EMG Power Spectrum and Integrated EMG of Ankle Planterflexors during Stepwise and Ramp Contractions.
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- Akasaka Kiyokazu
- Department of Restorative Neuromuscular Surgery and Rehabilitation, Tohoku University Graduate School of Medicine
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- Onishi Hideaki
- Department of Restorative Neuromuscular Surgery and Rehabilitation, Tohoku University Graduate School of Medicine
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- Momose Kimito
- Department of Restorative Neuromuscular Surgery and Rehabilitation, Tohoku University Graduate School of Medicine
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- Ihashi Kouji
- Department of Restorative Neuromuscular Surgery and Rehabilitation, Tohoku University Graduate School of Medicine
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- Yagi Ryo
- Department of Restorative Neuromuscular Surgery and Rehabilitation, Tohoku University Graduate School of Medicine
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- Handa Yasunobu
- Department of Restorative Neuromuscular Surgery and Rehabilitation, Tohoku University Graduate School of Medicine
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- Hoshimiya Nozomu
- Division of Engineering, Tohoku Univeristy Graduate School
抄録
The aim of this study was to investigate whether the median frequencies (MF) of the electromyogram (EMG) and the integrated EMG (IEMG) of histochemically differentiated ankle planterflexors, the gastrocnemius and soleus, were force dependent. Bipolar intramuscular wire electrodes were used to measure EMG of the soleus (SO), medial head of gastrocnemius (GM), and lateral head of gastrocnemius (GL) during ramp (single ongoing contractions) with the force increasing linearly from 0 to 100% of maximum voluntary contraction (MVC) and stepwise (steady force levels) ankle planterflexion at 10, 20, 30, 40, 60, and 80% MVC. EMG and force were measured simultaneously. Power spectral analysis of these signals was performed to calculate MF on 1024-point by fast Fourier transform (FFT) technique. IEMG value of each muscle was also obtained at the same levels of force. While IEMG of three heads of triceps surae in both stepwise and ramp contractions increased significantly with increasing force, MF values of GL during stepwise contraction increased significantly (20, 40, 60, 80% MVC). These results suggest that the sensitivity of EMG power spectrum might be influenced by the proportion of fast twitch muscle fibers, which histochemically corresponds to type II fibers.
収録刊行物
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- The Tohoku Journal of Experimental Medicine
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The Tohoku Journal of Experimental Medicine 182 (3), 207-216, 1997
東北ジャーナル刊行会
