Post-exercise facilitation and depression of M wave and motor evoked potentials in healthy subjects.
OBJECTIVE
To characterize so-called central fatigue, the effect of various levels of exercise on central and peripheral motor potentials were compared.


METHODS
Thirteen healthy subjects performed 4 levels of exercise following isometric dorsiflexion of the foot. Post-exercise recordings from the anterior tibial muscle of motor evoked potentials (MEP) evoked by transcranial magnetic stimulation (TMS) and M wave evoked by electrical stimulation of the peroneal nerve were performed.


RESULTS
After 5 s the post-exercise MEP amplitude increased. The increase was related to the degree of work performed. Subsequently, there was a gradually decrease of amplitude reaching statistical significance after 15 min. The area of the M wave increased significantly after 10 s and returned to baseline after 2-3 min.


CONCLUSIONS
Facilitation and depression of MEP after fatiguing exercise is at least partly a peripheral phenomenon dependent on the level of exercise performed.
Lentz
Marianne
M
Department of Neurology, Aarhus University Hospital, Denmark.
Nielsen
Jørgen Feldbaek
JF
D000328:Adult; D001921:Brain / Q000502:physiology; D002490:Central Nervous System / Q000502:physiology; D004558:Electric Stimulation; D004569:Electroencephalography; D004574:Electromagnetic Fields; D019054:Evoked Potentials, Motor / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D010525:Peripheral Nerves / Q000502:physiology