変位筋音図の計測と小型変位MMGセンサの開発  [in Japanese] Measurement of Displacement MMG and Development of a Small-sized Displacement MMG Transducer  [in Japanese]

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Abstract

<p>骨格筋の収縮機能を評価するには, 生化学的検査や画像診断の他に筋電位信号がよく用いられるが, これは筋を収縮させる入力側の信号である。筋音信号は筋収縮に伴う振動, すなわち出力側の信号であるので, 両者を計測・比較することによって筋の収縮様相を正しく評価できると考えられる。筋疲労や筋力トレーニングを行ったときの変位筋音信号を測定したところ, 速筋線維の寄与率変化が示唆された。さらに変位筋音信号を簡便に測定するために, フォトリフレクタを応用した小型・軽量の変位筋音センサを開発した。本センサはエルゴメータ運動やトレッドミル歩行中でも筋音信号の測定が可能で, 単収縮波形を算出することができた。</p>

<p>In addition to biochemical tests and image measurements, the electromyogram (EMG) is widely used to evaluate the contractile function of skeletal muscle, but this EMG is the input signal for muscle contraction. The mechanomyogram (MMG) is the vibration associated with muscle contraction, which is an output signal. When both the EMG and the MMG are measured simultaneously, muscle contraction can be evaluated correctly. Using the laser displacement transducer, we were able to measure the displacement MMG (dMMG) twitch waveform during ergometer exercise and treadmill walking and thus examine whether the contribution ratio of the fast fiber changed during these activities. As this transducer and the target muscle, however, should be fixed during the measurement, we have newly developed a small-sized MMG transducer that can easily measure the dMMG by applying a small, lightweight photo-reflector. The transducer measures 37 × 17 × 23 [mm] and weighs 4.8 [g] including the sensor cables. The steady background noise is ±1 [<i>μ</i>m] and around ±2 [<i>μ</i>m] for the external impact noise. Using this transducer, we were able to measure the d-MMG twitch waveform during ergometer exercise and treadmill walking.</p>

Journal

  • Biomechanisms

    Biomechanisms 21(0), 219-230, 2012

    Society of Biomechanisms

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