Proceedings of the 27th Annual International Conference of the Engineering in Medicine and Biology Society (IEEE-EMBS 2005), 5804–5807p. (2005) DOI:10.1109/IEMBS.2005.1615808
Linear and Non-Linear Features of Surface EMG during Fatigue and Recovery Period
Y. Hong-Chun, W. Du-Ming, W. JianAim: To investigate possible factors that affect the sEMG signal features, we analyzed the sEMG signals in bicep bracii(BB) muscle during fatiguing isometric flexions and recovery periods across a range of force levels.
Method: Twelve males performed isometric elbow flexions at 40%, 60%, 80% and 100% of their maximal voluntary contraction (MVC) with joint angle keeping at 90?. And then they performed 3 seconds of MVC at the 2nd, 4th, 6th, 8th, 10th, 20th, 30th, 60thand 120thsecond respectively during recovery periods. SEMG signals in BB were analyzed using both linear and non-linear methods to get parameters such as average EMG (AEMG), mean power frequency (MPF), Lempel_Ziv complexity (C(n)) and Determinism% (%DET).
Results: Non-linear parameter C(n) decreased whereas %DET increased during fatiguing flexions. There was no regularity in AEMG in recovery periods. MPF, C(n) and %DET recovered significantly only by seconds rest, and they regressed rapidly in the initial 10 seconds and then slowed down in the later.
Conclusions: The rapid changes of SEMG linear and non-linear parameters in recovery periods suggested that central controlling factor may play a more important role in shaping sEMG signals.
