• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.843-850
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• 2017

The EMG amplitude estimator, which has been investigated as an indicator of muscle force, is utilized as the control input to artificial prosthetic limbs. This paper describes an application of the optimal EMG amplitude estimator to the surface EMG signals recorded during constant isometric %MVC (maximum voluntary contraction) for 30 seconds and reports on assessing performance of the amplitude estimator from the application. Surface EMG signals, a total of 198 signals, were recorded from biceps brachii muscle over the range of 20-80%MVC isometric contraction. To examine the estimator performance, a SNR(signal-to-noise ratio) was computed from each amplitude estimate. The results of the study indicate that ARV(average rectified value) and RMS(root mean square) amplitude estimation with forth order whitening filter and 250[ms] moving average window length are optimal and showed the mean SNR improvement of about 50%, 40% and 20% for each 20%MVC, 50%MVC and 80%MVC surface EMG signals, respectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.809-816
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• 2007

This paper presents an analysis of the SEMG signal quantitatively and automatically using spike variables : MSF, MSA, MSS, and MSD. The SEMG signals were recorded in three muscle parts, first dorsal interosseus, biceps brachii and abductor policis brevis, from 14 normal subjects. Emphasis was placed on the following 3 points in the experiments. 1) Suggest proper window length to estimate the spike variables 2) Investigate variation of the spike variables to varying %MVC. 3) Investigate variation of the spike variables to the sustained contraction for 30 minutes. Quantitative results were showed and examined in point of practical clinical application.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.394-398
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• 1994

The aim of the present study was to determine the influence of vibration frequency and muscle contraction level at constant vibration displacement amplitudes on a commonly observed motor response elicited by local vibratory stimulation, i.e., the Tonic Vibration Reflex (TVR). Vibration was applied to the distal tendons of the hand flexor muscles. Changes in activity of the hand flexor and extensor muscles were analyzed as a function of the vibration frequency (40-200 Hz), displacement amplitude(200.mu.m and 300.mu.m peak-to-peak), and the initial contraction level of the flexor muscles (0%, 10%, and 20% of the maximal voluntary contraction: MVC). The main results indicate that the TVR increases with vibration frequency up to 100-150 Hz and decreases beyond, and the TVR attains its maximum at 10% MVC. It appears that high frequency vibration tends to induce less muscle/tendon stress. Such a result is of particular importance for the design of handheld vibrating tools.

• Journal of the Ergonomics Society of Korea
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• v.14 no.1
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• pp.9-23
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• 1995

The objectives of the study were twofole: (1) to investigate effects of rhythmic contraction and sustained contraction methods on recovery rate of isometric endurance capacity and (2) to compare aptterns of muscle recruitment of both arms observed during each contraction period. In the experiment, each of two subjects performed five successive rhythmic or sustained isometric contractions at 50% MVC with both arms to the point of fatigue, which was the failure to maintain the required tension. In making the contractions, the subjects stood erect with upper arms held at an angle of approximately 90 .deg. to the forearm. The interval between the successive contractions was kept constant at 3, 7, 20, or 40 minutes. Regardless of the contraction methods, the recovery rate was least at the shortest interval and was highest at the longest interval. However, a statistical analysis showed that the recovery rates for the rhythmic contractions were significantly lower than those for the sustained contractions throughout 4 different intervals. Furthermore, as the frequency of the rhythmic contractions per min, increased 4 to 6 times, the recovery rate of isometric endurance capacity decreased. From an EMG anglysis, recruitment pattern of the muscules of both arms was found to be common between two different contraction methods. The biceps muxcles of the upper arms played a major role in exerting 50% MVC, while the brachioradialis muscles of the forearms acted as synergists. As the contraction proceeded, the role of the biceps muscles as a prime mover lessened due to the fatigue. Then, the brachioradialis muscles exerted more strength to sustain 50% MVC. The implications of these finding were discussed.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.5
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• pp.348-357
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• 2005

We have tried to analyze the SEMG interference pattern quantitatively and automatically using T/A variables ZC, TN, mSA, mSD, UCA, AIPEA, ACT and NSS. For the analysis, we have carried out experiments on 14 SEMG interference patterns recorded from the biceps brachii, first dorsal interosseus and abductor policis brevis muscles. Emphasis was placed on the following 3 points in the experiments. 1) Suitable amplitude threshold for the automatic detection of the T/A variables. 2) Variation of the T/A variables to varying $\%$MVC. 3) Variation of the T/A variables to the sustained contraction for 30 seconds. Results of the experiments showed that T/A analysis of the SEMG interference Pattern can be effective tools for diagnostic purposes instead of the conventional NEMG method.