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Grégoire P. Millet
Institute of Sport Sciences University of Lausanne Lausanne Switzerland

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Journal article
Published: 22 August 2021 in Sensors
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Recent advances in wearable technologies integrating multi-modal sensors have enabled the in-field monitoring of several physiological metrics. In sport applications, wearable devices have been widely used to improve performance while minimizing the risk of injuries and illness. The objective of this project is to estimate breathing rate (BR) from respiratory sinus arrhythmia (RSA) using heart rate (HR) recorded with a chest belt during physical activities, yielding additional physiological insight without the need of an additional sensor. Thirty-one healthy adults performed a run at increasing speed until exhaustion on an instrumented treadmill. RR intervals were measured using the Polar H10 HR monitoring system attached to a chest belt. A metabolic measurement system was used as a reference to evaluate the accuracy of the BR estimation. The evaluation of the algorithms consisted of exploring two pre-processing methods (band-pass filters and relative RR intervals transformation) with different instantaneous frequency tracking algorithms (short-term Fourier transform, single frequency tracking, harmonic frequency tracking and peak detection). The two most accurate BR estimations were achieved by combining band-pass filters with short-term Fourier transform, and relative RR intervals transformation with harmonic frequency tracking, showing 5.5% and 7.6% errors, respectively. These two methods were found to provide reasonably accurate BR estimation over a wide range of breathing frequency. Future challenges consist in applying/validating our approaches during in-field endurance running in the context of fatigue assessment.

ACS Style

Gaëlle Prigent; Kamiar Aminian; Tiago Rodrigues; Jean-Marc Vesin; Grégoire P. Millet; Mathieu Falbriard; Frédéric Meyer; Anisoara Paraschiv-Ionescu. Indirect Estimation of Breathing Rate from Heart Rate Monitoring System during Running. Sensors 2021, 21, 5651 .

AMA Style

Gaëlle Prigent, Kamiar Aminian, Tiago Rodrigues, Jean-Marc Vesin, Grégoire P. Millet, Mathieu Falbriard, Frédéric Meyer, Anisoara Paraschiv-Ionescu. Indirect Estimation of Breathing Rate from Heart Rate Monitoring System during Running. Sensors. 2021; 21 (16):5651.

Chicago/Turabian Style

Gaëlle Prigent; Kamiar Aminian; Tiago Rodrigues; Jean-Marc Vesin; Grégoire P. Millet; Mathieu Falbriard; Frédéric Meyer; Anisoara Paraschiv-Ionescu. 2021. "Indirect Estimation of Breathing Rate from Heart Rate Monitoring System during Running." Sensors 21, no. 16: 5651.

Original article
Published: 06 August 2021 in Journal of Cachexia, Sarcopenia and Muscle
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Background Weak muscle strength has been associated with a wide range of adverse health outcomes. Yet, whether individuals with weaker muscle strength are more at risk for hospitalization due to severe COVID-19 is still unclear. The objective of this study was to investigate the independent association between muscle strength and COVID-19 hospitalization. Methods Data from adults 50 years of age or older were analysed using logistic models adjusted for several chronic conditions, body-mass index, age, and sex. Hand-grip strength was repeatedly measured between 2004 and 2017 using a handheld dynamometer. COVID-19 hospitalization during the lockdown was self-reported in summer 2020 and was used as an indicator of COVID-19 severity. Results The study was based on the Survey of Health, Ageing and Retirement in Europe (SHARE) and included 3600 older adults (68.8 ± 8.8 years, 2044 female), among whom 316 were tested positive for the severe acute respiratory syndrome coronavirus 2 (8.8%), and 83 (2.3%) were hospitalized due to COVID-19. Results showed that higher grip strength was associated with a lower risk of COVID-19 hospitalization [adjusted odds ratio (OR) per increase of 1 standard deviation in grip strength = 0.64, 95% confidence interval (95% CI) = 0.45–0.87, P = 0.015]. Results also showed that age (OR for a 10 -year period = 1.70, 95% CI = 1.32–2.20, P < 0.001) and obesity (OR = 2.01, 95% CI = 1.00–3.69, P = 0.025) were associated with higher risk of COVID-19 hospitalization. Sensitivity analyses using different measurements of grip strength as well as robustness analyses based on rare-events logistic regression and a different sample of participants (i.e. COVID-19 patients) were consistent with the main results. Conclusions Muscle strength is an independent risk factor for COVID-19 severity in adults 50 years of age or older.

ACS Style

Boris Cheval; Stefan Sieber; Silvio Maltagliati; Grégoire P. Millet; Tomáš Formánek; Aïna Chalabaev; Stéphane Cullati; Matthieu P. Boisgontier. Muscle strength is associated with COVID‐19 hospitalization in adults 50 years of age or older. Journal of Cachexia, Sarcopenia and Muscle 2021, 1 .

AMA Style

Boris Cheval, Stefan Sieber, Silvio Maltagliati, Grégoire P. Millet, Tomáš Formánek, Aïna Chalabaev, Stéphane Cullati, Matthieu P. Boisgontier. Muscle strength is associated with COVID‐19 hospitalization in adults 50 years of age or older. Journal of Cachexia, Sarcopenia and Muscle. 2021; ():1.

Chicago/Turabian Style

Boris Cheval; Stefan Sieber; Silvio Maltagliati; Grégoire P. Millet; Tomáš Formánek; Aïna Chalabaev; Stéphane Cullati; Matthieu P. Boisgontier. 2021. "Muscle strength is associated with COVID‐19 hospitalization in adults 50 years of age or older." Journal of Cachexia, Sarcopenia and Muscle , no. : 1.

Review article
Published: 31 July 2021 in Neurobiology of Aging
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Alpha-synuclein aggregation and mitochondrial dysfunction are main pathological hallmarks of Parkinson's disease (PD) and several other neurodegenerative diseases, collectively known as synucleinopathies. However, increasing evidence suggests that they may not be sufficient to cause PD. Here we propose the role of hypoxia as a missing link that connects the complex interplay between alpha-synuclein biochemistry and pathology, mitochondrial dysfunctions and neurodegeneration in PD. We review the partly conflicting literature on alpha-synuclein binding to membranes and mitochondria and its impact on mitochondrial functions. From there, we focus on adverse changes in cellular environments, revolving around hypoxic stress, that may trigger or facilitate PD progression. Inter-dependent structural re-arrangements of mitochondrial membranes, including increased cytoplasmic exposure of mitochondrial cardiolipins – and changes in alpha-synuclein localization and conformation are discussed consequences of such conditions. Enhancing cellular resilience could be an integral part of future combination-based therapies of PD. This may be achieved by boosting the capacity of cellular – and specifically mitochondrial – processes to regulate and adapt to altered proteostasis, redox, and inflammatory conditions and by inducing protective molecular and tissue re-modelling.

ACS Style

Johannes Burtscher; Muhammed Muazzam Kamil Syed; Markus A. Keller; Hilal A. Lashuel; Grégoire P. Millet. Fatal attraction – The role of hypoxia when alpha-synuclein gets intimate with mitochondria. Neurobiology of Aging 2021, 1 .

AMA Style

Johannes Burtscher, Muhammed Muazzam Kamil Syed, Markus A. Keller, Hilal A. Lashuel, Grégoire P. Millet. Fatal attraction – The role of hypoxia when alpha-synuclein gets intimate with mitochondria. Neurobiology of Aging. 2021; ():1.

Chicago/Turabian Style

Johannes Burtscher; Muhammed Muazzam Kamil Syed; Markus A. Keller; Hilal A. Lashuel; Grégoire P. Millet. 2021. "Fatal attraction – The role of hypoxia when alpha-synuclein gets intimate with mitochondria." Neurobiology of Aging , no. : 1.

Research article
Published: 28 July 2021 in Journal of Biomechanical Engineering
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The stress experienced by the tibia has contributions from the forces and moments acting on the tibia. We sought to quantify the influence of running grade on internal tibial forces and moments. Seventeen participants ran at 3.33 m/s on an instrumented treadmill at 0°, ±5°, and ±10° while motion data were captured. Ankle joint contact force was estimated from an anthropometrically-scaled musculoskeletal model using inverse dynamics-based static optimization. Internal tibial forces and moments were quantified at the distal 1/3rd of the tibia, by ensuring static equilibrium with all applied forces and moments. Downhill running conditions resulted in lower peak internal axial force (range of mean differences: -9 to -16%, p<0.001), lower peak internal anteroposterior force (-14 to -21%, p<0.001), and lower peak internal mediolateral force (-14 to -15%, p<0.001), compared to 0° and +5°. Furthermore, downhill conditions resulted in lower peak internal mediolateral moment (-11 to -21%, p<0.001), lower peak internal anteroposterior moment (-13 to -14%, p<0.001), and lower peak internal torsional moment (-9 to -21%, p<0.001), compared to 0°, +5°, and +10°. The +10° condition resulted in lower peak internal axial force (-7 to -9%, p<0.001) and lower peak internal mediolateral force (-9%, p=0.004), compared to 0° and +5°. These findings suggest that downhill running may be associated with lower tibial stresses than either level or uphill running.

ACS Style

Michael Baggaley; Timothy R. Derrick; Gianluca Vernillo; Guillaume Millet; W. Brent Edwards. Internal Tibial Forces and Moments During Graded Running. Journal of Biomechanical Engineering 2021, 1 .

AMA Style

Michael Baggaley, Timothy R. Derrick, Gianluca Vernillo, Guillaume Millet, W. Brent Edwards. Internal Tibial Forces and Moments During Graded Running. Journal of Biomechanical Engineering. 2021; ():1.

Chicago/Turabian Style

Michael Baggaley; Timothy R. Derrick; Gianluca Vernillo; Guillaume Millet; W. Brent Edwards. 2021. "Internal Tibial Forces and Moments During Graded Running." Journal of Biomechanical Engineering , no. : 1.

Editorial
Published: 14 July 2021 in British Journal of Sports Medicine
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ACS Style

Gregoire P Millet; Stephen Seiler; Guillaume Y Millet. Opportunities and obstacles of translating elite sport research to public health. British Journal of Sports Medicine 2021, 1 .

AMA Style

Gregoire P Millet, Stephen Seiler, Guillaume Y Millet. Opportunities and obstacles of translating elite sport research to public health. British Journal of Sports Medicine. 2021; ():1.

Chicago/Turabian Style

Gregoire P Millet; Stephen Seiler; Guillaume Y Millet. 2021. "Opportunities and obstacles of translating elite sport research to public health." British Journal of Sports Medicine , no. : 1.

Original article
Published: 25 June 2021 in Scandinavian Journal of Medicine & Science in Sports
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The etiology of changes in lower-limb neuromuscular function, especially to the central nervous system, may be affected by exercise duration. Direct evidence is lacking as few studies have directly compared different race distances. This study aimed to investigate the etiology of deficits in neuromuscular function following short versus long trail-running races. Thirty-two male trail runners completed one of five trail-running races as LONG (>100 km) or SHORT (<60 km). Pre- and post-race, maximal voluntary contraction (MVC) torque and evoked responses to electrical nerve stimulation during MVCs and at rest were used to assess voluntary activation and muscle contractile properties of knee-extensor (KE) and plantar-flexor (PF) muscles. Transcranial magnetic stimulation (TMS) was used to assess evoked responses and corticospinal excitability in maximal and submaximal KE contractions. Race distance correlated with KE MVC (ρ = -0.556) and twitch (ρ = -0.521) torque decreases (P ≤ 0.003). KE twitch torque decreased more in LONG (-28 ± 14%) than SHORT (-14 ± 10%, P = 0.005); however, KE MVC time × distance interaction was not significant (P = 0.073). No differences between LONG and SHORT for PF MVC or twitch torque were observed. Maximal voluntary activation decreased similarly in LONG and SHORT in both muscle groups (P ≥ 0.637). TMS-elicited silent period decreased in LONG (P = 0.021) but not SHORT (P = 0.912). Greater muscle-contractile property impairment in longer races, not central perturbations, contributed to the correlation between KE MVC loss and race distance. Conversely, PF fatigability was unaffected by race distance.

ACS Style

John Temesi; Thibault Besson; Audrey Parent; Benjamin Singh; Vincent Martin; Callum G. Brownstein; Loïc Espeit; Nicolas Royer; Diana Rimaud; Thomas Lapole; Léonard Féasson; Guillaume Y. Millet. Effect of race distance on performance fatigability in male trail and ultra‐trail runners. Scandinavian Journal of Medicine & Science in Sports 2021, 31, 1809 -1821.

AMA Style

John Temesi, Thibault Besson, Audrey Parent, Benjamin Singh, Vincent Martin, Callum G. Brownstein, Loïc Espeit, Nicolas Royer, Diana Rimaud, Thomas Lapole, Léonard Féasson, Guillaume Y. Millet. Effect of race distance on performance fatigability in male trail and ultra‐trail runners. Scandinavian Journal of Medicine & Science in Sports. 2021; 31 (9):1809-1821.

Chicago/Turabian Style

John Temesi; Thibault Besson; Audrey Parent; Benjamin Singh; Vincent Martin; Callum G. Brownstein; Loïc Espeit; Nicolas Royer; Diana Rimaud; Thomas Lapole; Léonard Féasson; Guillaume Y. Millet. 2021. "Effect of race distance on performance fatigability in male trail and ultra‐trail runners." Scandinavian Journal of Medicine & Science in Sports 31, no. 9: 1809-1821.

Journal article
Published: 22 June 2021 in Antioxidants
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The purpose of this study was to investigate the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on the skeletal muscle in Apolipoprotein E knockout (ApoE KO) and wild-type (WT) C57BL/6J mice. ApoE KO mice fed with a high-fat diet were randomly allocated into: Control group without exercise (ApoE−/− CON), HIIT group (ApoE−/− HIIT), and MICT group (ApoE−/− MICT). Exercise endurance, blood lipid profile, muscle antioxidative capacity, and myokine production were measured after six weeks of interventions. ApoE−/− CON mice exhibited hyperlipidemia and increased oxidative stress, compared to the WT mice. HIIT and MICT reduced blood lipid levels, ROS production, and protein carbonyl content in the skeletal muscle, while it enhanced the GSH generation and potently promoted mRNA expression of genes involved in the production of irisin and BAIBA. Moreover, ApoE−/− HIIT mice had significantly lower plasma HDL-C content, mRNA expression of MyHC-IIx and Vegfa165 in EDL, and ROS level; but remarkably higher mRNA expression of Hadha in the skeletal muscle than those of ApoE−/− MICT mice. These results demonstrated that both exercise programs were effective for the ApoE KO mice by attenuating the oxidative damage and promoting the myokines response and production. In particular, HIIT was more beneficial to reduce the ROS level in the skeletal muscle.

ACS Style

Linjia Wang; Jessica Lavier; Weicheng Hua; Yangwenjie Wang; Lijing Gong; Hao Wei; Jianxiong Wang; Maxime Pellegrin; Grégoire Millet; Ying Zhang. High-Intensity Interval Training and Moderate-Intensity Continuous Training Attenuate Oxidative Damage and Promote Myokine Response in the Skeletal Muscle of ApoE KO Mice on High-Fat Diet. Antioxidants 2021, 10, 992 .

AMA Style

Linjia Wang, Jessica Lavier, Weicheng Hua, Yangwenjie Wang, Lijing Gong, Hao Wei, Jianxiong Wang, Maxime Pellegrin, Grégoire Millet, Ying Zhang. High-Intensity Interval Training and Moderate-Intensity Continuous Training Attenuate Oxidative Damage and Promote Myokine Response in the Skeletal Muscle of ApoE KO Mice on High-Fat Diet. Antioxidants. 2021; 10 (7):992.

Chicago/Turabian Style

Linjia Wang; Jessica Lavier; Weicheng Hua; Yangwenjie Wang; Lijing Gong; Hao Wei; Jianxiong Wang; Maxime Pellegrin; Grégoire Millet; Ying Zhang. 2021. "High-Intensity Interval Training and Moderate-Intensity Continuous Training Attenuate Oxidative Damage and Promote Myokine Response in the Skeletal Muscle of ApoE KO Mice on High-Fat Diet." Antioxidants 10, no. 7: 992.

Journal article
Published: 21 June 2021 in Journal of Sport and Health Science
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This study used downhill running as a model to investigate the repeated bout effect (RBE) on neuromuscular performance, running biomechanics, and metabolic cost of running. Ten healthy recreational male runners performed 2 30-min bouts of downhill running (DR1 and DR2) at a -20% slope and 2.8 m/s 3 weeks apart. Neuromuscular fatigue, level running biomechanics during slow and fast running, and running economy parameters were recorded immediately before and after the downhill bouts, and at 24 h, 48 h, 72 h, 96 h, and 168 h thereafter (i.e., follow-up days). An RBE was confirmed by attenuated muscle soreness and serum creatine kinase rise after DR2 compared to DR1. An RBE was also observed in maximum voluntary contraction (MVC) force loss and voluntary activation where DR2 resulted in attenuated MVC force loss and voluntary activation immediately after the run and during follow-up days. The downhill running protocol significantly influenced level running biomechanics; an RBE was observed in which center of mass excursion and, therefore, lower-extremity compliance were greater during follow-up days after DR1 compared to DR2. The observed changes in level running biomechanics did not influence the energy cost of running. This study demonstrated evidence of adaptation in neural drive as well as biomechanical changes with the RBE after DR. The higher neural drive resulted in attenuated MVC force loss after the second bout. It can be concluded that the RBE after downhill running manifests as changes to global and central fatigue parameters and running biomechanics without substantially altering the energy cost of running.

ACS Style

Arash Khassetarash; Gianluca Vernillo; Renata L. Krüger; W. Brent Edwards; Guillaume Y. Millet. Neuromuscular, biomechanical, and energetic adjustments following repeated bouts of downhill running. Journal of Sport and Health Science 2021, 1 .

AMA Style

Arash Khassetarash, Gianluca Vernillo, Renata L. Krüger, W. Brent Edwards, Guillaume Y. Millet. Neuromuscular, biomechanical, and energetic adjustments following repeated bouts of downhill running. Journal of Sport and Health Science. 2021; ():1.

Chicago/Turabian Style

Arash Khassetarash; Gianluca Vernillo; Renata L. Krüger; W. Brent Edwards; Guillaume Y. Millet. 2021. "Neuromuscular, biomechanical, and energetic adjustments following repeated bouts of downhill running." Journal of Sport and Health Science , no. : 1.

Review
Published: 17 June 2021 in International Journal of Molecular Sciences
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Regular exercise is associated with pronounced health benefits. The molecular processes involved in physiological adaptations to exercise are best understood in skeletal muscle. Enhanced mitochondrial functions in muscle are central to exercise-induced adaptations. However, regular exercise also benefits the brain and is a major protective factor against neurodegenerative diseases, such as the most common age-related form of dementia, Alzheimer’s disease, or the most common neurodegenerative motor disorder, Parkinson’s disease. While there is evidence that exercise induces signalling from skeletal muscle to the brain, the mechanistic understanding of the crosstalk along the muscle–brain axis is incompletely understood. Mitochondria in both organs, however, seem to be central players. Here, we provide an overview on the central role of mitochondria in exercise-induced communication routes from muscle to the brain. These routes include circulating factors, such as myokines, the release of which often depends on mitochondria, and possibly direct mitochondrial transfer. On this basis, we examine the reported effects of different modes of exercise on mitochondrial features and highlight their expected benefits with regard to neurodegeneration prevention or mitigation. In addition, knowledge gaps in our current understanding related to the muscle–brain axis in neurodegenerative diseases are outlined.

ACS Style

Johannes Burtscher; Grégoire Millet; Nicolas Place; Bengt Kayser; Nadège Zanou. The Muscle-Brain Axis and Neurodegenerative Diseases: The Key Role of Mitochondria in Exercise-Induced Neuroprotection. International Journal of Molecular Sciences 2021, 22, 6479 .

AMA Style

Johannes Burtscher, Grégoire Millet, Nicolas Place, Bengt Kayser, Nadège Zanou. The Muscle-Brain Axis and Neurodegenerative Diseases: The Key Role of Mitochondria in Exercise-Induced Neuroprotection. International Journal of Molecular Sciences. 2021; 22 (12):6479.

Chicago/Turabian Style

Johannes Burtscher; Grégoire Millet; Nicolas Place; Bengt Kayser; Nadège Zanou. 2021. "The Muscle-Brain Axis and Neurodegenerative Diseases: The Key Role of Mitochondria in Exercise-Induced Neuroprotection." International Journal of Molecular Sciences 22, no. 12: 6479.

Journal article
Published: 07 June 2021 in Medicine & Science in Sports & Exercise
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Introduction Females have been shown to experience less neuromuscular fatigue than males in knee extensors (KE) and less peripheral fatigue in plantar flexors (PF) following ultra-trail running, but it is unknown if these differences exist for shorter trail running races and whether this may impact running economy. The purpose of this study was to characterize sex differences in fatigability over a range of running distances and to examine possible differences in the post-race alteration of the cost of running (Cr). Methods Eighteen pairs of males and females were matched by performance after completing different races ranging from 40 to 171 km, divided into SHORT vs LONG races (< 60 and > 100 km, respectively). NM function and Cr were tested before and after each race. NM function was evaluated on both KE and PF with voluntary and evoked contractions using electrical nerve (KE and PF) and transcranial magnetic (KE) stimulation. Oxygen uptake, respiratory exchange ratio and ventilation were measured on a treadmill and used to calculate Cr. Results Compared to males, females displayed a smaller decrease in maximal strength in KE (−36% vs −27%, respectively, p < 0.01), independent of race distance. In SHORT only, females displayed less peripheral fatigue in PF compared to males (Δ peak twitch: −10% vs −24%, respectively, p < 0.05). Cr increased similarly in males and females. Conclusion Females experience less neuromuscular fatigue than men following both ‘classic’ and ‘extreme’ prolonged running exercises but this does not impact the degradation of the energy cost of running.

ACS Style

Thibault Besson; Audrey Parent; Callum G Brownstein; Loïc Espeit; Thomas Lapole; Vincent Martin; Nicolas Royer; Diana Rimaud; Frederic Sabater Pastor; Benjamin Singh; Giorgio Varesco; Jeremy Rossi; John Temesi; Guillaume Y Millet. Sex Differences in Neuromuscular Fatigue and Changes in Cost of Running after Mountain Trail Races of Various Distances. Medicine & Science in Sports & Exercise 2021, Publish Ah, 1 .

AMA Style

Thibault Besson, Audrey Parent, Callum G Brownstein, Loïc Espeit, Thomas Lapole, Vincent Martin, Nicolas Royer, Diana Rimaud, Frederic Sabater Pastor, Benjamin Singh, Giorgio Varesco, Jeremy Rossi, John Temesi, Guillaume Y Millet. Sex Differences in Neuromuscular Fatigue and Changes in Cost of Running after Mountain Trail Races of Various Distances. Medicine & Science in Sports & Exercise. 2021; Publish Ah ():1.

Chicago/Turabian Style

Thibault Besson; Audrey Parent; Callum G Brownstein; Loïc Espeit; Thomas Lapole; Vincent Martin; Nicolas Royer; Diana Rimaud; Frederic Sabater Pastor; Benjamin Singh; Giorgio Varesco; Jeremy Rossi; John Temesi; Guillaume Y Millet. 2021. "Sex Differences in Neuromuscular Fatigue and Changes in Cost of Running after Mountain Trail Races of Various Distances." Medicine & Science in Sports & Exercise Publish Ah, no. : 1.

Regular paper
Published: 05 June 2021 in Acta Physiologica
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Aim The optimal exercise intensity to improve endothelial function remains unclear, as well as whether the addition of hypoxia could potentiate this function. Therefore, the aim of this study was to compare the effects of different exercise intensities in normoxia and hypoxia on vascular reactivity and nitric oxide (NO) bioavailability in mice. Methods C57BL/6 mice underwent treadmill running three times per week, for four weeks at either low, maximal or supramaximal intensity in normoxia or hypoxia (inspire oxygen fraction = 0.13). Vascular reactivity and expression of genes and proteins involved in NO production/bioavailability were assessed in aorta using isolated vessel tension experiments, RT-qPCR and western blot, respectively. Circulating NO metabolites and pro-/antioxidant markers were measured. Results Hypoxic exercise improved both acetylcholine-induced vasorelaxation and phenylephrine-induced vasoconstriction compared to normoxic exercise, independently of intensity. In hypoxia, a higher acetylcholine-induced vasorelaxation was observed with high intensities (supramaximal and maximal) compared to low intensity. Exercise protocols modulated endothelial NO synthase (eNOS) and α1-adrenergic receptor (α1-AR) mRNA level, but not superoxide dismutase 3 (SOD3) and p47phox. No significant differences were observed for protein expression of α1-AR, total eNOS, phosphorylated eNOS, SOD isoforms and p47phox. However, plasma SOD and catalase activities were significantly increased in hypoxic supramaximal compared to hypoxic low intensity, while concentration of nitrotyrosine significantly decreased. The latter was also observed in hypoxic maximal and supramaximal compared to the same intensities in normoxia. Conclusion Hypoxic high-intensity exercise increases NO bioavailability and improves vascular function, opening promising clinical perspectives for cardiovascular disease prevention.

ACS Style

Jessica Lavier; Manon Beaumann; Steeve Menétrey; Karima Bouzourène; Nathalie Rosenblatt‐Velin; Vincent Pialoux; Lucia Mazzolai; Anne‐Christine Peyter; Maxime Pellegrin; Grégoire P. Millet. High‐intensity exercise in hypoxia improves endothelial function via increased nitric oxide bioavailability in C57BL/6 mice. Acta Physiologica 2021, e13700 .

AMA Style

Jessica Lavier, Manon Beaumann, Steeve Menétrey, Karima Bouzourène, Nathalie Rosenblatt‐Velin, Vincent Pialoux, Lucia Mazzolai, Anne‐Christine Peyter, Maxime Pellegrin, Grégoire P. Millet. High‐intensity exercise in hypoxia improves endothelial function via increased nitric oxide bioavailability in C57BL/6 mice. Acta Physiologica. 2021; ():e13700.

Chicago/Turabian Style

Jessica Lavier; Manon Beaumann; Steeve Menétrey; Karima Bouzourène; Nathalie Rosenblatt‐Velin; Vincent Pialoux; Lucia Mazzolai; Anne‐Christine Peyter; Maxime Pellegrin; Grégoire P. Millet. 2021. "High‐intensity exercise in hypoxia improves endothelial function via increased nitric oxide bioavailability in C57BL/6 mice." Acta Physiologica , no. : e13700.

Journal article
Published: 04 June 2021 in Journal of Sport and Health Science
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ACS Style

Arash Khassetarash; Gianluca Vernillo; Renata L Krüger; W Brent Edwards; Guillaume Y Millet. Neuromuscular, biomechanical, and energetic adjustments following repeated bouts of downhill running. Journal of Sport and Health Science 2021, 1 .

AMA Style

Arash Khassetarash, Gianluca Vernillo, Renata L Krüger, W Brent Edwards, Guillaume Y Millet. Neuromuscular, biomechanical, and energetic adjustments following repeated bouts of downhill running. Journal of Sport and Health Science. 2021; ():1.

Chicago/Turabian Style

Arash Khassetarash; Gianluca Vernillo; Renata L Krüger; W Brent Edwards; Guillaume Y Millet. 2021. "Neuromuscular, biomechanical, and energetic adjustments following repeated bouts of downhill running." Journal of Sport and Health Science , no. : 1.

Epidemiology
Published: 03 June 2021 in BMJ Open
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Objectives The effects of altitude residence on ageing, longevity and mortality are poorly understood. While adaptations to chronic exposure to altitude may exert beneficial effects on cardiovascular risk factors and some types of cancer, an elevated risk to die from chronic respiratory diseases has been reported. Moreover, high-altitude residence may be correlated with increased depression and suicide rates. The present study tested the hypothesis that living at moderate altitudes (up to 2000 m) is associated with reduced mortality from all causes. Setting and participants We used a dataset comprising all deaths (n=467 834) across 10 years of a country (Austria) characterised by varying levels of altitudes up to 2000 m. Main outcome measures Total number of deaths, age-standardised mortality rates (ASMRs) per 100 000 population, cause-specific ASMRs. Results ASMRs for residents living in higher (>1000 m) versus lower (<251 m) altitude regions (with agriculture employment below 3%) were 485.8 versus 597.0 (rate ratio and 95% CI 0.81 (0.72 to 0.92); p<0.001) for men and 284.6 versus 365.5 (0.78; 0.66 to 0.91); p=0.002) for women. Higher levels of agriculture employment did not influence mortality rates. Diseases of the circulatory system and cancers were main contributors to lower mortality rates at higher altitude. Residence at higher altitude did not negatively affect mortality rates from any other diseases. We highlight gender effects and—beside environmental factors—also discuss socioeconomic factors that may be responsible for conflicting results with data from other populations. Conclusions Living at moderate altitude (1000–2000 m) elicits beneficial effects on all-cause mortality for both sexes, primarily due to lower ASMRs from circulatory diseases and cancer. The presented analysis on cause-specific ASMRs over a 10-year period among the entire population of an alpine country will contribute to a better understanding on the effects of altitude-related mortality.

ACS Style

Johannes Burtscher; Gregoire P Millet; Martin Burtscher. Does living at moderate altitudes in Austria affect mortality rates of various causes? An ecological study. BMJ Open 2021, 11, e048520 .

AMA Style

Johannes Burtscher, Gregoire P Millet, Martin Burtscher. Does living at moderate altitudes in Austria affect mortality rates of various causes? An ecological study. BMJ Open. 2021; 11 (6):e048520.

Chicago/Turabian Style

Johannes Burtscher; Gregoire P Millet; Martin Burtscher. 2021. "Does living at moderate altitudes in Austria affect mortality rates of various causes? An ecological study." BMJ Open 11, no. 6: e048520.

Editorial article
Published: 02 June 2021 in Frontiers in Sports and Active Living
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Editorial on the Research Topic Youth and Winter Sports Just before the beginning of the COVID-19 pandemic, Lausanne—known as the “Olympic capital” since it is the home of the International Olympic Committee—had the privilege and opportunity to organise the last international sporting event not affected by the virus. The 2020 Winter Youth Olympic Games was the third edition of the Winter Youth Olympic Games (YOG) and was held in Lausanne between January 9 and 22, 2020. The event featured 8 sports and 16 disciplines, including ski mountaineering and women's Nordic combined for the first time at the Olympics. A total of 1,788 athletes from 79 nations participated. Among several novelties was the location of the “Olympic village” on the campus of the University of Lausanne. The YOG was an opportunity to bring the academic and sports worlds closer together. The University of Lausanne collaborated with the IOC on various educational and scientific programmes for athletes and the public. Thus, in collaboration with IOC's Olympic Studies Centre and several academic institutions, the Institute of Sport Sciences (ISSUL) organised the congress “Youth and winter sports” https://wp.unil.ch/cyws20/program/ on January 7 and 8. It aimed to bring together sports scientists, coaches, and medics with an interest in winter sports, and around 200 people attended the congress. Several points (not only the pre-COVID date!) made this congress very special: 1. Free access for all UNIL students and all athletes or staff registered for the YOG with the goal of fruitful exchanges between scientists and practitioners. The Olympic village was only 200 m from the congress location, and we were visited by elite coaches. 2. This congress was officially a component of the educational program of the YOG overviewed by UNIL. 3. This congress was multidisciplinary with key notes and parallel sections on both life sciences and social sciences. We received communications about physical preparation, physiology, biomechanics, sports medicine, rehabilitation, history, sociology, management, psychology, and teaching. The following world-class experts gave six key-note presentations: • Milena Parent (Canada)—Governance and legacy of the YOG • Hans-Christer Holmberg (Sweden)—Biomechanics and physiology in nordic skiing • Andrew Denning (USA)—History of the human–environment relationships in the Alps through the sport of skiing • Erich E. Muller (Austria)—Biomechanics and prevention of injuries in alpine Skiing • Oyvind Sandbakk (Norway)—Norwegian success in winter sports • Laurent Schmitt (France) – Martin Fourcade's physiological adaptations-−10 years of training and monitoring. 4. This congress was not supported by a scientific society and was a one-shot organisation connected to the YOG. 5. The congress was supported by Frontiers in Sport and Active Living with the possibility for scientists to submit articles to the present Research Topic. Though the Research Topic is multidisciplinary, which is in line with the content of the congress, only articles concerning exercise physiology, biomechanics, and nutrition have been published. Four articles focused on biomechanical considerations in alpine skiing: 1. Pavailler et al. assessed the differences in glide time, ski edging, and plantar pressure distribution in national and regional cross-country skiers. The elite skiers exhibited better techniques, which is evidenced by the higher relative glide time induced by a larger body mass transfer above the ski particularly at the beginning of the gliding phase. 2. Nimmervoll, Çakmak et al. investigated the forces within the Alpine ski boots and reported that the location of the sensors is paramount for relevant data collection: the insole sensors located in the heel and front areas combined with the shaft sensors provide reliable data on forward and backward leanings. 3. Nimmervoll, Eckerstorfer et al. displayed a new method to release ski binding with an industrial robot. This method allows for the analysis of the respective forces and the release-retention behaviour of ski bindings. 4. Delhaye et al. investigated the kinetic and kinematic specificities of different line strategies (i.e., Z long straight line and sharper turns vs. S short straight line and long curved turns) in Giant slalom and the effects on the alpine skier performance and energy dissipation. Overall, these two strategies lead to similar energy dissipation characteristics, and the authors concluded that elite skiers need to possess a variety of these strategies. Two articles assessed the talent development in youth cross-country skiers: 1. Zoppirolli et al. reported the changes in anthropometric and physiological characteristics of male and female young cross-country skiers. They showed that, during the late teenage period, high values and threshold levels of VO2max appeared to be good indicators of further talent. 2. Wehrlin and Steiner similarly reported that early (16 and 19 years of age) physiological characteristics (i.e., high total haemoglobin mass expressed in g/kg) are relevant predictors of success at the senior level in endurance sports like cross-country skiing or triathlons. Finally, this Research Topic includes three reviews (compression garments, injuries, and nutritional considerations) relevant to all winter sports: 1. Yang et al. reviewed 18 studies about the effects of compression garments on performance, drag, and vibrations in several winter sports. 2. Xu et al. reviewed 39 studies on injury factors in winter sports and provided much interesting information: The highest injury incidence was recorded in freestyle skiing, followed by alpine skiing and snowboarding. The most injured body parts were the knees (30%), head and face (12%), shoulders and collarbone (10%), and lower back (9%). The most common injury types...

ACS Style

Grégoire P. Millet; Fabien Ohl. Editorial: Youth and Winter Sports. Frontiers in Sports and Active Living 2021, 3, 1 .

AMA Style

Grégoire P. Millet, Fabien Ohl. Editorial: Youth and Winter Sports. Frontiers in Sports and Active Living. 2021; 3 ():1.

Chicago/Turabian Style

Grégoire P. Millet; Fabien Ohl. 2021. "Editorial: Youth and Winter Sports." Frontiers in Sports and Active Living 3, no. : 1.

Journal article
Published: 01 June 2021 in Journal of Applied Physiology
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It is unknown whether minimum changes in power output (PO) below and above the maximal lactate steady state (MLSS) affect neuromuscular fatigue (NMF) development in females and males. The present data showed that a decrease or increase of 10 W in PO in relation to MLSS elicited lower and greater impairments in contractile function, respectively. Even though females had less of an overall decline in NMF than males, similar exercise intensity-dependent response occurred independently of sex.

ACS Style

Rafael De Almeida Azevedo; Jonas Forot; Danilo Iannetta; Martin J. MacInnis; Guillaume Y. Millet; Juan M. Murias. Slight power output manipulations around the maximal lactate steady state have a similar impact on fatigue in females and males. Journal of Applied Physiology 2021, 130, 1879 -1892.

AMA Style

Rafael De Almeida Azevedo, Jonas Forot, Danilo Iannetta, Martin J. MacInnis, Guillaume Y. Millet, Juan M. Murias. Slight power output manipulations around the maximal lactate steady state have a similar impact on fatigue in females and males. Journal of Applied Physiology. 2021; 130 (6):1879-1892.

Chicago/Turabian Style

Rafael De Almeida Azevedo; Jonas Forot; Danilo Iannetta; Martin J. MacInnis; Guillaume Y. Millet; Juan M. Murias. 2021. "Slight power output manipulations around the maximal lactate steady state have a similar impact on fatigue in females and males." Journal of Applied Physiology 130, no. 6: 1879-1892.

Journal article
Published: 01 June 2021 in Annals of Internal Medicine
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Johannes Burtscher; Grégoire P. Millet; PhD Martin Burtscher; PhD Sara Y. Tartof; PhD Lei Qian; Mph Vennis Hong; Ma Rong Wei; Md Ron F. Nadjafi; MD Anastasios Kollias; Konstantinos G. Kyriakoulis; Md Konstantinos Syrigos; Mb Andrew N. Bamji; Sameer B. Murali; Dphil Debbie E. Malden. Obesity and Mortality Among Patients Diagnosed With COVID-19. Annals of Internal Medicine 2021, 174, 887 .

AMA Style

Johannes Burtscher, Grégoire P. Millet, PhD Martin Burtscher, PhD Sara Y. Tartof, PhD Lei Qian, Mph Vennis Hong, Ma Rong Wei, Md Ron F. Nadjafi, MD Anastasios Kollias, Konstantinos G. Kyriakoulis, Md Konstantinos Syrigos, Mb Andrew N. Bamji, Sameer B. Murali, Dphil Debbie E. Malden. Obesity and Mortality Among Patients Diagnosed With COVID-19. Annals of Internal Medicine. 2021; 174 (6):887.

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Johannes Burtscher; Grégoire P. Millet; PhD Martin Burtscher; PhD Sara Y. Tartof; PhD Lei Qian; Mph Vennis Hong; Ma Rong Wei; Md Ron F. Nadjafi; MD Anastasios Kollias; Konstantinos G. Kyriakoulis; Md Konstantinos Syrigos; Mb Andrew N. Bamji; Sameer B. Murali; Dphil Debbie E. Malden. 2021. "Obesity and Mortality Among Patients Diagnosed With COVID-19." Annals of Internal Medicine 174, no. 6: 887.

Research article
Published: 26 May 2021 in Psychology & Health
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The purpose of the pilot MOVE-C study was to examine the effects of a 12-week high-intensity interval training (HIIT) plus lifestyle education program on quality of life (QoL), behavioural and psychosocial outcomes among inactive adults with coeliac disease. This study used a 3 (time: baseline, immediately post and three months post) × 2 (group: experimental versus waitlist control) mixed design. After completing baseline testing, 41 participants were randomised to one of two groups: HIIT + or waitlist control (WLC). The HIIT + intervention involved twice-weekly HIIT, during which participants progressed to 14 × 30 s intervals (90% heart rate max; HRmax), with 2-minute recovery (50% HRmax). The HIIT + intervention also included six bi-weekly education sessions. Participants in HIIT + reported significant improvements in QoL and exercise behaviour immediately post-intervention, and this was sustained three months post-intervention, whereas no changes in QoL nor exercise behaviour were reported in WLC. Improvements were also reported among HIIT + immediately after the intervention for gastrointestinal symptoms and self-compassion. All participants reported significant improvements in adherence to a GFD immediately post-intervention. Findings from this pilot study provide preliminary evidence that a tailored exercise and lifestyle intervention can lead to improved QoL, exercise behaviour, gastrointestinal symptoms and self-compassion among inactive adults with coeliac disease.

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A. Justine Dowd; Liam Kronlund; Cassandra Warbeck; Candice Parmar; Julia T. Daun; Kathryn Wytsma-Fisher; Raylene A. Reimer; Guillaume Millet; Tak Fung; S. Nicole Culos-Reed. Effects of a 12-week HIIT + group mediated cognitive behavioural intervention on quality of life among inactive adults with coeliac disease: findings from the pilot MOVE-C study. Psychology & Health 2021, 1 -17.

AMA Style

A. Justine Dowd, Liam Kronlund, Cassandra Warbeck, Candice Parmar, Julia T. Daun, Kathryn Wytsma-Fisher, Raylene A. Reimer, Guillaume Millet, Tak Fung, S. Nicole Culos-Reed. Effects of a 12-week HIIT + group mediated cognitive behavioural intervention on quality of life among inactive adults with coeliac disease: findings from the pilot MOVE-C study. Psychology & Health. 2021; ():1-17.

Chicago/Turabian Style

A. Justine Dowd; Liam Kronlund; Cassandra Warbeck; Candice Parmar; Julia T. Daun; Kathryn Wytsma-Fisher; Raylene A. Reimer; Guillaume Millet; Tak Fung; S. Nicole Culos-Reed. 2021. "Effects of a 12-week HIIT + group mediated cognitive behavioural intervention on quality of life among inactive adults with coeliac disease: findings from the pilot MOVE-C study." Psychology & Health , no. : 1-17.

Perspective
Published: 12 May 2021 in Immuno
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Like in other neurodegenerative diseases, protein aggregation, mitochondrial dysfunction, oxidative stress and neuroinflammation are hallmarks of Parkinson’s disease (PD). Differentiating characteristics of PD include the central role of α-synuclein in the aggregation pathology, a distinct vulnerability of the striato-nigral system with the related motor symptoms, as well as specific mitochondrial deficits. Which molecular alterations cause neurodegeneration and drive PD pathogenesis is poorly understood. Here, we summarize evidence of the involvement of three interdependent factors in PD and suggest that their interplay is likely a trigger and/or aggravator of PD-related neurodegeneration: hypoxia, acidification and inflammation. We aim to integrate the existing knowledge on the well-established role of inflammation and immunity, the emerging interest in the contribution of hypoxic insults and the rather neglected effects of brain acidification in PD pathogenesis. Their tight association as an important aspect of the disease merits detailed investigation. Consequences of related injuries are discussed in the context of aging and the interaction of different brain cell types, in particular with regard to potential consequences on the vulnerability of dopaminergic neurons in the substantia nigra. A special focus is put on the identification of current knowledge gaps and we emphasize the importance of related insights from other research fields, such as cancer research and immunometabolism, for neurodegeneration research. The highlighted interplay of hypoxia, acidification and inflammation is likely also of relevance for other neurodegenerative diseases, despite disease-specific biochemical and metabolic alterations.

ACS Style

Johannes Burtscher; Grégoire Millet. Hypoxia, Acidification and Inflammation: Partners in Crime in Parkinson’s Disease Pathogenesis? Immuno 2021, 1, 78 -90.

AMA Style

Johannes Burtscher, Grégoire Millet. Hypoxia, Acidification and Inflammation: Partners in Crime in Parkinson’s Disease Pathogenesis? Immuno. 2021; 1 (2):78-90.

Chicago/Turabian Style

Johannes Burtscher; Grégoire Millet. 2021. "Hypoxia, Acidification and Inflammation: Partners in Crime in Parkinson’s Disease Pathogenesis?" Immuno 1, no. 2: 78-90.

Journal article
Published: 01 May 2021 in Journal of Neurophysiology
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This study measured motoneuron excitability using cervicomedullary evoked potentials conditioned using transcranial magnetic stimulation (TMS-CMEPs) of both small and large amplitudes during sustained low- and high-intensity contractions of the elbow flexors. During the low-intensity task, only the small TMS-CMEP was reduced. During the high-intensity task, both small and large TMS-CMEPs were substantially reduced. These results indicate that repetitively active motoneurons are specifically reduced in excitability compared with less active motoneurons in the same pool.

ACS Style

Callum G. Brownstein; Loïc Espeit; Nicolas Royer; Paul Ansdell; Jakob Škarabot; Robin Souron; Thomas Lapole; Guillaume Y. Millet. Reductions in motoneuron excitability during sustained isometric contractions are dependent on stimulus and contraction intensity. Journal of Neurophysiology 2021, 125, 1636 -1646.

AMA Style

Callum G. Brownstein, Loïc Espeit, Nicolas Royer, Paul Ansdell, Jakob Škarabot, Robin Souron, Thomas Lapole, Guillaume Y. Millet. Reductions in motoneuron excitability during sustained isometric contractions are dependent on stimulus and contraction intensity. Journal of Neurophysiology. 2021; 125 (5):1636-1646.

Chicago/Turabian Style

Callum G. Brownstein; Loïc Espeit; Nicolas Royer; Paul Ansdell; Jakob Škarabot; Robin Souron; Thomas Lapole; Guillaume Y. Millet. 2021. "Reductions in motoneuron excitability during sustained isometric contractions are dependent on stimulus and contraction intensity." Journal of Neurophysiology 125, no. 5: 1636-1646.

Review article
Published: 23 April 2021 in Redox Biology
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Mitochondria are central regulators of cellular metabolism, most known for their role in energy production. They can be “enhanced” by physical activity (including exercise), which increases their integrity, efficiency and dynamic adaptation to stressors, in short “mitochondrial fitness”. Mitochondrial fitness is closely associated with cardiorespiratory fitness and physical activity. Given the importance of mitochondria in immune functions, it is thus not surprising that cardiorespiratory fitness is also an integral determinant of the antiviral host defense and vulnerability to infection. Here, we first briefly review the role of physical activity in viral infections. We then summarize mitochondrial functions that are relevant for the antiviral immune response with a particular focus on the current Coronavirus Disease (COVID-19) pandemic and on innate immune function. Finally, the modulation of mitochondrial and cardiorespiratory fitness by physical activity, aging and the chronic diseases that represent the most common comorbidities of COVID-19 is discussed. We conclude that a high mitochondrial - and related cardiorespiratory - fitness should be considered as protective factors for viral infections, including COVID-19. This assumption is corroborated by reduced mitochondrial fitness in many established risk factors of COVID-19, like age, various chronic diseases or obesity. We argue for regular analysis of the cardiorespiratory fitness of COVID-19 patients and the promotion of physical activity – with all its associated health benefits – as preventive measures against viral infection.

ACS Style

Johannes Burtscher; Martin Burtscher; Grégoire P. Millet. The central role of mitochondrial fitness on antiviral defenses: An advocacy for physical activity during the COVID-19 pandemic. Redox Biology 2021, 43, 101976 .

AMA Style

Johannes Burtscher, Martin Burtscher, Grégoire P. Millet. The central role of mitochondrial fitness on antiviral defenses: An advocacy for physical activity during the COVID-19 pandemic. Redox Biology. 2021; 43 ():101976.

Chicago/Turabian Style

Johannes Burtscher; Martin Burtscher; Grégoire P. Millet. 2021. "The central role of mitochondrial fitness on antiviral defenses: An advocacy for physical activity during the COVID-19 pandemic." Redox Biology 43, no. : 101976.