Publications by authors named "Callum Brownstein"

Gereduz Agapito, L, Brownstein, CG, and Maffiuletti, NA. Effects of soccer match-play on muscle strength, physical performance, and perceptual responses in elite female players. J Strength Cond Res 39(1): 79-85, 2025-The purpose of this study was to investigate the impact of actual soccer match-play on muscle strength, physical performance, and perceptual responses in elite female players.

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The response of spinal motoneurons to synaptic input greatly depends on the activation of persistent inward currents (PICs), the contribution of which can be estimated through the paired motor unit technique. Yet, the intra-session test-retest reliability of this measurement remains to be fully established. Twenty males performed isometric triangular dorsiflexion contractions to 20 and 50 % of maximal torque at baseline and after a 15-min resting period.

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Introduction: The effect of eccentric exercise-induced muscle damage (EIMD) on cycling efficiency is unknown. The aim of the present study was to assess the effect of EIMD on gross and delta efficiency and the cardiopulmonary responses to cycle ergometry.

Methods: Twenty-one recreational athletes performed cycling at 70%, 90%, and 110% of the gas exchange threshold (GET) under control conditions (Control) and 24 h following an eccentric damaging protocol (Damage).

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Article Synopsis
  • About 30% of COVID-19 patients need hospitalization, with 20% requiring ICU care, and many experience ongoing fatigue even weeks after recovery, highlighting the need to understand its causes.
  • The study involved 59 patients who had been in the ICU, where assessments included questionnaires, blood tests, and exercise testing to evaluate fatigue and lung function post-discharge.
  • Results showed 56% of patients reported fatigue, linked to poorer lung function and lower maximal voluntary activation; this suggests that respiratory health and muscle function are crucial for recovery and emphasizes the importance of rehabilitation.
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Introduction: Central nervous system excitability depends on the task performed, muscle group solicited, and contraction type. However, little is known on corticospinal and motoneuronal excitability measured during locomotor exercise. This study aimed at determining the reliability of motor-evoked potentials (MEP) and thoracic motor-evoked potentials (TMEP) in dynamic mode during unfatiguing and fatiguing cycling exercise.

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The physiological mechanisms determining the progressive decline in the maximal muscle torque production capacity during isometric contractions to task failure are known to depend on task demands. Task-specificity of the associated adjustments in motor unit discharge rate (MUDR), however, remains unclear. This study examined MUDR adjustments during different submaximal isometric knee extension tasks to failure.

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Intermittent team sports, involving high metabolic and mechanical demands, elicit prolonged impairments in neuromuscular function which persist for ∼48-72 h. Whether impairments in neuromuscular function are exacerbated when such exercise is repeated with incomplete recovery is unknown. This study assessed the neuromuscular, heart rate and metabolic responses to two bouts of ∼90 min modified team sport match simulations separated by 48 h in 12 competitive football players.

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Introduction: Fatigue is the most common and disabling symptom in multiple sclerosis (MS), being reported by 55% to 78% of patients with MS (PwMS). Etiology of MS-related fatigue remains poorly understood, but an increased neuromuscular fatigability (i.e.

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  • This study examined the effectiveness of two types of neuromuscular electrical stimulation (NMES)—conventional and wide-pulse—by comparing their impact on muscle torque, fatigability, and central nervous system (CNS) excitability.
  • Seventeen young men participated in three different NMES sessions, with various pulse settings, and neuromuscular assessments were conducted before and after each session to evaluate changes.
  • The results indicated that both NMES types produced similar levels of evoked torque and fatigue without significantly affecting CNS excitability, suggesting that chronic treatment effects might be equivalent for both methods.
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Introduction: Cost of locomotion (C L ) has been shown to increase after endurance running and cycling bouts. The main purpose of this study was to compare, in the same participants, the effect of both modalities on C L when matched for relative intensity and duration.

Methods: Seventeen recreational athletes performed two incremental tests in running and cycling to determine the first ventilatory threshold then two 3-h bouts of exercise at 105% of threshold, with gas exchange measurements taken for 10 min at the start, middle and end of the 3 h to calculate C L .

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Objectives: The aim of the current study was to investigate the level of cardiorespiratory fitness and neuromuscular function of ICU survivors after COVID-19 and to examine whether these outcomes are related to ICU stay/mechanical ventilation duration.

Design: Prospective nonrandomized study.

Setting: Patients hospitalized in ICU for COVID-19 infection.

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Introduction: Performance fatigability is substantially greater when exercising in the severe- versus heavy-intensity domain. However, the relevance of the boundary between moderate- and heavy-intensity exercise, the gas exchange threshold (GET), to performance fatigability is unclear. This study compared alterations in neuromuscular function during work-matched exercise above and below the GET.

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Introduction: Cancer-related fatigue (CRF) is a debilitating symptom that affects around one-third of people for months or years after cancer treatment. In a recent study, we found that people with posttreatment CRF have greater neuromuscular fatigability. The aim of this secondary analysis was to examine the etiology of neuromuscular fatigability in people with posttreatment CRF.

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Introduction: Running and cycling represent two of the most common forms of endurance exercise. However, a direct comparison of the neuromuscular consequences of these two modalities after prolonged exercise has never been made. The aim of this study was to compare the alterations in neuromuscular function induced by matched-intensity and duration cycling and running exercise.

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Purpose: Cancer-related fatigue (CRF) is a common and distressing symptom of cancer that may persist for years following treatment completion. However, little is known about the pathophysiology of CRF. Using a comprehensive group of gold-standard physiological and psychosocial assessments, this study aimed to identify correlates of CRF in a heterogenous group of cancer survivors.

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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.

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Article Synopsis
  • Women tend to show less neuromuscular fatigue compared to men in knee extensors after ultratrail running, but it’s unclear if this applies to shorter trails or affects running efficiency.
  • The study involved 18 pairs of male and female runners, matched by performance, and assessed their neuromuscular function and running cost before and after races ranging from 40 to 171 km.
  • Findings indicated that women had a smaller decrease in knee extension strength and experienced less peripheral fatigue in plantar flexors during shorter races, but this did not affect the overall increase in running cost post-race for either gender.
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Background: The Rating of Fatigue (ROF) scale can measure changes in perceived fatigue in a variety of contexts.

Objective: The aim of the present study was to translate and subsequently validate the ROF scale in the French language.

Methods: The study was composed of three phases.

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Cervicomedullary stimulation provides a means of assessing motoneuron excitability. Previous studies demonstrated that during low-intensity sustained contractions, small cervicomedullary evoked potentials (CMEPs) conditioned using transcranial magnetic stimulation (TMS-CMEPs) are reduced, whereas large TMS-CMEPs are less affected. As small TMS-CMEPs recruit motoneurons most active during low-intensity contractions whereas large TMS-CMEPs recruit a high proportion of motoneurons inactive during the task, these results suggest that reductions in motoneuron excitability could be dependent on repetitive activation.

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New Findings: What is the central question of this study? Are spinal and/or supraspinal perturbations implicated in central fatigue induced in the plantar flexor muscles following prolonged trail running races? What is the main finding and its importance? The study confirmed the presence of central fatigue following various trail running distances from 40 to 170 km. The reduction in the V-wave in conjunction with the lack of change in the H-reflex suggests that a major component of this central fatigue may arise from supraspinal mechanisms in the plantar flexor muscles.

Abstract: Trail running races are known to induce considerable impairments in neuromuscular function of which central mechanisms are a substantial component.

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Article Synopsis
  • * Studies show that resistance training may change how the brain controls muscles, specifically affecting intracortical inhibition, but inconsistent methods and limitations in research mean we can't draw solid conclusions yet.
  • * While most research has focused on the corticospinal tract, there is emerging interest in the reticulospinal tract, especially from studies in animals, but we need more human data to fully understand these neural adaptations.
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Purpose: To provide a comprehensive review of studies that have investigated fatigue in intensive care unit (ICU) survivors and questions the potential link between intensive care unit-acquired weakness (ICUAW), fatigability and fatigue. We also question whether the central nervous system (CNS) may be the link between these entities.

Material And Methods: A narrative review of the literature that investigated fatigue in ICU survivors and review of clinical trials enabling understanding of CNS alterations in response to ICU stays.

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Alibazi, RJ, Pearce, AJ, Rostami, M, Frazer, AK, Brownstein, C, and Kidgell, DJ. Determining the intracortical responses after a single session of aerobic exercise in young healthy individuals: a systematic review and best evidence synthesis. J Strength Cond Res 35(2): 562-575, 2021-A single bout of aerobic exercise (AE) may induce changes in the excitability of the intracortical circuits of the primary motor cortex (M1).

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Chronic fatigue is the most common and severe symptom in myelodysplastic syndromes (MDS) and has a strong negative association with health-related quality of life (HRQoL). Despite anemia being the most common objective manifestation of MDS, and the associated link between anemia and fatigue, evidence on treatments which temporarily mitigate anemia is equivocal regarding the effects on fatigue. Furthermore, previous work has found weak associations between anemia and chronic fatigue in MDS.

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Over the last two decades, an abundance of research has explored the impact of fatiguing locomotor exercise on the neuromuscular system. Neurostimulation techniques have been implemented prior to and following locomotor exercise tasks of a wide variety of intensities, durations, and modes. These techniques have allowed for the assessment of alterations occurring within the central nervous system and the muscle, while techniques such as transcranial magnetic stimulation and spinal electrical stimulation have permitted further segmentalization of locomotor exercise-induced changes along the motor pathway.

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