1
|
Jenkins JR, Salmon OF, Smith CM. Moderate and Severe Acute Normobaric Hypoxia and the 3-Repetition Deadlift, Hand-Release Push-Up, and Leg Tuck Events From the Army Combat Fitness Test. Mil Med 2023; 188:e753-e760. [PMID: 35072728 DOI: 10.1093/milmed/usab399] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/28/2021] [Accepted: 09/17/2021] [Indexed: 11/14/2022] Open
Abstract
INTRODUCTION The newly implemented Army Combat Fitness Test (ACFT) of the U.S. Army seeks to revolutionize the Army's fitness culture and reduce the rate of preventable injuries among soldiers. The initial rollout of the ACFT has been met with several challenges, including a gender-neutral scoring system. The ACFT has undergone several revisions to adapt to the present state of U.S. Army physical fitness; however, the test faces several more obstacles as more data become available. The ACFT was designed to measure combat readiness, a useful tool for units facing deployment or a change in duty station to a high-altitude environment. Reduced oxygen availability (hypoxia) at high altitude influences many physiological functions associated with physical fitness, such that there is an increased demand for oxygen in exercising muscle. Therefore, the purpose was to investigate the effects of normoxic and two levels of hypoxia exposure (moderate and severe; fraction of inspired oxygen [FiO2]: 16.0% and 14.3%) during the 3-repetition deadlift (MDL), hand-release push-up (HRP), and leg tuck (LTK) events of the ACFT. MATERIALS AND METHODS Fourteen recreationally active men (n = 10) and women (n = 4) soldier analogs (27.36 ± 1.12 years, height 1.71 ± 2.79 m, weight 80.60 ± 4.24 kg) completed the MDL, HRP, and LTK at normoxia and acute normobaric moderate (MH; FiO2 16%) and severe (SH; FiO2 14.3%) hypoxic exposure. Scores and performance were recorded for each event, and heart rate (HR) and total body oxygen saturation (SpO2) were monitored throughout. Repeated-measures analysis of variance (ANOVA) was used to assess differences in modified ACFT scores, performance, HR, and SpO2 among hypoxic conditions, with follow-up one-way ANOVA and paired t-test when appropriate. RESULTS Total body oxygen saturation was decreased at MH and SH conditions compared to normoxia but did not vary between ACFT events. Heart rate was not influenced by altitude but did increase in response to exercise. Scores of the modified total and individual ACFT events were not different between normoxia, MH, and SH. There was also no difference in performance based on the amount of weight lifted during the MDL and number of repetitions of the HRP and LTK events in response to hypoxic exposure. CONCLUSIONS Performance and scores of the modified ACFT were not influenced by acute normobaric MH and SH exposure compared to normoxia. Further investigations should examine the full testing battery of the ACFT to provide a comprehensive analysis and potential evidence for such differences.
Collapse
Affiliation(s)
- Jasmin R Jenkins
- Interdisciplinary Health Sciences PhD Program, College of Health Sciences, University of Texas at El Paso, El Paso, TX 79968, USA
- Human and Environmental Physiology Laboratory, College of Health Sciences, University of Texas at El Paso, El Paso, TX 79968, USA
| | - Owen F Salmon
- Interdisciplinary Health Sciences PhD Program, College of Health Sciences, University of Texas at El Paso, El Paso, TX 79968, USA
- Human and Environmental Physiology Laboratory, College of Health Sciences, University of Texas at El Paso, El Paso, TX 79968, USA
| | - Cory M Smith
- Interdisciplinary Health Sciences PhD Program, College of Health Sciences, University of Texas at El Paso, El Paso, TX 79968, USA
- Human and Environmental Physiology Laboratory, College of Health Sciences, University of Texas at El Paso, El Paso, TX 79968, USA
| |
Collapse
|
2
|
Marillier M, Borowik A, Chacaroun S, Baillieul S, Doutreleau S, Guinot M, Wuyam B, Tamisier R, Pépin JL, Estève F, Vergès S, Tessier D, Flore P. High-intensity interval training to promote cerebral oxygenation and affective valence during exercise in individuals with obesity. J Sports Sci 2022; 40:1500-1511. [PMID: 35942923 DOI: 10.1080/02640414.2022.2086658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
Left/right prefrontal cortex (PFC) activation is linked to positive/negative affects, respectively. Besides, larger left PFC oxygenation during exercise relates to higher cardiorespiratory fitness (CRF). High-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) in improving CRF. The influence of training on PFC oxygenation and affects during exercise in individuals with obesity is, however, currently unknown. Twenty participants with obesity (14 males, 48 ± 8 years, body-mass index = 35 ± 6 kg·m-2) were randomised to MICT [50% peak work rate (WRpeak)] or HIIT (1-min bouts 100% WRpeak; 3 sessions/week, 8 weeks). Before/after training, participants completed an incremental ergocycle test. Near-infrared spectroscopy and the Feeling Scale assessed PFC oxygenation and affects during exercise, respectively. Improvements in CRF (e.g., WRpeak: 32 ± 14 vs 20 ± 13 W) were greater after HIIT vs MICT (p < 0.05). Only HIIT induced larger left PFC oxygenation (haemoglobin difference from 7 ± 6 to 10 ± 7 μmol) and enhanced affective valence (from 0.7 ± 2.9 to 2.2 ± 2.0; p < 0.05) at intensities ≥ second ventilatory threshold. Exercise-training induced changes in left PFC oxygenation correlated with changes in CRF [e.g., WRpeak (% predicted), r = 0.46] and post-training affective valence (r = 0.45; p < 0.05). HIIT specifically improved left PFC oxygenation and affects during exercise in individuals with obesity. Implementing HIIT in exercise programmes may therefore have relevant implications for the management of obesity, since greater affective response to exercise is thought to be associated with future commitment to physical activity.
Collapse
Affiliation(s)
| | - Anna Borowik
- Inserm, CHU Grenoble Alpes, Univ. Grenoble Alpes, Grenoble, France
| | | | | | | | - Michel Guinot
- Inserm, CHU Grenoble Alpes, Univ. Grenoble Alpes, Grenoble, France
| | - Bernard Wuyam
- Inserm, CHU Grenoble Alpes, Univ. Grenoble Alpes, Grenoble, France
| | - Renaud Tamisier
- Inserm, CHU Grenoble Alpes, Univ. Grenoble Alpes, Grenoble, France
| | - Jean-Louis Pépin
- Inserm, CHU Grenoble Alpes, Univ. Grenoble Alpes, Grenoble, France
| | - François Estève
- CHU Grenoble Alpes, CLUNI, SCRIMM-Sud, Inserm - UA07 - Rayonnement Synchrotron pour la Recherche Biomédicale (STROBE) ID17 Installation Européenne du Rayonnement Synchrotron (ESRF), Grenoble, France
| | - Samuel Vergès
- Inserm, CHU Grenoble Alpes, Univ. Grenoble Alpes, Grenoble, France
| | - Damien Tessier
- Laboratoire SENS, Univ. Grenoble Alpes, Grenoble, France
| | - Patrice Flore
- Inserm, CHU Grenoble Alpes, Univ. Grenoble Alpes, Grenoble, France
| |
Collapse
|
3
|
Jenkins JR, Salmon OF, Hill EC, Boyle JB, Smith CM. Neuromuscular responses at acute moderate and severe hypoxic exposure during fatiguing exercise of the biceps brachii. Curr Res Physiol 2021; 4:209-215. [PMID: 34746840 PMCID: PMC8562136 DOI: 10.1016/j.crphys.2021.09.002] [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: 08/03/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/02/2022] Open
Abstract
Purpose The present study examined acute normobaric hypoxic exposure on the number of repetitions to failure, electromyographic (EMG) repetition duration (Time), EMG root mean square (RMS) and EMG mean power frequency (MPF) during biceps brachii (BB) dynamic constant external resistance (DCER) exercise. Methods Thirteen subjects performed two sets of fatiguing DCER arm curl repetitions to failure at 70% of their one repetition maximum under normoxic (NH), moderate hypoxia FiO2 = 15% (MH) and severe hypoxia FiO2 = 13% (SH). Electromyography of the BB was analyzed for EMG Time, EMG RMS, and EMG MPF. Repetitions were selected as 25%, 50%, 75%, and 100% of total repetitions (%Fail) completed. Pulse oximetry (SpO2) was measured pre-and post-fatigue. Results There was no significant three-way (Condition x Set x %Fail) or two-way (Condition x Set) interaction for any variable. The number of repetitions to failure significantly decreased from (mean ± SEM) 18.2 ± 1.4 to 9.5 ± 1.0 with each Set. In addition, EMG Time increased (25% < 50%<75% < 100%), EMG RMS decreased (50% > 75%>100%), and EMG MPF decreased (75% > 100%) as a result of fatiguing exercise. SpO2 was lower during MH (Δ5.3%) and SH (Δ9.2%) compared to NH and as a result of fatiguing exercise increased only in MH (Δ2.1%) and SH (Δ5.7%). Conclusion The changes in BB EMG variables indicated exercise caused myoelectric manifestations of fatigue, however, acute moderate or severe hypoxia had no additional influence on the rate of fatigue development or neuromuscular parameters. Acute MH (FiO2 15%) and SH (FiO2 14%) did not alter the muscle contractile process. Arm curl repetitions to failure decreased MU recruitment and conduction velocity. EMG fatigue analysis, hypoxia and arm curls to failure, EMG RMS, EMG MPF and Time. SpO2 was lower at MH and SH which increased following fatiguing exercise.
Collapse
Affiliation(s)
- Jasmin R Jenkins
- Interdisciplinary Health Sciences PhD Program, The University of Texas at El Paso, El Paso, TX, USA
| | - Owen F Salmon
- Interdisciplinary Health Sciences PhD Program, The University of Texas at El Paso, El Paso, TX, USA
| | - Ethan C Hill
- School of Kinesiology & Physical Therapy, Division of Kinesiology, University of Central Florida, Orlando, FL, USA
| | - Jason B Boyle
- Department of Kinesiology, The University of Texas at El Paso, El Paso, TX, USA
| | - Cory M Smith
- Interdisciplinary Health Sciences PhD Program, The University of Texas at El Paso, El Paso, TX, USA.,Department of Kinesiology, The University of Texas at El Paso, El Paso, TX, USA
| |
Collapse
|
4
|
Xiang ZQ, Huang YL, Luo GL, Ma HL, Zhang DL. Decreased Event-Related Desynchronization of Mental Rotation Tasks in Young Tibetan Immigrants. Front Hum Neurosci 2021; 15:664039. [PMID: 34276324 PMCID: PMC8278785 DOI: 10.3389/fnhum.2021.664039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 05/14/2021] [Indexed: 11/26/2022] Open
Abstract
The present study aimed to explore the cortical activity underlying mental rotation in high-altitude immigrants via the event-related desynchronization (ERD), the electroencephalogram time–frequency analysis, and source localization based on electroencephalographic data. When compared with the low-altitude individuals, the reaction time of mental rotation tasks was significantly slower in immigrants who had lived in high-altitude areas for 3 years. The time–frequency analysis showed that the alpha ERD and the beta ERD within the time window (400–700 ms) were decreased during the mental rotation tasks in these immigrants. The decreased ERD was observed at the parietal–occipital regions within the alpha band and at the central–parietal regions within the beta band. The decreased ERD might embody the sensorimotor-related cortical activity from hypoxia, which might be involved in cognitive control function in high-altitude immigrants, which provided insights into the neural mechanism of spatial cognition change on aspect of embodied cognition due to high-altitude exposure.
Collapse
Affiliation(s)
- Zu-Qiang Xiang
- Department of Psychology, School of Education, Guangzhou University, Guangzhou, China
| | - Yi-Lin Huang
- Department of Psychology, School of Education, Guangzhou University, Guangzhou, China
| | - Guang-Li Luo
- Department of Psychology, School of Education, Guangzhou University, Guangzhou, China.,The Fourth Primary School of Qiaotou Town, Dongguan, China
| | - Hai-Lin Ma
- Plateau Brain Science Research Center, Tibet University, Lhasa, China.,Plateau Brain Science Research Center, South China Normal University, Guangzhou, China
| | - De-Long Zhang
- Plateau Brain Science Research Center, Tibet University, Lhasa, China.,Plateau Brain Science Research Center, South China Normal University, Guangzhou, China.,Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education, Guangzhou, China.,School of Psychology, Center for Studies of Psychological Application, and Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, China
| |
Collapse
|
5
|
Marillier M, Bernard AC, Verges S, Moran-Mendoza O, O’Donnell DE, Neder JA. Influence of exertional hypoxemia on cerebral oxygenation in fibrotic interstitial lung disease. Respir Physiol Neurobiol 2021; 285:103601. [DOI: 10.1016/j.resp.2020.103601] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/10/2020] [Accepted: 12/13/2020] [Indexed: 11/17/2022]
|
6
|
Marillier M, Bernard AC, Verges S, Neder JA. The role of peripheral muscle fatigability on exercise intolerance in COPD. Expert Rev Respir Med 2020; 15:117-129. [PMID: 33148059 DOI: 10.1080/17476348.2021.1836964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Exercise limitation in chronic obstructive pulmonary disease (COPD) is multi-factorial; however, growing evidence indicates that muscle dysfunction may contribute in some patients. AREAS COVERED This work outlines current evidence for and against increased peripheral muscle fatigability in COPD through a comprehensive review of relevant literature available on PubMed/MEDLINE until May 2020. The authors first discuss key methodological issues relative to muscle fatigue assessment by non-volitional techniques, particularly magnetic stimulation. The authors then provide a detailed discussion of critical studies to have objectively measured skeletal muscle fatigue in individuals with COPD. EXPERT OPINION Current evidence indicates that localized (knee extension) and cycling exercise are associated with increased quadriceps fatigability in most COPD patients. Increased fatigability, however, has not been consistently found in response to walking, likely reflecting the tendency of 'central' respiratory constraints to overshadow potential functional impairments in the appendicular muscles in this form of exercise. Thus, addressing skeletal muscle abnormalities may be critical to translate improvements in lung mechanics (e.g., due to bronchodilator therapy) into better exercise tolerance. The positive effects of pulmonary rehabilitation on muscle fatigability are particularly encouraging and suggest a role for these measurements to test the efficacy of emerging adjunct training strategies focused on the peripheral muscles.
Collapse
Affiliation(s)
- Mathieu Marillier
- Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital , Kingston, ON, Canada.,HP2 Laboratory, INSERM U1042, Grenoble Alpes University , Grenoble, France
| | - Anne-Catherine Bernard
- Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital , Kingston, ON, Canada.,HP2 Laboratory, INSERM U1042, Grenoble Alpes University , Grenoble, France
| | - Samuel Verges
- HP2 Laboratory, INSERM U1042, Grenoble Alpes University , Grenoble, France
| | - J Alberto Neder
- Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital , Kingston, ON, Canada
| |
Collapse
|
7
|
Crespo A, Baillieul S, Marhuenda E, Bradicich M, Andrianopoulos V, Louvaris Z, Marillier M, Almendros I. ERS International Congress, Madrid, 2019: highlights from the Sleep and Clinical Physiology Assembly. ERJ Open Res 2020; 6:00373-2019. [PMID: 32714963 PMCID: PMC7369446 DOI: 10.1183/23120541.00373-2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 05/13/2020] [Indexed: 12/12/2022] Open
Abstract
The 2019 European Respiratory Society (ERS) International Congress took place in Madrid, Spain, and served as a platform to find out the latest advances in respiratory diseases research. The research aims are to understand the physiology and consequences of those diseases, as well as the improvement in their diagnoses, treatments and patient care. In particular, the scientific sessions arranged by ERS Assembly 4 provided novel insights into sleep-disordered breathing and new knowledge in respiratory physiology. This article, divided by session, will summarise the most relevant studies presented at the ERS International Congress. Each section has been written by Early Career Members specialising in the different fields of this interdisciplinary assembly.
Collapse
Affiliation(s)
- Andrea Crespo
- Multidisciplinary Sleep Unit, Dept of Pulmonology, Rio Hortega University Hospital, Valladolid, Spain
- Biomedical Engineering Group, University of Valladolid, Valladolid, Spain
- All authors contributed equally to this work
| | - Sébastien Baillieul
- HP2 Laboratory, INSERM U1042, Grenoble Alpes University, Grenoble, France
- FCR Laboratory, Grenoble Alpes University Hospital, Grenoble, France
- All authors contributed equally to this work
| | - Esther Marhuenda
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias CIBERES, Madrid, Spain
- All authors contributed equally to this work
| | - Matteo Bradicich
- Dept of Pulmonology and Sleep Disorders Centre, University Hospital Zurich, Zurich, Switzerland
- All authors contributed equally to this work
| | - Vasileios Andrianopoulos
- Institute for Pulmonary Rehabilitation Research, Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee, Germany
- All authors contributed equally to this work
| | - Zafeiris Louvaris
- Faculty of Kinesiology and Rehabilitation Sciences, Division of Respiratory Rehabilitation, Department Rehabilitation Sciences KU Leuven, University Hospitals Leuven, Leuven, Belgium
- All authors contributed equally to this work
| | - Mathieu Marillier
- Laboratory of Clinical Exercise Physiology, Queen's University, Kingston, ON, Canada
- All authors contributed equally to this work
| | - Isaac Almendros
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias CIBERES, Madrid, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- All authors contributed equally to this work
| |
Collapse
|
8
|
Marillier M, Rupp T, Bouzat P, Walther G, Baillieul S, Millet GY, Robach P, Verges S. Cerebral haemodynamics and oxygenation during whole‐body exercise over 5 days at high altitude. Exp Physiol 2020; 106:65-75. [DOI: 10.1113/ep088354] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/27/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Mathieu Marillier
- HP2 Laboratory INSERM Grenoble Alpes University CHU Grenoble Alpes Grenoble France
| | - Thomas Rupp
- HP2 Laboratory INSERM Grenoble Alpes University CHU Grenoble Alpes Grenoble France
- Inter‐University Laboratory of Human Movement Sciences EA 7424 University Savoie Mont Blanc Chambery France
| | - Pierre Bouzat
- Grenoble Institute of Neurosciences INSERM U836 Grenoble Alpes University Grenoble France
| | | | - Sébastien Baillieul
- HP2 Laboratory INSERM Grenoble Alpes University CHU Grenoble Alpes Grenoble France
| | - Guillaume Y. Millet
- HP2 Laboratory INSERM Grenoble Alpes University CHU Grenoble Alpes Grenoble France
- Univ Lyon UJM‐Saint‐Etienne Laboratoire Interuniversitaire de Biologie de la Motricité EA 7424 F‐42023 Saint‐Etienne France
| | - Paul Robach
- HP2 Laboratory INSERM Grenoble Alpes University CHU Grenoble Alpes Grenoble France
- Ecole Nationale des Sports de Montagne site de l'Ecole Nationale de Ski et d'Alpinisme Chamonix France
| | - Samuel Verges
- HP2 Laboratory INSERM Grenoble Alpes University CHU Grenoble Alpes Grenoble France
| |
Collapse
|
9
|
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.
Collapse
Affiliation(s)
- Luca Ruggiero
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, CANADA
| | | | | | | | | |
Collapse
|
10
|
Ruggiero L, Bruce CD, Cotton PD, Dix GU, McNeil CJ. Prolonged low-frequency force depression is underestimated when assessed with doublets compared with tetani in the dorsiflexors. J Appl Physiol (1985) 2019; 126:1352-1359. [PMID: 30870083 DOI: 10.1152/japplphysiol.00840.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Prolonged low-frequency force depression (PLFFD) after damaging eccentric exercise may last for several days. Historically, PLFFD has been calculated from the tetanic force responses to trains of supramaximal stimuli. More recently, for methodological reasons, stimulation has been reduced to two pulses. However, it is unknown whether doublet responses provide a valid measure of PLFFD in the days after eccentric exercise. In 12 participants, doublets and tetani were elicited at 10 and 100 Hz before and after (2, 3, 5 min, 48 and 96 h) 200 eccentric maximal voluntary contractions of the dorsiflexors. Doublet and tetanic torque responses at 10 Hz were similarly depressed throughout recovery (P > 0.05; e.g., 2 min: 58.9 ± 12.8% vs. 57.1 ± 14.5% baseline; 96 h: 85.6 ± 11.04% vs. 85.1 ± 10.8% baseline). At 100 Hz, doublet torque was impaired more than tetanic torque at all time points (P < 0.05; e.g., 2 min: 70.5 ± 14.2% vs. 88.1 ± 11.7% baseline; 96 h: 83.0 ± 14.2% vs. 98.7 ± 9.5% baseline). As a result, the postfatigue reduction of the 10 Hz-to-100 Hz ratio (PLFFD) was markedly greater for tetani than for doublets (P < 0.05; e.g., 2 min: 64.3 ± 15.1% vs. 83.0 ± 5.8% baseline). In addition, the doublet ratio recovered by 48 h (99.2 ± 5.0% baseline), whereas the tetanic ratio was still impaired at 96 h (88.2 ± 9.7% baseline). Our results indicate that doublets are not a valid measure of PLFFD in the minutes and days after eccentric exercise. If study design favors the use of paired stimuli, it should be acknowledged that the true magnitude and duration of PLFFD are likely underestimated. NEW & NOTEWORTHY Prolonged low-frequency force depression (PLFFD) will result from damaging exercise and may last for several days. After 200 eccentric maximal dorsiflexor contractions, we compared the gold-standard measure of PLFFD (calculated using trains of supramaximal stimulation) to the value obtained from an alternative technique that is becoming increasingly common (paired supramaximal stimuli). Doublets underestimated the magnitude and duration of PLFFD compared with tetani, so caution must be used when reporting PLFFD derived from paired stimuli.
Collapse
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, British Columbia , Canada
| | - Christina D Bruce
- 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
| | - Paul D Cotton
- 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
| | - Gabriel U Dix
- 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
| | - 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
| |
Collapse
|
11
|
Yang F, Zhou L, Song J, WangJinMei A, Yang Y, Tang ZW, Huang QY. Liver CEBPβ Modulates the Kynurenine Metabolism and Mediates the Motility for Hypoxia-Induced Central Fatigue in Mice. Front Physiol 2019; 10:243. [PMID: 30930794 PMCID: PMC6428026 DOI: 10.3389/fphys.2019.00243] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 02/25/2019] [Indexed: 12/29/2022] Open
Abstract
Central fatigue is defined as a failure of the central nervous system to adequately drive the muscle, manifesting limited development, and maintenance of locomotor activity. A plateau in hypoxia leads to central fatigue and followed by maximal motility recession. However, the underlying mechanism is still unclear. The present study describes a mechanism by which liver CEBPβ (CCAAT/enhancer-binding protein beta) induced by hypoxic environment alters the kynurenine (KYN) metabolism and causes the suppression of motility function recession. The activation of CEBPβ under hypoxia increases the liver expression of tryptophan dioxygenase, thereby enhancing the conversion of tryptophan into KYN; the KYN metabolite can traverse the blood-brain barrier and result in the suppression of motility function. However, the knockdown of CEBPβ by injecting pAAV-shRNA-CEBPβ via the hepatic portal vein reduces the KYN production and improves the motility function. KYN is a neurochemical that which restricts the exercise capacity after injection in the basal ganglia in mice. Reducing the plasma KYN protects the brain from hypoxia-induced changes associated with fatigue, and the knockdown liver of CEBPβ in mice renders resistance to fatigue post-acute hypoxia or tryptophan treatment. This study reveals resistance to central fatigue as a strategy for acclimatization to hypoxia mediated by transcription factor CEBPβ in the liver.
Collapse
Affiliation(s)
- Fan Yang
- Joint Surgery, General Hospital of Tibetan Military Command Lhasa, Lhasa, China.,Department of Cold Environment Medicine, College of High Altitude Military Medicine, Third Military Medical University and Key Laboratory of High Altitude Medicine, Ministry of Education, Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Li Zhou
- Department of Pharmacy, General Hospital of Tibetan Military Command Lhasa, Lhasa, China
| | - Jun Song
- Joint Surgery, General Hospital of Tibetan Military Command Lhasa, Lhasa, China
| | - A WangJinMei
- Joint Surgery, General Hospital of Tibetan Military Command Lhasa, Lhasa, China
| | - Yuan Yang
- Joint Surgery, General Hospital of Tibetan Military Command Lhasa, Lhasa, China
| | - Zhong-Wei Tang
- Department of Cold Environment Medicine, College of High Altitude Military Medicine, Third Military Medical University and Key Laboratory of High Altitude Medicine, Ministry of Education, Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| | - Qing-Yuan Huang
- Department of Cold Environment Medicine, College of High Altitude Military Medicine, Third Military Medical University and Key Laboratory of High Altitude Medicine, Ministry of Education, Key Laboratory of High Altitude Medicine, PLA, Chongqing, China
| |
Collapse
|
12
|
Curtin A, Tong S, Sun J, Wang J, Onaral B, Ayaz H. A Systematic Review of Integrated Functional Near-Infrared Spectroscopy (fNIRS) and Transcranial Magnetic Stimulation (TMS) Studies. Front Neurosci 2019; 13:84. [PMID: 30872985 PMCID: PMC6403189 DOI: 10.3389/fnins.2019.00084] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/25/2019] [Indexed: 01/10/2023] Open
Abstract
Background: The capacity for TMS to elicit neural activity and manipulate cortical excitability has created significant expectation regarding its use in both cognitive and clinical neuroscience. However, the absence of an ability to quantify stimulation effects, particularly outside of the motor cortex, has led clinicians and researchers to pair noninvasive brain stimulation with noninvasive neuroimaging techniques. fNIRS, as an optical and wearable neuroimaging technique, is an ideal candidate for integrated use with TMS. Together, TMS+fNIRS may offer a hybrid alternative to "blind" stimulation to assess NIBS in therapy and research. Objective: In this systematic review, the current body of research into the transient and prolonged effects of TMS on fNIRS-based cortical hemodynamic measures while at rest and during tasks are discussed. Additionally, studies investigating the relation of fNIRS to measures of cortical excitability as produced by TMS-evoked Motor-Evoked-Potential (MEP) are evaluated. The aim of this review is to outline the integrated use of TMS+fNIRS and consolidate findings related to use of fNIRS to monitor changes attributed to TMS and the relationship of fNIRS to cortical excitability itself. Methods: Key terms were searched in PubMed and Web-of-Science to identify studies investigating the use of both fNIRS and TMS. Works from Google-Scholar and referenced works in identified papers were also assessed for relevance. All published experimental studies using both fNIRS and TMS techniques in the study methodology were included. Results: A combined literature search of neuroimaging and neurostimulation studies identified 53 papers detailing the joint use of fNIRS and TMS. 22/53 investigated the immediate effects of TMS at rest in the DLPFC and M1 as measured by fNIRS. 21/22 studies reported a significant effect in [HbO] for 40/54 stimulation conditions with 14 resulting an increase and 26 in a decrease. While 15/22 studies also reported [HbR], only 5/37 conditions were significant. Task effects of fNIRS+TMS were detailed in 16 studies, including 10 with clinical populations. Most studies only reported significant changes in [HbO] related measures. Studies comparing fNIRS to changes in MEP-measured cortical excitability suggest that fNIRS measures may be spatially more diffuse but share similar traits. Conclusion: This review summarizes the progress in the development of this emerging hybrid neuroimaging & neurostimulation methodology and its applications. Despite encouraging progress and novel applications, a lack of replicated works, along with highly disparate methodological approaches, highlight the need for further controlled studies. Interpretation of current research directions, technical challenges of TMS+fNIRS, and recommendations regarding future works are discussed.
Collapse
Affiliation(s)
- Adrian Curtin
- Drexel University, School of Biomedical Engineering, Science and Health Systems, Philadelphia, PA, United States.,School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Shanbao Tong
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Junfeng Sun
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Jijun Wang
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Banu Onaral
- Drexel University, School of Biomedical Engineering, Science and Health Systems, Philadelphia, PA, United States
| | - Hasan Ayaz
- Drexel University, School of Biomedical Engineering, Science and Health Systems, Philadelphia, PA, United States.,Department of Family and Community Health, University of Pennsylvania, Philadelphia, PA, United States.,Center for Injury Research and Prevention, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| |
Collapse
|