CENTRAL AND PERIPHERAL FATIGUE DURING SUSTAINED MAXIMAL VOLUNTARY CONTRACTIONS IN TRAINED AND UNTRAINED HUMAN SUBJECTS
- VernacularTitle:鍛錬者と非鍛錬者における持続的な最大筋力発揮中の中枢性および末梢性疲労の発現
- Author:
TAKASHI ENDOH
;
MASASHI MITAMURA
;
TSUYOSHI NAKAJIMA
;
REI TAKAHASHI
;
TOMOYOSHI KOMIYAMA
- Publication Type:Journal Article
- Keywords:
muscle fatigue;
transcranial magnetic stimulation;
maximal voluntary contraction;
training;
voluntary activation
- From:Japanese Journal of Physical Fitness and Sports Medicine
2004;53(2):211-220
- CountryJapan
- Language:Japanese
-
Abstract:
The present study investigated how resistance training affects behaviors related to central and peripheral fatigue during a sustained maximal voluntary contraction (MVC) . The subjects were well-trained (TR, n=8) and sedentary untrained (UT, n=6) males. The subjects were asked to repetitively perform 3 sets of MVC (elbow flexion) for 1 min with a rest interval of 1 min. Transcranial magnetic stimulation (TMS) was delivered to the contralateral motor cortex to evoke the motor evoked potential (MEP) and electromyographic (EMG) silent period (SP) after the MEP. Ratio of root mean square (RMS) of the EMG and elbow flexion force (RMS/F) was also calculated.
The time course of the decrease in elbow flexion force that was standardized with respect to the maximal value obtained at the beginning of the first MVC was almost identical in both TR and UT. At the end of the task, the elbow flexion force decreased to around 30 % of the initial value in both groups. Decrease in voluntary activation (VA) estimated by the increment of the force after TMS was significantly larger in UT (77.3%) than in TR (88.2%) at the end of the task. Although the increase in MEP during the first set was significantly greater in UT than in TR, elongation of SP was significantly larger in UT than in TR. Increase in RMS/F, which is a manifestation of peripheral fatigue, was significantly larger in TR than in UT.
These results suggest that decrease in MVC in UT and in TR is respectively more attributable to central and peripheral fatigue, and that inhibitory inputs to motor cortex were larger in UT than in TR. It is concluded that expression of central and peripheral fatigue is affected by resistance training.
