Journal of Psychiatry

Delayed central fatigue after fatiguing submaximal exercise in adaptation to endurance training

Euro Global Summit and Medicare Expo on Psychiatry

July 20-22, 2015 Barcelona, Spain

Firas Zghal1, F Cottin1,2, I Kenoun3, H Rebai3, W Moalla3, M Dogui4, Z Tabka5 and V Martin1,6

Posters-Accepted Abstracts: J Psychiatry

Abstract:

Purpose: The purposes of this study were to evaluate the effect of endurance training on central fatigue development and recovery. Methods: A control group was compared to a training group which followed an 8-week endurance-training program consisting in low-force concentric and isometric contractions. Before (Pre) and after (Post) the training period, neuromuscular function of the knee extensor (KE) muscles was evaluated before, immediately after and during 33 minutes after an exhausting submaximal isometric task at 15% of the maximal voluntary contraction (MVC) force. After training, the trained group performed another test at iso-time, i.e., with the task maintained until the duration completed before training was matched (Post 2). The evaluation of neuromuscular function consisted in the determination of the voluntary activation level during MVCs from peripheral nerve electrical (VAPNS) and transcranial magnetic stimulations (VATMS). The amplitude of the potentiated twitch (Pt), the evoked (motor evoked potentials, cortical silent period (CSP)) and voluntary EMG activities were also recorded on the KE muscles. Results: Before training, the isometric task induced significant reductions of VAPNS, VATMS and Pt and an increased CSP. The training period induced a 3-fold increase of exercise duration, delayed central fatigue appearance as illustrated by the absence of modification of VAPNS, VATMS and CSP after Post 2. At Post, central fatigue magnitude and recovery were not modified but Pt reduction was greater. Conclusion: These results suggest that central fatigue partially adapts to endurance training. This adaptation principally translates into improved tolerance of peripheral fatigue by the central nervous system.