0000000000154567

AUTHOR

James G. Hopker

0000-0002-4786-7037

showing 3 related works from this author

Central alterations of neuromuscular function and feedback from group III-IV muscle afferents following exhaustive high-intensity one-leg dynamic exe…

2015

The aims of this investigation were to describe the central alterations of neuromuscular function induced by exhaustive high-intensity one-leg dynamic exercise (OLDE, study 1) and to indirectly quantify feedback from group III-IV muscle afferents via muscle occlusion (MO, study 2) in healthy adult male humans. We hypothesized that these central alterations and their recovery are associated with changes in afferent feedback. Both studies consisted of two time-to-exhaustion tests at 85% peak power output. In study 1, voluntary activation level (VAL), M-wave, cervicomedullary motor evoked potential (CMEP), motor evoked potential (MEP), and MEP cortical silent period (CSP) of the knee extensor…

MaleTime Factorscervicomedullary stimulationRefractory Period ElectrophysiologicalPhysiologynear-infrared spectroscopysilent periodmedicine.medical_treatmentendurance exerciseendurance performanceOcclusionMedicineEvoked potentialhumansquadriceps femorisFeedback PhysiologicalMotor CortexPain PerceptionAnatomyTranscranial Magnetic StimulationLower ExtremityAnesthesiamuscle fatiguecorticospinal excitabilitymedicine.symptomFemoral NerveperformanceMuscle contractionMuscle ContractionAdultPain ThresholdMean arterial pressurePainperipheral fatiguecomplex mixturesYoung AdultPhysiology (medical)Threshold of painskeletal-muscleNeurons AfferentMuscle SkeletalExerciseMuscle fatiguebusiness.industrycontractionEvoked Potentials MotorElectric Stimulationcentral fatigueTranscranial magnetic stimulation[ SDV.NEU ] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]Physical EnduranceSilent periodsport-sciencebusiness
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Comparison of inter-trial recovery times for the determination of critical power and W' in cycling

2017

Critical Power (CP) and W’ are often determined using multi-day testing protocols. To investigate this cumbersome testing method, the purpose of this study was to compare the differences between the conventional use of a 24-h inter-trial recovery time with those of 3 h and 30 min for the determination of CP and W’. Methods: 9 moderately trained cyclists performed an incremental test to exhaustion to establish the power output associated with the maximum oxygen uptake (p V O2max), and 3 protocols requiring time-to-exhaustion trials at a constant work-rate performed at 80%, 100% and 105% of p VO2max. Design: Protocol A utilised 24-h inter-trial recovery (CP24/W’24), protocol B utilised 3-h in…

validityTime FactorsTime Factorpower-duration relationshipPhysical Therapy Sports Therapy and RehabilitationAthletic Performance030204 cardiovascular system & hematology03 medical and health sciencesRecovery periodOxygen Consumption0302 clinical medicineAnimal scienceTesting protocolsHumansOrthopedics and Sports MedicinePower outputSimulationMathematicsexercise testingLimits of agreementVO2 max030229 sport sciencesQPIncremental testBicyclinganaerobic work capacityCritical intensityMuscle FatigueCritical powerExercise TestCyclingGVHuman
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Transcranial direct current stimulation improves isometric time to exhaustion of the knee extensors

2016

International audience; Transcranial direct current stimulation (tDCS) can increase cortical excitability of a targeted brain area, which may affect endurance exercise performance. However, optimal electrode placement for tDCS remains unclear. We tested the effect of two different tDCS electrode montages for improving exercise performance. Nine subjects underwent a control (CON), placebo (SHAM) and two different tDCS montage sessions in a randomized design. In one tDCS session, the anodal electrode was placed over the left motor cortex and the cathodal on contralateral forehead (HEAD), while for the other montage the anodal electrode was placed over the left motor cortex and cathodal electr…

Malemedicine.medical_treatmentIsometric exerciseFunctional LateralitytDCSRandom Allocation0302 clinical medicineHeart RateSingle-Blind Methodprefrontal cortexprimary motor cortexTranscranial direct-current stimulationexerciseGeneral NeuroscienceMotor Cortexvoluntary activationTranscranial Magnetic StimulationPeripheralmedicine.anatomical_structureMuscle FatiguePsychologyFemoral Nerveperformancemedicine.medical_specialtyShoulderintracortical inhibitionNeuroscience(all)B100brain stimulationPlacebo03 medical and health sciencesYoung AdultPhysical medicine and rehabilitationEndurance trainingIsometric ContractionHeart rateexcitabilitymedicineHumansneuromuscular functionMuscle Skeletalmagnetic stimulationhuman muscle fatigueLeg030229 sport sciencesEvoked Potentials MotorC600QPElectric Stimulationbody regionsBrain stimulation[ SDV.NEU ] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]ForeheadPhysical therapyPerceptionsupraspinal factors030217 neurology & neurosurgery
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