title: Central alterations of neuromuscular function and feedback from group III-IV muscle afferents following exhaustive high-intensity one-leg dynamic exercise.
abstract: 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 muscles were measured. In study 2, mean arterial pressure (MAP) and leg muscle pain were measured during MO. Measurements were performed preexercise, at exhaustion, and after 3 min recovery. Compared with preexercise values, VAL was lower at exhaustion (-13 ± 13%, P < 0.05) and after 3 min of recovery (-6 ± 6%, P = 0.05). CMEP area/M area was lower at exhaustion (-38 ± 13%, P < 0.01) and recovered after 3 min. MEP area/M area was higher at exhaustion (+25 ± 27%, P < 0.01) and after 3 min of recovery (+17 ± 20%, P < 0.01). CSP was higher (+19 ± 9%, P < 0.01) only at exhaustion and recovered after 3 min. Markers of afferent feedback (MAP and leg muscle pain during MO) were significantly higher only at exhaustion. These findings suggest that the alterations in spinal excitability and CSP induced by high-intensity OLDE are associated with an increase in afferent feedback at exhaustion, whereas central fatigue does not fully recover even when significant afferent feedback is no longer present.
authors: Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and benjaminpageaux@gmail.com.
authors: Benjamin
authors: B
authors: Pageaux
authors: Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and.
authors: Luca
authors: L
authors: Angius
authors: Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and.
authors: James G
authors: JG
authors: Hopker
authors: Laboratoire Institut national de la santé et de la recherche médical U1093, Université de Bourgogne, Faculté des Sciences du Sports, UFR STAPS, Dijon, France.
authors: Romuald
authors: R
authors: Lepers
authors: Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and.
authors: Samuele M
authors: SM
authors: Marcora
mesh_terms: D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D019054:Evoked Potentials, Motor; D015444:Exercise; D025461:Feedback, Physiological; D005267:Femoral Nerve / Q000502:physiology; D006801:Humans; D035002:Lower Extremity; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000294:innervation*; D009475:Neurons, Afferent / Q000502:physiology*; D010146:Pain / Q000503:physiopathology / Q000523:psychology; D058748:Pain Perception; D017288:Pain Threshold; D010807:Physical Endurance; D012032:Refractory Period, Electrophysiological; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: central fatigue; cervicomedullary stimulation; corticospinal excitability; endurance performance; muscle fatigue