CN103054575A - Method for studying muscle fatigue on basis of static myoelectricity after electrical stimulation - Google Patents

Abstract

A method for studying muscle fatigue on the basis of static myoelectricity after electrical stimulation includes respectively acquiring static surface myoelectric signals of each subject: selecting the subjects, arranging experimental periods, placing surface myoelectric electrodes and stimulating electrodes on the subjects, and acquiring the static surface myoelectric signals; and respectively analyzing power spectrums of the acquired static surface myoelectric signals: computing the acquired static surface myoelectric signals by a periodic diagram process to acquire the power spectrums, drawing frequency spectrograms according to the power spectrums, computing median frequencies and analyzing the median frequencies. The method has the advantages that change of the surface myoelectric signals after electrical stimulation can be represented, myoelectric response caused by electrical stimulation can be comprehensively evaluated in a frequency domain, an experimental basis is provided for follow-up study, accordingly, an idea is provided for technical standards for evaluating effects of electrical stimulation on human bodies, and development of electrical stimulation is promoted.

Description

Method based on static myoelectricity research muscle fatigue after the electricity irritation effect

Technical field

The present invention relates to a kind of method that electricity irritation causes muscle fatigue of estimating.Particularly relate to a kind of method based on static myoelectricity research muscle fatigue after the electricity irritation effect.

Background technology

Electricity irritation is applied to the multiple neuromuscular disease of clinical treatment gradually as a kind of safely and effectively rehabilitation mode, and its research and development has been subject to the attention of various countries.Yet the extensive use of electricity irritation also is subject to the restriction of a factor simultaneously, exactly by its muscle fatigue that brings out.Muscle fatigue typically refers to the temporary transient decline of this system's maximal work capacity or maximum collapse ability, and its effect that has a direct impact stimulation has reduced the contractile response of muscle.In the clinical treatment and neuromechanism research of electricity irritation, the measurement of muscle fatigue and Real Time Monitoring all are major issues.

The generation reason of muscle fatigue has exercise fatigue and stimulates tired, but the surface electromyogram signal when mostly being based on motion or stimulation and causing muscle contraction for the research of fatigue utilizes vibration to cause surface electromyogram signal in the fatigue process to estimate the people such as the experimentation of muscle fatigue and Wretcing such as people such as Chen Weiting and changes to estimate muscle fatigue by the myoelectricity of observing the moving contraction such as quadriceps femoris.These all bring out the variation that causes from the angle of muscle contraction to external force (moving or electricity irritation) and make analysis, yet behind the External Force Acting, the variation of the basic energy of myoelectricity itself does not have correlational study during the muscle attonity.

Summary of the invention

Technical problem to be solved by this invention is, the static surface electromyographic signal is carried out the analysis of muscle fatigue after providing a kind of method of utilizing power spectrum to the electricity irritation effect, can make from the emg response that frequency domain causes after to the electricity irritation effect method based on static myoelectricity research muscle fatigue after the electricity irritation effect of thoroughly evaluating.

The technical solution adopted in the present invention is: a kind of method based on static myoelectricity research muscle fatigue after the electricity irritation effect comprises the steps:

1) gather respectively each experimenter's static surface electromyographic signal, comprising:

(1) selects experimenter, the time that arranges each experimenter to accept to test;

(2) to experimenter's seating surface electromyographic electrode and stimulating electrode;

(3) gather the static surface electromyographic signal;

2) respectively the static surface electromyographic signal that collects is carried out power spectrumanalysis,

To the static surface electromyographic signal that collects, adopt period map method to calculate power spectrum, draw spectrogram according to power spectrum, calculate median frequency, and analyze.

Selecting experimenter's number in the step 1) is that age gap was less than 3 years old more than 5.

The arrangement of surface myoelectric electrode is in the step 1), the active electrode of recording electrode is placed the muscle belly of muscle place that surveys, reference electrode places tendon, it is neighbouring without the muscle place that ground electrode then is positioned over recording electrode, the arrangement of stimulating electrode is, be positioned over the nervus motorius place, with the distance of recording electrode less than or equal to 10cm.

Gather the static surface electromyographic signal in the step 1) and comprise following process:

(1) the tranquillization surface electromyogram signal before one group of electricity irritation effect of record is as initialize signal;

(2) experimenter is applied electricity irritation, stop after the certain time, the static surface electromyographic signal when recording one group of muscle attonity at once;

(3) rest 1min;

(4) carry out successively again (2), (3) process.

Step 2) power spectrum described in is to adopt following method to obtain:

Period map method is the N point observation data x stochastic signal x (n) _N(n) directly carry out Fourier transformation, n is 1,2 ... N obtains X _N(Ω), then the mould of composing is carried out square operation and try to achieve power spectrum, formula is:

$P_x\left(\mathrm{\Ω}\right)=\frac{1}{N}{\left|X_N\left(\mathrm{\Ω}\right)\right|}^2$

P in the formula _x(Ω) be real power spectrum P _xEstimated value (Ω).

Step 2) the calculating median frequency described in is to adopt following formula:

$\underset{0}{\overset{\mathrm{MDF}}{\∫}}P\left(f\right)\mathrm{df}=\underset{\mathrm{MDF}}{\overset{N}{\∫}}P\left(f\right)\mathrm{df}$

MDF is the median frequency of signal in the formula, and P (f) is the power spectrum energy value of each Frequency point, and N 〉=1 is signal data length.

Method based on static myoelectricity research muscle fatigue after the electricity irritation effect of the present invention, can characterize out the variation of electricity irritation effect rear surface electromyographic signal, can make comprehensive evaluation from the emg response that frequency domain causes the electricity irritation effect, for follow-up research provides experiment basis, thereby provide thinking for estimating electricity irritation to the technical standard of human body effect, promote the development of electricity irritation.

Description of drawings

Fig. 1 is the flow chart of the inventive method;

Fig. 2 is the flow chart that gathers the static surface electromyographic signal in the embodiments of the invention;

The specific embodiment

Below in conjunction with embodiment and accompanying drawing the method based on static myoelectricity research muscle fatigue after the electricity irritation effect of the present invention is made a detailed description.

Method based on static myoelectricity research muscle fatigue after the electricity irritation effect of the present invention comprises the steps:

1) gather respectively each experimenter's static surface electromyographic signal, comprising:

(1) select the experimenter, selecting experimenter's number is that age gap was less than 3 years old more than 5.The time that arranges each experimenter to accept to test; The experimenter is 7 in the present embodiment, and the age, physical condition was good between 23～25 years old, and 24h is not engaged in strenuous exercise before the experiment, and is subjective without arm muscle fatigue symptom.

(2) to experimenter's seating surface electromyographic electrode and stimulating electrode.

In the experiment of present embodiment, the amplification filtering of electromyographic signal and data acquisition system adopted be that the Micromed that is used for nerve diagnosis that Italian electric armarium company produces leads Physiological Signal Acquiring System more.Recording electrode adopts the bipolar electrode method, and the arrangement of surface myoelectric electrode is, the active electrode of recording electrode is placed the muscle belly of muscle place that surveys, i.e. the flexor carpi ulnaris m. place of experimenter's right upper extremity forearm, and reference electrode places tendon, and electrode diameter is 5mm.It is neighbouring without the muscle place that ground electrode then is positioned over recording electrode, as be placed on right finesse pisiform bone place, and electrode diameter is 5mm.With scrubbing cream skin is carried out frictional cleaning before the electrode arrangement, to reduce skin resistance.System carries electrostimulator and selects the constant current stimulation mode, and this mode can guarantee that larger variation does not occur because the experimenter is different from the impedance between stimulating electrode the electricity irritation degree.Stimulating electrode adopts copper saddle electrode, the arrangement of stimulating electrode is, be positioned over the nervus motorius place, with the distance of recording electrode less than or equal to 10cm, as be positioned over ulnar nerve place, right hand ancon top, and described stimulus parameter is that stimulus waveform is the pulse ripple, frequency is 5Hz, electric current is 6mA, and pulsewidth is 75us.

(3) gather the static surface electromyographic signal, as shown in Figure 2, comprise following process in the experiment of present embodiment:

(ⅰ) persistent period before one group of electricity irritation effect of record is that 5 seconds tranquillization surface electromyogram signal is as initialize signal;

(ⅱ) experimenter is applied cause tired electricity irritation, stimulus frequency is 5Hz, stops after the certain time, and present embodiment is to be to stop behind the 5min persistent period, the static surface electromyographic signal when recording one group of persistent period and be 5 seconds muscle attonity at once;

(ⅲ) rest 1min;

(ⅳ) carry out successively (ⅱ), (ⅲ) process, so circulation finishes for 15 times totally afterwards again.

2) respectively the static surface electromyographic signal that collects is carried out power spectrumanalysis,

To the static surface electromyographic signal that collects, adopt period map method to calculate power spectrum, draw spectrogram according to power spectrum, calculate median frequency, and analyze; Described power spectrum is to adopt following method to obtain:

Period map method is the N point observation data x stochastic signal x (n) _N(n) directly carry out Fourier transformation, n is 1,2 ... N obtains X _N(Ω), then the mould of composing is carried out square operation and try to achieve power spectrum, formula is:

$P_x\left(\mathrm{\Ω}\right)=\frac{1}{N}{\left|X_N\left(\mathrm{\Ω}\right)\right|}^2---\left(1\right)$

P in the formula _x(Ω) be real power spectrum P _xEstimated value (Ω).

After electricity irritation caused muscle fatigue, the spectrum energy of electromyographic signal had obvious increase.But whether spectrum energy has skew not find out from this result, so again signal has been carried out the median frequency analysis.

Described calculating median frequency is to adopt following formula:

$\underset{0}{\overset{\mathrm{MDF}}{\∫}}P\left(f\right)\mathrm{df}=\underset{\mathrm{MDF}}{\overset{N}{\∫}}P\left(f\right)\mathrm{df}---\left(2\right)$

MDF is the median frequency of signal in the formula, and P (f) is the power spectrum energy value of each Frequency point, and N 〉=1 is signal data length.

The generation of the muscle fatigue that causes along with electricity irritation, the median frequency of static surface electromyographic signal is on a declining curve, and then the explanation spectrum curve has the effect of moving to left.This also verified generally believe at present deepen the viewpoint that the sEMG signal spectrum distributes and will compress left with degree of fatigue.

Claims (6)

1. the method based on static myoelectricity research muscle fatigue after the electricity irritation effect is characterized in that, comprises the steps:

1) gather respectively each experimenter's static surface electromyographic signal, comprising:

(1) selects experimenter, the time that arranges each experimenter to accept to test;

(2) to experimenter's seating surface electromyographic electrode and stimulating electrode;

(3) gather the static surface electromyographic signal;

2) respectively the static surface electromyographic signal that collects is carried out power spectrumanalysis,

To the static surface electromyographic signal that collects, adopt period map method to calculate power spectrum, draw spectrogram according to power spectrum, calculate median frequency, and analyze.

2. the method based on static myoelectricity research muscle fatigue after the electricity irritation effect according to claim 1 is characterized in that selecting experimenter's number in the step 1) is that age gap was less than 3 years old more than 5.

3. the method based on static myoelectricity research muscle fatigue after the electricity irritation effect according to claim 1, it is characterized in that, the arrangement of surface myoelectric electrode is in the step 1), the active electrode of recording electrode is placed the muscle belly of muscle place that surveys, reference electrode places tendon, and it is neighbouring without the muscle place that ground electrode then is positioned over recording electrode, and the arrangement of stimulating electrode is, be positioned over the nervus motorius place, with the distance of recording electrode less than or equal to 10cm.

4. the method based on static myoelectricity research muscle fatigue after the electricity irritation effect according to claim 1 is characterized in that, gathers the static surface electromyographic signal in the step 1) and comprises following process:

(1) the tranquillization surface electromyogram signal before one group of electricity irritation effect of record is as initialize signal;

(2) experimenter is applied electricity irritation, stop after the certain time, the static surface electromyographic signal when recording one group of muscle attonity at once;

(3) rest 1min;

(4) carry out successively again (2), (3) process.

5. the method based on static myoelectricity research muscle fatigue after the electricity irritation effect according to claim 1 is characterized in that step 2) described in power spectrum be to adopt following method to obtain:

Period map method is the N point observation data x stochastic signal x (n) _N(n) directly carry out Fourier transformation, n is 1,2 ... N obtains X _N(Ω), then the mould of composing is carried out square operation and try to achieve power spectrum, formula is:

$P_x\left(\mathrm{\Ω}\right)=\frac{1}{N}{\left|X_N\left(\mathrm{\Ω}\right)\right|}^2$

P in the formula _x(Ω) be real power spectrum P _xEstimated value (Ω).

6. the method based on static myoelectricity research muscle fatigue after the electricity irritation effect according to claim 1 is characterized in that step 2) described in the calculating median frequency be to adopt following formula:

$\underset{0}{\overset{\mathrm{MDF}}{\∫}}P\left(f\right)\mathrm{df}=\underset{\mathrm{MDF}}{\overset{N}{\∫}}P\left(f\right)\mathrm{df}$

MDF is the median frequency of signal in the formula, and P (f) is the power spectrum energy value of each Frequency point, and N 〉=1 is signal data length.