Publications by authors named "Paul Ansdell"

Experimental studies show improvement in physical performance following acute application of transcranial direct current stimulation (tDCS). This study examined the neuromuscular and neural responses to a single training session () and following a 3 wk resistance training program () performed with the knee extensors, preceded by tDCS over the primary motor cortex. Twenty-four participants (age, 30 ± 7 yr; stature, 172 ± 8 cm; mass, 72 ± 15 kg) were randomly allocated to perform either resistance training with anodal tDCS (a-tDCS) or a placebo tDCS (Sham).

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Unaccustomed eccentric exercise (EE) is protective against muscle damage following a subsequent bout of similar exercise. One hypothesis suggests the existence of an alteration in motor unit (MU) behaviour during the second bout, which might contribute to the adaptive response. Accordingly, the present study investigated MU changes during repeated bouts of EE.

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Contraction intensity is a key factor determining the development of muscle fatigue, and it has been shown to induce distinct changes along the motor pathway. The role of cortical and spinal inputs that regulate motor unit (MU) behavior during fatiguing contractions is poorly understood. We studied the cortical, spinal, and neuromuscular response to sustained fatiguing isometric tasks performed at 20% and 70% of the maximum isometric voluntary contraction (MVC), together with MU behavior of knee extensors in healthy active males.

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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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Males and females experience different trajectories of neuromuscular function across the lifespan, with females demonstrating accelerated deconditioning in later life. We hypothesize that the menopause is a critical period in the female lifespan, during which the dramatic reduction in sex hormone concentrations negatively impacts synaptic input to the motoneuron pool, as well as motor unit discharge properties.

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The integrative response to exercise differs between sexes, with oxidative energy contribution purported as a potential mechanism. The present study investigated whether this difference was evident in the kinetics of oxygen uptake (V̇o) and extraction (HHb + Mb) during exercise. Sixteen adults (8 males, 8 females, age: 27 ± 5 yr) completed three experimental visits.

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Purpose: Reduced spinal excitability during the transcranial magnetic stimulation (TMS) silent period (SP) has recently been shown to last longer than previously thought in the upper limbs, as assessed via spinal electrical stimulation. Further, there is reason to expect that contraction intensity affects the duration of the reduced spinal excitability.

Methods: This study investigated spinal excitability at different time delays within the TMS-evoked SP in m.

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Single-pulse Transcranial Magnetic Stimulation (TMS) and, very recently, lumbar stimulation (LS) have been used to measure cortico-spinal excitability from various interventions using maximal or submaximal contractions in the lower limbs. However, reliability studies have overlooked a wide range of contraction intensities for MEPs, and no reliability data is available for LEPs. This study investigated the reliability of motor evoked potentials and lumbar evoked potentials at different stimulation intensities and contraction levels in m.

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There is currently equivocal evidence regarding sex-related differences in measures of muscle force and torque control. To that end, we investigated sex differences in knee extensor muscle torque control, using both magnitude- and complexity-based measures, across contraction intensities typical of activities of daily living. 50 participants (25 male, median age [and interquartile range] 23.

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Females demonstrate greater fatigue resistance compared to males in tasks ranging from single-limb contractions to whole-body exercise, including running. Many of the studies investigating sex differences in fatigability following running, however, occur after long duration, low-intensity tasks and it is unknown whether there is a sex difference in fatigability following high-intensity running. This study compared fatigability and recovery following a 5 km running time trial in young males and females.

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Resistance training increases volitional force-producing capacity, and it is widely accepted that such an increase is partly underpinned by adaptations in the central nervous system, particularly in the early phases of training. Despite this, the neural substrate(s) responsible for mediating adaptation remains largely unknown. Most studies have focused on the corticospinal tract, the main descending pathway controlling movement in humans, with equivocal findings.

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Severe acute respiratory syndrome coronavirus type-2 (SARS-CoV-2) transmission continues to impact people globally. Whilst the acute symptoms and management strategies are well documented, millions of people globally are experiencing a prolonged and debilitating symptom profile that is reported to last months and even years. COVID-19 is a multi-system disease however the magnitude of the effects and its associated legacy is presently not well understood.

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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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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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New Findings: What is the topic of this review? We review sex differences within physiological systems implicated in exercise performance; specifically, how they integrate to determine metabolic thresholds and fatigability. Thereafter, we discuss the implications that these sex differences might have for long-term adaptation to exercise. What advances does it highlight? The review collates evidence from recent physiological studies that have investigated sex as a biological variable, demonstrating that the physiological response to equivalent 'dosages' of exercise is not the same in males and females; thus, highlighting the need to research diversity in physiological responses to interventions.

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Key Points: Knee-extensors demonstrate greater fatigue resistance in females compared to males during single-limb and whole-body exercise. For single-limb exercise, the intensity-duration relationship is different between sexes, with females sustaining a greater relative intensity of exercise. This study established the power-duration relationship during cycling, then assessed fatigability during critical power-matched exercise within the heavy and severe intensity domains.

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Article Synopsis
  • Oral contraceptive pills (OCPs) alter hormonal levels in women by reducing natural hormones while supplementing with synthetic estrogen and progestin, potentially affecting exercise performance due to changes in the body's physiological processes.
  • This review aimed to analyze and compare the exercise performance of women using OCPs versus those with natural menstrual cycles, and observe performance variations during OCP intake versus OCP withdrawal.
  • Out of 42 studies involving 590 participants, most were of lower quality, and results indicated a potential impact of OCPs on exercise performance, though the effects varied based on the comparison made.
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  • The study investigates how the menstrual cycle (MC) affects exercise performance in women, as existing research lacks a clear consensus on this relationship.
  • The research involved a comprehensive review and meta-analysis of experimental studies, focusing on endurance and strength outcomes across different MC phases.
  • Results indicated that while there are slight reductions in performance during the early follicular phase, the overall effects on endurance and strength are trivial, suggesting little impact of the MC on exercise capabilities.
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New Findings: What is the central question of the study? Are corticospinal responses to acute and short-term squat resistance training task-specific? What is the main finding and its importance? A single bout of resistance training increased spinal excitability, but no changes in corticospinal responses were noted following 4 weeks of squat training despite task-specific increases in strength. The present data suggest that processes along the corticospinal pathway of the knee extensors play a limited role in the task-specific increase in strength following resistance training.

Abstract: Neural adaptations subserving strength increases have been shown to be task-specific, but responses and adaptation to lower-limb compound exercises such as the squat are commonly assessed in a single-limb isometric task.

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