Group III/IV locomotor muscle afferents alter motor cortical and corticospinal excitability and promote central fatigue during cycling exercise.

ABSTRACT:

Objective

To investigate the influence of group III/IV muscle afferents on the development of central fatigue and corticospinal excitability during exercise.

Methods

Fourteen males performed cycling-exercise both under control-conditions (CTRL) and with lumbar intrathecal fentanyl (FENT) impairing feedback from leg muscle afferents. Transcranial magnetic- and cervicomedullary stimulation was used to monitor cortical versus spinal excitability.

Results

While fentanyl-blockade during non-fatiguing cycling had no effect on motor-evoked potentials (MEPs), cervicomedullary-evoked motor potentials (CMEPs) were 13±3% higher (P<0.05), resulting in a decrease in MEP/CMEP (P<0.05). Although the pre- to post-exercise reduction in resting twitch was greater in FENT vs. CTRL (-53±

SUBMITTER: Sidhu SK 

PROVIDER: S-EPMC5240388 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature