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Protracted exercise without overt neuromuscular fatigue influences cortical excitability
Domenica Crupi1, Giuseppe Cruciata, Clara Moisello
1Department of Physiology, Pharmacology & Neuroscience, CUNY Medical School, New York, NY 10031, USA.
Journal of Motor Behavior
|March 16, 2013
Summary
Protracted exercise impairs corticospinal excitability, affecting motor control. Compensatory mechanisms in premotor areas attempt to maintain performance, but prolonged tasks lead to disruptions in motor rhythm and temporal modulation.
Area of Science:
- Neuroscience
- Motor Control
- Exercise Physiology
Background:
- Understanding the neural basis of motor performance disruption is crucial.
- Neuromuscular fatigue is often associated with performance decline, but sub-threshold exercise effects are less understood.
Purpose of the Study:
- To investigate cortical mechanisms underlying performance disruption after non-fatiguing motor exercise.
- To examine changes in corticospinal excitability and motor control following repetitive finger movements.
Main Methods:
- Transcranial magnetic stimulation (TMS) was used to assess corticospinal excitability.
- Forty-four subjects performed 5 or 10 minutes of repetitive finger movements at 2 Hz.
- TMS assessed motor evoked potentials at rest and during motor preparation (premovement facilitation).
Main Results:
- Movement rate variability increased, and average rate shifted towards self-paced rhythms.
- Motor evoked potential amplitudes decreased with task duration and TMS intensity.
- 5-min exercise showed compensatory premovement facilitation; 10-min exercise showed partial compensation with temporal modulation loss.
Conclusions:
- Protracted, non-fatiguing exercise significantly reduces corticospinal excitability.
- Impairment of phasic motor neurons occurs with increased exercise duration.
- Premotor area compensation may mitigate primary motor cortex efficiency loss, but prolonged exercise disrupts motor control.
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