0.05) and O2 cost (P > 0.05) were not significantly different between normoxia and hyperoxia. In contrast, the total ATP synthesis rate and the ATP cost of dynamic contraction were significantly lower in hyperoxia than normoxia (P < 0.05). As a result, the ratio of the rate of oxidative ATP synthesis from the quadriceps to V̇o2p was lower in hyperoxia than normoxia but did not reach statistical significance (16 ± 3 mM/ml in normoxia and 12 ± 5 mM/ml in hyperoxia, P = 0.07). Together, these findings reveal dynamic and independent regulations of mitochondrial and contractile efficiency as a consequence of O2 availability in young active individuals. Furthermore, muscle efficiency appears to be already optimized in normoxia and is unlikely to contribute to the well-established improvement in exercise capacity induced by hyperoxia.
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Affiliation(s)
- Gwenael Layec
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Center for Magnetic Resonance in Biology and Medicine, UMR 7339, Marseille, France; Division of Geriatrics, Department of 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;
| | - Aurélien Bringard
- Département des Neurosciences Fondamentales, Centre Médical Universitaire, University of Geneva, Geneva, Switzerland
| | - Yann Le Fur
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Center for Magnetic Resonance in Biology and Medicine, UMR 7339, Marseille, France
| | - Jean-Paul Micallef
- Movement To Health (M2H), EuroMov, Montpellier-1 University, Montpellier, France; and Institut National de la Santé et de la Recherche Médicale ADR 08, Montpellier, France
| | - Christophe Vilmen
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Center for Magnetic Resonance in Biology and Medicine, UMR 7339, Marseille, France
| | - Stéphane Perrey
- Movement To Health (M2H), EuroMov, Montpellier-1 University, Montpellier, France; and
| | - Patrick J Cozzone
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Center for Magnetic Resonance in Biology and Medicine, UMR 7339, Marseille, France
| | - David Bendahan
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Center for Magnetic Resonance in Biology and Medicine, UMR 7339, Marseille, France
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Oliveira MF, Zelt JTJ, Jones JH, Hirai DM, O'Donnell DE, Verges S, Neder JA. Does impaired O2 delivery during exercise accentuate central and peripheral fatigue in patients with coexistent COPD-CHF? Front Physiol 2015; 5:514. [PMID: 25610401 PMCID: PMC4285731 DOI: 10.3389/fphys.2014.00514] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 12/15/2014] [Indexed: 02/04/2023] Open
Abstract
Impairment in oxygen (O2) delivery to the central nervous system ("brain") and skeletal locomotor muscle during exercise has been associated with central and peripheral neuromuscular fatigue in healthy humans. From a clinical perspective, impaired tissue O2 transport is a key pathophysiological mechanism shared by cardiopulmonary diseases, such as chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). In addition to arterial hypoxemic conditions in COPD, there is growing evidence that cerebral and muscle blood flow and oxygenation can be reduced during exercise in both isolated COPD and CHF. Compromised cardiac output due to impaired cardiopulmonary function/interactions and blood flow redistribution to the overloaded respiratory muscles (i.e., ↑work of breathing) may underpin these abnormalities. Unfortunately, COPD and CHF coexist in almost a third of elderly patients making these mechanisms potentially more relevant to exercise intolerance. In this context, it remains unknown whether decreased O2 delivery accentuates neuromuscular manifestations of central and peripheral fatigue in coexistent COPD-CHF. If this holds true, it is conceivable that delivering a low-density gas mixture (heliox) through non-invasive positive pressure ventilation could ameliorate cardiopulmonary function/interactions and reduce the work of breathing during exercise in these patients. The major consequence would be increased O2 delivery to the brain and active muscles with potential benefits to exercise capacity (i.e., ↓central and peripheral neuromuscular fatigue, respectively). We therefore hypothesize that patients with coexistent COPD-CHF stop exercising prematurely due to impaired central motor drive and muscle contractility as the cardiorespiratory system fails to deliver sufficient O2 to simultaneously attend the metabolic demands of the brain and the active limb muscles.
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Affiliation(s)
- Mayron F Oliveira
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division, Department of Medicine, School of Medicine, Federal University of São Paulo (UNIFESP) São Paulo, Brazil
| | - Joel T J Zelt
- Laboratory of Clinical Exercise Physiology, Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University Kingston, ON, Canada
| | - Joshua H Jones
- Laboratory of Clinical Exercise Physiology, Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University Kingston, ON, Canada
| | - Daniel M Hirai
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division, Department of Medicine, School of Medicine, Federal University of São Paulo (UNIFESP) São Paulo, Brazil ; Laboratory of Clinical Exercise Physiology, Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University Kingston, ON, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University Kingston, ON, Canada
| | - Samuel Verges
- HP2 Laboratory, Grenoble Alpes University Grenoble, France
| | - J Alberto Neder
- Pulmonary Function and Clinical Exercise Physiology Unit (SEFICE), Respiratory Division, Department of Medicine, School of Medicine, Federal University of São Paulo (UNIFESP) São Paulo, Brazil ; Laboratory of Clinical Exercise Physiology, Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University Kingston, ON, Canada
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Modulation of exercise-induced spinal loop properties in response to oxygen availability. Eur J Appl Physiol 2014; 115:471-82. [PMID: 25361617 DOI: 10.1007/s00421-014-3032-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 10/15/2014] [Indexed: 10/24/2022]
Abstract
This study investigated the effects of acute hypoxia on spinal reflexes and soleus muscle function after a sustained contraction of the plantar flexors at 40% of maximal voluntary isometric contraction (MVC). Fifteen males (age 25.3 ± 0.9 year) performed the fatigue task at two different inspired O₂ fractions (FiO₂ = 0.21/0.11) in a randomized and single-blind fashion. Before, at task failure and after 6, 12 and 18 min of passive recovery, the Hoffman-reflex (H max) and M-wave (M max) were recorded at rest and voluntary activation (VA), surface electromyogram (RMSmax), M-wave (M sup) and V-wave (V sup) were recorded during MVC. Normalized H-reflex (H max/M max) was significantly depressed pre-exercise in hypoxia compared with normoxia (0.31 ± 0.08 and 0.36 ± 0.08, respectively, P < 0.05). Hypoxia did not affect time to task failure (mean time of 453.9 ± 32.0 s) and MVC decrease at task failure (-18% in normoxia vs. -16% in hypoxia). At task failure, VA (-8%), RMSmax/M sup (-11%), H max/M max (-27%) and V sup/M sup (-37%) decreased (P < 0.05), but with no FiO2 effect. H max/M max restored significantly throughout recovery in hypoxia but not in normoxia, while V sup/M sup restored significantly during recovery in normoxia but not in hypoxia (P < 0.05). Collectively, these findings indicate that central adaptations resulting from sustained submaximal fatiguing contraction were not different in hypoxia and normoxia at task failure. However, the FiO₂-induced differences in spinal loop properties pre-exercise and throughout recovery suggest possible specific mediation by the hypoxic-sensitive group III and IV muscle afferents, supraspinal regulation mechanisms being mainly involved in hypoxia while spinal ones may be predominant in normoxia.
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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: 127] [Impact Index Per Article: 12.7] [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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Katayama K, Yamashita S, Iwamoto E, Ishida K. Flow-mediated dilation in the inactive limb following acute hypoxic exercise. Clin Physiol Funct Imaging 2014; 36:60-9. [DOI: 10.1111/cpf.12194] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 09/01/2014] [Indexed: 01/24/2023]
Affiliation(s)
- Keisho Katayama
- Research Center of Health; Physical Fitness and Sports; Nagoya University; Nagoya Japan
| | - Shin Yamashita
- Graduate School of Education and Human Development; Nagoya University; Nagoya Japan
| | - Erika Iwamoto
- School of Health Sciences; Sapporo Medical University; Sapporo Japan
| | - Koji Ishida
- Research Center of Health; Physical Fitness and Sports; Nagoya University; Nagoya Japan
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47
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Christian RJ, Bishop DJ, Billaut F, Girard O. Peripheral fatigue is not critically regulated during maximal, intermittent, dynamic leg extensions. J Appl Physiol (1985) 2014; 117:1063-73. [PMID: 25213635 DOI: 10.1152/japplphysiol.00988.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Central motor drive to active muscles is believed to be reduced during numerous exercise tasks to prevent excessive peripheral fatigue development. The purpose of the present study was to use hypoxia to exacerbate physiological perturbations during a novel, intermittent exercise task and to explore the time-course and interplay between central and peripheral neuromuscular adjustments. On separate days, 14 healthy men performed four sets of 6 × 5 maximal-intensity, isokinetic leg extensions (1 repetition lasting ∼7 s) at 300°/s (15 and 100 s of passive rest between repetitions and sets, respectively) under normoxia (NM, fraction of inspired O2 0.21), moderate (MH, 0.14), and severe normobaric hypoxia (SH, 0.10). Neuromuscular assessments of the knee extensors were conducted before and immediately after each set. There was an interaction between time and condition on the mean peak torque produced during each set (P < 0.05). RMS/M-wave activity of the rectus femoris decreased across the four sets of exercise, but there was no difference between conditions (8.3 ± 5.1% all conditions compounded, P > 0.05). Potentiated twitch torque decreased post set 1 in all conditions (all P < 0.05) with greater reductions following each set in SH compared with NM but not MH (end-exercise reductions 41.3 ± 3.0% vs. 28.0 ± 3.2%, P < 0.05 and 32.1 ± 3.3%, P > 0.05). In conclusion, severe hypoxia exacerbates both peripheral fatigue development and performance decrements during maximal, intermittent, dynamic leg extensions. In contrast to observations with other exercise modes, during exercise involving a single muscle group the attenuation of central motor drive does not appear to independently regulate the development of peripheral muscle fatigue.
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Affiliation(s)
- Ryan J Christian
- College of Sport and Exercise Science, Victoria University, Melbourne, Australia; Aspetar - Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar;
| | - David J Bishop
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Australia
| | - François Billaut
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Australia; Université Laval, Département de Kinésiologie, Québec, Québec, Canada; and
| | - Olivier Girard
- Aspetar - Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Faculty of Biology and Medicine, Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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48
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Faiss R, Girard O, Millet GP. Advancing hypoxic training in team sports: from intermittent hypoxic training to repeated sprint training in hypoxia. Br J Sports Med 2014; 47 Suppl 1:i45-50. [PMID: 24282207 PMCID: PMC3903143 DOI: 10.1136/bjsports-2013-092741] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Over the past two decades, intermittent hypoxic training (IHT), that is, a method where athletes live at or near sea level but train under hypoxic conditions, has gained unprecedented popularity. By adding the stress of hypoxia during 'aerobic' or 'anaerobic' interval training, it is believed that IHT would potentiate greater performance improvements compared to similar training at sea level. A thorough analysis of studies including IHT, however, leads to strikingly poor benefits for sea-level performance improvement, compared to the same training method performed in normoxia. Despite the positive molecular adaptations observed after various IHT modalities, the characteristics of optimal training stimulus in hypoxia are still unclear and their functional translation in terms of whole-body performance enhancement is minimal. To overcome some of the inherent limitations of IHT (lower training stimulus due to hypoxia), recent studies have successfully investigated a new training method based on the repetition of short (<30 s) 'all-out' sprints with incomplete recoveries in hypoxia, the so-called repeated sprint training in hypoxia (RSH). The aims of the present review are therefore threefold: first, to summarise the main mechanisms for interval training and repeated sprint training in normoxia. Second, to critically analyse the results of the studies involving high-intensity exercises performed in hypoxia for sea-level performance enhancement by differentiating IHT and RSH. Third, to discuss the potential mechanisms underpinning the effectiveness of those methods, and their inherent limitations, along with the new research avenues surrounding this topic.
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Affiliation(s)
- Raphaël Faiss
- Department of Physiology, Faculty of Biology and Medicine, Institute of Sports Sciences, University of Lausanne, , Lausanne, Switzerland
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Bentley RF, Kellawan JM, Moynes JS, Poitras VJ, Walsh JJ, Tschakovsky ME. Individual susceptibility to hypoperfusion and reductions in exercise performance when perfusion pressure is reduced: evidence for vasodilator phenotypes. J Appl Physiol (1985) 2014; 117:392-405. [PMID: 24970851 DOI: 10.1152/japplphysiol.01155.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The primary objective of this study was to determine whether cardiovascular compensatory response phenotypes exist in the face of a reduced perfusion pressure challenge to exercising muscle oxygen delivery (O2D), and whether these responses might be exercise intensity (EI) dependent. Ten healthy men (19.5 ± 0.4 yr) completed two trials of progressive forearm isometric handgrip exercise to exhaustion (24.5 N increments every 3.5 min) in each of forearm above and below heart level [forearm arterial perfusion pressure (FAPP) difference of 29.5 ± 0.97 mmHg]. At the end of each EI, measurements of forearm blood flow (FBF; ml/min) via brachial artery Doppler and echo ultrasound, mean arterial blood pressure (MAP; mmHg) via finger photoplethysmography, and exercising forearm venous effluent via antecubital vein catheter revealed distinct cardiovascular response groups: n = 6 with compensatory vasodilation vs. n = 4 without compensatory vasodilation. Compensatory vasodilators were able to blunt the perfusion pressure-evoked reduction in submaximal O2D in the arm-above-heart condition, whereas nonvasodilators did not (-22.5 ± 13.6 vs. -65.4 ± 14.1 ml O2/min; P < 0.05), and in combination with being able to increase O2 extraction, nonvasodilators defended submaximal V̇o2 and experienced less of an accumulated submaximal O2D deficit (-80.7 ± 24.7 vs. -219.1 ± 36.0 ml O2/min; P < 0.05). As a result, the compensatory vasodilators experienced less of a compromise to peak EI than nonvasodilators (-24.5 ± 3.5 N vs. -52.1 ± 8.9 N; P < 0.05). In conclusion, in the forearm exercise model studied, vasodilatory response phenotypes exist that determine individual susceptibility to hypoperfusion and the degree to which aerobic metabolism and exercise performance are compromised.
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Affiliation(s)
- Robert F Bentley
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - J Mikhail Kellawan
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Jackie S Moynes
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Veronica J Poitras
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Jeremy J Walsh
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
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Goodall S, Twomey R, Amann M. Acute and chronic hypoxia: implications for cerebral function and exercise tolerance. FATIGUE-BIOMEDICINE HEALTH AND BEHAVIOR 2014; 2:73-92. [PMID: 25593787 DOI: 10.1080/21641846.2014.909963] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
PURPOSE To outline how hypoxia profoundly affects neuronal functionality and thus compromise exercise-performance. METHODS Investigations using electroencephalography (EEG) and transcranial magnetic stimulation (TMS) detecting neuronal changes at rest and those studying fatiguing effects on whole-body exercise performance in acute (AH) and chronic hypoxia (CH) were evaluated. RESULTS At rest during very early hypoxia (<1-h), slowing of cerebral neuronal activity is evident despite no change in corticospinal excitability. As time in hypoxia progresses (3-h), increased corticospinal excitability becomes evident; however, changes in neuronal activity are unknown. Prolonged exposure (3-5 d) causes a respiratory alkalosis which modulates Na+ channels, potentially explaining reduced neuronal excitability. Locomotor exercise in AH exacerbates the development of peripheral-fatigue; as the severity of hypoxia increases, mechanisms of peripheral-fatigue become less dominant and CNS hypoxia becomes the predominant factor. The greatest central-fatigue in AH occurs when SaO2 is ≤75%, a level that coincides with increasing impairments in neuronal activity. CH does not improve the level of peripheral-fatigue observed in AH; however, it attenuates the development of central-fatigue paralleling increases in cerebral O2 availability and corticospinal excitability. CONCLUSIONS The attenuated development of central-fatigue in CH might explain, the improvements in locomotor exercise-performance commonly observed after acclimatisation to high altitude.
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Affiliation(s)
- Stuart Goodall
- Faculty of Health and Life Sciences, Northumbria University, Newcastle, UK
| | - Rosie Twomey
- School of Sport and Service Management, University of Brighton, Eastbourne, UK
| | - Markus Amann
- Department of Medicine, University of Utah, Salt Lake City, UT, USA
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