The Research On The Force-sEMG Signal Relationship Of The Non-fatigue Muscle

sEMG signal is the one-dimensional and chaotic time series signal that recorded n the surface of the working neuro-muscle system. The force-SEMG signal elationgship refers to the relation between the force or the power outputting level generating from the working muscles in a non-fatigue state and the typical changes of he sEMG signals, hi the well-controlled condition, sEMG will show typical changes etween different states and different working levels. These changes can help us to understand the working mechanism of neuro-muscle system and has great practical ignificance in evaluating the function of local muscle in the research fields of ehabilitation medicine,ergonomics and sports science.The presupposition of using linear signal analysis to do research about EMG signal s that the signal is stable. However, more and more researches indicate that the sEMG iignal under various conditions are not the stable signals in a strict sense. Lempel梈iv Complexity (LC.) is a measure that non-linear mathematics used to rate the complication of the ion-linear system.It too with determinism%(determinism%) are considered to be an effctive way o evaluate the order of kinetics system.The present study was aimed at evaluating the capability of Lempel-Ziv and leterminism% together with the linear indices to detect myoelectric signal changes at different ractions during static and dynamic states and to compare their validity. Informed consent and iEMG recordings were obtained from 47 healthy human volunteers. 19 paticipated in an isometric :onstant force experient (step) and 11 in a non constant isometric force experient (ramp) and the ther 17 in a dynamic experient. sEMG signals were obtained from the right biceps brachii in static jxperients and from the right quadricepts in dynamic experient.Our main results are: i) AEMG inclined linearly with the increasing of the force or poweroutputting in both static and dynamic experients except at the rectus femoris of the male subjects, ii) The spectrum parameters MPF and MF display an increase followed by a palt in the isometric constant force experient but levelled off both in the non constant isometric force experient and the dynamic experient except of MPF at the rectus femoris of the male subjects, iii) LEMPEL-ZIV leveled off in both in the isometric force experient and in the dynamic experient except showed a linear increase at the rectus femoris of the male subjects, iv) With the force increased, determinism% dispalyed an decrease followed by a plat in the two experients of the right biceps brachii; hi the dynamic experient, determinism% did not show any significance during different power levels except that it became very low at l00w and 175w level of the vastus lateralis of the female subjects and increased linearly at the vastus lateralis of the male subjects. Our result suggested that the non-linear indices such as Lempel-Ziv and determinism% have large potential in distinguishing different working levels of the non-fatigue muscle and we should integrate the linear and the non-linear method in the future research.