Central and peripheral contributions to physical and electrical fatigue | ||
| Bulletin of Egyptian Society for Physiological Sciences | ||
| Article 9, Volume 26, Issue 1, June 2006, Pages 101-118 PDF (238.86 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/besps.2006.37437 | ||
| Authors | ||
| Omyma Galal* 1; Anwer Said1; Eman Khedr2; Manal Abd-elsameea1 | ||
| 1Department of Physiology,Assiut University Hospital, Assiut, EGYPT. | ||
| 2Department of Neurology, Assiut University Hospital, Assiut, EGYPT. | ||
| Abstract | ||
| Background: fatigue has long been attributed to peripheral mechanism within the motor units, however, the stimulus for muscular contraction is initiated in the brain and therefore central fatigue may occur.This study aimed to investigate central and peripheral contributions to muscle fatigue, immediately and 20 minutes after physical and electrical fatigue in 25 healthy male volunteers. Methods: physical fatigue was induced by sustained voluntary contraction of the first dorsal interossus muscle (FDI) lasted 10 minutes or till fatigue developed. While electrical fatigue was induced by transcutaneous electrical stimulation with trains of submaximal, 100-µs pulses at 20 Hz for 3 minutes. Resting motor threshold, input-out put curve, motor evoked potential, cortical silent period duration, interference pattern of the right FDI and M/F ratio of ulnar nerve, all were recorded before, immediately and 20 minutes after test of fatigue. Results: resting motor threshold, cortical silent period were significantly increased and input output curve was significantly suppressed immediately after physical fatigue. The reverse was observed after electrical fatigue. The amplitude of interference pattern and the envelope were significantly reduced immediately after physical fatigue. The same results were recorded after electrical fatigue. Almost all these changes returned nearly to baseline value 20 minutes after fatigue. Conclusion: Central inhibition was recorded after physical fatigue while some cortical facilitation was proofed after electrical fatigue. However, peripheral inhibition was observed after physical and electrical fatigue. These changes return nearly to the base line 20 minutes after rest. | ||
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